Blame view
kernel/rcu/tree.c
131 KB
64db4cfff "Tree RCU": scala... |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 |
/* * Read-Copy Update mechanism for mutual exclusion * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License |
87de1cfdc rcu: Stop trackin... |
15 16 |
* along with this program; if not, you can access it online at * http://www.gnu.org/licenses/gpl-2.0.html. |
64db4cfff "Tree RCU": scala... |
17 18 19 20 21 22 23 24 25 26 27 |
* * Copyright IBM Corporation, 2008 * * Authors: Dipankar Sarma <dipankar@in.ibm.com> * Manfred Spraul <manfred@colorfullife.com> * Paul E. McKenney <paulmck@linux.vnet.ibm.com> Hierarchical version * * Based on the original work by Paul McKenney <paulmck@us.ibm.com> * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen. * * For detailed explanation of Read-Copy Update mechanism see - |
a71fca58b rcu: Fix whitespa... |
28 |
* Documentation/RCU |
64db4cfff "Tree RCU": scala... |
29 30 31 32 33 34 35 36 37 |
*/ #include <linux/types.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/spinlock.h> #include <linux/smp.h> #include <linux/rcupdate.h> #include <linux/interrupt.h> #include <linux/sched.h> |
c1dc0b9c0 debug lockups: Im... |
38 |
#include <linux/nmi.h> |
8826f3b03 rcu: Avoid acquir... |
39 |
#include <linux/atomic.h> |
64db4cfff "Tree RCU": scala... |
40 |
#include <linux/bitops.h> |
9984de1a5 kernel: Map most ... |
41 |
#include <linux/export.h> |
64db4cfff "Tree RCU": scala... |
42 43 44 45 46 47 48 |
#include <linux/completion.h> #include <linux/moduleparam.h> #include <linux/percpu.h> #include <linux/notifier.h> #include <linux/cpu.h> #include <linux/mutex.h> #include <linux/time.h> |
bbad93798 rcu: slim down rc... |
49 |
#include <linux/kernel_stat.h> |
a26ac2455 rcu: move TREE_RC... |
50 51 |
#include <linux/wait.h> #include <linux/kthread.h> |
268bb0ce3 sanitize <linux/p... |
52 |
#include <linux/prefetch.h> |
3d3b7db0a rcu: Move synchro... |
53 54 |
#include <linux/delay.h> #include <linux/stop_machine.h> |
661a85dc0 rcu: Add random P... |
55 |
#include <linux/random.h> |
af658dca2 tracing: Rename f... |
56 |
#include <linux/trace_events.h> |
d1d74d14e rcu: Expedite gra... |
57 |
#include <linux/suspend.h> |
64db4cfff "Tree RCU": scala... |
58 |
|
4102adab9 rcu: Move RCU-rel... |
59 |
#include "tree.h" |
29c00b4a1 rcu: Add event-tr... |
60 |
#include "rcu.h" |
9f77da9f4 rcu: Move private... |
61 |
|
4102adab9 rcu: Move RCU-rel... |
62 63 64 65 |
#ifdef MODULE_PARAM_PREFIX #undef MODULE_PARAM_PREFIX #endif #define MODULE_PARAM_PREFIX "rcutree." |
64db4cfff "Tree RCU": scala... |
66 |
/* Data structures. */ |
f7f7bac9c rcu: Have the RCU... |
67 68 69 70 71 72 73 74 |
/* * In order to export the rcu_state name to the tracing tools, it * needs to be added in the __tracepoint_string section. * This requires defining a separate variable tp_<sname>_varname * that points to the string being used, and this will allow * the tracing userspace tools to be able to decipher the string * address to the matching string. */ |
a8a29b3b7 rcu: Define trace... |
75 76 |
#ifdef CONFIG_TRACING # define DEFINE_RCU_TPS(sname) \ |
f7f7bac9c rcu: Have the RCU... |
77 |
static char sname##_varname[] = #sname; \ |
a8a29b3b7 rcu: Define trace... |
78 79 80 81 82 83 84 85 86 |
static const char *tp_##sname##_varname __used __tracepoint_string = sname##_varname; # define RCU_STATE_NAME(sname) sname##_varname #else # define DEFINE_RCU_TPS(sname) # define RCU_STATE_NAME(sname) __stringify(sname) #endif #define RCU_STATE_INITIALIZER(sname, sabbr, cr) \ DEFINE_RCU_TPS(sname) \ |
c92fb0579 rcu: Make rcu_*_d... |
87 |
static DEFINE_PER_CPU_SHARED_ALIGNED(struct rcu_data, sname##_data); \ |
a41bfeb2f rcu: Simplify RCU... |
88 |
struct rcu_state sname##_state = { \ |
6c90cc7bf rcu: Prevent exce... |
89 |
.level = { &sname##_state.node[0] }, \ |
2723249a3 rcu: Wire ->rda p... |
90 |
.rda = &sname##_data, \ |
037b64ed0 rcu: Place pointe... |
91 |
.call = cr, \ |
77f81fe08 rcu: Finish foldi... |
92 |
.gp_state = RCU_GP_IDLE, \ |
42c3533ee rcu: Fix tracing ... |
93 94 |
.gpnum = 0UL - 300UL, \ .completed = 0UL - 300UL, \ |
7b2e6011f rcu: Rename ->ono... |
95 |
.orphan_lock = __RAW_SPIN_LOCK_UNLOCKED(&sname##_state.orphan_lock), \ |
6c90cc7bf rcu: Prevent exce... |
96 97 |
.orphan_nxttail = &sname##_state.orphan_nxtlist, \ .orphan_donetail = &sname##_state.orphan_donelist, \ |
7be7f0be9 rcu: Move rcu_bar... |
98 |
.barrier_mutex = __MUTEX_INITIALIZER(sname##_state.barrier_mutex), \ |
a8a29b3b7 rcu: Define trace... |
99 |
.name = RCU_STATE_NAME(sname), \ |
a48898585 rcu: Distinguish ... |
100 |
.abbr = sabbr, \ |
f6a12f34a rcu: Enforce expe... |
101 |
.exp_mutex = __MUTEX_INITIALIZER(sname##_state.exp_mutex), \ |
3b5f668e7 rcu: Overlap wake... |
102 |
.exp_wake_mutex = __MUTEX_INITIALIZER(sname##_state.exp_wake_mutex), \ |
2723249a3 rcu: Wire ->rda p... |
103 |
} |
64db4cfff "Tree RCU": scala... |
104 |
|
a41bfeb2f rcu: Simplify RCU... |
105 106 |
RCU_STATE_INITIALIZER(rcu_sched, 's', call_rcu_sched); RCU_STATE_INITIALIZER(rcu_bh, 'b', call_rcu_bh); |
b1f77b058 kmemtrace, rcu: f... |
107 |
|
b28a7c016 rcu: Tell the com... |
108 |
static struct rcu_state *const rcu_state_p; |
6ce75a232 rcu: Introduce fo... |
109 |
LIST_HEAD(rcu_struct_flavors); |
27f4d2805 rcu: priority boo... |
110 |
|
a3dc2948c rcu: Enable diagn... |
111 112 113 |
/* Dump rcu_node combining tree at boot to verify correct setup. */ static bool dump_tree; module_param(dump_tree, bool, 0444); |
7fa270010 rcu: Convert CONF... |
114 115 116 |
/* Control rcu_node-tree auto-balancing at boot time. */ static bool rcu_fanout_exact; module_param(rcu_fanout_exact, bool, 0444); |
47d631af5 rcu: Make RCU abl... |
117 118 |
/* Increase (but not decrease) the RCU_FANOUT_LEAF at boot time. */ static int rcu_fanout_leaf = RCU_FANOUT_LEAF; |
7e5c2dfb4 rcu: Make rcutree... |
119 |
module_param(rcu_fanout_leaf, int, 0444); |
f885b7f2b rcu: Control RCU_... |
120 |
int rcu_num_lvls __read_mostly = RCU_NUM_LVLS; |
cb0071023 rcu: Limit count ... |
121 122 |
/* Number of rcu_nodes at specified level. */ static int num_rcu_lvl[] = NUM_RCU_LVL_INIT; |
f885b7f2b rcu: Control RCU_... |
123 |
int rcu_num_nodes __read_mostly = NUM_RCU_NODES; /* Total # rcu_nodes in use. */ |
088e9d253 rcu: sysctl: Pani... |
124 125 |
/* panic() on RCU Stall sysctl. */ int sysctl_panic_on_rcu_stall __read_mostly; |
f885b7f2b rcu: Control RCU_... |
126 |
|
b0d304172 rcu: Prevent RCU ... |
127 |
/* |
90687fc3c rcu: Narrow early... |
128 129 130 131 |
* The rcu_scheduler_active variable is initialized to the value * RCU_SCHEDULER_INACTIVE and transitions RCU_SCHEDULER_INIT just before the * first task is spawned. So when this variable is RCU_SCHEDULER_INACTIVE, * RCU can assume that there is but one task, allowing RCU to (for example) |
0d95092cc rcu: Fix outdated... |
132 |
* optimize synchronize_rcu() to a simple barrier(). When this variable |
90687fc3c rcu: Narrow early... |
133 134 135 136 137 |
* is RCU_SCHEDULER_INIT, RCU must actually do all the hard work required * to detect real grace periods. This variable is also used to suppress * boot-time false positives from lockdep-RCU error checking. Finally, it * transitions from RCU_SCHEDULER_INIT to RCU_SCHEDULER_RUNNING after RCU * is fully initialized, including all of its kthreads having been spawned. |
b0d304172 rcu: Prevent RCU ... |
138 |
*/ |
bbad93798 rcu: slim down rc... |
139 140 |
int rcu_scheduler_active __read_mostly; EXPORT_SYMBOL_GPL(rcu_scheduler_active); |
b0d304172 rcu: Prevent RCU ... |
141 142 143 144 145 146 147 148 149 150 151 152 153 |
/* * The rcu_scheduler_fully_active variable transitions from zero to one * during the early_initcall() processing, which is after the scheduler * is capable of creating new tasks. So RCU processing (for example, * creating tasks for RCU priority boosting) must be delayed until after * rcu_scheduler_fully_active transitions from zero to one. We also * currently delay invocation of any RCU callbacks until after this point. * * It might later prove better for people registering RCU callbacks during * early boot to take responsibility for these callbacks, but one step at * a time. */ static int rcu_scheduler_fully_active __read_mostly; |
0aa04b055 rcu: Process offl... |
154 155 |
static void rcu_init_new_rnp(struct rcu_node *rnp_leaf); static void rcu_cleanup_dead_rnp(struct rcu_node *rnp_leaf); |
5d01bbd11 rcu: Yield simpler |
156 |
static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu); |
a46e0899e rcu: use softirq ... |
157 158 |
static void invoke_rcu_core(void); static void invoke_rcu_callbacks(struct rcu_state *rsp, struct rcu_data *rdp); |
6587a23b6 rcu: Switch synch... |
159 160 |
static void rcu_report_exp_rdp(struct rcu_state *rsp, struct rcu_data *rdp, bool wake); |
3549c2bc2 rcu: Move expedit... |
161 |
static void sync_sched_exp_online_cleanup(int cpu); |
a26ac2455 rcu: move TREE_RC... |
162 |
|
a94844b22 rcu: Optionally r... |
163 |
/* rcuc/rcub kthread realtime priority */ |
26730f55c rcu: Make RCU abl... |
164 |
#ifdef CONFIG_RCU_KTHREAD_PRIO |
a94844b22 rcu: Optionally r... |
165 |
static int kthread_prio = CONFIG_RCU_KTHREAD_PRIO; |
26730f55c rcu: Make RCU abl... |
166 167 168 |
#else /* #ifdef CONFIG_RCU_KTHREAD_PRIO */ static int kthread_prio = IS_ENABLED(CONFIG_RCU_BOOST) ? 1 : 0; #endif /* #else #ifdef CONFIG_RCU_KTHREAD_PRIO */ |
a94844b22 rcu: Optionally r... |
169 |
module_param(kthread_prio, int, 0644); |
8d7dc9283 rcu: Control grac... |
170 |
/* Delay in jiffies for grace-period initialization delays, debug only. */ |
0f41c0dda rcu: Provide diag... |
171 172 173 174 175 176 177 |
#ifdef CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT static int gp_preinit_delay = CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT_DELAY; module_param(gp_preinit_delay, int, 0644); #else /* #ifdef CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT */ static const int gp_preinit_delay; #endif /* #else #ifdef CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT */ |
8d7dc9283 rcu: Control grac... |
178 179 |
#ifdef CONFIG_RCU_TORTURE_TEST_SLOW_INIT static int gp_init_delay = CONFIG_RCU_TORTURE_TEST_SLOW_INIT_DELAY; |
37745d281 rcu: Provide diag... |
180 |
module_param(gp_init_delay, int, 0644); |
8d7dc9283 rcu: Control grac... |
181 182 183 |
#else /* #ifdef CONFIG_RCU_TORTURE_TEST_SLOW_INIT */ static const int gp_init_delay; #endif /* #else #ifdef CONFIG_RCU_TORTURE_TEST_SLOW_INIT */ |
eab128e83 rcu: Modulate gra... |
184 |
|
0f41c0dda rcu: Provide diag... |
185 186 187 188 189 190 |
#ifdef CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP static int gp_cleanup_delay = CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP_DELAY; module_param(gp_cleanup_delay, int, 0644); #else /* #ifdef CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP */ static const int gp_cleanup_delay; #endif /* #else #ifdef CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP */ |
eab128e83 rcu: Modulate gra... |
191 192 193 194 195 196 197 198 199 200 |
/* * Number of grace periods between delays, normalized by the duration of * the delay. The longer the the delay, the more the grace periods between * each delay. The reason for this normalization is that it means that, * for non-zero delays, the overall slowdown of grace periods is constant * regardless of the duration of the delay. This arrangement balances * the need for long delays to increase some race probabilities with the * need for fast grace periods to increase other race probabilities. */ #define PER_RCU_NODE_PERIOD 3 /* Number of grace periods between delays. */ |
37745d281 rcu: Provide diag... |
201 |
|
a26ac2455 rcu: move TREE_RC... |
202 |
/* |
4a2986568 rcu: make rcutort... |
203 204 205 206 207 208 209 210 211 212 213 214 |
* Track the rcutorture test sequence number and the update version * number within a given test. The rcutorture_testseq is incremented * on every rcutorture module load and unload, so has an odd value * when a test is running. The rcutorture_vernum is set to zero * when rcutorture starts and is incremented on each rcutorture update. * These variables enable correlating rcutorture output with the * RCU tracing information. */ unsigned long rcutorture_testseq; unsigned long rcutorture_vernum; /* |
0aa04b055 rcu: Process offl... |
215 216 217 218 219 220 221 |
* Compute the mask of online CPUs for the specified rcu_node structure. * This will not be stable unless the rcu_node structure's ->lock is * held, but the bit corresponding to the current CPU will be stable * in most contexts. */ unsigned long rcu_rnp_online_cpus(struct rcu_node *rnp) { |
7d0ae8086 rcu: Convert ACCE... |
222 |
return READ_ONCE(rnp->qsmaskinitnext); |
0aa04b055 rcu: Process offl... |
223 224 225 |
} /* |
7d0ae8086 rcu: Convert ACCE... |
226 |
* Return true if an RCU grace period is in progress. The READ_ONCE()s |
fc2219d49 rcu: Clean up cod... |
227 228 229 230 231 |
* permit this function to be invoked without holding the root rcu_node * structure's ->lock, but of course results can be subject to change. */ static int rcu_gp_in_progress(struct rcu_state *rsp) { |
7d0ae8086 rcu: Convert ACCE... |
232 |
return READ_ONCE(rsp->completed) != READ_ONCE(rsp->gpnum); |
fc2219d49 rcu: Clean up cod... |
233 234 235 |
} /* |
d6714c22b rcu: Renamings to... |
236 |
* Note a quiescent state. Because we do not need to know |
b1f77b058 kmemtrace, rcu: f... |
237 |
* how many quiescent states passed, just if there was at least |
d6714c22b rcu: Renamings to... |
238 |
* one since the start of the grace period, this just sets a flag. |
e4cc1f22b rcu: Simplify qui... |
239 |
* The caller must have disabled preemption. |
b1f77b058 kmemtrace, rcu: f... |
240 |
*/ |
284a8c93a rcu: Per-CPU oper... |
241 |
void rcu_sched_qs(void) |
b1f77b058 kmemtrace, rcu: f... |
242 |
{ |
fecbf6f01 rcu: Simplify rcu... |
243 244 245 246 247 248 249 250 |
if (!__this_cpu_read(rcu_sched_data.cpu_no_qs.s)) return; trace_rcu_grace_period(TPS("rcu_sched"), __this_cpu_read(rcu_sched_data.gpnum), TPS("cpuqs")); __this_cpu_write(rcu_sched_data.cpu_no_qs.b.norm, false); if (!__this_cpu_read(rcu_sched_data.cpu_no_qs.b.exp)) return; |
46a5d164d rcu: Stop disabli... |
251 252 253 |
__this_cpu_write(rcu_sched_data.cpu_no_qs.b.exp, false); rcu_report_exp_rdp(&rcu_sched_state, this_cpu_ptr(&rcu_sched_data), true); |
b1f77b058 kmemtrace, rcu: f... |
254 |
} |
284a8c93a rcu: Per-CPU oper... |
255 |
void rcu_bh_qs(void) |
b1f77b058 kmemtrace, rcu: f... |
256 |
{ |
5b74c4589 rcu: Make ->cpu_n... |
257 |
if (__this_cpu_read(rcu_bh_data.cpu_no_qs.s)) { |
284a8c93a rcu: Per-CPU oper... |
258 259 260 |
trace_rcu_grace_period(TPS("rcu_bh"), __this_cpu_read(rcu_bh_data.gpnum), TPS("cpuqs")); |
5b74c4589 rcu: Make ->cpu_n... |
261 |
__this_cpu_write(rcu_bh_data.cpu_no_qs.b.norm, false); |
284a8c93a rcu: Per-CPU oper... |
262 |
} |
b1f77b058 kmemtrace, rcu: f... |
263 |
} |
64db4cfff "Tree RCU": scala... |
264 |
|
4a81e8328 rcu: Reduce overh... |
265 266 267 268 269 270 271 272 273 274 |
static DEFINE_PER_CPU(int, rcu_sched_qs_mask); static DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = { .dynticks_nesting = DYNTICK_TASK_EXIT_IDLE, .dynticks = ATOMIC_INIT(1), #ifdef CONFIG_NO_HZ_FULL_SYSIDLE .dynticks_idle_nesting = DYNTICK_TASK_NEST_VALUE, .dynticks_idle = ATOMIC_INIT(1), #endif /* #ifdef CONFIG_NO_HZ_FULL_SYSIDLE */ }; |
5cd37193c rcu: Make cond_re... |
275 276 |
DEFINE_PER_CPU_SHARED_ALIGNED(unsigned long, rcu_qs_ctr); EXPORT_PER_CPU_SYMBOL_GPL(rcu_qs_ctr); |
4a81e8328 rcu: Reduce overh... |
277 278 279 280 281 282 283 284 285 286 |
/* * Let the RCU core know that this CPU has gone through the scheduler, * which is a quiescent state. This is called when the need for a * quiescent state is urgent, so we burn an atomic operation and full * memory barriers to let the RCU core know about it, regardless of what * this CPU might (or might not) do in the near future. * * We inform the RCU core by emulating a zero-duration dyntick-idle * period, which we in turn do by incrementing the ->dynticks counter * by two. |
46a5d164d rcu: Stop disabli... |
287 288 |
* * The caller must have disabled interrupts. |
4a81e8328 rcu: Reduce overh... |
289 290 291 |
*/ static void rcu_momentary_dyntick_idle(void) { |
4a81e8328 rcu: Reduce overh... |
292 293 294 295 |
struct rcu_data *rdp; struct rcu_dynticks *rdtp; int resched_mask; struct rcu_state *rsp; |
4a81e8328 rcu: Reduce overh... |
296 297 298 299 300 301 302 303 304 305 306 307 308 |
/* * Yes, we can lose flag-setting operations. This is OK, because * the flag will be set again after some delay. */ resched_mask = raw_cpu_read(rcu_sched_qs_mask); raw_cpu_write(rcu_sched_qs_mask, 0); /* Find the flavor that needs a quiescent state. */ for_each_rcu_flavor(rsp) { rdp = raw_cpu_ptr(rsp->rda); if (!(resched_mask & rsp->flavor_mask)) continue; smp_mb(); /* rcu_sched_qs_mask before cond_resched_completed. */ |
7d0ae8086 rcu: Convert ACCE... |
309 310 |
if (READ_ONCE(rdp->mynode->completed) != READ_ONCE(rdp->cond_resched_completed)) |
4a81e8328 rcu: Reduce overh... |
311 312 313 314 315 316 317 318 319 320 321 322 323 324 |
continue; /* * Pretend to be momentarily idle for the quiescent state. * This allows the grace-period kthread to record the * quiescent state, with no need for this CPU to do anything * further. */ rdtp = this_cpu_ptr(&rcu_dynticks); smp_mb__before_atomic(); /* Earlier stuff before QS. */ atomic_add(2, &rdtp->dynticks); /* QS. */ smp_mb__after_atomic(); /* Later stuff after QS. */ break; } |
4a81e8328 rcu: Reduce overh... |
325 |
} |
25502a6c1 rcu: refactor RCU... |
326 327 328 |
/* * Note a context switch. This is a quiescent state for RCU-sched, * and requires special handling for preemptible RCU. |
46a5d164d rcu: Stop disabli... |
329 |
* The caller must have disabled interrupts. |
25502a6c1 rcu: refactor RCU... |
330 |
*/ |
38200cf24 rcu: Remove "cpu"... |
331 |
void rcu_note_context_switch(void) |
25502a6c1 rcu: refactor RCU... |
332 |
{ |
bb73c52ba rcu: Don't disabl... |
333 |
barrier(); /* Avoid RCU read-side critical sections leaking down. */ |
f7f7bac9c rcu: Have the RCU... |
334 |
trace_rcu_utilization(TPS("Start context switch")); |
284a8c93a rcu: Per-CPU oper... |
335 |
rcu_sched_qs(); |
38200cf24 rcu: Remove "cpu"... |
336 |
rcu_preempt_note_context_switch(); |
4a81e8328 rcu: Reduce overh... |
337 338 |
if (unlikely(raw_cpu_read(rcu_sched_qs_mask))) rcu_momentary_dyntick_idle(); |
f7f7bac9c rcu: Have the RCU... |
339 |
trace_rcu_utilization(TPS("End context switch")); |
bb73c52ba rcu: Don't disabl... |
340 |
barrier(); /* Avoid RCU read-side critical sections leaking up. */ |
25502a6c1 rcu: refactor RCU... |
341 |
} |
29ce83100 rcu: provide rcu_... |
342 |
EXPORT_SYMBOL_GPL(rcu_note_context_switch); |
25502a6c1 rcu: refactor RCU... |
343 |
|
5cd37193c rcu: Make cond_re... |
344 |
/* |
1925d1967 rcu: Fix a couple... |
345 |
* Register a quiescent state for all RCU flavors. If there is an |
5cd37193c rcu: Make cond_re... |
346 347 |
* emergency, invoke rcu_momentary_dyntick_idle() to do a heavy-weight * dyntick-idle quiescent state visible to other CPUs (but only for those |
1925d1967 rcu: Fix a couple... |
348 |
* RCU flavors in desperate need of a quiescent state, which will normally |
5cd37193c rcu: Make cond_re... |
349 350 |
* be none of them). Either way, do a lightweight quiescent state for * all RCU flavors. |
bb73c52ba rcu: Don't disabl... |
351 352 353 354 355 |
* * The barrier() calls are redundant in the common case when this is * called externally, but just in case this is called from within this * file. * |
5cd37193c rcu: Make cond_re... |
356 357 358 |
*/ void rcu_all_qs(void) { |
46a5d164d rcu: Stop disabli... |
359 |
unsigned long flags; |
bb73c52ba rcu: Don't disabl... |
360 |
barrier(); /* Avoid RCU read-side critical sections leaking down. */ |
46a5d164d rcu: Stop disabli... |
361 362 |
if (unlikely(raw_cpu_read(rcu_sched_qs_mask))) { local_irq_save(flags); |
5cd37193c rcu: Make cond_re... |
363 |
rcu_momentary_dyntick_idle(); |
46a5d164d rcu: Stop disabli... |
364 365 |
local_irq_restore(flags); } |
a1e122484 rcu: Make cond_re... |
366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 |
if (unlikely(raw_cpu_read(rcu_sched_data.cpu_no_qs.b.exp))) { /* * Yes, we just checked a per-CPU variable with preemption * enabled, so we might be migrated to some other CPU at * this point. That is OK because in that case, the * migration will supply the needed quiescent state. * We might end up needlessly disabling preemption and * invoking rcu_sched_qs() on the destination CPU, but * the probability and cost are both quite low, so this * should not be a problem in practice. */ preempt_disable(); rcu_sched_qs(); preempt_enable(); } |
5cd37193c rcu: Make cond_re... |
381 |
this_cpu_inc(rcu_qs_ctr); |
bb73c52ba rcu: Don't disabl... |
382 |
barrier(); /* Avoid RCU read-side critical sections leaking up. */ |
5cd37193c rcu: Make cond_re... |
383 384 |
} EXPORT_SYMBOL_GPL(rcu_all_qs); |
878d7439d rcu: Fix batch-li... |
385 386 387 |
static long blimit = 10; /* Maximum callbacks per rcu_do_batch. */ static long qhimark = 10000; /* If this many pending, ignore blimit. */ static long qlowmark = 100; /* Once only this many pending, use blimit. */ |
64db4cfff "Tree RCU": scala... |
388 |
|
878d7439d rcu: Fix batch-li... |
389 390 391 |
module_param(blimit, long, 0444); module_param(qhimark, long, 0444); module_param(qlowmark, long, 0444); |
3d76c0829 rcu: Clean up cod... |
392 |
|
026ad2835 rcu: Drive quiesc... |
393 394 |
static ulong jiffies_till_first_fqs = ULONG_MAX; static ulong jiffies_till_next_fqs = ULONG_MAX; |
8c7c4829a rcu: Awaken grace... |
395 |
static bool rcu_kick_kthreads; |
d40011f60 rcu: Control grac... |
396 397 398 |
module_param(jiffies_till_first_fqs, ulong, 0644); module_param(jiffies_till_next_fqs, ulong, 0644); |
8c7c4829a rcu: Awaken grace... |
399 |
module_param(rcu_kick_kthreads, bool, 0644); |
d40011f60 rcu: Control grac... |
400 |
|
4a81e8328 rcu: Reduce overh... |
401 402 403 404 405 406 |
/* * How long the grace period must be before we start recruiting * quiescent-state help from rcu_note_context_switch(). */ static ulong jiffies_till_sched_qs = HZ / 20; module_param(jiffies_till_sched_qs, ulong, 0644); |
48a7639ce rcu: Make callers... |
407 |
static bool rcu_start_gp_advanced(struct rcu_state *rsp, struct rcu_node *rnp, |
910ee45db rcu: Make rcu_acc... |
408 |
struct rcu_data *rdp); |
217af2a2f nohz_full: Add fu... |
409 410 411 412 |
static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *rsp, bool *isidle, unsigned long *maxj), bool *isidle, unsigned long *maxj); |
4cdfc175c rcu: Move quiesce... |
413 |
static void force_quiescent_state(struct rcu_state *rsp); |
e3950ecd5 rcu: Remove "cpu"... |
414 |
static int rcu_pending(void); |
64db4cfff "Tree RCU": scala... |
415 416 |
/* |
917963d0b rcutorture: Check... |
417 |
* Return the number of RCU batches started thus far for debug & stats. |
64db4cfff "Tree RCU": scala... |
418 |
*/ |
917963d0b rcutorture: Check... |
419 420 421 422 423 424 425 426 |
unsigned long rcu_batches_started(void) { return rcu_state_p->gpnum; } EXPORT_SYMBOL_GPL(rcu_batches_started); /* * Return the number of RCU-sched batches started thus far for debug & stats. |
64db4cfff "Tree RCU": scala... |
427 |
*/ |
917963d0b rcutorture: Check... |
428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 |
unsigned long rcu_batches_started_sched(void) { return rcu_sched_state.gpnum; } EXPORT_SYMBOL_GPL(rcu_batches_started_sched); /* * Return the number of RCU BH batches started thus far for debug & stats. */ unsigned long rcu_batches_started_bh(void) { return rcu_bh_state.gpnum; } EXPORT_SYMBOL_GPL(rcu_batches_started_bh); /* * Return the number of RCU batches completed thus far for debug & stats. */ unsigned long rcu_batches_completed(void) { return rcu_state_p->completed; } EXPORT_SYMBOL_GPL(rcu_batches_completed); /* * Return the number of RCU-sched batches completed thus far for debug & stats. |
64db4cfff "Tree RCU": scala... |
454 |
*/ |
9733e4f0a rcu: Make _batche... |
455 |
unsigned long rcu_batches_completed_sched(void) |
64db4cfff "Tree RCU": scala... |
456 |
{ |
d6714c22b rcu: Renamings to... |
457 |
return rcu_sched_state.completed; |
64db4cfff "Tree RCU": scala... |
458 |
} |
d6714c22b rcu: Renamings to... |
459 |
EXPORT_SYMBOL_GPL(rcu_batches_completed_sched); |
64db4cfff "Tree RCU": scala... |
460 461 |
/* |
917963d0b rcutorture: Check... |
462 |
* Return the number of RCU BH batches completed thus far for debug & stats. |
64db4cfff "Tree RCU": scala... |
463 |
*/ |
9733e4f0a rcu: Make _batche... |
464 |
unsigned long rcu_batches_completed_bh(void) |
64db4cfff "Tree RCU": scala... |
465 466 467 468 469 470 |
{ return rcu_bh_state.completed; } EXPORT_SYMBOL_GPL(rcu_batches_completed_bh); /* |
291783b8a rcutorture: Exped... |
471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 |
* Return the number of RCU expedited batches completed thus far for * debug & stats. Odd numbers mean that a batch is in progress, even * numbers mean idle. The value returned will thus be roughly double * the cumulative batches since boot. */ unsigned long rcu_exp_batches_completed(void) { return rcu_state_p->expedited_sequence; } EXPORT_SYMBOL_GPL(rcu_exp_batches_completed); /* * Return the number of RCU-sched expedited batches completed thus far * for debug & stats. Similar to rcu_exp_batches_completed(). */ unsigned long rcu_exp_batches_completed_sched(void) { return rcu_sched_state.expedited_sequence; } EXPORT_SYMBOL_GPL(rcu_exp_batches_completed_sched); /* |
a381d757d rcu: Merge rcu_sc... |
493 494 495 496 |
* Force a quiescent state. */ void rcu_force_quiescent_state(void) { |
e534165bb rcu: Variable nam... |
497 |
force_quiescent_state(rcu_state_p); |
a381d757d rcu: Merge rcu_sc... |
498 499 500 501 |
} EXPORT_SYMBOL_GPL(rcu_force_quiescent_state); /* |
bf66f18e7 rcu: Add force_qu... |
502 503 504 505 |
* Force a quiescent state for RCU BH. */ void rcu_bh_force_quiescent_state(void) { |
4cdfc175c rcu: Move quiesce... |
506 |
force_quiescent_state(&rcu_bh_state); |
bf66f18e7 rcu: Add force_qu... |
507 508 509 510 |
} EXPORT_SYMBOL_GPL(rcu_bh_force_quiescent_state); /* |
e7580f338 rcu: Get rcu_sche... |
511 512 513 514 515 516 517 518 519 |
* Force a quiescent state for RCU-sched. */ void rcu_sched_force_quiescent_state(void) { force_quiescent_state(&rcu_sched_state); } EXPORT_SYMBOL_GPL(rcu_sched_force_quiescent_state); /* |
afea227fd rcutorture: Expor... |
520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 |
* Show the state of the grace-period kthreads. */ void show_rcu_gp_kthreads(void) { struct rcu_state *rsp; for_each_rcu_flavor(rsp) { pr_info("%s: wait state: %d ->state: %#lx ", rsp->name, rsp->gp_state, rsp->gp_kthread->state); /* sched_show_task(rsp->gp_kthread); */ } } EXPORT_SYMBOL_GPL(show_rcu_gp_kthreads); /* |
4a2986568 rcu: make rcutort... |
536 537 538 539 540 541 542 543 544 545 546 547 548 549 |
* Record the number of times rcutorture tests have been initiated and * terminated. This information allows the debugfs tracing stats to be * correlated to the rcutorture messages, even when the rcutorture module * is being repeatedly loaded and unloaded. In other words, we cannot * store this state in rcutorture itself. */ void rcutorture_record_test_transition(void) { rcutorture_testseq++; rcutorture_vernum = 0; } EXPORT_SYMBOL_GPL(rcutorture_record_test_transition); /* |
ad0dc7f94 rcutorture: Add f... |
550 551 552 553 554 555 556 557 558 |
* Send along grace-period-related data for rcutorture diagnostics. */ void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags, unsigned long *gpnum, unsigned long *completed) { struct rcu_state *rsp = NULL; switch (test_type) { case RCU_FLAVOR: |
e534165bb rcu: Variable nam... |
559 |
rsp = rcu_state_p; |
ad0dc7f94 rcutorture: Add f... |
560 561 562 563 564 565 566 567 568 569 570 |
break; case RCU_BH_FLAVOR: rsp = &rcu_bh_state; break; case RCU_SCHED_FLAVOR: rsp = &rcu_sched_state; break; default: break; } if (rsp != NULL) { |
7d0ae8086 rcu: Convert ACCE... |
571 572 573 |
*flags = READ_ONCE(rsp->gp_flags); *gpnum = READ_ONCE(rsp->gpnum); *completed = READ_ONCE(rsp->completed); |
ad0dc7f94 rcutorture: Add f... |
574 575 576 577 578 579 580 581 582 |
return; } *flags = 0; *gpnum = 0; *completed = 0; } EXPORT_SYMBOL_GPL(rcutorture_get_gp_data); /* |
4a2986568 rcu: make rcutort... |
583 584 585 586 587 588 589 590 591 592 593 |
* Record the number of writer passes through the current rcutorture test. * This is also used to correlate debugfs tracing stats with the rcutorture * messages. */ void rcutorture_record_progress(unsigned long vernum) { rcutorture_vernum++; } EXPORT_SYMBOL_GPL(rcutorture_record_progress); /* |
64db4cfff "Tree RCU": scala... |
594 595 596 597 598 |
* Does the CPU have callbacks ready to be invoked? */ static int cpu_has_callbacks_ready_to_invoke(struct rcu_data *rdp) { |
3fbfbf7a3 rcu: Add callback... |
599 600 |
return &rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL] && rdp->nxttail[RCU_DONE_TAIL] != NULL; |
64db4cfff "Tree RCU": scala... |
601 602 603 |
} /* |
365187fbc rcu: Update cpu_n... |
604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 |
* Return the root node of the specified rcu_state structure. */ static struct rcu_node *rcu_get_root(struct rcu_state *rsp) { return &rsp->node[0]; } /* * Is there any need for future grace periods? * Interrupts must be disabled. If the caller does not hold the root * rnp_node structure's ->lock, the results are advisory only. */ static int rcu_future_needs_gp(struct rcu_state *rsp) { struct rcu_node *rnp = rcu_get_root(rsp); |
7d0ae8086 rcu: Convert ACCE... |
619 |
int idx = (READ_ONCE(rnp->completed) + 1) & 0x1; |
365187fbc rcu: Update cpu_n... |
620 |
int *fp = &rnp->need_future_gp[idx]; |
7d0ae8086 rcu: Convert ACCE... |
621 |
return READ_ONCE(*fp); |
365187fbc rcu: Update cpu_n... |
622 623 624 |
} /* |
dc35c8934 rcu: Tag callback... |
625 626 627 |
* Does the current CPU require a not-yet-started grace period? * The caller must have disabled interrupts to prevent races with * normal callback registry. |
64db4cfff "Tree RCU": scala... |
628 |
*/ |
d117c8aa1 rcu: Make cpu_nee... |
629 |
static bool |
64db4cfff "Tree RCU": scala... |
630 631 |
cpu_needs_another_gp(struct rcu_state *rsp, struct rcu_data *rdp) { |
dc35c8934 rcu: Tag callback... |
632 |
int i; |
3fbfbf7a3 rcu: Add callback... |
633 |
|
dc35c8934 rcu: Tag callback... |
634 |
if (rcu_gp_in_progress(rsp)) |
d117c8aa1 rcu: Make cpu_nee... |
635 |
return false; /* No, a grace period is already in progress. */ |
365187fbc rcu: Update cpu_n... |
636 |
if (rcu_future_needs_gp(rsp)) |
d117c8aa1 rcu: Make cpu_nee... |
637 |
return true; /* Yes, a no-CBs CPU needs one. */ |
dc35c8934 rcu: Tag callback... |
638 |
if (!rdp->nxttail[RCU_NEXT_TAIL]) |
d117c8aa1 rcu: Make cpu_nee... |
639 |
return false; /* No, this is a no-CBs (or offline) CPU. */ |
dc35c8934 rcu: Tag callback... |
640 |
if (*rdp->nxttail[RCU_NEXT_READY_TAIL]) |
d117c8aa1 rcu: Make cpu_nee... |
641 |
return true; /* Yes, CPU has newly registered callbacks. */ |
dc35c8934 rcu: Tag callback... |
642 643 |
for (i = RCU_WAIT_TAIL; i < RCU_NEXT_TAIL; i++) if (rdp->nxttail[i - 1] != rdp->nxttail[i] && |
7d0ae8086 rcu: Convert ACCE... |
644 |
ULONG_CMP_LT(READ_ONCE(rsp->completed), |
dc35c8934 rcu: Tag callback... |
645 |
rdp->nxtcompleted[i])) |
d117c8aa1 rcu: Make cpu_nee... |
646 647 |
return true; /* Yes, CBs for future grace period. */ return false; /* No grace period needed. */ |
64db4cfff "Tree RCU": scala... |
648 649 650 |
} /* |
adf5091e6 rcu: New rcu_user... |
651 |
* rcu_eqs_enter_common - current CPU is moving towards extended quiescent state |
9b2e4f188 rcu: Track idlene... |
652 653 654 655 656 |
* * If the new value of the ->dynticks_nesting counter now is zero, * we really have entered idle, and must do the appropriate accounting. * The caller must have disabled interrupts. */ |
28ced795c rcu: Remove rcu_d... |
657 |
static void rcu_eqs_enter_common(long long oldval, bool user) |
9b2e4f188 rcu: Track idlene... |
658 |
{ |
96d3fd0d3 rcu: Break call_r... |
659 660 |
struct rcu_state *rsp; struct rcu_data *rdp; |
28ced795c rcu: Remove rcu_d... |
661 |
struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks); |
96d3fd0d3 rcu: Break call_r... |
662 |
|
f7f7bac9c rcu: Have the RCU... |
663 |
trace_rcu_dyntick(TPS("Start"), oldval, rdtp->dynticks_nesting); |
1ce46ee59 rcu: Conditionall... |
664 665 |
if (IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !user && !is_idle_task(current)) { |
289828e62 rcu: Silence unus... |
666 667 |
struct task_struct *idle __maybe_unused = idle_task(smp_processor_id()); |
0989cb467 rcu: Add more inf... |
668 |
|
f7f7bac9c rcu: Have the RCU... |
669 |
trace_rcu_dyntick(TPS("Error on entry: not idle task"), oldval, 0); |
274529ba9 rcu: Consolidate ... |
670 |
rcu_ftrace_dump(DUMP_ORIG); |
0989cb467 rcu: Add more inf... |
671 672 673 |
WARN_ONCE(1, "Current pid: %d comm: %s / Idle pid: %d comm: %s", current->pid, current->comm, idle->pid, idle->comm); /* must be idle task! */ |
9b2e4f188 rcu: Track idlene... |
674 |
} |
96d3fd0d3 rcu: Break call_r... |
675 676 677 678 |
for_each_rcu_flavor(rsp) { rdp = this_cpu_ptr(rsp->rda); do_nocb_deferred_wakeup(rdp); } |
198bbf812 rcu: Remove "cpu"... |
679 |
rcu_prepare_for_idle(); |
9b2e4f188 rcu: Track idlene... |
680 |
/* CPUs seeing atomic_inc() must see prior RCU read-side crit sects */ |
4e857c58e arch: Mass conver... |
681 |
smp_mb__before_atomic(); /* See above. */ |
9b2e4f188 rcu: Track idlene... |
682 |
atomic_inc(&rdtp->dynticks); |
4e857c58e arch: Mass conver... |
683 |
smp_mb__after_atomic(); /* Force ordering with next sojourn. */ |
1ce46ee59 rcu: Conditionall... |
684 685 |
WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && atomic_read(&rdtp->dynticks) & 0x1); |
176f8f7a5 rcu: Make TASKS_R... |
686 |
rcu_dynticks_task_enter(); |
c44e2cdda rcu: Check for id... |
687 688 |
/* |
adf5091e6 rcu: New rcu_user... |
689 |
* It is illegal to enter an extended quiescent state while |
c44e2cdda rcu: Check for id... |
690 691 |
* in an RCU read-side critical section. */ |
f78f5b90c rcu: Rename rcu_l... |
692 693 694 695 696 697 |
RCU_LOCKDEP_WARN(lock_is_held(&rcu_lock_map), "Illegal idle entry in RCU read-side critical section."); RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map), "Illegal idle entry in RCU-bh read-side critical section."); RCU_LOCKDEP_WARN(lock_is_held(&rcu_sched_lock_map), "Illegal idle entry in RCU-sched read-side critical section."); |
9b2e4f188 rcu: Track idlene... |
698 |
} |
64db4cfff "Tree RCU": scala... |
699 |
|
adf5091e6 rcu: New rcu_user... |
700 701 702 |
/* * Enter an RCU extended quiescent state, which can be either the * idle loop or adaptive-tickless usermode execution. |
64db4cfff "Tree RCU": scala... |
703 |
*/ |
adf5091e6 rcu: New rcu_user... |
704 |
static void rcu_eqs_enter(bool user) |
64db4cfff "Tree RCU": scala... |
705 |
{ |
4145fa7fb rcu: Deconfuse dy... |
706 |
long long oldval; |
64db4cfff "Tree RCU": scala... |
707 |
struct rcu_dynticks *rdtp; |
c9d4b0af9 rcu: Replace __ge... |
708 |
rdtp = this_cpu_ptr(&rcu_dynticks); |
4145fa7fb rcu: Deconfuse dy... |
709 |
oldval = rdtp->dynticks_nesting; |
1ce46ee59 rcu: Conditionall... |
710 711 |
WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && (oldval & DYNTICK_TASK_NEST_MASK) == 0); |
3a5924052 rcu: Allow task-l... |
712 |
if ((oldval & DYNTICK_TASK_NEST_MASK) == DYNTICK_TASK_NEST_VALUE) { |
29e37d814 rcu: Allow nestin... |
713 |
rdtp->dynticks_nesting = 0; |
28ced795c rcu: Remove rcu_d... |
714 |
rcu_eqs_enter_common(oldval, user); |
3a5924052 rcu: Allow task-l... |
715 |
} else { |
29e37d814 rcu: Allow nestin... |
716 |
rdtp->dynticks_nesting -= DYNTICK_TASK_NEST_VALUE; |
3a5924052 rcu: Allow task-l... |
717 |
} |
64db4cfff "Tree RCU": scala... |
718 |
} |
adf5091e6 rcu: New rcu_user... |
719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 |
/** * rcu_idle_enter - inform RCU that current CPU is entering idle * * Enter idle mode, in other words, -leave- the mode in which RCU * read-side critical sections can occur. (Though RCU read-side * critical sections can occur in irq handlers in idle, a possibility * handled by irq_enter() and irq_exit().) * * We crowbar the ->dynticks_nesting field to zero to allow for * the possibility of usermode upcalls having messed up our count * of interrupt nesting level during the prior busy period. */ void rcu_idle_enter(void) { |
c5d900bf6 rcu: Allow rcu_us... |
734 735 736 |
unsigned long flags; local_irq_save(flags); |
cb349ca95 rcu: Apply micro-... |
737 |
rcu_eqs_enter(false); |
28ced795c rcu: Remove rcu_d... |
738 |
rcu_sysidle_enter(0); |
c5d900bf6 rcu: Allow rcu_us... |
739 |
local_irq_restore(flags); |
adf5091e6 rcu: New rcu_user... |
740 |
} |
8a2ecf474 rcu: Add RCU_NONI... |
741 |
EXPORT_SYMBOL_GPL(rcu_idle_enter); |
64db4cfff "Tree RCU": scala... |
742 |
|
d1ec4c34c rcu: Drop RCU_USE... |
743 |
#ifdef CONFIG_NO_HZ_FULL |
9b2e4f188 rcu: Track idlene... |
744 |
/** |
adf5091e6 rcu: New rcu_user... |
745 746 747 748 749 750 751 752 753 |
* rcu_user_enter - inform RCU that we are resuming userspace. * * Enter RCU idle mode right before resuming userspace. No use of RCU * is permitted between this call and rcu_user_exit(). This way the * CPU doesn't need to maintain the tick for RCU maintenance purposes * when the CPU runs in userspace. */ void rcu_user_enter(void) { |
91d1aa43d context_tracking:... |
754 |
rcu_eqs_enter(1); |
adf5091e6 rcu: New rcu_user... |
755 |
} |
d1ec4c34c rcu: Drop RCU_USE... |
756 |
#endif /* CONFIG_NO_HZ_FULL */ |
19dd1591f rcu: New rcu_user... |
757 758 |
/** |
9b2e4f188 rcu: Track idlene... |
759 760 761 762 |
* rcu_irq_exit - inform RCU that current CPU is exiting irq towards idle * * Exit from an interrupt handler, which might possibly result in entering * idle mode, in other words, leaving the mode in which read-side critical |
7c9906ca5 rcu: Don't redund... |
763 |
* sections can occur. The caller must have disabled interrupts. |
64db4cfff "Tree RCU": scala... |
764 |
* |
9b2e4f188 rcu: Track idlene... |
765 766 767 768 769 770 771 772 |
* This code assumes that the idle loop never does anything that might * result in unbalanced calls to irq_enter() and irq_exit(). If your * architecture violates this assumption, RCU will give you what you * deserve, good and hard. But very infrequently and irreproducibly. * * Use things like work queues to work around this limitation. * * You have been warned. |
64db4cfff "Tree RCU": scala... |
773 |
*/ |
9b2e4f188 rcu: Track idlene... |
774 |
void rcu_irq_exit(void) |
64db4cfff "Tree RCU": scala... |
775 |
{ |
4145fa7fb rcu: Deconfuse dy... |
776 |
long long oldval; |
64db4cfff "Tree RCU": scala... |
777 |
struct rcu_dynticks *rdtp; |
7c9906ca5 rcu: Don't redund... |
778 |
RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_irq_exit() invoked with irqs enabled!!!"); |
c9d4b0af9 rcu: Replace __ge... |
779 |
rdtp = this_cpu_ptr(&rcu_dynticks); |
4145fa7fb rcu: Deconfuse dy... |
780 |
oldval = rdtp->dynticks_nesting; |
9b2e4f188 rcu: Track idlene... |
781 |
rdtp->dynticks_nesting--; |
1ce46ee59 rcu: Conditionall... |
782 783 |
WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && rdtp->dynticks_nesting < 0); |
b6fc60201 rcu: Don't check ... |
784 |
if (rdtp->dynticks_nesting) |
f7f7bac9c rcu: Have the RCU... |
785 |
trace_rcu_dyntick(TPS("--="), oldval, rdtp->dynticks_nesting); |
b6fc60201 rcu: Don't check ... |
786 |
else |
28ced795c rcu: Remove rcu_d... |
787 788 |
rcu_eqs_enter_common(oldval, true); rcu_sysidle_enter(1); |
7c9906ca5 rcu: Don't redund... |
789 790 791 792 793 794 795 796 797 798 799 |
} /* * Wrapper for rcu_irq_exit() where interrupts are enabled. */ void rcu_irq_exit_irqson(void) { unsigned long flags; local_irq_save(flags); rcu_irq_exit(); |
9b2e4f188 rcu: Track idlene... |
800 801 802 803 |
local_irq_restore(flags); } /* |
adf5091e6 rcu: New rcu_user... |
804 |
* rcu_eqs_exit_common - current CPU moving away from extended quiescent state |
9b2e4f188 rcu: Track idlene... |
805 806 807 808 809 |
* * If the new value of the ->dynticks_nesting counter was previously zero, * we really have exited idle, and must do the appropriate accounting. * The caller must have disabled interrupts. */ |
28ced795c rcu: Remove rcu_d... |
810 |
static void rcu_eqs_exit_common(long long oldval, int user) |
9b2e4f188 rcu: Track idlene... |
811 |
{ |
28ced795c rcu: Remove rcu_d... |
812 |
struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks); |
176f8f7a5 rcu: Make TASKS_R... |
813 |
rcu_dynticks_task_exit(); |
4e857c58e arch: Mass conver... |
814 |
smp_mb__before_atomic(); /* Force ordering w/previous sojourn. */ |
23b5c8fa0 rcu: Decrease mem... |
815 816 |
atomic_inc(&rdtp->dynticks); /* CPUs seeing atomic_inc() must see later RCU read-side crit sects */ |
4e857c58e arch: Mass conver... |
817 |
smp_mb__after_atomic(); /* See above. */ |
1ce46ee59 rcu: Conditionall... |
818 819 |
WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !(atomic_read(&rdtp->dynticks) & 0x1)); |
8fa7845df rcu: Remove "cpu"... |
820 |
rcu_cleanup_after_idle(); |
f7f7bac9c rcu: Have the RCU... |
821 |
trace_rcu_dyntick(TPS("End"), oldval, rdtp->dynticks_nesting); |
1ce46ee59 rcu: Conditionall... |
822 823 |
if (IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !user && !is_idle_task(current)) { |
289828e62 rcu: Silence unus... |
824 825 |
struct task_struct *idle __maybe_unused = idle_task(smp_processor_id()); |
0989cb467 rcu: Add more inf... |
826 |
|
f7f7bac9c rcu: Have the RCU... |
827 |
trace_rcu_dyntick(TPS("Error on exit: not idle task"), |
4145fa7fb rcu: Deconfuse dy... |
828 |
oldval, rdtp->dynticks_nesting); |
274529ba9 rcu: Consolidate ... |
829 |
rcu_ftrace_dump(DUMP_ORIG); |
0989cb467 rcu: Add more inf... |
830 831 832 |
WARN_ONCE(1, "Current pid: %d comm: %s / Idle pid: %d comm: %s", current->pid, current->comm, idle->pid, idle->comm); /* must be idle task! */ |
9b2e4f188 rcu: Track idlene... |
833 834 |
} } |
adf5091e6 rcu: New rcu_user... |
835 836 837 |
/* * Exit an RCU extended quiescent state, which can be either the * idle loop or adaptive-tickless usermode execution. |
9b2e4f188 rcu: Track idlene... |
838 |
*/ |
adf5091e6 rcu: New rcu_user... |
839 |
static void rcu_eqs_exit(bool user) |
9b2e4f188 rcu: Track idlene... |
840 |
{ |
9b2e4f188 rcu: Track idlene... |
841 842 |
struct rcu_dynticks *rdtp; long long oldval; |
c9d4b0af9 rcu: Replace __ge... |
843 |
rdtp = this_cpu_ptr(&rcu_dynticks); |
9b2e4f188 rcu: Track idlene... |
844 |
oldval = rdtp->dynticks_nesting; |
1ce46ee59 rcu: Conditionall... |
845 |
WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && oldval < 0); |
3a5924052 rcu: Allow task-l... |
846 |
if (oldval & DYNTICK_TASK_NEST_MASK) { |
29e37d814 rcu: Allow nestin... |
847 |
rdtp->dynticks_nesting += DYNTICK_TASK_NEST_VALUE; |
3a5924052 rcu: Allow task-l... |
848 |
} else { |
29e37d814 rcu: Allow nestin... |
849 |
rdtp->dynticks_nesting = DYNTICK_TASK_EXIT_IDLE; |
28ced795c rcu: Remove rcu_d... |
850 |
rcu_eqs_exit_common(oldval, user); |
3a5924052 rcu: Allow task-l... |
851 |
} |
9b2e4f188 rcu: Track idlene... |
852 |
} |
adf5091e6 rcu: New rcu_user... |
853 854 855 856 857 858 859 860 861 862 863 864 865 866 |
/** * rcu_idle_exit - inform RCU that current CPU is leaving idle * * Exit idle mode, in other words, -enter- the mode in which RCU * read-side critical sections can occur. * * We crowbar the ->dynticks_nesting field to DYNTICK_TASK_NEST to * allow for the possibility of usermode upcalls messing up our count * of interrupt nesting level during the busy period that is just * now starting. */ void rcu_idle_exit(void) { |
c5d900bf6 rcu: Allow rcu_us... |
867 868 869 |
unsigned long flags; local_irq_save(flags); |
cb349ca95 rcu: Apply micro-... |
870 |
rcu_eqs_exit(false); |
28ced795c rcu: Remove rcu_d... |
871 |
rcu_sysidle_exit(0); |
c5d900bf6 rcu: Allow rcu_us... |
872 |
local_irq_restore(flags); |
adf5091e6 rcu: New rcu_user... |
873 |
} |
8a2ecf474 rcu: Add RCU_NONI... |
874 |
EXPORT_SYMBOL_GPL(rcu_idle_exit); |
9b2e4f188 rcu: Track idlene... |
875 |
|
d1ec4c34c rcu: Drop RCU_USE... |
876 |
#ifdef CONFIG_NO_HZ_FULL |
9b2e4f188 rcu: Track idlene... |
877 |
/** |
adf5091e6 rcu: New rcu_user... |
878 879 880 881 882 883 884 |
* rcu_user_exit - inform RCU that we are exiting userspace. * * Exit RCU idle mode while entering the kernel because it can * run a RCU read side critical section anytime. */ void rcu_user_exit(void) { |
91d1aa43d context_tracking:... |
885 |
rcu_eqs_exit(1); |
adf5091e6 rcu: New rcu_user... |
886 |
} |
d1ec4c34c rcu: Drop RCU_USE... |
887 |
#endif /* CONFIG_NO_HZ_FULL */ |
19dd1591f rcu: New rcu_user... |
888 889 |
/** |
9b2e4f188 rcu: Track idlene... |
890 891 892 893 |
* rcu_irq_enter - inform RCU that current CPU is entering irq away from idle * * Enter an interrupt handler, which might possibly result in exiting * idle mode, in other words, entering the mode in which read-side critical |
7c9906ca5 rcu: Don't redund... |
894 |
* sections can occur. The caller must have disabled interrupts. |
9b2e4f188 rcu: Track idlene... |
895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 |
* * Note that the Linux kernel is fully capable of entering an interrupt * handler that it never exits, for example when doing upcalls to * user mode! This code assumes that the idle loop never does upcalls to * user mode. If your architecture does do upcalls from the idle loop (or * does anything else that results in unbalanced calls to the irq_enter() * and irq_exit() functions), RCU will give you what you deserve, good * and hard. But very infrequently and irreproducibly. * * Use things like work queues to work around this limitation. * * You have been warned. */ void rcu_irq_enter(void) { |
9b2e4f188 rcu: Track idlene... |
910 911 |
struct rcu_dynticks *rdtp; long long oldval; |
7c9906ca5 rcu: Don't redund... |
912 |
RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_irq_enter() invoked with irqs enabled!!!"); |
c9d4b0af9 rcu: Replace __ge... |
913 |
rdtp = this_cpu_ptr(&rcu_dynticks); |
9b2e4f188 rcu: Track idlene... |
914 915 |
oldval = rdtp->dynticks_nesting; rdtp->dynticks_nesting++; |
1ce46ee59 rcu: Conditionall... |
916 917 |
WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && rdtp->dynticks_nesting == 0); |
b6fc60201 rcu: Don't check ... |
918 |
if (oldval) |
f7f7bac9c rcu: Have the RCU... |
919 |
trace_rcu_dyntick(TPS("++="), oldval, rdtp->dynticks_nesting); |
b6fc60201 rcu: Don't check ... |
920 |
else |
28ced795c rcu: Remove rcu_d... |
921 922 |
rcu_eqs_exit_common(oldval, true); rcu_sysidle_exit(1); |
7c9906ca5 rcu: Don't redund... |
923 924 925 926 927 928 929 930 931 932 933 |
} /* * Wrapper for rcu_irq_enter() where interrupts are enabled. */ void rcu_irq_enter_irqson(void) { unsigned long flags; local_irq_save(flags); rcu_irq_enter(); |
64db4cfff "Tree RCU": scala... |
934 |
local_irq_restore(flags); |
64db4cfff "Tree RCU": scala... |
935 936 937 938 939 |
} /** * rcu_nmi_enter - inform RCU of entry to NMI context * |
734d16801 rcu: Make rcu_nmi... |
940 941 942 943 944 |
* If the CPU was idle from RCU's viewpoint, update rdtp->dynticks and * rdtp->dynticks_nmi_nesting to let the RCU grace-period handling know * that the CPU is active. This implementation permits nested NMIs, as * long as the nesting level does not overflow an int. (You will probably * run out of stack space first.) |
64db4cfff "Tree RCU": scala... |
945 946 947 |
*/ void rcu_nmi_enter(void) { |
c9d4b0af9 rcu: Replace __ge... |
948 |
struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks); |
734d16801 rcu: Make rcu_nmi... |
949 |
int incby = 2; |
64db4cfff "Tree RCU": scala... |
950 |
|
734d16801 rcu: Make rcu_nmi... |
951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 |
/* Complain about underflow. */ WARN_ON_ONCE(rdtp->dynticks_nmi_nesting < 0); /* * If idle from RCU viewpoint, atomically increment ->dynticks * to mark non-idle and increment ->dynticks_nmi_nesting by one. * Otherwise, increment ->dynticks_nmi_nesting by two. This means * if ->dynticks_nmi_nesting is equal to one, we are guaranteed * to be in the outermost NMI handler that interrupted an RCU-idle * period (observation due to Andy Lutomirski). */ if (!(atomic_read(&rdtp->dynticks) & 0x1)) { smp_mb__before_atomic(); /* Force delay from prior write. */ atomic_inc(&rdtp->dynticks); /* atomic_inc() before later RCU read-side crit sects */ smp_mb__after_atomic(); /* See above. */ WARN_ON_ONCE(!(atomic_read(&rdtp->dynticks) & 0x1)); incby = 1; } rdtp->dynticks_nmi_nesting += incby; barrier(); |
64db4cfff "Tree RCU": scala... |
972 973 974 975 976 |
} /** * rcu_nmi_exit - inform RCU of exit from NMI context * |
734d16801 rcu: Make rcu_nmi... |
977 978 979 980 |
* If we are returning from the outermost NMI handler that interrupted an * RCU-idle period, update rdtp->dynticks and rdtp->dynticks_nmi_nesting * to let the RCU grace-period handling know that the CPU is back to * being RCU-idle. |
64db4cfff "Tree RCU": scala... |
981 982 983 |
*/ void rcu_nmi_exit(void) { |
c9d4b0af9 rcu: Replace __ge... |
984 |
struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks); |
64db4cfff "Tree RCU": scala... |
985 |
|
734d16801 rcu: Make rcu_nmi... |
986 987 988 989 990 991 992 993 994 995 996 997 998 999 |
/* * Check for ->dynticks_nmi_nesting underflow and bad ->dynticks. * (We are exiting an NMI handler, so RCU better be paying attention * to us!) */ WARN_ON_ONCE(rdtp->dynticks_nmi_nesting <= 0); WARN_ON_ONCE(!(atomic_read(&rdtp->dynticks) & 0x1)); /* * If the nesting level is not 1, the CPU wasn't RCU-idle, so * leave it in non-RCU-idle state. */ if (rdtp->dynticks_nmi_nesting != 1) { rdtp->dynticks_nmi_nesting -= 2; |
64db4cfff "Tree RCU": scala... |
1000 |
return; |
734d16801 rcu: Make rcu_nmi... |
1001 1002 1003 1004 |
} /* This NMI interrupted an RCU-idle CPU, restore RCU-idleness. */ rdtp->dynticks_nmi_nesting = 0; |
23b5c8fa0 rcu: Decrease mem... |
1005 |
/* CPUs seeing atomic_inc() must see prior RCU read-side crit sects */ |
4e857c58e arch: Mass conver... |
1006 |
smp_mb__before_atomic(); /* See above. */ |
23b5c8fa0 rcu: Decrease mem... |
1007 |
atomic_inc(&rdtp->dynticks); |
4e857c58e arch: Mass conver... |
1008 |
smp_mb__after_atomic(); /* Force delay to next write. */ |
23b5c8fa0 rcu: Decrease mem... |
1009 |
WARN_ON_ONCE(atomic_read(&rdtp->dynticks) & 0x1); |
64db4cfff "Tree RCU": scala... |
1010 1011 1012 |
} /** |
5c173eb8b rcu: Consistent r... |
1013 1014 1015 1016 1017 1018 1019 |
* __rcu_is_watching - are RCU read-side critical sections safe? * * Return true if RCU is watching the running CPU, which means that * this CPU can safely enter RCU read-side critical sections. Unlike * rcu_is_watching(), the caller of __rcu_is_watching() must have at * least disabled preemption. */ |
9418fb208 rcu: Do not trace... |
1020 |
bool notrace __rcu_is_watching(void) |
5c173eb8b rcu: Consistent r... |
1021 1022 1023 1024 1025 1026 |
{ return atomic_read(this_cpu_ptr(&rcu_dynticks.dynticks)) & 0x1; } /** * rcu_is_watching - see if RCU thinks that the current CPU is idle |
64db4cfff "Tree RCU": scala... |
1027 |
* |
9b2e4f188 rcu: Track idlene... |
1028 |
* If the current CPU is in its idle loop and is neither in an interrupt |
34240697d rcu: Disable pree... |
1029 |
* or NMI handler, return true. |
64db4cfff "Tree RCU": scala... |
1030 |
*/ |
9418fb208 rcu: Do not trace... |
1031 |
bool notrace rcu_is_watching(void) |
64db4cfff "Tree RCU": scala... |
1032 |
{ |
f534ed1fd rcu: Use bool typ... |
1033 |
bool ret; |
34240697d rcu: Disable pree... |
1034 |
|
46f00d18f rcu: Make rcu_is_... |
1035 |
preempt_disable_notrace(); |
5c173eb8b rcu: Consistent r... |
1036 |
ret = __rcu_is_watching(); |
46f00d18f rcu: Make rcu_is_... |
1037 |
preempt_enable_notrace(); |
34240697d rcu: Disable pree... |
1038 |
return ret; |
64db4cfff "Tree RCU": scala... |
1039 |
} |
5c173eb8b rcu: Consistent r... |
1040 |
EXPORT_SYMBOL_GPL(rcu_is_watching); |
64db4cfff "Tree RCU": scala... |
1041 |
|
62fde6edf rcu: Make __call_... |
1042 |
#if defined(CONFIG_PROVE_RCU) && defined(CONFIG_HOTPLUG_CPU) |
c0d6d01bf rcu: Check for il... |
1043 1044 1045 1046 1047 1048 1049 |
/* * Is the current CPU online? Disable preemption to avoid false positives * that could otherwise happen due to the current CPU number being sampled, * this task being preempted, its old CPU being taken offline, resuming * on some other CPU, then determining that its old CPU is now offline. * It is OK to use RCU on an offline processor during initial boot, hence |
2036d94a7 rcu: Rework detec... |
1050 1051 1052 1053 1054 1055 |
* the check for rcu_scheduler_fully_active. Note also that it is OK * for a CPU coming online to use RCU for one jiffy prior to marking itself * online in the cpu_online_mask. Similarly, it is OK for a CPU going * offline to continue to use RCU for one jiffy after marking itself * offline in the cpu_online_mask. This leniency is necessary given the * non-atomic nature of the online and offline processing, for example, |
4df837425 rcu: Convert rcut... |
1056 1057 |
* the fact that a CPU enters the scheduler after completing the teardown * of the CPU. |
2036d94a7 rcu: Rework detec... |
1058 |
* |
4df837425 rcu: Convert rcut... |
1059 1060 |
* This is also why RCU internally marks CPUs online during in the * preparation phase and offline after the CPU has been taken down. |
c0d6d01bf rcu: Check for il... |
1061 1062 1063 1064 1065 1066 |
* * Disable checking if in an NMI handler because we cannot safely report * errors from NMI handlers anyway. */ bool rcu_lockdep_current_cpu_online(void) { |
2036d94a7 rcu: Rework detec... |
1067 1068 |
struct rcu_data *rdp; struct rcu_node *rnp; |
c0d6d01bf rcu: Check for il... |
1069 1070 1071 |
bool ret; if (in_nmi()) |
f6f7ee9af rcu: Fix coccinel... |
1072 |
return true; |
c0d6d01bf rcu: Check for il... |
1073 |
preempt_disable(); |
c9d4b0af9 rcu: Replace __ge... |
1074 |
rdp = this_cpu_ptr(&rcu_sched_data); |
2036d94a7 rcu: Rework detec... |
1075 |
rnp = rdp->mynode; |
0aa04b055 rcu: Process offl... |
1076 |
ret = (rdp->grpmask & rcu_rnp_online_cpus(rnp)) || |
c0d6d01bf rcu: Check for il... |
1077 1078 1079 1080 1081 |
!rcu_scheduler_fully_active; preempt_enable(); return ret; } EXPORT_SYMBOL_GPL(rcu_lockdep_current_cpu_online); |
62fde6edf rcu: Make __call_... |
1082 |
#endif /* #if defined(CONFIG_PROVE_RCU) && defined(CONFIG_HOTPLUG_CPU) */ |
9b2e4f188 rcu: Track idlene... |
1083 |
|
64db4cfff "Tree RCU": scala... |
1084 |
/** |
9b2e4f188 rcu: Track idlene... |
1085 |
* rcu_is_cpu_rrupt_from_idle - see if idle or immediately interrupted from idle |
64db4cfff "Tree RCU": scala... |
1086 |
* |
9b2e4f188 rcu: Track idlene... |
1087 1088 1089 |
* If the current CPU is idle or running at a first-level (not nested) * interrupt from idle, return true. The caller must have at least * disabled preemption. |
64db4cfff "Tree RCU": scala... |
1090 |
*/ |
62e3cb143 rcu: Make rcu_is_... |
1091 |
static int rcu_is_cpu_rrupt_from_idle(void) |
64db4cfff "Tree RCU": scala... |
1092 |
{ |
c9d4b0af9 rcu: Replace __ge... |
1093 |
return __this_cpu_read(rcu_dynticks.dynticks_nesting) <= 1; |
64db4cfff "Tree RCU": scala... |
1094 |
} |
64db4cfff "Tree RCU": scala... |
1095 |
/* |
64db4cfff "Tree RCU": scala... |
1096 1097 |
* Snapshot the specified CPU's dynticks counter so that we can later * credit them with an implicit quiescent state. Return 1 if this CPU |
1eba8f843 rcu: Clean up cod... |
1098 |
* is in dynticks idle mode, which is an extended quiescent state. |
64db4cfff "Tree RCU": scala... |
1099 |
*/ |
217af2a2f nohz_full: Add fu... |
1100 1101 |
static int dyntick_save_progress_counter(struct rcu_data *rdp, bool *isidle, unsigned long *maxj) |
64db4cfff "Tree RCU": scala... |
1102 |
{ |
23b5c8fa0 rcu: Decrease mem... |
1103 |
rdp->dynticks_snap = atomic_add_return(0, &rdp->dynticks->dynticks); |
0edd1b178 nohz_full: Add fu... |
1104 |
rcu_sysidle_check_cpu(rdp, isidle, maxj); |
7941dbdeb rcu: Add event tr... |
1105 1106 |
if ((rdp->dynticks_snap & 0x1) == 0) { trace_rcu_fqs(rdp->rsp->name, rdp->gpnum, rdp->cpu, TPS("dti")); |
7d0ae8086 rcu: Convert ACCE... |
1107 |
if (ULONG_CMP_LT(READ_ONCE(rdp->gpnum) + ULONG_MAX / 4, |
e3663b102 rcu: Handle gpnum... |
1108 |
rdp->mynode->gpnum)) |
7d0ae8086 rcu: Convert ACCE... |
1109 |
WRITE_ONCE(rdp->gpwrap, true); |
23a9bacd3 rcu: Set rdp->gpw... |
1110 |
return 1; |
7941dbdeb rcu: Add event tr... |
1111 |
} |
23a9bacd3 rcu: Set rdp->gpw... |
1112 |
return 0; |
64db4cfff "Tree RCU": scala... |
1113 1114 1115 1116 1117 1118 |
} /* * Return true if the specified CPU has passed through a quiescent * state by virtue of being in or having passed through an dynticks * idle state since the last call to dyntick_save_progress_counter() |
a82dcc760 rcu: Make offline... |
1119 |
* for this same CPU, or by virtue of having been offline. |
64db4cfff "Tree RCU": scala... |
1120 |
*/ |
217af2a2f nohz_full: Add fu... |
1121 1122 |
static int rcu_implicit_dynticks_qs(struct rcu_data *rdp, bool *isidle, unsigned long *maxj) |
64db4cfff "Tree RCU": scala... |
1123 |
{ |
7eb4f4553 rcu: Make rcu_imp... |
1124 |
unsigned int curr; |
4a81e8328 rcu: Reduce overh... |
1125 |
int *rcrmp; |
7eb4f4553 rcu: Make rcu_imp... |
1126 |
unsigned int snap; |
64db4cfff "Tree RCU": scala... |
1127 |
|
7eb4f4553 rcu: Make rcu_imp... |
1128 1129 |
curr = (unsigned int)atomic_add_return(0, &rdp->dynticks->dynticks); snap = (unsigned int)rdp->dynticks_snap; |
64db4cfff "Tree RCU": scala... |
1130 1131 1132 1133 1134 1135 1136 1137 1138 |
/* * If the CPU passed through or entered a dynticks idle phase with * no active irq/NMI handlers, then we can safely pretend that the CPU * already acknowledged the request to pass through a quiescent * state. Either way, that CPU cannot possibly be in an RCU * read-side critical section that started before the beginning * of the current RCU grace period. */ |
7eb4f4553 rcu: Make rcu_imp... |
1139 |
if ((curr & 0x1) == 0 || UINT_CMP_GE(curr, snap + 2)) { |
f7f7bac9c rcu: Have the RCU... |
1140 |
trace_rcu_fqs(rdp->rsp->name, rdp->gpnum, rdp->cpu, TPS("dti")); |
64db4cfff "Tree RCU": scala... |
1141 1142 1143 |
rdp->dynticks_fqs++; return 1; } |
a82dcc760 rcu: Make offline... |
1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 |
/* * Check for the CPU being offline, but only if the grace period * is old enough. We don't need to worry about the CPU changing * state: If we see it offline even once, it has been through a * quiescent state. * * The reason for insisting that the grace period be at least * one jiffy old is that CPUs that are not quite online and that * have just gone offline can still execute RCU read-side critical * sections. */ if (ULONG_CMP_GE(rdp->rsp->gp_start + 2, jiffies)) return 0; /* Grace period is not old enough. */ barrier(); if (cpu_is_offline(rdp->cpu)) { |
f7f7bac9c rcu: Have the RCU... |
1159 |
trace_rcu_fqs(rdp->rsp->name, rdp->gpnum, rdp->cpu, TPS("ofl")); |
a82dcc760 rcu: Make offline... |
1160 1161 1162 |
rdp->offline_fqs++; return 1; } |
65d798f0f rcu: Kick adaptiv... |
1163 1164 |
/* |
4a81e8328 rcu: Reduce overh... |
1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 |
* A CPU running for an extended time within the kernel can * delay RCU grace periods. When the CPU is in NO_HZ_FULL mode, * even context-switching back and forth between a pair of * in-kernel CPU-bound tasks cannot advance grace periods. * So if the grace period is old enough, make the CPU pay attention. * Note that the unsynchronized assignments to the per-CPU * rcu_sched_qs_mask variable are safe. Yes, setting of * bits can be lost, but they will be set again on the next * force-quiescent-state pass. So lost bit sets do not result * in incorrect behavior, merely in a grace period lasting * a few jiffies longer than it might otherwise. Because * there are at most four threads involved, and because the * updates are only once every few jiffies, the probability of * lossage (and thus of slight grace-period extension) is * quite low. * * Note that if the jiffies_till_sched_qs boot/sysfs parameter * is set too high, we override with half of the RCU CPU stall * warning delay. |
6193c76ab rcu: Kick CPU hal... |
1184 |
*/ |
4a81e8328 rcu: Reduce overh... |
1185 1186 1187 |
rcrmp = &per_cpu(rcu_sched_qs_mask, rdp->cpu); if (ULONG_CMP_GE(jiffies, rdp->rsp->gp_start + jiffies_till_sched_qs) || |
cb1e78cfa rcu: Remove ACCES... |
1188 |
ULONG_CMP_GE(jiffies, rdp->rsp->jiffies_resched)) { |
7d0ae8086 rcu: Convert ACCE... |
1189 1190 1191 |
if (!(READ_ONCE(*rcrmp) & rdp->rsp->flavor_mask)) { WRITE_ONCE(rdp->cond_resched_completed, READ_ONCE(rdp->mynode->completed)); |
4a81e8328 rcu: Reduce overh... |
1192 |
smp_mb(); /* ->cond_resched_completed before *rcrmp. */ |
7d0ae8086 rcu: Convert ACCE... |
1193 1194 |
WRITE_ONCE(*rcrmp, READ_ONCE(*rcrmp) + rdp->rsp->flavor_mask); |
4a81e8328 rcu: Reduce overh... |
1195 |
} |
4914950aa rcu: Stop treatin... |
1196 |
rdp->rsp->jiffies_resched += 5; /* Re-enable beating. */ |
6193c76ab rcu: Kick CPU hal... |
1197 |
} |
4914950aa rcu: Stop treatin... |
1198 1199 1200 1201 1202 |
/* And if it has been a really long time, kick the CPU as well. */ if (ULONG_CMP_GE(jiffies, rdp->rsp->gp_start + 2 * jiffies_till_sched_qs) || ULONG_CMP_GE(jiffies, rdp->rsp->gp_start + jiffies_till_sched_qs)) resched_cpu(rdp->cpu); /* Force CPU into scheduler. */ |
a82dcc760 rcu: Make offline... |
1203 |
return 0; |
64db4cfff "Tree RCU": scala... |
1204 |
} |
64db4cfff "Tree RCU": scala... |
1205 1206 |
static void record_gp_stall_check_time(struct rcu_state *rsp) { |
cb1e78cfa rcu: Remove ACCES... |
1207 |
unsigned long j = jiffies; |
6193c76ab rcu: Kick CPU hal... |
1208 |
unsigned long j1; |
26cdfedf6 rcu: Reject memor... |
1209 1210 1211 |
rsp->gp_start = j; smp_wmb(); /* Record start time before stall time. */ |
6193c76ab rcu: Kick CPU hal... |
1212 |
j1 = rcu_jiffies_till_stall_check(); |
7d0ae8086 rcu: Convert ACCE... |
1213 |
WRITE_ONCE(rsp->jiffies_stall, j + j1); |
6193c76ab rcu: Kick CPU hal... |
1214 |
rsp->jiffies_resched = j + j1 / 2; |
7d0ae8086 rcu: Convert ACCE... |
1215 |
rsp->n_force_qs_gpstart = READ_ONCE(rsp->n_force_qs); |
64db4cfff "Tree RCU": scala... |
1216 |
} |
b637a328b rcu: Print remote... |
1217 |
/* |
6b50e119c rcutorture: Print... |
1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 |
* Convert a ->gp_state value to a character string. */ static const char *gp_state_getname(short gs) { if (gs < 0 || gs >= ARRAY_SIZE(gp_state_names)) return "???"; return gp_state_names[gs]; } /* |
fb81a44b8 rcu: Add GP-kthre... |
1228 1229 1230 1231 1232 1233 1234 1235 |
* Complain about starvation of grace-period kthread. */ static void rcu_check_gp_kthread_starvation(struct rcu_state *rsp) { unsigned long gpa; unsigned long j; j = jiffies; |
7d0ae8086 rcu: Convert ACCE... |
1236 |
gpa = READ_ONCE(rsp->gp_activity); |
b1adb3e27 rcutorture: Dump... |
1237 |
if (j - gpa > 2 * HZ) { |
6b50e119c rcutorture: Print... |
1238 1239 |
pr_err("%s kthread starved for %ld jiffies! g%lu c%lu f%#x %s(%d) ->state=%#lx ", |
81e701e43 rcu: Add more deb... |
1240 |
rsp->name, j - gpa, |
319362c90 rcu: Provide more... |
1241 |
rsp->gpnum, rsp->completed, |
6b50e119c rcutorture: Print... |
1242 1243 |
rsp->gp_flags, gp_state_getname(rsp->gp_state), rsp->gp_state, |
a0e3a3aa2 rcutorture: Flag ... |
1244 |
rsp->gp_kthread ? rsp->gp_kthread->state : ~0); |
86057b80a rcu: Awaken grace... |
1245 |
if (rsp->gp_kthread) { |
b1adb3e27 rcutorture: Dump... |
1246 |
sched_show_task(rsp->gp_kthread); |
86057b80a rcu: Awaken grace... |
1247 1248 |
wake_up_process(rsp->gp_kthread); } |
b1adb3e27 rcutorture: Dump... |
1249 |
} |
64db4cfff "Tree RCU": scala... |
1250 |
} |
b637a328b rcu: Print remote... |
1251 |
/* |
bc1dce514 rcu: Don't use NM... |
1252 |
* Dump stacks of all tasks running on stalled CPUs. |
b637a328b rcu: Print remote... |
1253 1254 1255 1256 1257 1258 1259 1260 |
*/ static void rcu_dump_cpu_stacks(struct rcu_state *rsp) { int cpu; unsigned long flags; struct rcu_node *rnp; rcu_for_each_leaf_node(rsp, rnp) { |
6cf100812 rcu: Add transiti... |
1261 |
raw_spin_lock_irqsave_rcu_node(rnp, flags); |
b637a328b rcu: Print remote... |
1262 |
if (rnp->qsmask != 0) { |
bc75e9998 rcu: Correctly ha... |
1263 1264 1265 |
for_each_leaf_node_possible_cpu(rnp, cpu) if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu)) dump_cpu_task(cpu); |
b637a328b rcu: Print remote... |
1266 |
} |
67c583a7d RCU: Privatize rc... |
1267 |
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); |
b637a328b rcu: Print remote... |
1268 1269 |
} } |
8c7c4829a rcu: Awaken grace... |
1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 |
/* * If too much time has passed in the current grace period, and if * so configured, go kick the relevant kthreads. */ static void rcu_stall_kick_kthreads(struct rcu_state *rsp) { unsigned long j; if (!rcu_kick_kthreads) return; j = READ_ONCE(rsp->jiffies_kick_kthreads); if (time_after(jiffies, j) && rsp->gp_kthread) { WARN_ONCE(1, "Kicking %s grace-period kthread ", rsp->name); |
5dffed1e5 rcu: Dump ftrace ... |
1284 |
rcu_ftrace_dump(DUMP_ALL); |
8c7c4829a rcu: Awaken grace... |
1285 1286 1287 1288 |
wake_up_process(rsp->gp_kthread); WRITE_ONCE(rsp->jiffies_kick_kthreads, j + HZ); } } |
088e9d253 rcu: sysctl: Pani... |
1289 1290 1291 1292 1293 1294 |
static inline void panic_on_rcu_stall(void) { if (sysctl_panic_on_rcu_stall) panic("RCU Stall "); } |
6ccd2ecd4 rcu: Improve diag... |
1295 |
static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum) |
64db4cfff "Tree RCU": scala... |
1296 1297 1298 1299 |
{ int cpu; long delta; unsigned long flags; |
6ccd2ecd4 rcu: Improve diag... |
1300 1301 |
unsigned long gpa; unsigned long j; |
285fe2948 rcu: Fix detectio... |
1302 |
int ndetected = 0; |
64db4cfff "Tree RCU": scala... |
1303 |
struct rcu_node *rnp = rcu_get_root(rsp); |
53bb857c3 rcu: Dump number ... |
1304 |
long totqlen = 0; |
64db4cfff "Tree RCU": scala... |
1305 |
|
8c7c4829a rcu: Awaken grace... |
1306 1307 1308 1309 |
/* Kick and suppress, if so configured. */ rcu_stall_kick_kthreads(rsp); if (rcu_cpu_stall_suppress) return; |
64db4cfff "Tree RCU": scala... |
1310 |
/* Only let one CPU complain about others per time interval. */ |
6cf100812 rcu: Add transiti... |
1311 |
raw_spin_lock_irqsave_rcu_node(rnp, flags); |
7d0ae8086 rcu: Convert ACCE... |
1312 |
delta = jiffies - READ_ONCE(rsp->jiffies_stall); |
fc2219d49 rcu: Clean up cod... |
1313 |
if (delta < RCU_STALL_RAT_DELAY || !rcu_gp_in_progress(rsp)) { |
67c583a7d RCU: Privatize rc... |
1314 |
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); |
64db4cfff "Tree RCU": scala... |
1315 1316 |
return; } |
7d0ae8086 rcu: Convert ACCE... |
1317 1318 |
WRITE_ONCE(rsp->jiffies_stall, jiffies + 3 * rcu_jiffies_till_stall_check() + 3); |
67c583a7d RCU: Privatize rc... |
1319 |
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); |
64db4cfff "Tree RCU": scala... |
1320 |
|
8cdd32a91 rcu: refer RCU CP... |
1321 1322 1323 1324 1325 |
/* * OK, time to rat on our buddy... * See Documentation/RCU/stallwarn.txt for info on how to debug * RCU CPU stall warnings. */ |
d7f3e2073 rcu: Convert rcut... |
1326 |
pr_err("INFO: %s detected stalls on CPUs/tasks:", |
4300aa642 rcu: improve RCU ... |
1327 |
rsp->name); |
a858af287 rcu: Print schedu... |
1328 |
print_cpu_stall_info_begin(); |
a0b6c9a78 rcu: Clean up cod... |
1329 |
rcu_for_each_leaf_node(rsp, rnp) { |
6cf100812 rcu: Add transiti... |
1330 |
raw_spin_lock_irqsave_rcu_node(rnp, flags); |
9bc8b5586 rcu: Suppress NMI... |
1331 |
ndetected += rcu_print_task_stall(rnp); |
c8020a67e rcu: Protect rcu_... |
1332 |
if (rnp->qsmask != 0) { |
bc75e9998 rcu: Correctly ha... |
1333 1334 1335 |
for_each_leaf_node_possible_cpu(rnp, cpu) if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu)) { print_cpu_stall_info(rsp, cpu); |
c8020a67e rcu: Protect rcu_... |
1336 1337 1338 |
ndetected++; } } |
67c583a7d RCU: Privatize rc... |
1339 |
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); |
64db4cfff "Tree RCU": scala... |
1340 |
} |
a858af287 rcu: Print schedu... |
1341 |
|
a858af287 rcu: Print schedu... |
1342 |
print_cpu_stall_info_end(); |
53bb857c3 rcu: Dump number ... |
1343 1344 |
for_each_possible_cpu(cpu) totqlen += per_cpu_ptr(rsp->rda, cpu)->qlen; |
83ebe63ea rcu: Print negati... |
1345 1346 |
pr_cont("(detected by %d, t=%ld jiffies, g=%ld, c=%ld, q=%lu) ", |
eee058826 rcu: Add grace-pe... |
1347 |
smp_processor_id(), (long)(jiffies - rsp->gp_start), |
83ebe63ea rcu: Print negati... |
1348 |
(long)rsp->gpnum, (long)rsp->completed, totqlen); |
6ccd2ecd4 rcu: Improve diag... |
1349 |
if (ndetected) { |
b637a328b rcu: Print remote... |
1350 |
rcu_dump_cpu_stacks(rsp); |
6ccd2ecd4 rcu: Improve diag... |
1351 |
} else { |
7d0ae8086 rcu: Convert ACCE... |
1352 1353 |
if (READ_ONCE(rsp->gpnum) != gpnum || READ_ONCE(rsp->completed) == gpnum) { |
6ccd2ecd4 rcu: Improve diag... |
1354 1355 1356 1357 |
pr_err("INFO: Stall ended before state dump start "); } else { j = jiffies; |
7d0ae8086 rcu: Convert ACCE... |
1358 |
gpa = READ_ONCE(rsp->gp_activity); |
237a0f219 rcu: Detect stall... |
1359 1360 |
pr_err("All QSes seen, last %s kthread activity %ld (%ld-%ld), jiffies_till_next_fqs=%ld, root ->qsmask %#lx ", |
6ccd2ecd4 rcu: Improve diag... |
1361 |
rsp->name, j - gpa, j, gpa, |
237a0f219 rcu: Detect stall... |
1362 1363 |
jiffies_till_next_fqs, rcu_get_root(rsp)->qsmask); |
6ccd2ecd4 rcu: Improve diag... |
1364 1365 1366 1367 |
/* In this case, the current CPU might be at fault. */ sched_show_task(current); } } |
c1dc0b9c0 debug lockups: Im... |
1368 |
|
4cdfc175c rcu: Move quiesce... |
1369 |
/* Complain about tasks blocking the grace period. */ |
1ed509a22 rcu: Add RCU_CPU_... |
1370 |
rcu_print_detail_task_stall(rsp); |
fb81a44b8 rcu: Add GP-kthre... |
1371 |
rcu_check_gp_kthread_starvation(rsp); |
088e9d253 rcu: sysctl: Pani... |
1372 |
panic_on_rcu_stall(); |
4cdfc175c rcu: Move quiesce... |
1373 |
force_quiescent_state(rsp); /* Kick them all. */ |
64db4cfff "Tree RCU": scala... |
1374 1375 1376 1377 |
} static void print_cpu_stall(struct rcu_state *rsp) { |
53bb857c3 rcu: Dump number ... |
1378 |
int cpu; |
64db4cfff "Tree RCU": scala... |
1379 1380 |
unsigned long flags; struct rcu_node *rnp = rcu_get_root(rsp); |
53bb857c3 rcu: Dump number ... |
1381 |
long totqlen = 0; |
64db4cfff "Tree RCU": scala... |
1382 |
|
8c7c4829a rcu: Awaken grace... |
1383 1384 1385 1386 |
/* Kick and suppress, if so configured. */ rcu_stall_kick_kthreads(rsp); if (rcu_cpu_stall_suppress) return; |
8cdd32a91 rcu: refer RCU CP... |
1387 1388 1389 1390 1391 |
/* * OK, time to rat on ourselves... * See Documentation/RCU/stallwarn.txt for info on how to debug * RCU CPU stall warnings. */ |
d7f3e2073 rcu: Convert rcut... |
1392 |
pr_err("INFO: %s self-detected stall on CPU", rsp->name); |
a858af287 rcu: Print schedu... |
1393 1394 1395 |
print_cpu_stall_info_begin(); print_cpu_stall_info(rsp, smp_processor_id()); print_cpu_stall_info_end(); |
53bb857c3 rcu: Dump number ... |
1396 1397 |
for_each_possible_cpu(cpu) totqlen += per_cpu_ptr(rsp->rda, cpu)->qlen; |
83ebe63ea rcu: Print negati... |
1398 1399 1400 1401 |
pr_cont(" (t=%lu jiffies g=%ld c=%ld q=%lu) ", jiffies - rsp->gp_start, (long)rsp->gpnum, (long)rsp->completed, totqlen); |
fb81a44b8 rcu: Add GP-kthre... |
1402 1403 |
rcu_check_gp_kthread_starvation(rsp); |
bc1dce514 rcu: Don't use NM... |
1404 |
rcu_dump_cpu_stacks(rsp); |
c1dc0b9c0 debug lockups: Im... |
1405 |
|
6cf100812 rcu: Add transiti... |
1406 |
raw_spin_lock_irqsave_rcu_node(rnp, flags); |
7d0ae8086 rcu: Convert ACCE... |
1407 1408 1409 |
if (ULONG_CMP_GE(jiffies, READ_ONCE(rsp->jiffies_stall))) WRITE_ONCE(rsp->jiffies_stall, jiffies + 3 * rcu_jiffies_till_stall_check() + 3); |
67c583a7d RCU: Privatize rc... |
1410 |
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); |
c1dc0b9c0 debug lockups: Im... |
1411 |
|
088e9d253 rcu: sysctl: Pani... |
1412 |
panic_on_rcu_stall(); |
b021fe3e2 sched, rcu: Make ... |
1413 1414 1415 1416 1417 1418 1419 1420 |
/* * Attempt to revive the RCU machinery by forcing a context switch. * * A context switch would normally allow the RCU state machine to make * progress and it could be we're stuck in kernel space without context * switches for an entirely unreasonable amount of time. */ resched_cpu(smp_processor_id()); |
64db4cfff "Tree RCU": scala... |
1421 1422 1423 1424 |
} static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp) { |
26cdfedf6 rcu: Reject memor... |
1425 1426 1427 |
unsigned long completed; unsigned long gpnum; unsigned long gps; |
bad6e1393 rcu: get rid of s... |
1428 1429 |
unsigned long j; unsigned long js; |
64db4cfff "Tree RCU": scala... |
1430 |
struct rcu_node *rnp; |
8c7c4829a rcu: Awaken grace... |
1431 1432 |
if ((rcu_cpu_stall_suppress && !rcu_kick_kthreads) || !rcu_gp_in_progress(rsp)) |
c68de2097 rcu: disable CPU ... |
1433 |
return; |
8c7c4829a rcu: Awaken grace... |
1434 |
rcu_stall_kick_kthreads(rsp); |
cb1e78cfa rcu: Remove ACCES... |
1435 |
j = jiffies; |
26cdfedf6 rcu: Reject memor... |
1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 |
/* * Lots of memory barriers to reject false positives. * * The idea is to pick up rsp->gpnum, then rsp->jiffies_stall, * then rsp->gp_start, and finally rsp->completed. These values * are updated in the opposite order with memory barriers (or * equivalent) during grace-period initialization and cleanup. * Now, a false positive can occur if we get an new value of * rsp->gp_start and a old value of rsp->jiffies_stall. But given * the memory barriers, the only way that this can happen is if one * grace period ends and another starts between these two fetches. * Detect this by comparing rsp->completed with the previous fetch * from rsp->gpnum. * * Given this check, comparisons of jiffies, rsp->jiffies_stall, * and rsp->gp_start suffice to forestall false positives. */ |
7d0ae8086 rcu: Convert ACCE... |
1454 |
gpnum = READ_ONCE(rsp->gpnum); |
26cdfedf6 rcu: Reject memor... |
1455 |
smp_rmb(); /* Pick up ->gpnum first... */ |
7d0ae8086 rcu: Convert ACCE... |
1456 |
js = READ_ONCE(rsp->jiffies_stall); |
26cdfedf6 rcu: Reject memor... |
1457 |
smp_rmb(); /* ...then ->jiffies_stall before the rest... */ |
7d0ae8086 rcu: Convert ACCE... |
1458 |
gps = READ_ONCE(rsp->gp_start); |
26cdfedf6 rcu: Reject memor... |
1459 |
smp_rmb(); /* ...and finally ->gp_start before ->completed. */ |
7d0ae8086 rcu: Convert ACCE... |
1460 |
completed = READ_ONCE(rsp->completed); |
26cdfedf6 rcu: Reject memor... |
1461 1462 1463 1464 |
if (ULONG_CMP_GE(completed, gpnum) || ULONG_CMP_LT(j, js) || ULONG_CMP_GE(gps, js)) return; /* No stall or GP completed since entering function. */ |
64db4cfff "Tree RCU": scala... |
1465 |
rnp = rdp->mynode; |
c96ea7cfd rcu: Avoid spurio... |
1466 |
if (rcu_gp_in_progress(rsp) && |
7d0ae8086 rcu: Convert ACCE... |
1467 |
(READ_ONCE(rnp->qsmask) & rdp->grpmask)) { |
64db4cfff "Tree RCU": scala... |
1468 1469 1470 |
/* We haven't checked in, so go dump stack. */ print_cpu_stall(rsp); |
bad6e1393 rcu: get rid of s... |
1471 1472 |
} else if (rcu_gp_in_progress(rsp) && ULONG_CMP_GE(j, js + RCU_STALL_RAT_DELAY)) { |
64db4cfff "Tree RCU": scala... |
1473 |
|
bad6e1393 rcu: get rid of s... |
1474 |
/* They had a few time units to dump stack, so complain. */ |
6ccd2ecd4 rcu: Improve diag... |
1475 |
print_other_cpu_stall(rsp, gpnum); |
64db4cfff "Tree RCU": scala... |
1476 1477 |
} } |
53d84e004 rcu: permit suppr... |
1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 |
/** * rcu_cpu_stall_reset - prevent further stall warnings in current grace period * * Set the stall-warning timeout way off into the future, thus preventing * any RCU CPU stall-warning messages from appearing in the current set of * RCU grace periods. * * The caller must disable hard irqs. */ void rcu_cpu_stall_reset(void) { |
6ce75a232 rcu: Introduce fo... |
1489 1490 1491 |
struct rcu_state *rsp; for_each_rcu_flavor(rsp) |
7d0ae8086 rcu: Convert ACCE... |
1492 |
WRITE_ONCE(rsp->jiffies_stall, jiffies + ULONG_MAX / 2); |
53d84e004 rcu: permit suppr... |
1493 |
} |
64db4cfff "Tree RCU": scala... |
1494 |
/* |
d3f3f3f25 rcu: Abstract def... |
1495 1496 1497 |
* Initialize the specified rcu_data structure's default callback list * to empty. The default callback list is the one that is not used by * no-callbacks CPUs. |
3f5d3ea64 rcu: Consolidate ... |
1498 |
*/ |
d3f3f3f25 rcu: Abstract def... |
1499 |
static void init_default_callback_list(struct rcu_data *rdp) |
3f5d3ea64 rcu: Consolidate ... |
1500 1501 1502 1503 1504 1505 1506 1507 1508 |
{ int i; rdp->nxtlist = NULL; for (i = 0; i < RCU_NEXT_SIZE; i++) rdp->nxttail[i] = &rdp->nxtlist; } /* |
d3f3f3f25 rcu: Abstract def... |
1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 |
* Initialize the specified rcu_data structure's callback list to empty. */ static void init_callback_list(struct rcu_data *rdp) { if (init_nocb_callback_list(rdp)) return; init_default_callback_list(rdp); } /* |
dc35c8934 rcu: Tag callback... |
1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 |
* Determine the value that ->completed will have at the end of the * next subsequent grace period. This is used to tag callbacks so that * a CPU can invoke callbacks in a timely fashion even if that CPU has * been dyntick-idle for an extended period with callbacks under the * influence of RCU_FAST_NO_HZ. * * The caller must hold rnp->lock with interrupts disabled. */ static unsigned long rcu_cbs_completed(struct rcu_state *rsp, struct rcu_node *rnp) { /* * If RCU is idle, we just wait for the next grace period. * But we can only be sure that RCU is idle if we are looking * at the root rcu_node structure -- otherwise, a new grace * period might have started, but just not yet gotten around * to initializing the current non-root rcu_node structure. */ if (rcu_get_root(rsp) == rnp && rnp->gpnum == rnp->completed) return rnp->completed + 1; /* * Otherwise, wait for a possible partial grace period and * then the subsequent full grace period. */ return rnp->completed + 2; } /* |
0446be489 rcu: Abstract rcu... |
1548 1549 1550 1551 |
* Trace-event helper function for rcu_start_future_gp() and * rcu_nocb_wait_gp(). */ static void trace_rcu_future_gp(struct rcu_node *rnp, struct rcu_data *rdp, |
e66c33d57 rcu: Add const an... |
1552 |
unsigned long c, const char *s) |
0446be489 rcu: Abstract rcu... |
1553 1554 1555 1556 1557 1558 1559 1560 1561 |
{ trace_rcu_future_grace_period(rdp->rsp->name, rnp->gpnum, rnp->completed, c, rnp->level, rnp->grplo, rnp->grphi, s); } /* * Start some future grace period, as needed to handle newly arrived * callbacks. The required future grace periods are recorded in each |
48a7639ce rcu: Make callers... |
1562 1563 |
* rcu_node structure's ->need_future_gp field. Returns true if there * is reason to awaken the grace-period kthread. |
0446be489 rcu: Abstract rcu... |
1564 1565 1566 |
* * The caller must hold the specified rcu_node structure's ->lock. */ |
48a7639ce rcu: Make callers... |
1567 1568 1569 |
static bool __maybe_unused rcu_start_future_gp(struct rcu_node *rnp, struct rcu_data *rdp, unsigned long *c_out) |
0446be489 rcu: Abstract rcu... |
1570 1571 1572 |
{ unsigned long c; int i; |
48a7639ce rcu: Make callers... |
1573 |
bool ret = false; |
0446be489 rcu: Abstract rcu... |
1574 1575 1576 1577 1578 1579 1580 |
struct rcu_node *rnp_root = rcu_get_root(rdp->rsp); /* * Pick up grace-period number for new callbacks. If this * grace period is already marked as needed, return to the caller. */ c = rcu_cbs_completed(rdp->rsp, rnp); |
f7f7bac9c rcu: Have the RCU... |
1581 |
trace_rcu_future_gp(rnp, rdp, c, TPS("Startleaf")); |
0446be489 rcu: Abstract rcu... |
1582 |
if (rnp->need_future_gp[c & 0x1]) { |
f7f7bac9c rcu: Have the RCU... |
1583 |
trace_rcu_future_gp(rnp, rdp, c, TPS("Prestartleaf")); |
48a7639ce rcu: Make callers... |
1584 |
goto out; |
0446be489 rcu: Abstract rcu... |
1585 1586 1587 1588 1589 1590 1591 |
} /* * If either this rcu_node structure or the root rcu_node structure * believe that a grace period is in progress, then we must wait * for the one following, which is in "c". Because our request * will be noticed at the end of the current grace period, we don't |
48bd8e9b8 rcu: Check both r... |
1592 1593 1594 1595 1596 1597 1598 |
* need to explicitly start one. We only do the lockless check * of rnp_root's fields if the current rcu_node structure thinks * there is no grace period in flight, and because we hold rnp->lock, * the only possible change is when rnp_root's two fields are * equal, in which case rnp_root->gpnum might be concurrently * incremented. But that is OK, as it will just result in our * doing some extra useless work. |
0446be489 rcu: Abstract rcu... |
1599 1600 |
*/ if (rnp->gpnum != rnp->completed || |
7d0ae8086 rcu: Convert ACCE... |
1601 |
READ_ONCE(rnp_root->gpnum) != READ_ONCE(rnp_root->completed)) { |
0446be489 rcu: Abstract rcu... |
1602 |
rnp->need_future_gp[c & 0x1]++; |
f7f7bac9c rcu: Have the RCU... |
1603 |
trace_rcu_future_gp(rnp, rdp, c, TPS("Startedleaf")); |
48a7639ce rcu: Make callers... |
1604 |
goto out; |
0446be489 rcu: Abstract rcu... |
1605 1606 1607 1608 1609 1610 1611 |
} /* * There might be no grace period in progress. If we don't already * hold it, acquire the root rcu_node structure's lock in order to * start one (if needed). */ |
2a67e741b rcu: Create trans... |
1612 1613 |
if (rnp != rnp_root) raw_spin_lock_rcu_node(rnp_root); |
0446be489 rcu: Abstract rcu... |
1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 |
/* * Get a new grace-period number. If there really is no grace * period in progress, it will be smaller than the one we obtained * earlier. Adjust callbacks as needed. Note that even no-CBs * CPUs have a ->nxtcompleted[] array, so no no-CBs checks needed. */ c = rcu_cbs_completed(rdp->rsp, rnp_root); for (i = RCU_DONE_TAIL; i < RCU_NEXT_TAIL; i++) if (ULONG_CMP_LT(c, rdp->nxtcompleted[i])) rdp->nxtcompleted[i] = c; /* * If the needed for the required grace period is already * recorded, trace and leave. */ if (rnp_root->need_future_gp[c & 0x1]) { |
f7f7bac9c rcu: Have the RCU... |
1631 |
trace_rcu_future_gp(rnp, rdp, c, TPS("Prestartedroot")); |
0446be489 rcu: Abstract rcu... |
1632 1633 1634 1635 1636 1637 1638 1639 |
goto unlock_out; } /* Record the need for the future grace period. */ rnp_root->need_future_gp[c & 0x1]++; /* If a grace period is not already in progress, start one. */ if (rnp_root->gpnum != rnp_root->completed) { |
f7f7bac9c rcu: Have the RCU... |
1640 |
trace_rcu_future_gp(rnp, rdp, c, TPS("Startedleafroot")); |
0446be489 rcu: Abstract rcu... |
1641 |
} else { |
f7f7bac9c rcu: Have the RCU... |
1642 |
trace_rcu_future_gp(rnp, rdp, c, TPS("Startedroot")); |
48a7639ce rcu: Make callers... |
1643 |
ret = rcu_start_gp_advanced(rdp->rsp, rnp_root, rdp); |
0446be489 rcu: Abstract rcu... |
1644 1645 1646 |
} unlock_out: if (rnp != rnp_root) |
67c583a7d RCU: Privatize rc... |
1647 |
raw_spin_unlock_rcu_node(rnp_root); |
48a7639ce rcu: Make callers... |
1648 1649 1650 1651 |
out: if (c_out != NULL) *c_out = c; return ret; |
0446be489 rcu: Abstract rcu... |
1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 |
} /* * Clean up any old requests for the just-ended grace period. Also return * whether any additional grace periods have been requested. Also invoke * rcu_nocb_gp_cleanup() in order to wake up any no-callbacks kthreads * waiting for this grace period to complete. */ static int rcu_future_gp_cleanup(struct rcu_state *rsp, struct rcu_node *rnp) { int c = rnp->completed; int needmore; struct rcu_data *rdp = this_cpu_ptr(rsp->rda); |
0446be489 rcu: Abstract rcu... |
1665 1666 |
rnp->need_future_gp[c & 0x1] = 0; needmore = rnp->need_future_gp[(c + 1) & 0x1]; |
f7f7bac9c rcu: Have the RCU... |
1667 1668 |
trace_rcu_future_gp(rnp, rdp, c, needmore ? TPS("CleanupMore") : TPS("Cleanup")); |
0446be489 rcu: Abstract rcu... |
1669 1670 1671 1672 |
return needmore; } /* |
48a7639ce rcu: Make callers... |
1673 1674 1675 1676 1677 1678 1679 1680 1681 |
* Awaken the grace-period kthread for the specified flavor of RCU. * Don't do a self-awaken, and don't bother awakening when there is * nothing for the grace-period kthread to do (as in several CPUs * raced to awaken, and we lost), and finally don't try to awaken * a kthread that has not yet been created. */ static void rcu_gp_kthread_wake(struct rcu_state *rsp) { if (current == rsp->gp_kthread || |
7d0ae8086 rcu: Convert ACCE... |
1682 |
!READ_ONCE(rsp->gp_flags) || |
48a7639ce rcu: Make callers... |
1683 1684 |
!rsp->gp_kthread) return; |
abedf8e24 rcu: Use simple w... |
1685 |
swake_up(&rsp->gp_wq); |
48a7639ce rcu: Make callers... |
1686 1687 1688 |
} /* |
dc35c8934 rcu: Tag callback... |
1689 1690 1691 1692 1693 1694 |
* If there is room, assign a ->completed number to any callbacks on * this CPU that have not already been assigned. Also accelerate any * callbacks that were previously assigned a ->completed number that has * since proven to be too conservative, which can happen if callbacks get * assigned a ->completed number while RCU is idle, but with reference to * a non-root rcu_node structure. This function is idempotent, so it does |
48a7639ce rcu: Make callers... |
1695 1696 |
* not hurt to call it repeatedly. Returns an flag saying that we should * awaken the RCU grace-period kthread. |
dc35c8934 rcu: Tag callback... |
1697 1698 1699 |
* * The caller must hold rnp->lock with interrupts disabled. */ |
48a7639ce rcu: Make callers... |
1700 |
static bool rcu_accelerate_cbs(struct rcu_state *rsp, struct rcu_node *rnp, |
dc35c8934 rcu: Tag callback... |
1701 1702 1703 1704 |
struct rcu_data *rdp) { unsigned long c; int i; |
48a7639ce rcu: Make callers... |
1705 |
bool ret; |
dc35c8934 rcu: Tag callback... |
1706 1707 1708 |
/* If the CPU has no callbacks, nothing to do. */ if (!rdp->nxttail[RCU_NEXT_TAIL] || !*rdp->nxttail[RCU_DONE_TAIL]) |
48a7639ce rcu: Make callers... |
1709 |
return false; |
dc35c8934 rcu: Tag callback... |
1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 |
/* * Starting from the sublist containing the callbacks most * recently assigned a ->completed number and working down, find the * first sublist that is not assignable to an upcoming grace period. * Such a sublist has something in it (first two tests) and has * a ->completed number assigned that will complete sooner than * the ->completed number for newly arrived callbacks (last test). * * The key point is that any later sublist can be assigned the * same ->completed number as the newly arrived callbacks, which * means that the callbacks in any of these later sublist can be * grouped into a single sublist, whether or not they have already * been assigned a ->completed number. */ c = rcu_cbs_completed(rsp, rnp); for (i = RCU_NEXT_TAIL - 1; i > RCU_DONE_TAIL; i--) if (rdp->nxttail[i] != rdp->nxttail[i - 1] && !ULONG_CMP_GE(rdp->nxtcompleted[i], c)) break; /* * If there are no sublist for unassigned callbacks, leave. * At the same time, advance "i" one sublist, so that "i" will * index into the sublist where all the remaining callbacks should * be grouped into. */ if (++i >= RCU_NEXT_TAIL) |
48a7639ce rcu: Make callers... |
1738 |
return false; |
dc35c8934 rcu: Tag callback... |
1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 |
/* * Assign all subsequent callbacks' ->completed number to the next * full grace period and group them all in the sublist initially * indexed by "i". */ for (; i <= RCU_NEXT_TAIL; i++) { rdp->nxttail[i] = rdp->nxttail[RCU_NEXT_TAIL]; rdp->nxtcompleted[i] = c; } |
910ee45db rcu: Make rcu_acc... |
1749 |
/* Record any needed additional grace periods. */ |
48a7639ce rcu: Make callers... |
1750 |
ret = rcu_start_future_gp(rnp, rdp, NULL); |
6d4b418c7 rcu: Trace callba... |
1751 1752 1753 |
/* Trace depending on how much we were able to accelerate. */ if (!*rdp->nxttail[RCU_WAIT_TAIL]) |
f7f7bac9c rcu: Have the RCU... |
1754 |
trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("AccWaitCB")); |
6d4b418c7 rcu: Trace callba... |
1755 |
else |
f7f7bac9c rcu: Have the RCU... |
1756 |
trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("AccReadyCB")); |
48a7639ce rcu: Make callers... |
1757 |
return ret; |
dc35c8934 rcu: Tag callback... |
1758 1759 1760 1761 1762 1763 1764 1765 |
} /* * Move any callbacks whose grace period has completed to the * RCU_DONE_TAIL sublist, then compact the remaining sublists and * assign ->completed numbers to any callbacks in the RCU_NEXT_TAIL * sublist. This function is idempotent, so it does not hurt to * invoke it repeatedly. As long as it is not invoked -too- often... |
48a7639ce rcu: Make callers... |
1766 |
* Returns true if the RCU grace-period kthread needs to be awakened. |
dc35c8934 rcu: Tag callback... |
1767 1768 1769 |
* * The caller must hold rnp->lock with interrupts disabled. */ |
48a7639ce rcu: Make callers... |
1770 |
static bool rcu_advance_cbs(struct rcu_state *rsp, struct rcu_node *rnp, |
dc35c8934 rcu: Tag callback... |
1771 1772 1773 1774 1775 1776 |
struct rcu_data *rdp) { int i, j; /* If the CPU has no callbacks, nothing to do. */ if (!rdp->nxttail[RCU_NEXT_TAIL] || !*rdp->nxttail[RCU_DONE_TAIL]) |
48a7639ce rcu: Make callers... |
1777 |
return false; |
dc35c8934 rcu: Tag callback... |
1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 |
/* * Find all callbacks whose ->completed numbers indicate that they * are ready to invoke, and put them into the RCU_DONE_TAIL sublist. */ for (i = RCU_WAIT_TAIL; i < RCU_NEXT_TAIL; i++) { if (ULONG_CMP_LT(rnp->completed, rdp->nxtcompleted[i])) break; rdp->nxttail[RCU_DONE_TAIL] = rdp->nxttail[i]; } /* Clean up any sublist tail pointers that were misordered above. */ for (j = RCU_WAIT_TAIL; j < i; j++) rdp->nxttail[j] = rdp->nxttail[RCU_DONE_TAIL]; /* Copy down callbacks to fill in empty sublists. */ for (j = RCU_WAIT_TAIL; i < RCU_NEXT_TAIL; i++, j++) { if (rdp->nxttail[j] == rdp->nxttail[RCU_NEXT_TAIL]) break; rdp->nxttail[j] = rdp->nxttail[i]; rdp->nxtcompleted[j] = rdp->nxtcompleted[i]; } /* Classify any remaining callbacks. */ |
48a7639ce rcu: Make callers... |
1801 |
return rcu_accelerate_cbs(rsp, rnp, rdp); |
dc35c8934 rcu: Tag callback... |
1802 1803 1804 |
} /* |
ba9fbe955 rcu: Merge __rcu_... |
1805 1806 1807 |
* Update CPU-local rcu_data state to record the beginnings and ends of * grace periods. The caller must hold the ->lock of the leaf rcu_node * structure corresponding to the current CPU, and must have irqs disabled. |
48a7639ce rcu: Make callers... |
1808 |
* Returns true if the grace-period kthread needs to be awakened. |
d09b62dfa rcu: Fix synchron... |
1809 |
*/ |
48a7639ce rcu: Make callers... |
1810 1811 |
static bool __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp, struct rcu_data *rdp) |
d09b62dfa rcu: Fix synchron... |
1812 |
{ |
48a7639ce rcu: Make callers... |
1813 |
bool ret; |
3563a438f rcu: Avoid redund... |
1814 |
bool need_gp; |
48a7639ce rcu: Make callers... |
1815 |
|
ba9fbe955 rcu: Merge __rcu_... |
1816 |
/* Handle the ends of any preceding grace periods first. */ |
e3663b102 rcu: Handle gpnum... |
1817 |
if (rdp->completed == rnp->completed && |
7d0ae8086 rcu: Convert ACCE... |
1818 |
!unlikely(READ_ONCE(rdp->gpwrap))) { |
d09b62dfa rcu: Fix synchron... |
1819 |
|
ba9fbe955 rcu: Merge __rcu_... |
1820 |
/* No grace period end, so just accelerate recent callbacks. */ |
48a7639ce rcu: Make callers... |
1821 |
ret = rcu_accelerate_cbs(rsp, rnp, rdp); |
d09b62dfa rcu: Fix synchron... |
1822 |
|
dc35c8934 rcu: Tag callback... |
1823 1824 1825 |
} else { /* Advance callbacks. */ |
48a7639ce rcu: Make callers... |
1826 |
ret = rcu_advance_cbs(rsp, rnp, rdp); |
d09b62dfa rcu: Fix synchron... |
1827 1828 1829 |
/* Remember that we saw this grace-period completion. */ rdp->completed = rnp->completed; |
f7f7bac9c rcu: Have the RCU... |
1830 |
trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("cpuend")); |
d09b62dfa rcu: Fix synchron... |
1831 |
} |
398ebe600 rcu: Make __note_... |
1832 |
|
7d0ae8086 rcu: Convert ACCE... |
1833 |
if (rdp->gpnum != rnp->gpnum || unlikely(READ_ONCE(rdp->gpwrap))) { |
6eaef633d rcu: Move code to... |
1834 1835 1836 1837 1838 1839 |
/* * If the current grace period is waiting for this CPU, * set up to detect a quiescent state, otherwise don't * go looking for one. */ rdp->gpnum = rnp->gpnum; |
f7f7bac9c rcu: Have the RCU... |
1840 |
trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("cpustart")); |
3563a438f rcu: Avoid redund... |
1841 1842 |
need_gp = !!(rnp->qsmask & rdp->grpmask); rdp->cpu_no_qs.b.norm = need_gp; |
5cd37193c rcu: Make cond_re... |
1843 |
rdp->rcu_qs_ctr_snap = __this_cpu_read(rcu_qs_ctr); |
3563a438f rcu: Avoid redund... |
1844 |
rdp->core_needs_qs = need_gp; |
6eaef633d rcu: Move code to... |
1845 |
zero_cpu_stall_ticks(rdp); |
7d0ae8086 rcu: Convert ACCE... |
1846 |
WRITE_ONCE(rdp->gpwrap, false); |
6eaef633d rcu: Move code to... |
1847 |
} |
48a7639ce rcu: Make callers... |
1848 |
return ret; |
6eaef633d rcu: Move code to... |
1849 |
} |
d34ea3221 rcu: Rename note_... |
1850 |
static void note_gp_changes(struct rcu_state *rsp, struct rcu_data *rdp) |
6eaef633d rcu: Move code to... |
1851 1852 |
{ unsigned long flags; |
48a7639ce rcu: Make callers... |
1853 |
bool needwake; |
6eaef633d rcu: Move code to... |
1854 1855 1856 1857 |
struct rcu_node *rnp; local_irq_save(flags); rnp = rdp->mynode; |
7d0ae8086 rcu: Convert ACCE... |
1858 1859 1860 |
if ((rdp->gpnum == READ_ONCE(rnp->gpnum) && rdp->completed == READ_ONCE(rnp->completed) && !unlikely(READ_ONCE(rdp->gpwrap))) || /* w/out lock. */ |
2a67e741b rcu: Create trans... |
1861 |
!raw_spin_trylock_rcu_node(rnp)) { /* irqs already off, so later. */ |
6eaef633d rcu: Move code to... |
1862 1863 1864 |
local_irq_restore(flags); return; } |
48a7639ce rcu: Make callers... |
1865 |
needwake = __note_gp_changes(rsp, rnp, rdp); |
67c583a7d RCU: Privatize rc... |
1866 |
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); |
48a7639ce rcu: Make callers... |
1867 1868 |
if (needwake) rcu_gp_kthread_wake(rsp); |
6eaef633d rcu: Move code to... |
1869 |
} |
0f41c0dda rcu: Provide diag... |
1870 1871 1872 1873 1874 1875 |
static void rcu_gp_slow(struct rcu_state *rsp, int delay) { if (delay > 0 && !(rsp->gpnum % (rcu_num_nodes * PER_RCU_NODE_PERIOD * delay))) schedule_timeout_uninterruptible(delay); } |
6eaef633d rcu: Move code to... |
1876 |
/* |
45fed3e7c rcu: Make rcu_gp_... |
1877 |
* Initialize a new grace period. Return false if no grace period required. |
b3dbec76e rcu: Move RCU gra... |
1878 |
*/ |
45fed3e7c rcu: Make rcu_gp_... |
1879 |
static bool rcu_gp_init(struct rcu_state *rsp) |
b3dbec76e rcu: Move RCU gra... |
1880 |
{ |
0aa04b055 rcu: Process offl... |
1881 |
unsigned long oldmask; |
b3dbec76e rcu: Move RCU gra... |
1882 |
struct rcu_data *rdp; |
7fdefc10e rcu: Break up rcu... |
1883 |
struct rcu_node *rnp = rcu_get_root(rsp); |
b3dbec76e rcu: Move RCU gra... |
1884 |
|
7d0ae8086 rcu: Convert ACCE... |
1885 |
WRITE_ONCE(rsp->gp_activity, jiffies); |
2a67e741b rcu: Create trans... |
1886 |
raw_spin_lock_irq_rcu_node(rnp); |
7d0ae8086 rcu: Convert ACCE... |
1887 |
if (!READ_ONCE(rsp->gp_flags)) { |
f7be82093 rcu: Improve grac... |
1888 |
/* Spurious wakeup, tell caller to go back to sleep. */ |
67c583a7d RCU: Privatize rc... |
1889 |
raw_spin_unlock_irq_rcu_node(rnp); |
45fed3e7c rcu: Make rcu_gp_... |
1890 |
return false; |
f7be82093 rcu: Improve grac... |
1891 |
} |
7d0ae8086 rcu: Convert ACCE... |
1892 |
WRITE_ONCE(rsp->gp_flags, 0); /* Clear all flags: New grace period. */ |
b3dbec76e rcu: Move RCU gra... |
1893 |
|
f7be82093 rcu: Improve grac... |
1894 1895 1896 1897 1898 |
if (WARN_ON_ONCE(rcu_gp_in_progress(rsp))) { /* * Grace period already in progress, don't start another. * Not supposed to be able to happen. */ |
67c583a7d RCU: Privatize rc... |
1899 |
raw_spin_unlock_irq_rcu_node(rnp); |
45fed3e7c rcu: Make rcu_gp_... |
1900 |
return false; |
7fdefc10e rcu: Break up rcu... |
1901 |
} |
7fdefc10e rcu: Break up rcu... |
1902 |
/* Advance to a new grace period and initialize state. */ |
26cdfedf6 rcu: Reject memor... |
1903 |
record_gp_stall_check_time(rsp); |
765a3f4fe rcu: Provide grac... |
1904 1905 |
/* Record GP times before starting GP, hence smp_store_release(). */ smp_store_release(&rsp->gpnum, rsp->gpnum + 1); |
f7f7bac9c rcu: Have the RCU... |
1906 |
trace_rcu_grace_period(rsp->name, rsp->gpnum, TPS("start")); |
67c583a7d RCU: Privatize rc... |
1907 |
raw_spin_unlock_irq_rcu_node(rnp); |
7fdefc10e rcu: Break up rcu... |
1908 |
|
7fdefc10e rcu: Break up rcu... |
1909 |
/* |
0aa04b055 rcu: Process offl... |
1910 1911 1912 1913 1914 1915 |
* Apply per-leaf buffered online and offline operations to the * rcu_node tree. Note that this new grace period need not wait * for subsequent online CPUs, and that quiescent-state forcing * will handle subsequent offline CPUs. */ rcu_for_each_leaf_node(rsp, rnp) { |
0f41c0dda rcu: Provide diag... |
1916 |
rcu_gp_slow(rsp, gp_preinit_delay); |
2a67e741b rcu: Create trans... |
1917 |
raw_spin_lock_irq_rcu_node(rnp); |
0aa04b055 rcu: Process offl... |
1918 1919 1920 |
if (rnp->qsmaskinit == rnp->qsmaskinitnext && !rnp->wait_blkd_tasks) { /* Nothing to do on this leaf rcu_node structure. */ |
67c583a7d RCU: Privatize rc... |
1921 |
raw_spin_unlock_irq_rcu_node(rnp); |
0aa04b055 rcu: Process offl... |
1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 |
continue; } /* Record old state, apply changes to ->qsmaskinit field. */ oldmask = rnp->qsmaskinit; rnp->qsmaskinit = rnp->qsmaskinitnext; /* If zero-ness of ->qsmaskinit changed, propagate up tree. */ if (!oldmask != !rnp->qsmaskinit) { if (!oldmask) /* First online CPU for this rcu_node. */ rcu_init_new_rnp(rnp); else if (rcu_preempt_has_tasks(rnp)) /* blocked tasks */ rnp->wait_blkd_tasks = true; else /* Last offline CPU and can propagate. */ rcu_cleanup_dead_rnp(rnp); } /* * If all waited-on tasks from prior grace period are * done, and if all this rcu_node structure's CPUs are * still offline, propagate up the rcu_node tree and * clear ->wait_blkd_tasks. Otherwise, if one of this * rcu_node structure's CPUs has since come back online, * simply clear ->wait_blkd_tasks (but rcu_cleanup_dead_rnp() * checks for this, so just call it unconditionally). */ if (rnp->wait_blkd_tasks && (!rcu_preempt_has_tasks(rnp) || rnp->qsmaskinit)) { rnp->wait_blkd_tasks = false; rcu_cleanup_dead_rnp(rnp); } |
67c583a7d RCU: Privatize rc... |
1954 |
raw_spin_unlock_irq_rcu_node(rnp); |
0aa04b055 rcu: Process offl... |
1955 |
} |
7fdefc10e rcu: Break up rcu... |
1956 1957 1958 1959 1960 1961 1962 1963 |
/* * Set the quiescent-state-needed bits in all the rcu_node * structures for all currently online CPUs in breadth-first order, * starting from the root rcu_node structure, relying on the layout * of the tree within the rsp->node[] array. Note that other CPUs * will access only the leaves of the hierarchy, thus seeing that no * grace period is in progress, at least until the corresponding |
590d1757b rcu: Fix outdated... |
1964 |
* leaf node has been initialized. |
7fdefc10e rcu: Break up rcu... |
1965 1966 1967 1968 1969 |
* * The grace period cannot complete until the initialization * process finishes, because this kthread handles both. */ rcu_for_each_node_breadth_first(rsp, rnp) { |
0f41c0dda rcu: Provide diag... |
1970 |
rcu_gp_slow(rsp, gp_init_delay); |
2a67e741b rcu: Create trans... |
1971 |
raw_spin_lock_irq_rcu_node(rnp); |
b3dbec76e rcu: Move RCU gra... |
1972 |
rdp = this_cpu_ptr(rsp->rda); |
7fdefc10e rcu: Break up rcu... |
1973 1974 |
rcu_preempt_check_blocked_tasks(rnp); rnp->qsmask = rnp->qsmaskinit; |
7d0ae8086 rcu: Convert ACCE... |
1975 |
WRITE_ONCE(rnp->gpnum, rsp->gpnum); |
3f47da0f3 rcu_tree: Avoid t... |
1976 |
if (WARN_ON_ONCE(rnp->completed != rsp->completed)) |
7d0ae8086 rcu: Convert ACCE... |
1977 |
WRITE_ONCE(rnp->completed, rsp->completed); |
7fdefc10e rcu: Break up rcu... |
1978 |
if (rnp == rdp->mynode) |
48a7639ce rcu: Make callers... |
1979 |
(void)__note_gp_changes(rsp, rnp, rdp); |
7fdefc10e rcu: Break up rcu... |
1980 1981 1982 1983 |
rcu_preempt_boost_start_gp(rnp); trace_rcu_grace_period_init(rsp->name, rnp->gpnum, rnp->level, rnp->grplo, rnp->grphi, rnp->qsmask); |
67c583a7d RCU: Privatize rc... |
1984 |
raw_spin_unlock_irq_rcu_node(rnp); |
bde6c3aa9 rcu: Provide cond... |
1985 |
cond_resched_rcu_qs(); |
7d0ae8086 rcu: Convert ACCE... |
1986 |
WRITE_ONCE(rsp->gp_activity, jiffies); |
7fdefc10e rcu: Break up rcu... |
1987 |
} |
b3dbec76e rcu: Move RCU gra... |
1988 |
|
45fed3e7c rcu: Make rcu_gp_... |
1989 |
return true; |
7fdefc10e rcu: Break up rcu... |
1990 |
} |
b3dbec76e rcu: Move RCU gra... |
1991 |
|
7fdefc10e rcu: Break up rcu... |
1992 |
/* |
b9a425cfc rcu: Pull out wai... |
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 |
* Helper function for wait_event_interruptible_timeout() wakeup * at force-quiescent-state time. */ static bool rcu_gp_fqs_check_wake(struct rcu_state *rsp, int *gfp) { struct rcu_node *rnp = rcu_get_root(rsp); /* Someone like call_rcu() requested a force-quiescent-state scan. */ *gfp = READ_ONCE(rsp->gp_flags); if (*gfp & RCU_GP_FLAG_FQS) return true; /* The current grace period has completed. */ if (!READ_ONCE(rnp->qsmask) && !rcu_preempt_blocked_readers_cgp(rnp)) return true; return false; } /* |
4cdfc175c rcu: Move quiesce... |
2013 2014 |
* Do one round of quiescent-state forcing. */ |
77f81fe08 rcu: Finish foldi... |
2015 |
static void rcu_gp_fqs(struct rcu_state *rsp, bool first_time) |
4cdfc175c rcu: Move quiesce... |
2016 |
{ |
217af2a2f nohz_full: Add fu... |
2017 2018 |
bool isidle = false; unsigned long maxj; |
4cdfc175c rcu: Move quiesce... |
2019 |
struct rcu_node *rnp = rcu_get_root(rsp); |
7d0ae8086 rcu: Convert ACCE... |
2020 |
WRITE_ONCE(rsp->gp_activity, jiffies); |
4cdfc175c rcu: Move quiesce... |
2021 |
rsp->n_force_qs++; |
77f81fe08 rcu: Finish foldi... |
2022 |
if (first_time) { |
4cdfc175c rcu: Move quiesce... |
2023 |
/* Collect dyntick-idle snapshots. */ |
0edd1b178 nohz_full: Add fu... |
2024 |
if (is_sysidle_rcu_state(rsp)) { |
e02b2edfa rcu: Use true/fal... |
2025 |
isidle = true; |
0edd1b178 nohz_full: Add fu... |
2026 2027 |
maxj = jiffies - ULONG_MAX / 4; } |
217af2a2f nohz_full: Add fu... |
2028 2029 |
force_qs_rnp(rsp, dyntick_save_progress_counter, &isidle, &maxj); |
0edd1b178 nohz_full: Add fu... |
2030 |
rcu_sysidle_report_gp(rsp, isidle, maxj); |
4cdfc175c rcu: Move quiesce... |
2031 2032 |
} else { /* Handle dyntick-idle and offline CPUs. */ |
675da67f2 rcu: Fixes to NO_... |
2033 |
isidle = true; |
217af2a2f nohz_full: Add fu... |
2034 |
force_qs_rnp(rsp, rcu_implicit_dynticks_qs, &isidle, &maxj); |
4cdfc175c rcu: Move quiesce... |
2035 2036 |
} /* Clear flag to prevent immediate re-entry. */ |
7d0ae8086 rcu: Convert ACCE... |
2037 |
if (READ_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) { |
2a67e741b rcu: Create trans... |
2038 |
raw_spin_lock_irq_rcu_node(rnp); |
7d0ae8086 rcu: Convert ACCE... |
2039 2040 |
WRITE_ONCE(rsp->gp_flags, READ_ONCE(rsp->gp_flags) & ~RCU_GP_FLAG_FQS); |
67c583a7d RCU: Privatize rc... |
2041 |
raw_spin_unlock_irq_rcu_node(rnp); |
4cdfc175c rcu: Move quiesce... |
2042 |
} |
4cdfc175c rcu: Move quiesce... |
2043 2044 2045 |
} /* |
7fdefc10e rcu: Break up rcu... |
2046 2047 |
* Clean up after the old grace period. */ |
4cdfc175c rcu: Move quiesce... |
2048 |
static void rcu_gp_cleanup(struct rcu_state *rsp) |
7fdefc10e rcu: Break up rcu... |
2049 2050 |
{ unsigned long gp_duration; |
48a7639ce rcu: Make callers... |
2051 |
bool needgp = false; |
dae6e64d2 rcu: Introduce pr... |
2052 |
int nocb = 0; |
7fdefc10e rcu: Break up rcu... |
2053 2054 |
struct rcu_data *rdp; struct rcu_node *rnp = rcu_get_root(rsp); |
abedf8e24 rcu: Use simple w... |
2055 |
struct swait_queue_head *sq; |
b3dbec76e rcu: Move RCU gra... |
2056 |
|
7d0ae8086 rcu: Convert ACCE... |
2057 |
WRITE_ONCE(rsp->gp_activity, jiffies); |
2a67e741b rcu: Create trans... |
2058 |
raw_spin_lock_irq_rcu_node(rnp); |
7fdefc10e rcu: Break up rcu... |
2059 2060 2061 |
gp_duration = jiffies - rsp->gp_start; if (gp_duration > rsp->gp_max) rsp->gp_max = gp_duration; |
b3dbec76e rcu: Move RCU gra... |
2062 |
|
7fdefc10e rcu: Break up rcu... |
2063 2064 2065 2066 2067 2068 2069 |
/* * We know the grace period is complete, but to everyone else * it appears to still be ongoing. But it is also the case * that to everyone else it looks like there is nothing that * they can do to advance the grace period. It is therefore * safe for us to drop the lock in order to mark the grace * period as completed in all of the rcu_node structures. |
7fdefc10e rcu: Break up rcu... |
2070 |
*/ |
67c583a7d RCU: Privatize rc... |
2071 |
raw_spin_unlock_irq_rcu_node(rnp); |
b3dbec76e rcu: Move RCU gra... |
2072 |
|
5d4b86594 rcu: Fix day-zero... |
2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 |
/* * Propagate new ->completed value to rcu_node structures so * that other CPUs don't have to wait until the start of the next * grace period to process their callbacks. This also avoids * some nasty RCU grace-period initialization races by forcing * the end of the current grace period to be completely recorded in * all of the rcu_node structures before the beginning of the next * grace period is recorded in any of the rcu_node structures. */ rcu_for_each_node_breadth_first(rsp, rnp) { |
2a67e741b rcu: Create trans... |
2083 |
raw_spin_lock_irq_rcu_node(rnp); |
5c60d25fa rcu: Add diagnost... |
2084 2085 |
WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)); WARN_ON_ONCE(rnp->qsmask); |
7d0ae8086 rcu: Convert ACCE... |
2086 |
WRITE_ONCE(rnp->completed, rsp->gpnum); |
b11cc5760 rcu: Accelerate R... |
2087 2088 |
rdp = this_cpu_ptr(rsp->rda); if (rnp == rdp->mynode) |
48a7639ce rcu: Make callers... |
2089 |
needgp = __note_gp_changes(rsp, rnp, rdp) || needgp; |
78e4bc34e rcu: Fix and comm... |
2090 |
/* smp_mb() provided by prior unlock-lock pair. */ |
0446be489 rcu: Abstract rcu... |
2091 |
nocb += rcu_future_gp_cleanup(rsp, rnp); |
065bb78c5 rcu: Do not call ... |
2092 |
sq = rcu_nocb_gp_get(rnp); |
67c583a7d RCU: Privatize rc... |
2093 |
raw_spin_unlock_irq_rcu_node(rnp); |
065bb78c5 rcu: Do not call ... |
2094 |
rcu_nocb_gp_cleanup(sq); |
bde6c3aa9 rcu: Provide cond... |
2095 |
cond_resched_rcu_qs(); |
7d0ae8086 rcu: Convert ACCE... |
2096 |
WRITE_ONCE(rsp->gp_activity, jiffies); |
0f41c0dda rcu: Provide diag... |
2097 |
rcu_gp_slow(rsp, gp_cleanup_delay); |
7fdefc10e rcu: Break up rcu... |
2098 |
} |
5d4b86594 rcu: Fix day-zero... |
2099 |
rnp = rcu_get_root(rsp); |
2a67e741b rcu: Create trans... |
2100 |
raw_spin_lock_irq_rcu_node(rnp); /* Order GP before ->completed update. */ |
dae6e64d2 rcu: Introduce pr... |
2101 |
rcu_nocb_gp_set(rnp, nocb); |
7fdefc10e rcu: Break up rcu... |
2102 |
|
765a3f4fe rcu: Provide grac... |
2103 |
/* Declare grace period done. */ |
7d0ae8086 rcu: Convert ACCE... |
2104 |
WRITE_ONCE(rsp->completed, rsp->gpnum); |
f7f7bac9c rcu: Have the RCU... |
2105 |
trace_rcu_grace_period(rsp->name, rsp->completed, TPS("end")); |
77f81fe08 rcu: Finish foldi... |
2106 |
rsp->gp_state = RCU_GP_IDLE; |
5d4b86594 rcu: Fix day-zero... |
2107 |
rdp = this_cpu_ptr(rsp->rda); |
48a7639ce rcu: Make callers... |
2108 2109 2110 |
/* Advance CBs to reduce false positives below. */ needgp = rcu_advance_cbs(rsp, rnp, rdp) || needgp; if (needgp || cpu_needs_another_gp(rsp, rdp)) { |
7d0ae8086 rcu: Convert ACCE... |
2111 |
WRITE_ONCE(rsp->gp_flags, RCU_GP_FLAG_INIT); |
bb311eccb rcu: Add tracing ... |
2112 |
trace_rcu_grace_period(rsp->name, |
7d0ae8086 rcu: Convert ACCE... |
2113 |
READ_ONCE(rsp->gpnum), |
bb311eccb rcu: Add tracing ... |
2114 2115 |
TPS("newreq")); } |
67c583a7d RCU: Privatize rc... |
2116 |
raw_spin_unlock_irq_rcu_node(rnp); |
7fdefc10e rcu: Break up rcu... |
2117 2118 2119 2120 2121 2122 2123 |
} /* * Body of kthread that handles grace periods. */ static int __noreturn rcu_gp_kthread(void *arg) { |
77f81fe08 rcu: Finish foldi... |
2124 |
bool first_gp_fqs; |
88d6df612 rcu: Prevent spur... |
2125 |
int gf; |
d40011f60 rcu: Control grac... |
2126 |
unsigned long j; |
4cdfc175c rcu: Move quiesce... |
2127 |
int ret; |
7fdefc10e rcu: Break up rcu... |
2128 2129 |
struct rcu_state *rsp = arg; struct rcu_node *rnp = rcu_get_root(rsp); |
5871968d5 rcu: Tighten up a... |
2130 |
rcu_bind_gp_kthread(); |
7fdefc10e rcu: Break up rcu... |
2131 2132 2133 2134 |
for (;;) { /* Handle grace-period start. */ for (;;) { |
63c4db78e rcu: Add tracing ... |
2135 |
trace_rcu_grace_period(rsp->name, |
7d0ae8086 rcu: Convert ACCE... |
2136 |
READ_ONCE(rsp->gpnum), |
63c4db78e rcu: Add tracing ... |
2137 |
TPS("reqwait")); |
afea227fd rcutorture: Expor... |
2138 |
rsp->gp_state = RCU_GP_WAIT_GPS; |
abedf8e24 rcu: Use simple w... |
2139 |
swait_event_interruptible(rsp->gp_wq, |
7d0ae8086 rcu: Convert ACCE... |
2140 |
READ_ONCE(rsp->gp_flags) & |
4cdfc175c rcu: Move quiesce... |
2141 |
RCU_GP_FLAG_INIT); |
319362c90 rcu: Provide more... |
2142 |
rsp->gp_state = RCU_GP_DONE_GPS; |
78e4bc34e rcu: Fix and comm... |
2143 |
/* Locking provides needed memory barrier. */ |
f7be82093 rcu: Improve grac... |
2144 |
if (rcu_gp_init(rsp)) |
7fdefc10e rcu: Break up rcu... |
2145 |
break; |
bde6c3aa9 rcu: Provide cond... |
2146 |
cond_resched_rcu_qs(); |
7d0ae8086 rcu: Convert ACCE... |
2147 |
WRITE_ONCE(rsp->gp_activity, jiffies); |
73a860cd5 rcu: Replace flus... |
2148 |
WARN_ON(signal_pending(current)); |
63c4db78e rcu: Add tracing ... |
2149 |
trace_rcu_grace_period(rsp->name, |
7d0ae8086 rcu: Convert ACCE... |
2150 |
READ_ONCE(rsp->gpnum), |
63c4db78e rcu: Add tracing ... |
2151 |
TPS("reqwaitsig")); |
7fdefc10e rcu: Break up rcu... |
2152 |
} |
cabc49c1f rcu: Move RCU gra... |
2153 |
|
4cdfc175c rcu: Move quiesce... |
2154 |
/* Handle quiescent-state forcing. */ |
77f81fe08 rcu: Finish foldi... |
2155 |
first_gp_fqs = true; |
d40011f60 rcu: Control grac... |
2156 2157 2158 2159 2160 |
j = jiffies_till_first_fqs; if (j > HZ) { j = HZ; jiffies_till_first_fqs = HZ; } |
88d6df612 rcu: Prevent spur... |
2161 |
ret = 0; |
cabc49c1f rcu: Move RCU gra... |
2162 |
for (;;) { |
8c7c4829a rcu: Awaken grace... |
2163 |
if (!ret) { |
88d6df612 rcu: Prevent spur... |
2164 |
rsp->jiffies_force_qs = jiffies + j; |
8c7c4829a rcu: Awaken grace... |
2165 2166 2167 |
WRITE_ONCE(rsp->jiffies_kick_kthreads, jiffies + 3 * j); } |
63c4db78e rcu: Add tracing ... |
2168 |
trace_rcu_grace_period(rsp->name, |
7d0ae8086 rcu: Convert ACCE... |
2169 |
READ_ONCE(rsp->gpnum), |
63c4db78e rcu: Add tracing ... |
2170 |
TPS("fqswait")); |
afea227fd rcutorture: Expor... |
2171 |
rsp->gp_state = RCU_GP_WAIT_FQS; |
abedf8e24 rcu: Use simple w... |
2172 |
ret = swait_event_interruptible_timeout(rsp->gp_wq, |
b9a425cfc rcu: Pull out wai... |
2173 |
rcu_gp_fqs_check_wake(rsp, &gf), j); |
32bb1c799 rcu: Rename RCU_G... |
2174 |
rsp->gp_state = RCU_GP_DOING_FQS; |
78e4bc34e rcu: Fix and comm... |
2175 |
/* Locking provides needed memory barriers. */ |
4cdfc175c rcu: Move quiesce... |
2176 |
/* If grace period done, leave loop. */ |
7d0ae8086 rcu: Convert ACCE... |
2177 |
if (!READ_ONCE(rnp->qsmask) && |
4cdfc175c rcu: Move quiesce... |
2178 |
!rcu_preempt_blocked_readers_cgp(rnp)) |
cabc49c1f rcu: Move RCU gra... |
2179 |
break; |
4cdfc175c rcu: Move quiesce... |
2180 |
/* If time for quiescent-state forcing, do it. */ |
88d6df612 rcu: Prevent spur... |
2181 2182 |
if (ULONG_CMP_GE(jiffies, rsp->jiffies_force_qs) || (gf & RCU_GP_FLAG_FQS)) { |
63c4db78e rcu: Add tracing ... |
2183 |
trace_rcu_grace_period(rsp->name, |
7d0ae8086 rcu: Convert ACCE... |
2184 |
READ_ONCE(rsp->gpnum), |
63c4db78e rcu: Add tracing ... |
2185 |
TPS("fqsstart")); |
77f81fe08 rcu: Finish foldi... |
2186 2187 |
rcu_gp_fqs(rsp, first_gp_fqs); first_gp_fqs = false; |
63c4db78e rcu: Add tracing ... |
2188 |
trace_rcu_grace_period(rsp->name, |
7d0ae8086 rcu: Convert ACCE... |
2189 |
READ_ONCE(rsp->gpnum), |
63c4db78e rcu: Add tracing ... |
2190 |
TPS("fqsend")); |
bde6c3aa9 rcu: Provide cond... |
2191 |
cond_resched_rcu_qs(); |
7d0ae8086 rcu: Convert ACCE... |
2192 |
WRITE_ONCE(rsp->gp_activity, jiffies); |
fcfd0a237 rcu: Make FQS sch... |
2193 2194 2195 2196 2197 2198 2199 2200 2201 |
ret = 0; /* Force full wait till next FQS. */ j = jiffies_till_next_fqs; if (j > HZ) { j = HZ; jiffies_till_next_fqs = HZ; } else if (j < 1) { j = 1; jiffies_till_next_fqs = 1; } |
4cdfc175c rcu: Move quiesce... |
2202 2203 |
} else { /* Deal with stray signal. */ |
bde6c3aa9 rcu: Provide cond... |
2204 |
cond_resched_rcu_qs(); |
7d0ae8086 rcu: Convert ACCE... |
2205 |
WRITE_ONCE(rsp->gp_activity, jiffies); |
73a860cd5 rcu: Replace flus... |
2206 |
WARN_ON(signal_pending(current)); |
63c4db78e rcu: Add tracing ... |
2207 |
trace_rcu_grace_period(rsp->name, |
7d0ae8086 rcu: Convert ACCE... |
2208 |
READ_ONCE(rsp->gpnum), |
63c4db78e rcu: Add tracing ... |
2209 |
TPS("fqswaitsig")); |
fcfd0a237 rcu: Make FQS sch... |
2210 2211 2212 2213 2214 2215 |
ret = 1; /* Keep old FQS timing. */ j = jiffies; if (time_after(jiffies, rsp->jiffies_force_qs)) j = 1; else j = rsp->jiffies_force_qs - j; |
d40011f60 rcu: Control grac... |
2216 |
} |
cabc49c1f rcu: Move RCU gra... |
2217 |
} |
4cdfc175c rcu: Move quiesce... |
2218 2219 |
/* Handle grace-period end. */ |
319362c90 rcu: Provide more... |
2220 |
rsp->gp_state = RCU_GP_CLEANUP; |
4cdfc175c rcu: Move quiesce... |
2221 |
rcu_gp_cleanup(rsp); |
319362c90 rcu: Provide more... |
2222 |
rsp->gp_state = RCU_GP_CLEANED; |
b3dbec76e rcu: Move RCU gra... |
2223 |
} |
b3dbec76e rcu: Move RCU gra... |
2224 2225 2226 |
} /* |
64db4cfff "Tree RCU": scala... |
2227 2228 |
* Start a new RCU grace period if warranted, re-initializing the hierarchy * in preparation for detecting the next grace period. The caller must hold |
b8462084a rcu: Push lock re... |
2229 |
* the root node's ->lock and hard irqs must be disabled. |
e56014000 rcu: Simplify off... |
2230 2231 2232 2233 |
* * Note that it is legal for a dying CPU (which is marked as offline) to * invoke this function. This can happen when the dying CPU reports its * quiescent state. |
48a7639ce rcu: Make callers... |
2234 2235 |
* * Returns true if the grace-period kthread must be awakened. |
64db4cfff "Tree RCU": scala... |
2236 |
*/ |
48a7639ce rcu: Make callers... |
2237 |
static bool |
910ee45db rcu: Make rcu_acc... |
2238 2239 |
rcu_start_gp_advanced(struct rcu_state *rsp, struct rcu_node *rnp, struct rcu_data *rdp) |
64db4cfff "Tree RCU": scala... |
2240 |
{ |
b8462084a rcu: Push lock re... |
2241 |
if (!rsp->gp_kthread || !cpu_needs_another_gp(rsp, rdp)) { |
afe24b122 rcu: Move propaga... |
2242 |
/* |
b3dbec76e rcu: Move RCU gra... |
2243 |
* Either we have not yet spawned the grace-period |
62da19212 rcu: Accelerate c... |
2244 2245 |
* task, this CPU does not need another grace period, * or a grace period is already in progress. |
b3dbec76e rcu: Move RCU gra... |
2246 |
* Either way, don't start a new grace period. |
afe24b122 rcu: Move propaga... |
2247 |
*/ |
48a7639ce rcu: Make callers... |
2248 |
return false; |
afe24b122 rcu: Move propaga... |
2249 |
} |
7d0ae8086 rcu: Convert ACCE... |
2250 2251 |
WRITE_ONCE(rsp->gp_flags, RCU_GP_FLAG_INIT); trace_rcu_grace_period(rsp->name, READ_ONCE(rsp->gpnum), |
bb311eccb rcu: Add tracing ... |
2252 |
TPS("newreq")); |
62da19212 rcu: Accelerate c... |
2253 |
|
016a8d5be rcu: Don't call w... |
2254 2255 |
/* * We can't do wakeups while holding the rnp->lock, as that |
1eafd31c6 rcu: Avoid redund... |
2256 |
* could cause possible deadlocks with the rq->lock. Defer |
48a7639ce rcu: Make callers... |
2257 |
* the wakeup to our caller. |
016a8d5be rcu: Don't call w... |
2258 |
*/ |
48a7639ce rcu: Make callers... |
2259 |
return true; |
64db4cfff "Tree RCU": scala... |
2260 2261 2262 |
} /* |
910ee45db rcu: Make rcu_acc... |
2263 2264 2265 2266 2267 |
* Similar to rcu_start_gp_advanced(), but also advance the calling CPU's * callbacks. Note that rcu_start_gp_advanced() cannot do this because it * is invoked indirectly from rcu_advance_cbs(), which would result in * endless recursion -- or would do so if it wasn't for the self-deadlock * that is encountered beforehand. |
48a7639ce rcu: Make callers... |
2268 2269 |
* * Returns true if the grace-period kthread needs to be awakened. |
910ee45db rcu: Make rcu_acc... |
2270 |
*/ |
48a7639ce rcu: Make callers... |
2271 |
static bool rcu_start_gp(struct rcu_state *rsp) |
910ee45db rcu: Make rcu_acc... |
2272 2273 2274 |
{ struct rcu_data *rdp = this_cpu_ptr(rsp->rda); struct rcu_node *rnp = rcu_get_root(rsp); |
48a7639ce rcu: Make callers... |
2275 |
bool ret = false; |
910ee45db rcu: Make rcu_acc... |
2276 2277 2278 2279 2280 2281 2282 2283 2284 |
/* * If there is no grace period in progress right now, any * callbacks we have up to this point will be satisfied by the * next grace period. Also, advancing the callbacks reduces the * probability of false positives from cpu_needs_another_gp() * resulting in pointless grace periods. So, advance callbacks * then start the grace period! */ |
48a7639ce rcu: Make callers... |
2285 2286 2287 |
ret = rcu_advance_cbs(rsp, rnp, rdp) || ret; ret = rcu_start_gp_advanced(rsp, rnp, rdp) || ret; return ret; |
910ee45db rcu: Make rcu_acc... |
2288 2289 2290 |
} /* |
8994515cf rcu: Update rcu_r... |
2291 2292 2293 2294 2295 2296 2297 |
* Report a full set of quiescent states to the specified rcu_state data * structure. Invoke rcu_gp_kthread_wake() to awaken the grace-period * kthread if another grace period is required. Whether we wake * the grace-period kthread or it awakens itself for the next round * of quiescent-state forcing, that kthread will clean up after the * just-completed grace period. Note that the caller must hold rnp->lock, * which is released before return. |
f41d911f8 rcu: Merge preemp... |
2298 |
*/ |
d3f6bad39 rcu: Rename "quie... |
2299 |
static void rcu_report_qs_rsp(struct rcu_state *rsp, unsigned long flags) |
fc2219d49 rcu: Clean up cod... |
2300 |
__releases(rcu_get_root(rsp)->lock) |
f41d911f8 rcu: Merge preemp... |
2301 |
{ |
fc2219d49 rcu: Clean up cod... |
2302 |
WARN_ON_ONCE(!rcu_gp_in_progress(rsp)); |
cd73ca21c rcu: Force wakeup... |
2303 |
WRITE_ONCE(rsp->gp_flags, READ_ONCE(rsp->gp_flags) | RCU_GP_FLAG_FQS); |
67c583a7d RCU: Privatize rc... |
2304 |
raw_spin_unlock_irqrestore_rcu_node(rcu_get_root(rsp), flags); |
94d447767 rcu: Use rcu_gp_k... |
2305 |
rcu_gp_kthread_wake(rsp); |
f41d911f8 rcu: Merge preemp... |
2306 2307 2308 |
} /* |
d3f6bad39 rcu: Rename "quie... |
2309 2310 2311 |
* Similar to rcu_report_qs_rdp(), for which it is a helper function. * Allows quiescent states for a group of CPUs to be reported at one go * to the specified rcu_node structure, though all the CPUs in the group |
654e95334 rcu: Associate qu... |
2312 2313 2314 2315 2316 |
* must be represented by the same rcu_node structure (which need not be a * leaf rcu_node structure, though it often will be). The gps parameter * is the grace-period snapshot, which means that the quiescent states * are valid only if rnp->gpnum is equal to gps. That structure's lock * must be held upon entry, and it is released before return. |
64db4cfff "Tree RCU": scala... |
2317 2318 |
*/ static void |
d3f6bad39 rcu: Rename "quie... |
2319 |
rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp, |
654e95334 rcu: Associate qu... |
2320 |
struct rcu_node *rnp, unsigned long gps, unsigned long flags) |
64db4cfff "Tree RCU": scala... |
2321 2322 |
__releases(rnp->lock) { |
654e95334 rcu: Associate qu... |
2323 |
unsigned long oldmask = 0; |
28ecd5802 rcu: Add WARN_ON_... |
2324 |
struct rcu_node *rnp_c; |
64db4cfff "Tree RCU": scala... |
2325 2326 |
/* Walk up the rcu_node hierarchy. */ for (;;) { |
654e95334 rcu: Associate qu... |
2327 |
if (!(rnp->qsmask & mask) || rnp->gpnum != gps) { |
64db4cfff "Tree RCU": scala... |
2328 |
|
654e95334 rcu: Associate qu... |
2329 2330 2331 2332 |
/* * Our bit has already been cleared, or the * relevant grace period is already over, so done. */ |
67c583a7d RCU: Privatize rc... |
2333 |
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); |
64db4cfff "Tree RCU": scala... |
2334 2335 |
return; } |
654e95334 rcu: Associate qu... |
2336 |
WARN_ON_ONCE(oldmask); /* Any child must be all zeroed! */ |
64db4cfff "Tree RCU": scala... |
2337 |
rnp->qsmask &= ~mask; |
d4c08f2ac rcu: Add grace-pe... |
2338 2339 2340 2341 |
trace_rcu_quiescent_state_report(rsp->name, rnp->gpnum, mask, rnp->qsmask, rnp->level, rnp->grplo, rnp->grphi, !!rnp->gp_tasks); |
27f4d2805 rcu: priority boo... |
2342 |
if (rnp->qsmask != 0 || rcu_preempt_blocked_readers_cgp(rnp)) { |
64db4cfff "Tree RCU": scala... |
2343 2344 |
/* Other bits still set at this level, so done. */ |
67c583a7d RCU: Privatize rc... |
2345 |
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); |
64db4cfff "Tree RCU": scala... |
2346 2347 2348 2349 2350 2351 2352 2353 2354 |
return; } mask = rnp->grpmask; if (rnp->parent == NULL) { /* No more levels. Exit loop holding root lock. */ break; } |
67c583a7d RCU: Privatize rc... |
2355 |
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); |
28ecd5802 rcu: Add WARN_ON_... |
2356 |
rnp_c = rnp; |
64db4cfff "Tree RCU": scala... |
2357 |
rnp = rnp->parent; |
2a67e741b rcu: Create trans... |
2358 |
raw_spin_lock_irqsave_rcu_node(rnp, flags); |
654e95334 rcu: Associate qu... |
2359 |
oldmask = rnp_c->qsmask; |
64db4cfff "Tree RCU": scala... |
2360 2361 2362 2363 |
} /* * Get here if we are the last CPU to pass through a quiescent |
d3f6bad39 rcu: Rename "quie... |
2364 |
* state for this grace period. Invoke rcu_report_qs_rsp() |
f41d911f8 rcu: Merge preemp... |
2365 |
* to clean up and start the next grace period if one is needed. |
64db4cfff "Tree RCU": scala... |
2366 |
*/ |
d3f6bad39 rcu: Rename "quie... |
2367 |
rcu_report_qs_rsp(rsp, flags); /* releases rnp->lock. */ |
64db4cfff "Tree RCU": scala... |
2368 2369 2370 |
} /* |
cc99a310c rcu: Move rcu_rep... |
2371 2372 2373 2374 2375 2376 |
* Record a quiescent state for all tasks that were previously queued * on the specified rcu_node structure and that were blocking the current * RCU grace period. The caller must hold the specified rnp->lock with * irqs disabled, and this lock is released upon return, but irqs remain * disabled. */ |
0aa04b055 rcu: Process offl... |
2377 |
static void rcu_report_unblock_qs_rnp(struct rcu_state *rsp, |
cc99a310c rcu: Move rcu_rep... |
2378 2379 2380 |
struct rcu_node *rnp, unsigned long flags) __releases(rnp->lock) { |
654e95334 rcu: Associate qu... |
2381 |
unsigned long gps; |
cc99a310c rcu: Move rcu_rep... |
2382 2383 |
unsigned long mask; struct rcu_node *rnp_p; |
a77da14ce rcu: Yet another ... |
2384 2385 |
if (rcu_state_p == &rcu_sched_state || rsp != rcu_state_p || rnp->qsmask != 0 || rcu_preempt_blocked_readers_cgp(rnp)) { |
67c583a7d RCU: Privatize rc... |
2386 |
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); |
cc99a310c rcu: Move rcu_rep... |
2387 2388 2389 2390 2391 2392 |
return; /* Still need more quiescent states! */ } rnp_p = rnp->parent; if (rnp_p == NULL) { /* |
a77da14ce rcu: Yet another ... |
2393 2394 |
* Only one rcu_node structure in the tree, so don't * try to report up to its nonexistent parent! |
cc99a310c rcu: Move rcu_rep... |
2395 2396 2397 2398 |
*/ rcu_report_qs_rsp(rsp, flags); return; } |
654e95334 rcu: Associate qu... |
2399 2400 |
/* Report up the rest of the hierarchy, tracking current ->gpnum. */ gps = rnp->gpnum; |
cc99a310c rcu: Move rcu_rep... |
2401 |
mask = rnp->grpmask; |
67c583a7d RCU: Privatize rc... |
2402 |
raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled. */ |
2a67e741b rcu: Create trans... |
2403 |
raw_spin_lock_rcu_node(rnp_p); /* irqs already disabled. */ |
654e95334 rcu: Associate qu... |
2404 |
rcu_report_qs_rnp(mask, rsp, rnp_p, gps, flags); |
cc99a310c rcu: Move rcu_rep... |
2405 2406 2407 |
} /* |
d3f6bad39 rcu: Rename "quie... |
2408 |
* Record a quiescent state for the specified CPU to that CPU's rcu_data |
4b455dc3e rcu: Catch up rcu... |
2409 |
* structure. This must be called from the specified CPU. |
64db4cfff "Tree RCU": scala... |
2410 2411 |
*/ static void |
d7d6a11e8 rcu: Simplify qui... |
2412 |
rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp) |
64db4cfff "Tree RCU": scala... |
2413 2414 2415 |
{ unsigned long flags; unsigned long mask; |
48a7639ce rcu: Make callers... |
2416 |
bool needwake; |
64db4cfff "Tree RCU": scala... |
2417 2418 2419 |
struct rcu_node *rnp; rnp = rdp->mynode; |
2a67e741b rcu: Create trans... |
2420 |
raw_spin_lock_irqsave_rcu_node(rnp, flags); |
5b74c4589 rcu: Make ->cpu_n... |
2421 |
if ((rdp->cpu_no_qs.b.norm && |
5cd37193c rcu: Make cond_re... |
2422 2423 2424 |
rdp->rcu_qs_ctr_snap == __this_cpu_read(rcu_qs_ctr)) || rdp->gpnum != rnp->gpnum || rnp->completed == rnp->gpnum || rdp->gpwrap) { |
64db4cfff "Tree RCU": scala... |
2425 2426 |
/* |
e4cc1f22b rcu: Simplify qui... |
2427 2428 2429 2430 |
* The grace period in which this quiescent state was * recorded has ended, so don't report it upwards. * We will instead need a new quiescent state that lies * within the current grace period. |
64db4cfff "Tree RCU": scala... |
2431 |
*/ |
5b74c4589 rcu: Make ->cpu_n... |
2432 |
rdp->cpu_no_qs.b.norm = true; /* need qs for new gp. */ |
5cd37193c rcu: Make cond_re... |
2433 |
rdp->rcu_qs_ctr_snap = __this_cpu_read(rcu_qs_ctr); |
67c583a7d RCU: Privatize rc... |
2434 |
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); |
64db4cfff "Tree RCU": scala... |
2435 2436 2437 2438 |
return; } mask = rdp->grpmask; if ((rnp->qsmask & mask) == 0) { |
67c583a7d RCU: Privatize rc... |
2439 |
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); |
64db4cfff "Tree RCU": scala... |
2440 |
} else { |
bb53e416e rcu: Assign false... |
2441 |
rdp->core_needs_qs = false; |
64db4cfff "Tree RCU": scala... |
2442 2443 2444 2445 2446 |
/* * This GP can't end until cpu checks in, so all of our * callbacks can be processed during the next GP. */ |
48a7639ce rcu: Make callers... |
2447 |
needwake = rcu_accelerate_cbs(rsp, rnp, rdp); |
64db4cfff "Tree RCU": scala... |
2448 |
|
654e95334 rcu: Associate qu... |
2449 2450 |
rcu_report_qs_rnp(mask, rsp, rnp, rnp->gpnum, flags); /* ^^^ Released rnp->lock */ |
48a7639ce rcu: Make callers... |
2451 2452 |
if (needwake) rcu_gp_kthread_wake(rsp); |
64db4cfff "Tree RCU": scala... |
2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 |
} } /* * Check to see if there is a new grace period of which this CPU * is not yet aware, and if so, set up local rcu_data state for it. * Otherwise, see if this CPU has just passed through its first * quiescent state for this grace period, and record that fact if so. */ static void rcu_check_quiescent_state(struct rcu_state *rsp, struct rcu_data *rdp) { |
05eb552bf rcu: Move redunda... |
2465 2466 |
/* Check for grace-period ends and beginnings. */ note_gp_changes(rsp, rdp); |
64db4cfff "Tree RCU": scala... |
2467 2468 2469 2470 2471 |
/* * Does this CPU still need to do its part for current grace period? * If no, return and let the other CPUs do their part as well. */ |
97c668b8e rcu: Rename qs_pe... |
2472 |
if (!rdp->core_needs_qs) |
64db4cfff "Tree RCU": scala... |
2473 2474 2475 2476 2477 2478 |
return; /* * Was there a quiescent state since the beginning of the grace * period? If no, then exit and wait for the next call. */ |
5b74c4589 rcu: Make ->cpu_n... |
2479 |
if (rdp->cpu_no_qs.b.norm && |
5cd37193c rcu: Make cond_re... |
2480 |
rdp->rcu_qs_ctr_snap == __this_cpu_read(rcu_qs_ctr)) |
64db4cfff "Tree RCU": scala... |
2481 |
return; |
d3f6bad39 rcu: Rename "quie... |
2482 2483 2484 2485 |
/* * Tell RCU we are done (but rcu_report_qs_rdp() will be the * judge of that). */ |
d7d6a11e8 rcu: Simplify qui... |
2486 |
rcu_report_qs_rdp(rdp->cpu, rsp, rdp); |
64db4cfff "Tree RCU": scala... |
2487 |
} |
64db4cfff "Tree RCU": scala... |
2488 |
/* |
b1420f1c8 rcu: Make rcu_bar... |
2489 2490 |
* Send the specified CPU's RCU callbacks to the orphanage. The * specified CPU must be offline, and the caller must hold the |
7b2e6011f rcu: Rename ->ono... |
2491 |
* ->orphan_lock. |
e74f4c456 rcu: Make hot-unp... |
2492 |
*/ |
b1420f1c8 rcu: Make rcu_bar... |
2493 2494 2495 |
static void rcu_send_cbs_to_orphanage(int cpu, struct rcu_state *rsp, struct rcu_node *rnp, struct rcu_data *rdp) |
e74f4c456 rcu: Make hot-unp... |
2496 |
{ |
3fbfbf7a3 rcu: Add callback... |
2497 |
/* No-CBs CPUs do not have orphanable callbacks. */ |
ea46351ce rcu: Eliminate HO... |
2498 |
if (!IS_ENABLED(CONFIG_HOTPLUG_CPU) || rcu_is_nocb_cpu(rdp->cpu)) |
3fbfbf7a3 rcu: Add callback... |
2499 |
return; |
b1420f1c8 rcu: Make rcu_bar... |
2500 2501 |
/* * Orphan the callbacks. First adjust the counts. This is safe |
abfd6e58a rcu: Fix comment ... |
2502 2503 |
* because _rcu_barrier() excludes CPU-hotplug operations, so it * cannot be running now. Thus no memory barrier is required. |
b1420f1c8 rcu: Make rcu_bar... |
2504 |
*/ |
a50c3af91 rcu: Don't make c... |
2505 |
if (rdp->nxtlist != NULL) { |
b1420f1c8 rcu: Make rcu_bar... |
2506 2507 2508 |
rsp->qlen_lazy += rdp->qlen_lazy; rsp->qlen += rdp->qlen; rdp->n_cbs_orphaned += rdp->qlen; |
a50c3af91 rcu: Don't make c... |
2509 |
rdp->qlen_lazy = 0; |
7d0ae8086 rcu: Convert ACCE... |
2510 |
WRITE_ONCE(rdp->qlen, 0); |
a50c3af91 rcu: Don't make c... |
2511 2512 2513 |
} /* |
b1420f1c8 rcu: Make rcu_bar... |
2514 2515 2516 2517 2518 2519 2520 |
* Next, move those callbacks still needing a grace period to * the orphanage, where some other CPU will pick them up. * Some of the callbacks might have gone partway through a grace * period, but that is too bad. They get to start over because we * cannot assume that grace periods are synchronized across CPUs. * We don't bother updating the ->nxttail[] array yet, instead * we just reset the whole thing later on. |
a50c3af91 rcu: Don't make c... |
2521 |
*/ |
b1420f1c8 rcu: Make rcu_bar... |
2522 2523 2524 2525 |
if (*rdp->nxttail[RCU_DONE_TAIL] != NULL) { *rsp->orphan_nxttail = *rdp->nxttail[RCU_DONE_TAIL]; rsp->orphan_nxttail = rdp->nxttail[RCU_NEXT_TAIL]; *rdp->nxttail[RCU_DONE_TAIL] = NULL; |
a50c3af91 rcu: Don't make c... |
2526 2527 2528 |
} /* |
b1420f1c8 rcu: Make rcu_bar... |
2529 2530 2531 |
* Then move the ready-to-invoke callbacks to the orphanage, * where some other CPU will pick them up. These will not be * required to pass though another grace period: They are done. |
a50c3af91 rcu: Don't make c... |
2532 |
*/ |
e56014000 rcu: Simplify off... |
2533 |
if (rdp->nxtlist != NULL) { |
b1420f1c8 rcu: Make rcu_bar... |
2534 2535 |
*rsp->orphan_donetail = rdp->nxtlist; rsp->orphan_donetail = rdp->nxttail[RCU_DONE_TAIL]; |
e56014000 rcu: Simplify off... |
2536 |
} |
e74f4c456 rcu: Make hot-unp... |
2537 |
|
b33078b60 rcu: Consolidate ... |
2538 2539 2540 2541 |
/* * Finally, initialize the rcu_data structure's list to empty and * disallow further callbacks on this CPU. */ |
3f5d3ea64 rcu: Consolidate ... |
2542 |
init_callback_list(rdp); |
b33078b60 rcu: Consolidate ... |
2543 |
rdp->nxttail[RCU_NEXT_TAIL] = NULL; |
b1420f1c8 rcu: Make rcu_bar... |
2544 2545 2546 2547 |
} /* * Adopt the RCU callbacks from the specified rcu_state structure's |
7b2e6011f rcu: Rename ->ono... |
2548 |
* orphanage. The caller must hold the ->orphan_lock. |
b1420f1c8 rcu: Make rcu_bar... |
2549 |
*/ |
96d3fd0d3 rcu: Break call_r... |
2550 |
static void rcu_adopt_orphan_cbs(struct rcu_state *rsp, unsigned long flags) |
b1420f1c8 rcu: Make rcu_bar... |
2551 2552 |
{ int i; |
fa07a58f7 rcu: Replace __th... |
2553 |
struct rcu_data *rdp = raw_cpu_ptr(rsp->rda); |
b1420f1c8 rcu: Make rcu_bar... |
2554 |
|
3fbfbf7a3 rcu: Add callback... |
2555 |
/* No-CBs CPUs are handled specially. */ |
ea46351ce rcu: Eliminate HO... |
2556 2557 |
if (!IS_ENABLED(CONFIG_HOTPLUG_CPU) || rcu_nocb_adopt_orphan_cbs(rsp, rdp, flags)) |
3fbfbf7a3 rcu: Add callback... |
2558 |
return; |
b1420f1c8 rcu: Make rcu_bar... |
2559 2560 2561 2562 |
/* Do the accounting first. */ rdp->qlen_lazy += rsp->qlen_lazy; rdp->qlen += rsp->qlen; rdp->n_cbs_adopted += rsp->qlen; |
8f5af6f1f rcu: RCU_FAST_NO_... |
2563 2564 |
if (rsp->qlen_lazy != rsp->qlen) rcu_idle_count_callbacks_posted(); |
b1420f1c8 rcu: Make rcu_bar... |
2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 |
rsp->qlen_lazy = 0; rsp->qlen = 0; /* * We do not need a memory barrier here because the only way we * can get here if there is an rcu_barrier() in flight is if * we are the task doing the rcu_barrier(). */ /* First adopt the ready-to-invoke callbacks. */ if (rsp->orphan_donelist != NULL) { *rsp->orphan_donetail = *rdp->nxttail[RCU_DONE_TAIL]; *rdp->nxttail[RCU_DONE_TAIL] = rsp->orphan_donelist; for (i = RCU_NEXT_SIZE - 1; i >= RCU_DONE_TAIL; i--) if (rdp->nxttail[i] == rdp->nxttail[RCU_DONE_TAIL]) rdp->nxttail[i] = rsp->orphan_donetail; rsp->orphan_donelist = NULL; rsp->orphan_donetail = &rsp->orphan_donelist; } /* And then adopt the callbacks that still need a grace period. */ if (rsp->orphan_nxtlist != NULL) { *rdp->nxttail[RCU_NEXT_TAIL] = rsp->orphan_nxtlist; rdp->nxttail[RCU_NEXT_TAIL] = rsp->orphan_nxttail; rsp->orphan_nxtlist = NULL; rsp->orphan_nxttail = &rsp->orphan_nxtlist; } } /* * Trace the fact that this CPU is going offline. */ static void rcu_cleanup_dying_cpu(struct rcu_state *rsp) { RCU_TRACE(unsigned long mask); RCU_TRACE(struct rcu_data *rdp = this_cpu_ptr(rsp->rda)); RCU_TRACE(struct rcu_node *rnp = rdp->mynode); |
ea46351ce rcu: Eliminate HO... |
2602 2603 |
if (!IS_ENABLED(CONFIG_HOTPLUG_CPU)) return; |
b1420f1c8 rcu: Make rcu_bar... |
2604 |
RCU_TRACE(mask = rdp->grpmask); |
e56014000 rcu: Simplify off... |
2605 2606 |
trace_rcu_grace_period(rsp->name, rnp->gpnum + 1 - !!(rnp->qsmask & mask), |
f7f7bac9c rcu: Have the RCU... |
2607 |
TPS("cpuofl")); |
64db4cfff "Tree RCU": scala... |
2608 2609 2610 |
} /* |
8af3a5e78 rcu: Abstract rcu... |
2611 2612 2613 2614 2615 2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 |
* All CPUs for the specified rcu_node structure have gone offline, * and all tasks that were preempted within an RCU read-side critical * section while running on one of those CPUs have since exited their RCU * read-side critical section. Some other CPU is reporting this fact with * the specified rcu_node structure's ->lock held and interrupts disabled. * This function therefore goes up the tree of rcu_node structures, * clearing the corresponding bits in the ->qsmaskinit fields. Note that * the leaf rcu_node structure's ->qsmaskinit field has already been * updated * * This function does check that the specified rcu_node structure has * all CPUs offline and no blocked tasks, so it is OK to invoke it * prematurely. That said, invoking it after the fact will cost you * a needless lock acquisition. So once it has done its work, don't * invoke it again. */ static void rcu_cleanup_dead_rnp(struct rcu_node *rnp_leaf) { long mask; struct rcu_node *rnp = rnp_leaf; |
ea46351ce rcu: Eliminate HO... |
2631 2632 |
if (!IS_ENABLED(CONFIG_HOTPLUG_CPU) || rnp->qsmaskinit || rcu_preempt_has_tasks(rnp)) |
8af3a5e78 rcu: Abstract rcu... |
2633 2634 2635 2636 2637 2638 |
return; for (;;) { mask = rnp->grpmask; rnp = rnp->parent; if (!rnp) break; |
2a67e741b rcu: Create trans... |
2639 |
raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */ |
8af3a5e78 rcu: Abstract rcu... |
2640 |
rnp->qsmaskinit &= ~mask; |
0aa04b055 rcu: Process offl... |
2641 |
rnp->qsmask &= ~mask; |
8af3a5e78 rcu: Abstract rcu... |
2642 |
if (rnp->qsmaskinit) { |
67c583a7d RCU: Privatize rc... |
2643 2644 |
raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled. */ |
8af3a5e78 rcu: Abstract rcu... |
2645 2646 |
return; } |
67c583a7d RCU: Privatize rc... |
2647 |
raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled. */ |
8af3a5e78 rcu: Abstract rcu... |
2648 2649 2650 2651 |
} } /* |
e56014000 rcu: Simplify off... |
2652 |
* The CPU has been completely removed, and some other CPU is reporting |
b1420f1c8 rcu: Make rcu_bar... |
2653 2654 |
* this fact from process context. Do the remainder of the cleanup, * including orphaning the outgoing CPU's RCU callbacks, and also |
1331e7a1b rcu: Remove _rcu_... |
2655 2656 |
* adopting them. There can only be one CPU hotplug operation at a time, * so no other CPU can be attempting to update rcu_cpu_kthread_task. |
64db4cfff "Tree RCU": scala... |
2657 |
*/ |
e56014000 rcu: Simplify off... |
2658 |
static void rcu_cleanup_dead_cpu(int cpu, struct rcu_state *rsp) |
64db4cfff "Tree RCU": scala... |
2659 |
{ |
2036d94a7 rcu: Rework detec... |
2660 |
unsigned long flags; |
e56014000 rcu: Simplify off... |
2661 |
struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); |
b1420f1c8 rcu: Make rcu_bar... |
2662 |
struct rcu_node *rnp = rdp->mynode; /* Outgoing CPU's rdp & rnp. */ |
e56014000 rcu: Simplify off... |
2663 |
|
ea46351ce rcu: Eliminate HO... |
2664 2665 |
if (!IS_ENABLED(CONFIG_HOTPLUG_CPU)) return; |
2036d94a7 rcu: Rework detec... |
2666 |
/* Adjust any no-longer-needed kthreads. */ |
5d01bbd11 rcu: Yield simpler |
2667 |
rcu_boost_kthread_setaffinity(rnp, -1); |
2036d94a7 rcu: Rework detec... |
2668 |
|
b1420f1c8 rcu: Make rcu_bar... |
2669 |
/* Orphan the dead CPU's callbacks, and adopt them if appropriate. */ |
78043c467 rcu: Put all orph... |
2670 |
raw_spin_lock_irqsave(&rsp->orphan_lock, flags); |
b1420f1c8 rcu: Make rcu_bar... |
2671 |
rcu_send_cbs_to_orphanage(cpu, rsp, rnp, rdp); |
96d3fd0d3 rcu: Break call_r... |
2672 |
rcu_adopt_orphan_cbs(rsp, flags); |
a8f4cbadf rcu: Shorten irq-... |
2673 |
raw_spin_unlock_irqrestore(&rsp->orphan_lock, flags); |
b1420f1c8 rcu: Make rcu_bar... |
2674 |
|
cf01537ec rcu: Add check fo... |
2675 2676 2677 2678 |
WARN_ONCE(rdp->qlen != 0 || rdp->nxtlist != NULL, "rcu_cleanup_dead_cpu: Callbacks on offline CPU %d: qlen=%lu, nxtlist=%p ", cpu, rdp->qlen, rdp->nxtlist); |
64db4cfff "Tree RCU": scala... |
2679 |
} |
64db4cfff "Tree RCU": scala... |
2680 2681 2682 2683 |
/* * Invoke any RCU callbacks that have made it to the end of their grace * period. Thottle as specified by rdp->blimit. */ |
37c72e56f rcu: Prevent RCU ... |
2684 |
static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp) |
64db4cfff "Tree RCU": scala... |
2685 2686 2687 |
{ unsigned long flags; struct rcu_head *next, *list, **tail; |
878d7439d rcu: Fix batch-li... |
2688 2689 |
long bl, count, count_lazy; int i; |
64db4cfff "Tree RCU": scala... |
2690 |
|
dc35c8934 rcu: Tag callback... |
2691 |
/* If no callbacks are ready, just return. */ |
29c00b4a1 rcu: Add event-tr... |
2692 |
if (!cpu_has_callbacks_ready_to_invoke(rdp)) { |
486e25934 rcu: Avoid waking... |
2693 |
trace_rcu_batch_start(rsp->name, rdp->qlen_lazy, rdp->qlen, 0); |
7d0ae8086 rcu: Convert ACCE... |
2694 |
trace_rcu_batch_end(rsp->name, 0, !!READ_ONCE(rdp->nxtlist), |
4968c300e rcu: Augment rcu_... |
2695 2696 |
need_resched(), is_idle_task(current), rcu_is_callbacks_kthread()); |
64db4cfff "Tree RCU": scala... |
2697 |
return; |
29c00b4a1 rcu: Add event-tr... |
2698 |
} |
64db4cfff "Tree RCU": scala... |
2699 2700 2701 2702 2703 2704 |
/* * Extract the list of ready callbacks, disabling to prevent * races with call_rcu() from interrupt handlers. */ local_irq_save(flags); |
8146c4e2e rcu: Check for ca... |
2705 |
WARN_ON_ONCE(cpu_is_offline(smp_processor_id())); |
29c00b4a1 rcu: Add event-tr... |
2706 |
bl = rdp->blimit; |
486e25934 rcu: Avoid waking... |
2707 |
trace_rcu_batch_start(rsp->name, rdp->qlen_lazy, rdp->qlen, bl); |
64db4cfff "Tree RCU": scala... |
2708 2709 2710 2711 |
list = rdp->nxtlist; rdp->nxtlist = *rdp->nxttail[RCU_DONE_TAIL]; *rdp->nxttail[RCU_DONE_TAIL] = NULL; tail = rdp->nxttail[RCU_DONE_TAIL]; |
b41772abe rcu: Stop rcu_do_... |
2712 2713 2714 |
for (i = RCU_NEXT_SIZE - 1; i >= 0; i--) if (rdp->nxttail[i] == rdp->nxttail[RCU_DONE_TAIL]) rdp->nxttail[i] = &rdp->nxtlist; |
64db4cfff "Tree RCU": scala... |
2715 2716 2717 |
local_irq_restore(flags); /* Invoke callbacks. */ |
486e25934 rcu: Avoid waking... |
2718 |
count = count_lazy = 0; |
64db4cfff "Tree RCU": scala... |
2719 2720 2721 |
while (list) { next = list->next; prefetch(next); |
551d55a94 tree/tiny rcu: Ad... |
2722 |
debug_rcu_head_unqueue(list); |
486e25934 rcu: Avoid waking... |
2723 2724 |
if (__rcu_reclaim(rsp->name, list)) count_lazy++; |
64db4cfff "Tree RCU": scala... |
2725 |
list = next; |
dff1672d9 rcu: Keep invokin... |
2726 2727 2728 2729 |
/* Stop only if limit reached and CPU has something to do. */ if (++count >= bl && (need_resched() || (!is_idle_task(current) && !rcu_is_callbacks_kthread()))) |
64db4cfff "Tree RCU": scala... |
2730 2731 2732 2733 |
break; } local_irq_save(flags); |
4968c300e rcu: Augment rcu_... |
2734 2735 2736 |
trace_rcu_batch_end(rsp->name, count, !!list, need_resched(), is_idle_task(current), rcu_is_callbacks_kthread()); |
64db4cfff "Tree RCU": scala... |
2737 2738 |
/* Update count, and requeue any remaining callbacks. */ |
64db4cfff "Tree RCU": scala... |
2739 2740 2741 |
if (list != NULL) { *tail = rdp->nxtlist; rdp->nxtlist = list; |
b41772abe rcu: Stop rcu_do_... |
2742 2743 2744 |
for (i = 0; i < RCU_NEXT_SIZE; i++) if (&rdp->nxtlist == rdp->nxttail[i]) rdp->nxttail[i] = tail; |
64db4cfff "Tree RCU": scala... |
2745 2746 2747 |
else break; } |
b1420f1c8 rcu: Make rcu_bar... |
2748 2749 |
smp_mb(); /* List handling before counting for rcu_barrier(). */ rdp->qlen_lazy -= count_lazy; |
7d0ae8086 rcu: Convert ACCE... |
2750 |
WRITE_ONCE(rdp->qlen, rdp->qlen - count); |
b1420f1c8 rcu: Make rcu_bar... |
2751 |
rdp->n_cbs_invoked += count; |
64db4cfff "Tree RCU": scala... |
2752 2753 2754 2755 |
/* Reinstate batch limit if we have worked down the excess. */ if (rdp->blimit == LONG_MAX && rdp->qlen <= qlowmark) rdp->blimit = blimit; |
37c72e56f rcu: Prevent RCU ... |
2756 2757 2758 2759 2760 2761 |
/* Reset ->qlen_last_fqs_check trigger if enough CBs have drained. */ if (rdp->qlen == 0 && rdp->qlen_last_fqs_check != 0) { rdp->qlen_last_fqs_check = 0; rdp->n_force_qs_snap = rsp->n_force_qs; } else if (rdp->qlen < rdp->qlen_last_fqs_check - qhimark) rdp->qlen_last_fqs_check = rdp->qlen; |
cfca92797 rcu: Introduce ch... |
2762 |
WARN_ON_ONCE((rdp->nxtlist == NULL) != (rdp->qlen == 0)); |
37c72e56f rcu: Prevent RCU ... |
2763 |
|
64db4cfff "Tree RCU": scala... |
2764 |
local_irq_restore(flags); |
e0f23060a rcu: Update comme... |
2765 |
/* Re-invoke RCU core processing if there are callbacks remaining. */ |
64db4cfff "Tree RCU": scala... |
2766 |
if (cpu_has_callbacks_ready_to_invoke(rdp)) |
a46e0899e rcu: use softirq ... |
2767 |
invoke_rcu_core(); |
64db4cfff "Tree RCU": scala... |
2768 2769 2770 2771 2772 |
} /* * Check to see if this CPU is in a non-context-switch quiescent state * (user mode or idle loop for rcu, non-softirq execution for rcu_bh). |
e0f23060a rcu: Update comme... |
2773 |
* Also schedule RCU core processing. |
64db4cfff "Tree RCU": scala... |
2774 |
* |
9b2e4f188 rcu: Track idlene... |
2775 |
* This function must be called from hardirq context. It is normally |
64db4cfff "Tree RCU": scala... |
2776 2777 2778 |
* invoked from the scheduling-clock interrupt. If rcu_pending returns * false, there is no point in invoking rcu_check_callbacks(). */ |
c3377c2da rcu: Remove "cpu"... |
2779 |
void rcu_check_callbacks(int user) |
64db4cfff "Tree RCU": scala... |
2780 |
{ |
f7f7bac9c rcu: Have the RCU... |
2781 |
trace_rcu_utilization(TPS("Start scheduler-tick")); |
a858af287 rcu: Print schedu... |
2782 |
increment_cpu_stall_ticks(); |
9b2e4f188 rcu: Track idlene... |
2783 |
if (user || rcu_is_cpu_rrupt_from_idle()) { |
64db4cfff "Tree RCU": scala... |
2784 2785 2786 2787 2788 |
/* * Get here if this CPU took its interrupt from user * mode or from the idle loop, and if this is not a * nested interrupt. In this case, the CPU is in |
d6714c22b rcu: Renamings to... |
2789 |
* a quiescent state, so note it. |
64db4cfff "Tree RCU": scala... |
2790 2791 |
* * No memory barrier is required here because both |
d6714c22b rcu: Renamings to... |
2792 2793 2794 |
* rcu_sched_qs() and rcu_bh_qs() reference only CPU-local * variables that other CPUs neither access nor modify, * at least not while the corresponding CPU is online. |
64db4cfff "Tree RCU": scala... |
2795 |
*/ |
284a8c93a rcu: Per-CPU oper... |
2796 2797 |
rcu_sched_qs(); rcu_bh_qs(); |
64db4cfff "Tree RCU": scala... |
2798 2799 2800 2801 2802 2803 2804 |
} else if (!in_softirq()) { /* * Get here if this CPU did not take its interrupt from * softirq, in other words, if it is not interrupting * a rcu_bh read-side critical section. This is an _bh |
d6714c22b rcu: Renamings to... |
2805 |
* critical section, so note it. |
64db4cfff "Tree RCU": scala... |
2806 |
*/ |
284a8c93a rcu: Per-CPU oper... |
2807 |
rcu_bh_qs(); |
64db4cfff "Tree RCU": scala... |
2808 |
} |
86aea0e6e rcu: Remove "cpu"... |
2809 |
rcu_preempt_check_callbacks(); |
e3950ecd5 rcu: Remove "cpu"... |
2810 |
if (rcu_pending()) |
a46e0899e rcu: use softirq ... |
2811 |
invoke_rcu_core(); |
8315f4229 rcu: Add call_rcu... |
2812 2813 |
if (user) rcu_note_voluntary_context_switch(current); |
f7f7bac9c rcu: Have the RCU... |
2814 |
trace_rcu_utilization(TPS("End scheduler-tick")); |
64db4cfff "Tree RCU": scala... |
2815 |
} |
64db4cfff "Tree RCU": scala... |
2816 2817 2818 |
/* * Scan the leaf rcu_node structures, processing dyntick state for any that * have not yet encountered a quiescent state, using the function specified. |
27f4d2805 rcu: priority boo... |
2819 2820 |
* Also initiate boosting for any threads blocked on the root rcu_node. * |
ee47eb9f4 rcu: Remove leg o... |
2821 |
* The caller must have suppressed start of new grace periods. |
64db4cfff "Tree RCU": scala... |
2822 |
*/ |
217af2a2f nohz_full: Add fu... |
2823 2824 2825 2826 |
static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *rsp, bool *isidle, unsigned long *maxj), bool *isidle, unsigned long *maxj) |
64db4cfff "Tree RCU": scala... |
2827 |
{ |
64db4cfff "Tree RCU": scala... |
2828 2829 2830 |
int cpu; unsigned long flags; unsigned long mask; |
a0b6c9a78 rcu: Clean up cod... |
2831 |
struct rcu_node *rnp; |
64db4cfff "Tree RCU": scala... |
2832 |
|
a0b6c9a78 rcu: Clean up cod... |
2833 |
rcu_for_each_leaf_node(rsp, rnp) { |
bde6c3aa9 rcu: Provide cond... |
2834 |
cond_resched_rcu_qs(); |
64db4cfff "Tree RCU": scala... |
2835 |
mask = 0; |
2a67e741b rcu: Create trans... |
2836 |
raw_spin_lock_irqsave_rcu_node(rnp, flags); |
a0b6c9a78 rcu: Clean up cod... |
2837 |
if (rnp->qsmask == 0) { |
a77da14ce rcu: Yet another ... |
2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 |
if (rcu_state_p == &rcu_sched_state || rsp != rcu_state_p || rcu_preempt_blocked_readers_cgp(rnp)) { /* * No point in scanning bits because they * are all zero. But we might need to * priority-boost blocked readers. */ rcu_initiate_boost(rnp, flags); /* rcu_initiate_boost() releases rnp->lock */ continue; } if (rnp->parent && (rnp->parent->qsmask & rnp->grpmask)) { /* * Race between grace-period * initialization and task exiting RCU * read-side critical section: Report. */ rcu_report_unblock_qs_rnp(rsp, rnp, flags); /* rcu_report_unblock_qs_rnp() rlses ->lock */ continue; } |
64db4cfff "Tree RCU": scala... |
2861 |
} |
bc75e9998 rcu: Correctly ha... |
2862 2863 |
for_each_leaf_node_possible_cpu(rnp, cpu) { unsigned long bit = leaf_node_cpu_bit(rnp, cpu); |
0edd1b178 nohz_full: Add fu... |
2864 |
if ((rnp->qsmask & bit) != 0) { |
0edd1b178 nohz_full: Add fu... |
2865 2866 2867 |
if (f(per_cpu_ptr(rsp->rda, cpu), isidle, maxj)) mask |= bit; } |
64db4cfff "Tree RCU": scala... |
2868 |
} |
45f014c52 rcu: Remove redun... |
2869 |
if (mask != 0) { |
654e95334 rcu: Associate qu... |
2870 2871 |
/* Idle/offline CPUs, report (releases rnp->lock. */ rcu_report_qs_rnp(mask, rsp, rnp, rnp->gpnum, flags); |
0aa04b055 rcu: Process offl... |
2872 2873 |
} else { /* Nothing to do here, so just drop the lock. */ |
67c583a7d RCU: Privatize rc... |
2874 |
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); |
64db4cfff "Tree RCU": scala... |
2875 |
} |
64db4cfff "Tree RCU": scala... |
2876 |
} |
64db4cfff "Tree RCU": scala... |
2877 2878 2879 2880 2881 2882 |
} /* * Force quiescent states on reluctant CPUs, and also detect which * CPUs are in dyntick-idle mode. */ |
4cdfc175c rcu: Move quiesce... |
2883 |
static void force_quiescent_state(struct rcu_state *rsp) |
64db4cfff "Tree RCU": scala... |
2884 2885 |
{ unsigned long flags; |
394f2769a rcu: Prevent forc... |
2886 2887 2888 2889 2890 |
bool ret; struct rcu_node *rnp; struct rcu_node *rnp_old = NULL; /* Funnel through hierarchy to reduce memory contention. */ |
d860d4032 rcu: Use __this_c... |
2891 |
rnp = __this_cpu_read(rsp->rda->mynode); |
394f2769a rcu: Prevent forc... |
2892 |
for (; rnp != NULL; rnp = rnp->parent) { |
7d0ae8086 rcu: Convert ACCE... |
2893 |
ret = (READ_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) || |
394f2769a rcu: Prevent forc... |
2894 2895 2896 2897 |
!raw_spin_trylock(&rnp->fqslock); if (rnp_old != NULL) raw_spin_unlock(&rnp_old->fqslock); if (ret) { |
a792563bd rcu: Eliminate re... |
2898 |
rsp->n_force_qs_lh++; |
394f2769a rcu: Prevent forc... |
2899 2900 2901 2902 2903 |
return; } rnp_old = rnp; } /* rnp_old == rcu_get_root(rsp), rnp == NULL. */ |
64db4cfff "Tree RCU": scala... |
2904 |
|
394f2769a rcu: Prevent forc... |
2905 |
/* Reached the root of the rcu_node tree, acquire lock. */ |
2a67e741b rcu: Create trans... |
2906 |
raw_spin_lock_irqsave_rcu_node(rnp_old, flags); |
394f2769a rcu: Prevent forc... |
2907 |
raw_spin_unlock(&rnp_old->fqslock); |
7d0ae8086 rcu: Convert ACCE... |
2908 |
if (READ_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) { |
a792563bd rcu: Eliminate re... |
2909 |
rsp->n_force_qs_lh++; |
67c583a7d RCU: Privatize rc... |
2910 |
raw_spin_unlock_irqrestore_rcu_node(rnp_old, flags); |
4cdfc175c rcu: Move quiesce... |
2911 |
return; /* Someone beat us to it. */ |
46a1e34ed rcu: Make force_q... |
2912 |
} |
7d0ae8086 rcu: Convert ACCE... |
2913 |
WRITE_ONCE(rsp->gp_flags, READ_ONCE(rsp->gp_flags) | RCU_GP_FLAG_FQS); |
67c583a7d RCU: Privatize rc... |
2914 |
raw_spin_unlock_irqrestore_rcu_node(rnp_old, flags); |
94d447767 rcu: Use rcu_gp_k... |
2915 |
rcu_gp_kthread_wake(rsp); |
64db4cfff "Tree RCU": scala... |
2916 |
} |
64db4cfff "Tree RCU": scala... |
2917 |
/* |
e0f23060a rcu: Update comme... |
2918 2919 2920 |
* This does the RCU core processing work for the specified rcu_state * and rcu_data structures. This may be called only from the CPU to * whom the rdp belongs. |
64db4cfff "Tree RCU": scala... |
2921 2922 |
*/ static void |
1bca8cf1a rcu: Remove unnee... |
2923 |
__rcu_process_callbacks(struct rcu_state *rsp) |
64db4cfff "Tree RCU": scala... |
2924 2925 |
{ unsigned long flags; |
48a7639ce rcu: Make callers... |
2926 |
bool needwake; |
fa07a58f7 rcu: Replace __th... |
2927 |
struct rcu_data *rdp = raw_cpu_ptr(rsp->rda); |
64db4cfff "Tree RCU": scala... |
2928 |
|
2e5975580 rcu: Simplify RCU... |
2929 |
WARN_ON_ONCE(rdp->beenonline == 0); |
64db4cfff "Tree RCU": scala... |
2930 2931 2932 2933 |
/* Update RCU state based on any recent quiescent states. */ rcu_check_quiescent_state(rsp, rdp); /* Does this CPU require a not-yet-started grace period? */ |
dc35c8934 rcu: Tag callback... |
2934 |
local_irq_save(flags); |
64db4cfff "Tree RCU": scala... |
2935 |
if (cpu_needs_another_gp(rsp, rdp)) { |
6cf100812 rcu: Add transiti... |
2936 |
raw_spin_lock_rcu_node(rcu_get_root(rsp)); /* irqs disabled. */ |
48a7639ce rcu: Make callers... |
2937 |
needwake = rcu_start_gp(rsp); |
67c583a7d RCU: Privatize rc... |
2938 |
raw_spin_unlock_irqrestore_rcu_node(rcu_get_root(rsp), flags); |
48a7639ce rcu: Make callers... |
2939 2940 |
if (needwake) rcu_gp_kthread_wake(rsp); |
dc35c8934 rcu: Tag callback... |
2941 2942 |
} else { local_irq_restore(flags); |
64db4cfff "Tree RCU": scala... |
2943 2944 2945 |
} /* If there are callbacks ready, invoke them. */ |
09223371d rcu: Use softirq ... |
2946 |
if (cpu_has_callbacks_ready_to_invoke(rdp)) |
a46e0899e rcu: use softirq ... |
2947 |
invoke_rcu_callbacks(rsp, rdp); |
96d3fd0d3 rcu: Break call_r... |
2948 2949 2950 |
/* Do any needed deferred wakeups of rcuo kthreads. */ do_nocb_deferred_wakeup(rdp); |
09223371d rcu: Use softirq ... |
2951 |
} |
64db4cfff "Tree RCU": scala... |
2952 |
/* |
e0f23060a rcu: Update comme... |
2953 |
* Do RCU core processing for the current CPU. |
64db4cfff "Tree RCU": scala... |
2954 |
*/ |
0766f788e latent_entropy: M... |
2955 |
static __latent_entropy void rcu_process_callbacks(struct softirq_action *unused) |
64db4cfff "Tree RCU": scala... |
2956 |
{ |
6ce75a232 rcu: Introduce fo... |
2957 |
struct rcu_state *rsp; |
bfa00b4c4 rcu: Prevent offl... |
2958 2959 |
if (cpu_is_offline(smp_processor_id())) return; |
f7f7bac9c rcu: Have the RCU... |
2960 |
trace_rcu_utilization(TPS("Start RCU core")); |
6ce75a232 rcu: Introduce fo... |
2961 2962 |
for_each_rcu_flavor(rsp) __rcu_process_callbacks(rsp); |
f7f7bac9c rcu: Have the RCU... |
2963 |
trace_rcu_utilization(TPS("End RCU core")); |
64db4cfff "Tree RCU": scala... |
2964 |
} |
a26ac2455 rcu: move TREE_RC... |
2965 |
/* |
e0f23060a rcu: Update comme... |
2966 2967 2968 |
* Schedule RCU callback invocation. If the specified type of RCU * does not support RCU priority boosting, just do a direct call, * otherwise wake up the per-CPU kernel kthread. Note that because we |
924df8a01 rcu: Fix invoke_r... |
2969 |
* are running on the current CPU with softirqs disabled, the |
e0f23060a rcu: Update comme... |
2970 |
* rcu_cpu_kthread_task cannot disappear out from under us. |
a26ac2455 rcu: move TREE_RC... |
2971 |
*/ |
a46e0899e rcu: use softirq ... |
2972 |
static void invoke_rcu_callbacks(struct rcu_state *rsp, struct rcu_data *rdp) |
a26ac2455 rcu: move TREE_RC... |
2973 |
{ |
7d0ae8086 rcu: Convert ACCE... |
2974 |
if (unlikely(!READ_ONCE(rcu_scheduler_fully_active))) |
b0d304172 rcu: Prevent RCU ... |
2975 |
return; |
a46e0899e rcu: use softirq ... |
2976 2977 |
if (likely(!rsp->boost)) { rcu_do_batch(rsp, rdp); |
a26ac2455 rcu: move TREE_RC... |
2978 2979 |
return; } |
a46e0899e rcu: use softirq ... |
2980 |
invoke_rcu_callbacks_kthread(); |
a26ac2455 rcu: move TREE_RC... |
2981 |
} |
a46e0899e rcu: use softirq ... |
2982 |
static void invoke_rcu_core(void) |
09223371d rcu: Use softirq ... |
2983 |
{ |
b0f740360 rcu: Avoid invoki... |
2984 2985 |
if (cpu_online(smp_processor_id())) raise_softirq(RCU_SOFTIRQ); |
09223371d rcu: Use softirq ... |
2986 |
} |
29154c57e rcu: Split RCU co... |
2987 2988 2989 2990 2991 |
/* * Handle any core-RCU processing required by a call_rcu() invocation. */ static void __call_rcu_core(struct rcu_state *rsp, struct rcu_data *rdp, struct rcu_head *head, unsigned long flags) |
64db4cfff "Tree RCU": scala... |
2992 |
{ |
48a7639ce rcu: Make callers... |
2993 |
bool needwake; |
62fde6edf rcu: Make __call_... |
2994 2995 2996 2997 |
/* * If called from an extended quiescent state, invoke the RCU * core in order to force a re-evaluation of RCU's idleness. */ |
9910affa8 rcu: Remove redun... |
2998 |
if (!rcu_is_watching()) |
62fde6edf rcu: Make __call_... |
2999 |
invoke_rcu_core(); |
a16b7a693 rcu: Prevent __ca... |
3000 |
/* If interrupts were disabled or CPU offline, don't invoke RCU core. */ |
29154c57e rcu: Split RCU co... |
3001 |
if (irqs_disabled_flags(flags) || cpu_is_offline(smp_processor_id())) |
2655d57ef rcu: prevent call... |
3002 |
return; |
64db4cfff "Tree RCU": scala... |
3003 |
|
37c72e56f rcu: Prevent RCU ... |
3004 3005 3006 3007 3008 3009 3010 |
/* * Force the grace period if too many callbacks or too long waiting. * Enforce hysteresis, and don't invoke force_quiescent_state() * if some other CPU has recently done so. Also, don't bother * invoking force_quiescent_state() if the newly enqueued callback * is the only one waiting for a grace period to complete. */ |
2655d57ef rcu: prevent call... |
3011 |
if (unlikely(rdp->qlen > rdp->qlen_last_fqs_check + qhimark)) { |
b52573d27 rcu: reduce __cal... |
3012 3013 |
/* Are we ignoring a completed grace period? */ |
470716fc0 rcu: Switch calle... |
3014 |
note_gp_changes(rsp, rdp); |
b52573d27 rcu: reduce __cal... |
3015 3016 3017 |
/* Start a new grace period if one not already started. */ if (!rcu_gp_in_progress(rsp)) { |
b52573d27 rcu: reduce __cal... |
3018 |
struct rcu_node *rnp_root = rcu_get_root(rsp); |
2a67e741b rcu: Create trans... |
3019 |
raw_spin_lock_rcu_node(rnp_root); |
48a7639ce rcu: Make callers... |
3020 |
needwake = rcu_start_gp(rsp); |
67c583a7d RCU: Privatize rc... |
3021 |
raw_spin_unlock_rcu_node(rnp_root); |
48a7639ce rcu: Make callers... |
3022 3023 |
if (needwake) rcu_gp_kthread_wake(rsp); |
b52573d27 rcu: reduce __cal... |
3024 3025 3026 3027 3028 |
} else { /* Give the grace period a kick. */ rdp->blimit = LONG_MAX; if (rsp->n_force_qs == rdp->n_force_qs_snap && *rdp->nxttail[RCU_DONE_TAIL] != head) |
4cdfc175c rcu: Move quiesce... |
3029 |
force_quiescent_state(rsp); |
b52573d27 rcu: reduce __cal... |
3030 3031 3032 |
rdp->n_force_qs_snap = rsp->n_force_qs; rdp->qlen_last_fqs_check = rdp->qlen; } |
4cdfc175c rcu: Move quiesce... |
3033 |
} |
29154c57e rcu: Split RCU co... |
3034 |
} |
3fbfbf7a3 rcu: Add callback... |
3035 |
/* |
ae1501845 rcu: Make call_rc... |
3036 3037 3038 3039 3040 3041 3042 |
* RCU callback function to leak a callback. */ static void rcu_leak_callback(struct rcu_head *rhp) { } /* |
3fbfbf7a3 rcu: Add callback... |
3043 3044 3045 3046 3047 |
* Helper function for call_rcu() and friends. The cpu argument will * normally be -1, indicating "currently running CPU". It may specify * a CPU only if that CPU is a no-CBs CPU. Currently, only _rcu_barrier() * is expected to specify a CPU. */ |
64db4cfff "Tree RCU": scala... |
3048 |
static void |
b6a4ae766 rcu: Use rcu_call... |
3049 |
__call_rcu(struct rcu_head *head, rcu_callback_t func, |
3fbfbf7a3 rcu: Add callback... |
3050 |
struct rcu_state *rsp, int cpu, bool lazy) |
64db4cfff "Tree RCU": scala... |
3051 3052 3053 |
{ unsigned long flags; struct rcu_data *rdp; |
1146edcbe rcu: Loosen __cal... |
3054 |
WARN_ON_ONCE((unsigned long)head & 0x1); /* Misaligned rcu_head! */ |
ae1501845 rcu: Make call_rc... |
3055 3056 |
if (debug_rcu_head_queue(head)) { /* Probable double call_rcu(), so leak the callback. */ |
7d0ae8086 rcu: Convert ACCE... |
3057 |
WRITE_ONCE(head->func, rcu_leak_callback); |
ae1501845 rcu: Make call_rc... |
3058 3059 3060 3061 |
WARN_ONCE(1, "__call_rcu(): Leaked duplicate callback "); return; } |
64db4cfff "Tree RCU": scala... |
3062 3063 |
head->func = func; head->next = NULL; |
64db4cfff "Tree RCU": scala... |
3064 3065 3066 3067 3068 3069 3070 |
/* * Opportunistically note grace-period endings and beginnings. * Note that we might see a beginning right after we see an * end, but never vice versa, since this CPU has to pass through * a quiescent state betweentimes. */ local_irq_save(flags); |
394f99a90 rcu: simplify the... |
3071 |
rdp = this_cpu_ptr(rsp->rda); |
64db4cfff "Tree RCU": scala... |
3072 3073 |
/* Add the callback to our list. */ |
3fbfbf7a3 rcu: Add callback... |
3074 3075 3076 3077 3078 |
if (unlikely(rdp->nxttail[RCU_NEXT_TAIL] == NULL) || cpu != -1) { int offline; if (cpu != -1) rdp = per_cpu_ptr(rsp->rda, cpu); |
143da9c2f rcu: Prevent earl... |
3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 |
if (likely(rdp->mynode)) { /* Post-boot, so this should be for a no-CBs CPU. */ offline = !__call_rcu_nocb(rdp, head, lazy, flags); WARN_ON_ONCE(offline); /* Offline CPU, _call_rcu() illegal, leak callback. */ local_irq_restore(flags); return; } /* * Very early boot, before rcu_init(). Initialize if needed * and then drop through to queue the callback. */ BUG_ON(cpu != -1); |
34404ca8f rcu: Move early-b... |
3092 |
WARN_ON_ONCE(!rcu_is_watching()); |
143da9c2f rcu: Prevent earl... |
3093 3094 |
if (!likely(rdp->nxtlist)) init_default_callback_list(rdp); |
0d8ee37e2 rcu: Disallow cal... |
3095 |
} |
7d0ae8086 rcu: Convert ACCE... |
3096 |
WRITE_ONCE(rdp->qlen, rdp->qlen + 1); |
486e25934 rcu: Avoid waking... |
3097 3098 |
if (lazy) rdp->qlen_lazy++; |
c57afe80d rcu: Make RCU_FAS... |
3099 3100 |
else rcu_idle_count_callbacks_posted(); |
b1420f1c8 rcu: Make rcu_bar... |
3101 3102 3103 |
smp_mb(); /* Count before adding callback for rcu_barrier(). */ *rdp->nxttail[RCU_NEXT_TAIL] = head; rdp->nxttail[RCU_NEXT_TAIL] = &head->next; |
2655d57ef rcu: prevent call... |
3104 |
|
d4c08f2ac rcu: Add grace-pe... |
3105 3106 |
if (__is_kfree_rcu_offset((unsigned long)func)) trace_rcu_kfree_callback(rsp->name, head, (unsigned long)func, |
486e25934 rcu: Avoid waking... |
3107 |
rdp->qlen_lazy, rdp->qlen); |
d4c08f2ac rcu: Add grace-pe... |
3108 |
else |
486e25934 rcu: Avoid waking... |
3109 |
trace_rcu_callback(rsp->name, head, rdp->qlen_lazy, rdp->qlen); |
d4c08f2ac rcu: Add grace-pe... |
3110 |
|
29154c57e rcu: Split RCU co... |
3111 3112 |
/* Go handle any RCU core processing required. */ __call_rcu_core(rsp, rdp, head, flags); |
64db4cfff "Tree RCU": scala... |
3113 3114 3115 3116 |
local_irq_restore(flags); } /* |
d6714c22b rcu: Renamings to... |
3117 |
* Queue an RCU-sched callback for invocation after a grace period. |
64db4cfff "Tree RCU": scala... |
3118 |
*/ |
b6a4ae766 rcu: Use rcu_call... |
3119 |
void call_rcu_sched(struct rcu_head *head, rcu_callback_t func) |
64db4cfff "Tree RCU": scala... |
3120 |
{ |
3fbfbf7a3 rcu: Add callback... |
3121 |
__call_rcu(head, func, &rcu_sched_state, -1, 0); |
64db4cfff "Tree RCU": scala... |
3122 |
} |
d6714c22b rcu: Renamings to... |
3123 |
EXPORT_SYMBOL_GPL(call_rcu_sched); |
64db4cfff "Tree RCU": scala... |
3124 3125 |
/* |
486e25934 rcu: Avoid waking... |
3126 |
* Queue an RCU callback for invocation after a quicker grace period. |
64db4cfff "Tree RCU": scala... |
3127 |
*/ |
b6a4ae766 rcu: Use rcu_call... |
3128 |
void call_rcu_bh(struct rcu_head *head, rcu_callback_t func) |
64db4cfff "Tree RCU": scala... |
3129 |
{ |
3fbfbf7a3 rcu: Add callback... |
3130 |
__call_rcu(head, func, &rcu_bh_state, -1, 0); |
64db4cfff "Tree RCU": scala... |
3131 3132 |
} EXPORT_SYMBOL_GPL(call_rcu_bh); |
6d8133919 rcu: Document why... |
3133 |
/* |
495aa969d rcu: Consolidate ... |
3134 3135 3136 3137 3138 3139 3140 |
* Queue an RCU callback for lazy invocation after a grace period. * This will likely be later named something like "call_rcu_lazy()", * but this change will require some way of tagging the lazy RCU * callbacks in the list of pending callbacks. Until then, this * function may only be called from __kfree_rcu(). */ void kfree_call_rcu(struct rcu_head *head, |
b6a4ae766 rcu: Use rcu_call... |
3141 |
rcu_callback_t func) |
495aa969d rcu: Consolidate ... |
3142 |
{ |
e534165bb rcu: Variable nam... |
3143 |
__call_rcu(head, func, rcu_state_p, -1, 1); |
495aa969d rcu: Consolidate ... |
3144 3145 3146 3147 |
} EXPORT_SYMBOL_GPL(kfree_call_rcu); /* |
6d8133919 rcu: Document why... |
3148 3149 3150 3151 3152 3153 3154 |
* Because a context switch is a grace period for RCU-sched and RCU-bh, * any blocking grace-period wait automatically implies a grace period * if there is only one CPU online at any point time during execution * of either synchronize_sched() or synchronize_rcu_bh(). It is OK to * occasionally incorrectly indicate that there are multiple CPUs online * when there was in fact only one the whole time, as this just adds * some overhead: RCU still operates correctly. |
6d8133919 rcu: Document why... |
3155 3156 3157 |
*/ static inline int rcu_blocking_is_gp(void) { |
95f0c1de3 rcu: Disable pree... |
3158 |
int ret; |
6d8133919 rcu: Document why... |
3159 |
might_sleep(); /* Check for RCU read-side critical section. */ |
95f0c1de3 rcu: Disable pree... |
3160 3161 3162 3163 |
preempt_disable(); ret = num_online_cpus() <= 1; preempt_enable(); return ret; |
6d8133919 rcu: Document why... |
3164 |
} |
6ebb237be rcu: Re-arrange c... |
3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 |
/** * synchronize_sched - wait until an rcu-sched grace period has elapsed. * * Control will return to the caller some time after a full rcu-sched * grace period has elapsed, in other words after all currently executing * rcu-sched read-side critical sections have completed. These read-side * critical sections are delimited by rcu_read_lock_sched() and * rcu_read_unlock_sched(), and may be nested. Note that preempt_disable(), * local_irq_disable(), and so on may be used in place of * rcu_read_lock_sched(). * * This means that all preempt_disable code sequences, including NMI and |
f0a0e6f28 rcu: Clarify memo... |
3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 |
* non-threaded hardware-interrupt handlers, in progress on entry will * have completed before this primitive returns. However, this does not * guarantee that softirq handlers will have completed, since in some * kernels, these handlers can run in process context, and can block. * * Note that this guarantee implies further memory-ordering guarantees. * On systems with more than one CPU, when synchronize_sched() returns, * each CPU is guaranteed to have executed a full memory barrier since the * end of its last RCU-sched read-side critical section whose beginning * preceded the call to synchronize_sched(). In addition, each CPU having * an RCU read-side critical section that extends beyond the return from * synchronize_sched() is guaranteed to have executed a full memory barrier * after the beginning of synchronize_sched() and before the beginning of * that RCU read-side critical section. Note that these guarantees include * CPUs that are offline, idle, or executing in user mode, as well as CPUs * that are executing in the kernel. * * Furthermore, if CPU A invoked synchronize_sched(), which returned * to its caller on CPU B, then both CPU A and CPU B are guaranteed * to have executed a full memory barrier during the execution of * synchronize_sched() -- even if CPU A and CPU B are the same CPU (but * again only if the system has more than one CPU). |
6ebb237be rcu: Re-arrange c... |
3199 3200 3201 3202 3203 3204 3205 3206 3207 |
* * This primitive provides the guarantees made by the (now removed) * synchronize_kernel() API. In contrast, synchronize_rcu() only * guarantees that rcu_read_lock() sections will have completed. * In "classic RCU", these two guarantees happen to be one and * the same, but can differ in realtime RCU implementations. */ void synchronize_sched(void) { |
f78f5b90c rcu: Rename rcu_l... |
3208 3209 3210 3211 |
RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) || lock_is_held(&rcu_lock_map) || lock_is_held(&rcu_sched_lock_map), "Illegal synchronize_sched() in RCU-sched read-side critical section"); |
6ebb237be rcu: Re-arrange c... |
3212 3213 |
if (rcu_blocking_is_gp()) return; |
5afff48bd rcu: Update from ... |
3214 |
if (rcu_gp_is_expedited()) |
3705b88db rcu: Add a module... |
3215 3216 3217 |
synchronize_sched_expedited(); else wait_rcu_gp(call_rcu_sched); |
6ebb237be rcu: Re-arrange c... |
3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 |
} EXPORT_SYMBOL_GPL(synchronize_sched); /** * synchronize_rcu_bh - wait until an rcu_bh grace period has elapsed. * * Control will return to the caller some time after a full rcu_bh grace * period has elapsed, in other words after all currently executing rcu_bh * read-side critical sections have completed. RCU read-side critical * sections are delimited by rcu_read_lock_bh() and rcu_read_unlock_bh(), * and may be nested. |
f0a0e6f28 rcu: Clarify memo... |
3229 3230 3231 |
* * See the description of synchronize_sched() for more detailed information * on memory ordering guarantees. |
6ebb237be rcu: Re-arrange c... |
3232 3233 3234 |
*/ void synchronize_rcu_bh(void) { |
f78f5b90c rcu: Rename rcu_l... |
3235 3236 3237 3238 |
RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) || lock_is_held(&rcu_lock_map) || lock_is_held(&rcu_sched_lock_map), "Illegal synchronize_rcu_bh() in RCU-bh read-side critical section"); |
6ebb237be rcu: Re-arrange c... |
3239 3240 |
if (rcu_blocking_is_gp()) return; |
5afff48bd rcu: Update from ... |
3241 |
if (rcu_gp_is_expedited()) |
3705b88db rcu: Add a module... |
3242 3243 3244 |
synchronize_rcu_bh_expedited(); else wait_rcu_gp(call_rcu_bh); |
6ebb237be rcu: Re-arrange c... |
3245 3246 |
} EXPORT_SYMBOL_GPL(synchronize_rcu_bh); |
765a3f4fe rcu: Provide grac... |
3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 |
/** * get_state_synchronize_rcu - Snapshot current RCU state * * Returns a cookie that is used by a later call to cond_synchronize_rcu() * to determine whether or not a full grace period has elapsed in the * meantime. */ unsigned long get_state_synchronize_rcu(void) { /* * Any prior manipulation of RCU-protected data must happen * before the load from ->gpnum. */ smp_mb(); /* ^^^ */ /* * Make sure this load happens before the purportedly * time-consuming work between get_state_synchronize_rcu() * and cond_synchronize_rcu(). */ |
e534165bb rcu: Variable nam... |
3267 |
return smp_load_acquire(&rcu_state_p->gpnum); |
765a3f4fe rcu: Provide grac... |
3268 3269 3270 3271 3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291 3292 |
} EXPORT_SYMBOL_GPL(get_state_synchronize_rcu); /** * cond_synchronize_rcu - Conditionally wait for an RCU grace period * * @oldstate: return value from earlier call to get_state_synchronize_rcu() * * If a full RCU grace period has elapsed since the earlier call to * get_state_synchronize_rcu(), just return. Otherwise, invoke * synchronize_rcu() to wait for a full grace period. * * Yes, this function does not take counter wrap into account. But * counter wrap is harmless. If the counter wraps, we have waited for * more than 2 billion grace periods (and way more on a 64-bit system!), * so waiting for one additional grace period should be just fine. */ void cond_synchronize_rcu(unsigned long oldstate) { unsigned long newstate; /* * Ensure that this load happens before any RCU-destructive * actions the caller might carry out after we return. */ |
e534165bb rcu: Variable nam... |
3293 |
newstate = smp_load_acquire(&rcu_state_p->completed); |
765a3f4fe rcu: Provide grac... |
3294 3295 3296 3297 |
if (ULONG_CMP_GE(oldstate, newstate)) synchronize_rcu(); } EXPORT_SYMBOL_GPL(cond_synchronize_rcu); |
24560056d rcu: Add RCU-sche... |
3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323 3324 3325 3326 3327 3328 3329 3330 3331 3332 3333 3334 3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347 3348 |
/** * get_state_synchronize_sched - Snapshot current RCU-sched state * * Returns a cookie that is used by a later call to cond_synchronize_sched() * to determine whether or not a full grace period has elapsed in the * meantime. */ unsigned long get_state_synchronize_sched(void) { /* * Any prior manipulation of RCU-protected data must happen * before the load from ->gpnum. */ smp_mb(); /* ^^^ */ /* * Make sure this load happens before the purportedly * time-consuming work between get_state_synchronize_sched() * and cond_synchronize_sched(). */ return smp_load_acquire(&rcu_sched_state.gpnum); } EXPORT_SYMBOL_GPL(get_state_synchronize_sched); /** * cond_synchronize_sched - Conditionally wait for an RCU-sched grace period * * @oldstate: return value from earlier call to get_state_synchronize_sched() * * If a full RCU-sched grace period has elapsed since the earlier call to * get_state_synchronize_sched(), just return. Otherwise, invoke * synchronize_sched() to wait for a full grace period. * * Yes, this function does not take counter wrap into account. But * counter wrap is harmless. If the counter wraps, we have waited for * more than 2 billion grace periods (and way more on a 64-bit system!), * so waiting for one additional grace period should be just fine. */ void cond_synchronize_sched(unsigned long oldstate) { unsigned long newstate; /* * Ensure that this load happens before any RCU-destructive * actions the caller might carry out after we return. */ newstate = smp_load_acquire(&rcu_sched_state.completed); if (ULONG_CMP_GE(oldstate, newstate)) synchronize_sched(); } EXPORT_SYMBOL_GPL(cond_synchronize_sched); |
28f00767e rcu: Abstract seq... |
3349 3350 3351 3352 3353 3354 3355 3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 |
/* Adjust sequence number for start of update-side operation. */ static void rcu_seq_start(unsigned long *sp) { WRITE_ONCE(*sp, *sp + 1); smp_mb(); /* Ensure update-side operation after counter increment. */ WARN_ON_ONCE(!(*sp & 0x1)); } /* Adjust sequence number for end of update-side operation. */ static void rcu_seq_end(unsigned long *sp) { smp_mb(); /* Ensure update-side operation before counter increment. */ WRITE_ONCE(*sp, *sp + 1); WARN_ON_ONCE(*sp & 0x1); } /* Take a snapshot of the update side's sequence number. */ static unsigned long rcu_seq_snap(unsigned long *sp) { unsigned long s; |
28f00767e rcu: Abstract seq... |
3369 3370 3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 |
s = (READ_ONCE(*sp) + 3) & ~0x1; smp_mb(); /* Above access must not bleed into critical section. */ return s; } /* * Given a snapshot from rcu_seq_snap(), determine whether or not a * full update-side operation has occurred. */ static bool rcu_seq_done(unsigned long *sp, unsigned long s) { return ULONG_CMP_GE(READ_ONCE(*sp), s); } |
64db4cfff "Tree RCU": scala... |
3382 3383 3384 3385 3386 3387 3388 3389 3390 |
/* * Check to see if there is any immediate RCU-related work to be done * by the current CPU, for the specified type of RCU, returning 1 if so. * The checks are in order of increasing expense: checks that can be * carried out against CPU-local state are performed first. However, * we must check for CPU stalls first, else we might not get a chance. */ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp) { |
2f51f9884 rcu: Eliminate __... |
3391 |
struct rcu_node *rnp = rdp->mynode; |
64db4cfff "Tree RCU": scala... |
3392 3393 3394 3395 |
rdp->n_rcu_pending++; /* Check for CPU stalls, if enabled. */ check_cpu_stall(rsp, rdp); |
a096932f0 rcu: Don't activa... |
3396 3397 3398 |
/* Is this CPU a NO_HZ_FULL CPU that should ignore RCU? */ if (rcu_nohz_full_cpu(rsp)) return 0; |
64db4cfff "Tree RCU": scala... |
3399 |
/* Is the RCU core waiting for a quiescent state from this CPU? */ |
5c51dd734 rcu: Prevent earl... |
3400 |
if (rcu_scheduler_fully_active && |
5b74c4589 rcu: Make ->cpu_n... |
3401 |
rdp->core_needs_qs && rdp->cpu_no_qs.b.norm && |
5cd37193c rcu: Make cond_re... |
3402 |
rdp->rcu_qs_ctr_snap == __this_cpu_read(rcu_qs_ctr)) { |
97c668b8e rcu: Rename qs_pe... |
3403 3404 |
rdp->n_rp_core_needs_qs++; } else if (rdp->core_needs_qs && |
5b74c4589 rcu: Make ->cpu_n... |
3405 |
(!rdp->cpu_no_qs.b.norm || |
5cd37193c rcu: Make cond_re... |
3406 |
rdp->rcu_qs_ctr_snap != __this_cpu_read(rcu_qs_ctr))) { |
d21670aca rcu: reduce the n... |
3407 |
rdp->n_rp_report_qs++; |
64db4cfff "Tree RCU": scala... |
3408 |
return 1; |
7ba5c840e rcu: Add __rcu_pe... |
3409 |
} |
64db4cfff "Tree RCU": scala... |
3410 3411 |
/* Does this CPU have callbacks ready to invoke? */ |
7ba5c840e rcu: Add __rcu_pe... |
3412 3413 |
if (cpu_has_callbacks_ready_to_invoke(rdp)) { rdp->n_rp_cb_ready++; |
64db4cfff "Tree RCU": scala... |
3414 |
return 1; |
7ba5c840e rcu: Add __rcu_pe... |
3415 |
} |
64db4cfff "Tree RCU": scala... |
3416 3417 |
/* Has RCU gone idle with this CPU needing another grace period? */ |
7ba5c840e rcu: Add __rcu_pe... |
3418 3419 |
if (cpu_needs_another_gp(rsp, rdp)) { rdp->n_rp_cpu_needs_gp++; |
64db4cfff "Tree RCU": scala... |
3420 |
return 1; |
7ba5c840e rcu: Add __rcu_pe... |
3421 |
} |
64db4cfff "Tree RCU": scala... |
3422 3423 |
/* Has another RCU grace period completed? */ |
7d0ae8086 rcu: Convert ACCE... |
3424 |
if (READ_ONCE(rnp->completed) != rdp->completed) { /* outside lock */ |
7ba5c840e rcu: Add __rcu_pe... |
3425 |
rdp->n_rp_gp_completed++; |
64db4cfff "Tree RCU": scala... |
3426 |
return 1; |
7ba5c840e rcu: Add __rcu_pe... |
3427 |
} |
64db4cfff "Tree RCU": scala... |
3428 3429 |
/* Has a new RCU grace period started? */ |
7d0ae8086 rcu: Convert ACCE... |
3430 3431 |
if (READ_ONCE(rnp->gpnum) != rdp->gpnum || unlikely(READ_ONCE(rdp->gpwrap))) { /* outside lock */ |
7ba5c840e rcu: Add __rcu_pe... |
3432 |
rdp->n_rp_gp_started++; |
64db4cfff "Tree RCU": scala... |
3433 |
return 1; |
7ba5c840e rcu: Add __rcu_pe... |
3434 |
} |
64db4cfff "Tree RCU": scala... |
3435 |
|
96d3fd0d3 rcu: Break call_r... |
3436 3437 3438 3439 3440 |
/* Does this CPU need a deferred NOCB wakeup? */ if (rcu_nocb_need_deferred_wakeup(rdp)) { rdp->n_rp_nocb_defer_wakeup++; return 1; } |
64db4cfff "Tree RCU": scala... |
3441 |
/* nothing to do */ |
7ba5c840e rcu: Add __rcu_pe... |
3442 |
rdp->n_rp_need_nothing++; |
64db4cfff "Tree RCU": scala... |
3443 3444 3445 3446 3447 3448 3449 3450 |
return 0; } /* * Check to see if there is any immediate RCU-related work to be done * by the current CPU, returning 1 if so. This function is part of the * RCU implementation; it is -not- an exported member of the RCU API. */ |
e3950ecd5 rcu: Remove "cpu"... |
3451 |
static int rcu_pending(void) |
64db4cfff "Tree RCU": scala... |
3452 |
{ |
6ce75a232 rcu: Introduce fo... |
3453 3454 3455 |
struct rcu_state *rsp; for_each_rcu_flavor(rsp) |
e3950ecd5 rcu: Remove "cpu"... |
3456 |
if (__rcu_pending(rsp, this_cpu_ptr(rsp->rda))) |
6ce75a232 rcu: Introduce fo... |
3457 3458 |
return 1; return 0; |
64db4cfff "Tree RCU": scala... |
3459 3460 3461 |
} /* |
c0f4dfd4f rcu: Make RCU_FAS... |
3462 3463 3464 |
* Return true if the specified CPU has any callback. If all_lazy is * non-NULL, store an indication of whether all callbacks are lazy. * (If there are no callbacks, all of them are deemed to be lazy.) |
64db4cfff "Tree RCU": scala... |
3465 |
*/ |
82072c4fc rcu: Change funct... |
3466 |
static bool __maybe_unused rcu_cpu_has_callbacks(bool *all_lazy) |
64db4cfff "Tree RCU": scala... |
3467 |
{ |
c0f4dfd4f rcu: Make RCU_FAS... |
3468 3469 3470 |
bool al = true; bool hc = false; struct rcu_data *rdp; |
6ce75a232 rcu: Introduce fo... |
3471 |
struct rcu_state *rsp; |
c0f4dfd4f rcu: Make RCU_FAS... |
3472 |
for_each_rcu_flavor(rsp) { |
aa6da5140 rcu: Remove "cpu"... |
3473 |
rdp = this_cpu_ptr(rsp->rda); |
69c8d28c9 rcu: Micro-optimi... |
3474 3475 3476 3477 |
if (!rdp->nxtlist) continue; hc = true; if (rdp->qlen != rdp->qlen_lazy || !all_lazy) { |
c0f4dfd4f rcu: Make RCU_FAS... |
3478 |
al = false; |
69c8d28c9 rcu: Micro-optimi... |
3479 3480 |
break; } |
c0f4dfd4f rcu: Make RCU_FAS... |
3481 3482 3483 3484 |
} if (all_lazy) *all_lazy = al; return hc; |
64db4cfff "Tree RCU": scala... |
3485 |
} |
b1420f1c8 rcu: Make rcu_bar... |
3486 |
/* |
a83eff0a8 rcu: Add tracing ... |
3487 3488 3489 |
* Helper function for _rcu_barrier() tracing. If tracing is disabled, * the compiler is expected to optimize this away. */ |
e66c33d57 rcu: Add const an... |
3490 |
static void _rcu_barrier_trace(struct rcu_state *rsp, const char *s, |
a83eff0a8 rcu: Add tracing ... |
3491 3492 3493 3494 3495 3496 3497 |
int cpu, unsigned long done) { trace_rcu_barrier(rsp->name, s, cpu, atomic_read(&rsp->barrier_cpu_count), done); } /* |
b1420f1c8 rcu: Make rcu_bar... |
3498 3499 3500 |
* RCU callback function for _rcu_barrier(). If we are last, wake * up the task executing _rcu_barrier(). */ |
24ebbca8e rcu: Move rcu_bar... |
3501 |
static void rcu_barrier_callback(struct rcu_head *rhp) |
d0ec774cb rcu: Move rcu_bar... |
3502 |
{ |
24ebbca8e rcu: Move rcu_bar... |
3503 3504 |
struct rcu_data *rdp = container_of(rhp, struct rcu_data, barrier_head); struct rcu_state *rsp = rdp->rsp; |
a83eff0a8 rcu: Add tracing ... |
3505 |
if (atomic_dec_and_test(&rsp->barrier_cpu_count)) { |
4f525a528 rcu: Apply rcu_se... |
3506 |
_rcu_barrier_trace(rsp, "LastCB", -1, rsp->barrier_sequence); |
7db74df88 rcu: Move rcu_bar... |
3507 |
complete(&rsp->barrier_completion); |
a83eff0a8 rcu: Add tracing ... |
3508 |
} else { |
4f525a528 rcu: Apply rcu_se... |
3509 |
_rcu_barrier_trace(rsp, "CB", -1, rsp->barrier_sequence); |
a83eff0a8 rcu: Add tracing ... |
3510 |
} |
d0ec774cb rcu: Move rcu_bar... |
3511 3512 3513 3514 3515 3516 3517 |
} /* * Called with preemption disabled, and from cross-cpu IRQ context. */ static void rcu_barrier_func(void *type) { |
037b64ed0 rcu: Place pointe... |
3518 |
struct rcu_state *rsp = type; |
fa07a58f7 rcu: Replace __th... |
3519 |
struct rcu_data *rdp = raw_cpu_ptr(rsp->rda); |
d0ec774cb rcu: Move rcu_bar... |
3520 |
|
4f525a528 rcu: Apply rcu_se... |
3521 |
_rcu_barrier_trace(rsp, "IRQ", -1, rsp->barrier_sequence); |
24ebbca8e rcu: Move rcu_bar... |
3522 |
atomic_inc(&rsp->barrier_cpu_count); |
06668efa9 rcu: Move _rcu_ba... |
3523 |
rsp->call(&rdp->barrier_head, rcu_barrier_callback); |
d0ec774cb rcu: Move rcu_bar... |
3524 |
} |
d0ec774cb rcu: Move rcu_bar... |
3525 3526 3527 3528 |
/* * Orchestrate the specified type of RCU barrier, waiting for all * RCU callbacks of the specified type to complete. */ |
037b64ed0 rcu: Place pointe... |
3529 |
static void _rcu_barrier(struct rcu_state *rsp) |
d0ec774cb rcu: Move rcu_bar... |
3530 |
{ |
b1420f1c8 rcu: Make rcu_bar... |
3531 |
int cpu; |
b1420f1c8 rcu: Make rcu_bar... |
3532 |
struct rcu_data *rdp; |
4f525a528 rcu: Apply rcu_se... |
3533 |
unsigned long s = rcu_seq_snap(&rsp->barrier_sequence); |
b1420f1c8 rcu: Make rcu_bar... |
3534 |
|
4f525a528 rcu: Apply rcu_se... |
3535 |
_rcu_barrier_trace(rsp, "Begin", -1, s); |
b1420f1c8 rcu: Make rcu_bar... |
3536 |
|
e74f4c456 rcu: Make hot-unp... |
3537 |
/* Take mutex to serialize concurrent rcu_barrier() requests. */ |
7be7f0be9 rcu: Move rcu_bar... |
3538 |
mutex_lock(&rsp->barrier_mutex); |
b1420f1c8 rcu: Make rcu_bar... |
3539 |
|
4f525a528 rcu: Apply rcu_se... |
3540 3541 3542 |
/* Did someone else do our work for us? */ if (rcu_seq_done(&rsp->barrier_sequence, s)) { _rcu_barrier_trace(rsp, "EarlyExit", -1, rsp->barrier_sequence); |
cf3a9c484 rcu: Increase rcu... |
3543 3544 3545 3546 |
smp_mb(); /* caller's subsequent code after above check. */ mutex_unlock(&rsp->barrier_mutex); return; } |
4f525a528 rcu: Apply rcu_se... |
3547 3548 3549 |
/* Mark the start of the barrier operation. */ rcu_seq_start(&rsp->barrier_sequence); _rcu_barrier_trace(rsp, "Inc1", -1, rsp->barrier_sequence); |
b1420f1c8 rcu: Make rcu_bar... |
3550 |
|
d0ec774cb rcu: Move rcu_bar... |
3551 |
/* |
b1420f1c8 rcu: Make rcu_bar... |
3552 3553 |
* Initialize the count to one rather than to zero in order to * avoid a too-soon return to zero in case of a short grace period |
1331e7a1b rcu: Remove _rcu_... |
3554 3555 |
* (or preemption of this task). Exclude CPU-hotplug operations * to ensure that no offline CPU has callbacks queued. |
d0ec774cb rcu: Move rcu_bar... |
3556 |
*/ |
7db74df88 rcu: Move rcu_bar... |
3557 |
init_completion(&rsp->barrier_completion); |
24ebbca8e rcu: Move rcu_bar... |
3558 |
atomic_set(&rsp->barrier_cpu_count, 1); |
1331e7a1b rcu: Remove _rcu_... |
3559 |
get_online_cpus(); |
b1420f1c8 rcu: Make rcu_bar... |
3560 3561 |
/* |
1331e7a1b rcu: Remove _rcu_... |
3562 3563 3564 |
* Force each CPU with callbacks to register a new callback. * When that callback is invoked, we will know that all of the * corresponding CPU's preceding callbacks have been invoked. |
b1420f1c8 rcu: Make rcu_bar... |
3565 |
*/ |
3fbfbf7a3 rcu: Add callback... |
3566 |
for_each_possible_cpu(cpu) { |
d1e43fa5f nohz: Ensure full... |
3567 |
if (!cpu_online(cpu) && !rcu_is_nocb_cpu(cpu)) |
3fbfbf7a3 rcu: Add callback... |
3568 |
continue; |
b1420f1c8 rcu: Make rcu_bar... |
3569 |
rdp = per_cpu_ptr(rsp->rda, cpu); |
d1e43fa5f nohz: Ensure full... |
3570 |
if (rcu_is_nocb_cpu(cpu)) { |
d7e299339 rcu: Make rcu_bar... |
3571 3572 |
if (!rcu_nocb_cpu_needs_barrier(rsp, cpu)) { _rcu_barrier_trace(rsp, "OfflineNoCB", cpu, |
4f525a528 rcu: Apply rcu_se... |
3573 |
rsp->barrier_sequence); |
d7e299339 rcu: Make rcu_bar... |
3574 3575 |
} else { _rcu_barrier_trace(rsp, "OnlineNoCB", cpu, |
4f525a528 rcu: Apply rcu_se... |
3576 |
rsp->barrier_sequence); |
41050a009 rcu: Fix rcu_barr... |
3577 |
smp_mb__before_atomic(); |
d7e299339 rcu: Make rcu_bar... |
3578 3579 3580 3581 |
atomic_inc(&rsp->barrier_cpu_count); __call_rcu(&rdp->barrier_head, rcu_barrier_callback, rsp, cpu, 0); } |
7d0ae8086 rcu: Convert ACCE... |
3582 |
} else if (READ_ONCE(rdp->qlen)) { |
a83eff0a8 rcu: Add tracing ... |
3583 |
_rcu_barrier_trace(rsp, "OnlineQ", cpu, |
4f525a528 rcu: Apply rcu_se... |
3584 |
rsp->barrier_sequence); |
037b64ed0 rcu: Place pointe... |
3585 |
smp_call_function_single(cpu, rcu_barrier_func, rsp, 1); |
b1420f1c8 rcu: Make rcu_bar... |
3586 |
} else { |
a83eff0a8 rcu: Add tracing ... |
3587 |
_rcu_barrier_trace(rsp, "OnlineNQ", cpu, |
4f525a528 rcu: Apply rcu_se... |
3588 |
rsp->barrier_sequence); |
b1420f1c8 rcu: Make rcu_bar... |
3589 3590 |
} } |
1331e7a1b rcu: Remove _rcu_... |
3591 |
put_online_cpus(); |
b1420f1c8 rcu: Make rcu_bar... |
3592 3593 3594 3595 3596 |
/* * Now that we have an rcu_barrier_callback() callback on each * CPU, and thus each counted, remove the initial count. */ |
24ebbca8e rcu: Move rcu_bar... |
3597 |
if (atomic_dec_and_test(&rsp->barrier_cpu_count)) |
7db74df88 rcu: Move rcu_bar... |
3598 |
complete(&rsp->barrier_completion); |
b1420f1c8 rcu: Make rcu_bar... |
3599 3600 |
/* Wait for all rcu_barrier_callback() callbacks to be invoked. */ |
7db74df88 rcu: Move rcu_bar... |
3601 |
wait_for_completion(&rsp->barrier_completion); |
b1420f1c8 rcu: Make rcu_bar... |
3602 |
|
4f525a528 rcu: Apply rcu_se... |
3603 3604 3605 |
/* Mark the end of the barrier operation. */ _rcu_barrier_trace(rsp, "Inc2", -1, rsp->barrier_sequence); rcu_seq_end(&rsp->barrier_sequence); |
b1420f1c8 rcu: Make rcu_bar... |
3606 |
/* Other rcu_barrier() invocations can now safely proceed. */ |
7be7f0be9 rcu: Move rcu_bar... |
3607 |
mutex_unlock(&rsp->barrier_mutex); |
d0ec774cb rcu: Move rcu_bar... |
3608 |
} |
d0ec774cb rcu: Move rcu_bar... |
3609 3610 3611 3612 3613 3614 |
/** * rcu_barrier_bh - Wait until all in-flight call_rcu_bh() callbacks complete. */ void rcu_barrier_bh(void) { |
037b64ed0 rcu: Place pointe... |
3615 |
_rcu_barrier(&rcu_bh_state); |
d0ec774cb rcu: Move rcu_bar... |
3616 3617 3618 3619 3620 3621 3622 3623 |
} EXPORT_SYMBOL_GPL(rcu_barrier_bh); /** * rcu_barrier_sched - Wait for in-flight call_rcu_sched() callbacks. */ void rcu_barrier_sched(void) { |
037b64ed0 rcu: Place pointe... |
3624 |
_rcu_barrier(&rcu_sched_state); |
d0ec774cb rcu: Move rcu_bar... |
3625 3626 |
} EXPORT_SYMBOL_GPL(rcu_barrier_sched); |
64db4cfff "Tree RCU": scala... |
3627 |
/* |
0aa04b055 rcu: Process offl... |
3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 |
* Propagate ->qsinitmask bits up the rcu_node tree to account for the * first CPU in a given leaf rcu_node structure coming online. The caller * must hold the corresponding leaf rcu_node ->lock with interrrupts * disabled. */ static void rcu_init_new_rnp(struct rcu_node *rnp_leaf) { long mask; struct rcu_node *rnp = rnp_leaf; for (;;) { mask = rnp->grpmask; rnp = rnp->parent; if (rnp == NULL) return; |
6cf100812 rcu: Add transiti... |
3643 |
raw_spin_lock_rcu_node(rnp); /* Interrupts already disabled. */ |
0aa04b055 rcu: Process offl... |
3644 |
rnp->qsmaskinit |= mask; |
67c583a7d RCU: Privatize rc... |
3645 |
raw_spin_unlock_rcu_node(rnp); /* Interrupts remain disabled. */ |
0aa04b055 rcu: Process offl... |
3646 3647 3648 3649 |
} } /* |
27569620c rcu: Split hierar... |
3650 |
* Do boot-time initialization of a CPU's per-CPU RCU data. |
64db4cfff "Tree RCU": scala... |
3651 |
*/ |
27569620c rcu: Split hierar... |
3652 3653 |
static void __init rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp) |
64db4cfff "Tree RCU": scala... |
3654 3655 |
{ unsigned long flags; |
394f99a90 rcu: simplify the... |
3656 |
struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); |
27569620c rcu: Split hierar... |
3657 3658 3659 |
struct rcu_node *rnp = rcu_get_root(rsp); /* Set up local state, ensuring consistent view of global state. */ |
6cf100812 rcu: Add transiti... |
3660 |
raw_spin_lock_irqsave_rcu_node(rnp, flags); |
bc75e9998 rcu: Correctly ha... |
3661 |
rdp->grpmask = leaf_node_cpu_bit(rdp->mynode, cpu); |
27569620c rcu: Split hierar... |
3662 |
rdp->dynticks = &per_cpu(rcu_dynticks, cpu); |
29e37d814 rcu: Allow nestin... |
3663 |
WARN_ON_ONCE(rdp->dynticks->dynticks_nesting != DYNTICK_TASK_EXIT_IDLE); |
9b2e4f188 rcu: Track idlene... |
3664 |
WARN_ON_ONCE(atomic_read(&rdp->dynticks->dynticks) != 1); |
27569620c rcu: Split hierar... |
3665 |
rdp->cpu = cpu; |
d4c08f2ac rcu: Add grace-pe... |
3666 |
rdp->rsp = rsp; |
3fbfbf7a3 rcu: Add callback... |
3667 |
rcu_boot_init_nocb_percpu_data(rdp); |
67c583a7d RCU: Privatize rc... |
3668 |
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); |
27569620c rcu: Split hierar... |
3669 3670 3671 3672 3673 3674 3675 |
} /* * Initialize a CPU's per-CPU RCU data. Note that only one online or * offline event can be happening at a given time. Note also that we * can accept some slop in the rsp->completed access due to the fact * that this CPU cannot possibly have any RCU callbacks in flight yet. |
64db4cfff "Tree RCU": scala... |
3676 |
*/ |
49fb4c629 rcu: delete __cpu... |
3677 |
static void |
9b67122ae rcu: Remove unuse... |
3678 |
rcu_init_percpu_data(int cpu, struct rcu_state *rsp) |
64db4cfff "Tree RCU": scala... |
3679 3680 |
{ unsigned long flags; |
64db4cfff "Tree RCU": scala... |
3681 |
unsigned long mask; |
394f99a90 rcu: simplify the... |
3682 |
struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); |
64db4cfff "Tree RCU": scala... |
3683 3684 3685 |
struct rcu_node *rnp = rcu_get_root(rsp); /* Set up local state, ensuring consistent view of global state. */ |
6cf100812 rcu: Add transiti... |
3686 |
raw_spin_lock_irqsave_rcu_node(rnp, flags); |
37c72e56f rcu: Prevent RCU ... |
3687 3688 |
rdp->qlen_last_fqs_check = 0; rdp->n_force_qs_snap = rsp->n_force_qs; |
64db4cfff "Tree RCU": scala... |
3689 |
rdp->blimit = blimit; |
39c8d313c rcu: Avoid clobbe... |
3690 3691 |
if (!rdp->nxtlist) init_callback_list(rdp); /* Re-enable callbacks on this CPU. */ |
29e37d814 rcu: Allow nestin... |
3692 |
rdp->dynticks->dynticks_nesting = DYNTICK_TASK_EXIT_IDLE; |
2333210b2 nohz_full: Add rc... |
3693 |
rcu_sysidle_init_percpu_data(rdp->dynticks); |
c92b131bd rcu: Remove dynti... |
3694 3695 |
atomic_set(&rdp->dynticks->dynticks, (atomic_read(&rdp->dynticks->dynticks) & ~0x1) + 1); |
67c583a7d RCU: Privatize rc... |
3696 |
raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled. */ |
64db4cfff "Tree RCU": scala... |
3697 |
|
0aa04b055 rcu: Process offl... |
3698 3699 3700 3701 3702 |
/* * Add CPU to leaf rcu_node pending-online bitmask. Any needed * propagation up the rcu_node tree will happen at the beginning * of the next grace period. */ |
64db4cfff "Tree RCU": scala... |
3703 3704 |
rnp = rdp->mynode; mask = rdp->grpmask; |
2a67e741b rcu: Create trans... |
3705 |
raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */ |
b9585e940 rcu: Consolidate ... |
3706 3707 3708 |
if (!rdp->beenonline) WRITE_ONCE(rsp->ncpus, READ_ONCE(rsp->ncpus) + 1); rdp->beenonline = true; /* We have now been online. */ |
0aa04b055 rcu: Process offl... |
3709 3710 |
rdp->gpnum = rnp->completed; /* Make CPU later note any new GP. */ rdp->completed = rnp->completed; |
5b74c4589 rcu: Make ->cpu_n... |
3711 |
rdp->cpu_no_qs.b.norm = true; |
a738eec6c rcu: Correctly in... |
3712 |
rdp->rcu_qs_ctr_snap = per_cpu(rcu_qs_ctr, cpu); |
97c668b8e rcu: Rename qs_pe... |
3713 |
rdp->core_needs_qs = false; |
0aa04b055 rcu: Process offl... |
3714 |
trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("cpuonl")); |
67c583a7d RCU: Privatize rc... |
3715 |
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); |
64db4cfff "Tree RCU": scala... |
3716 |
} |
4df837425 rcu: Convert rcut... |
3717 |
int rcutree_prepare_cpu(unsigned int cpu) |
64db4cfff "Tree RCU": scala... |
3718 |
{ |
6ce75a232 rcu: Introduce fo... |
3719 3720 3721 |
struct rcu_state *rsp; for_each_rcu_flavor(rsp) |
9b67122ae rcu: Remove unuse... |
3722 |
rcu_init_percpu_data(cpu, rsp); |
4df837425 rcu: Convert rcut... |
3723 3724 3725 3726 3727 3728 3729 3730 3731 3732 3733 3734 3735 3736 3737 3738 3739 3740 3741 3742 3743 3744 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754 3755 3756 3757 3758 3759 3760 3761 3762 3763 3764 3765 3766 3767 3768 |
rcu_prepare_kthreads(cpu); rcu_spawn_all_nocb_kthreads(cpu); return 0; } static void rcutree_affinity_setting(unsigned int cpu, int outgoing) { struct rcu_data *rdp = per_cpu_ptr(rcu_state_p->rda, cpu); rcu_boost_kthread_setaffinity(rdp->mynode, outgoing); } int rcutree_online_cpu(unsigned int cpu) { sync_sched_exp_online_cleanup(cpu); rcutree_affinity_setting(cpu, -1); return 0; } int rcutree_offline_cpu(unsigned int cpu) { rcutree_affinity_setting(cpu, cpu); return 0; } int rcutree_dying_cpu(unsigned int cpu) { struct rcu_state *rsp; for_each_rcu_flavor(rsp) rcu_cleanup_dying_cpu(rsp); return 0; } int rcutree_dead_cpu(unsigned int cpu) { struct rcu_state *rsp; for_each_rcu_flavor(rsp) { rcu_cleanup_dead_cpu(cpu, rsp); do_nocb_deferred_wakeup(per_cpu_ptr(rsp->rda, cpu)); } return 0; |
64db4cfff "Tree RCU": scala... |
3769 |
} |
7ec99de36 rcu: Provide exac... |
3770 3771 3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 |
/* * Mark the specified CPU as being online so that subsequent grace periods * (both expedited and normal) will wait on it. Note that this means that * incoming CPUs are not allowed to use RCU read-side critical sections * until this function is called. Failing to observe this restriction * will result in lockdep splats. */ void rcu_cpu_starting(unsigned int cpu) { unsigned long flags; unsigned long mask; struct rcu_data *rdp; struct rcu_node *rnp; struct rcu_state *rsp; for_each_rcu_flavor(rsp) { rdp = this_cpu_ptr(rsp->rda); rnp = rdp->mynode; mask = rdp->grpmask; raw_spin_lock_irqsave_rcu_node(rnp, flags); rnp->qsmaskinitnext |= mask; rnp->expmaskinitnext |= mask; raw_spin_unlock_irqrestore_rcu_node(rnp, flags); } } |
27d50c7ee rcu: Make CPU_DYI... |
3795 3796 3797 3798 3799 |
#ifdef CONFIG_HOTPLUG_CPU /* * The CPU is exiting the idle loop into the arch_cpu_idle_dead() * function. We now remove it from the rcu_node tree's ->qsmaskinit * bit masks. |
710d60cbf Merge branch 'smp... |
3800 3801 3802 |
* The CPU is exiting the idle loop into the arch_cpu_idle_dead() * function. We now remove it from the rcu_node tree's ->qsmaskinit * bit masks. |
27d50c7ee rcu: Make CPU_DYI... |
3803 3804 3805 3806 3807 3808 3809 |
*/ static void rcu_cleanup_dying_idle_cpu(int cpu, struct rcu_state *rsp) { unsigned long flags; unsigned long mask; struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); struct rcu_node *rnp = rdp->mynode; /* Outgoing CPU's rdp & rnp. */ |
27d50c7ee rcu: Make CPU_DYI... |
3810 3811 3812 3813 |
/* Remove outgoing CPU from mask in the leaf rcu_node structure. */ mask = rdp->grpmask; raw_spin_lock_irqsave_rcu_node(rnp, flags); /* Enforce GP memory-order guarantee. */ rnp->qsmaskinitnext &= ~mask; |
710d60cbf Merge branch 'smp... |
3814 |
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); |
27d50c7ee rcu: Make CPU_DYI... |
3815 3816 3817 3818 3819 3820 3821 3822 3823 3824 3825 3826 3827 3828 3829 |
} void rcu_report_dead(unsigned int cpu) { struct rcu_state *rsp; /* QS for any half-done expedited RCU-sched GP. */ preempt_disable(); rcu_report_exp_rdp(&rcu_sched_state, this_cpu_ptr(rcu_sched_state.rda), true); preempt_enable(); for_each_rcu_flavor(rsp) rcu_cleanup_dying_idle_cpu(cpu, rsp); } #endif |
d1d74d14e rcu: Expedite gra... |
3830 3831 3832 3833 3834 3835 3836 |
static int rcu_pm_notify(struct notifier_block *self, unsigned long action, void *hcpu) { switch (action) { case PM_HIBERNATION_PREPARE: case PM_SUSPEND_PREPARE: if (nr_cpu_ids <= 256) /* Expediting bad for large systems. */ |
5afff48bd rcu: Update from ... |
3837 |
rcu_expedite_gp(); |
d1d74d14e rcu: Expedite gra... |
3838 3839 3840 |
break; case PM_POST_HIBERNATION: case PM_POST_SUSPEND: |
5afff48bd rcu: Update from ... |
3841 3842 |
if (nr_cpu_ids <= 256) /* Expediting bad for large systems. */ rcu_unexpedite_gp(); |
d1d74d14e rcu: Expedite gra... |
3843 3844 3845 3846 3847 3848 |
break; default: break; } return NOTIFY_OK; } |
64db4cfff "Tree RCU": scala... |
3849 |
/* |
9386c0b75 rcu: Rationalize ... |
3850 |
* Spawn the kthreads that handle each RCU flavor's grace periods. |
b3dbec76e rcu: Move RCU gra... |
3851 3852 3853 3854 |
*/ static int __init rcu_spawn_gp_kthread(void) { unsigned long flags; |
a94844b22 rcu: Optionally r... |
3855 |
int kthread_prio_in = kthread_prio; |
b3dbec76e rcu: Move RCU gra... |
3856 3857 |
struct rcu_node *rnp; struct rcu_state *rsp; |
a94844b22 rcu: Optionally r... |
3858 |
struct sched_param sp; |
b3dbec76e rcu: Move RCU gra... |
3859 |
struct task_struct *t; |
a94844b22 rcu: Optionally r... |
3860 3861 3862 3863 3864 3865 3866 3867 3868 3869 3870 |
/* Force priority into range. */ if (IS_ENABLED(CONFIG_RCU_BOOST) && kthread_prio < 1) kthread_prio = 1; else if (kthread_prio < 0) kthread_prio = 0; else if (kthread_prio > 99) kthread_prio = 99; if (kthread_prio != kthread_prio_in) pr_alert("rcu_spawn_gp_kthread(): Limited prio to %d from %d ", kthread_prio, kthread_prio_in); |
9386c0b75 rcu: Rationalize ... |
3871 |
rcu_scheduler_fully_active = 1; |
b3dbec76e rcu: Move RCU gra... |
3872 |
for_each_rcu_flavor(rsp) { |
a94844b22 rcu: Optionally r... |
3873 |
t = kthread_create(rcu_gp_kthread, rsp, "%s", rsp->name); |
b3dbec76e rcu: Move RCU gra... |
3874 3875 |
BUG_ON(IS_ERR(t)); rnp = rcu_get_root(rsp); |
6cf100812 rcu: Add transiti... |
3876 |
raw_spin_lock_irqsave_rcu_node(rnp, flags); |
b3dbec76e rcu: Move RCU gra... |
3877 |
rsp->gp_kthread = t; |
a94844b22 rcu: Optionally r... |
3878 3879 3880 3881 |
if (kthread_prio) { sp.sched_priority = kthread_prio; sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); } |
67c583a7d RCU: Privatize rc... |
3882 |
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); |
e11f13355 rcu: Move wakeup ... |
3883 |
wake_up_process(t); |
b3dbec76e rcu: Move RCU gra... |
3884 |
} |
35ce7f29a rcu: Create rcuo ... |
3885 |
rcu_spawn_nocb_kthreads(); |
9386c0b75 rcu: Rationalize ... |
3886 |
rcu_spawn_boost_kthreads(); |
b3dbec76e rcu: Move RCU gra... |
3887 3888 3889 3890 3891 |
return 0; } early_initcall(rcu_spawn_gp_kthread); /* |
90687fc3c rcu: Narrow early... |
3892 3893 3894 3895 3896 3897 3898 3899 |
* This function is invoked towards the end of the scheduler's * initialization process. Before this is called, the idle task might * contain synchronous grace-period primitives (during which time, this idle * task is booting the system, and such primitives are no-ops). After this * function is called, any synchronous grace-period primitives are run as * expedited, with the requesting task driving the grace period forward. * A later core_initcall() rcu_exp_runtime_mode() will switch to full * runtime RCU functionality. |
bbad93798 rcu: slim down rc... |
3900 3901 3902 3903 3904 |
*/ void rcu_scheduler_starting(void) { WARN_ON(num_online_cpus() != 1); WARN_ON(nr_context_switches() > 0); |
90687fc3c rcu: Narrow early... |
3905 3906 3907 |
rcu_test_sync_prims(); rcu_scheduler_active = RCU_SCHEDULER_INIT; rcu_test_sync_prims(); |
bbad93798 rcu: slim down rc... |
3908 3909 3910 |
} /* |
64db4cfff "Tree RCU": scala... |
3911 |
* Compute the per-level fanout, either using the exact fanout specified |
7fa270010 rcu: Convert CONF... |
3912 |
* or balancing the tree, depending on the rcu_fanout_exact boot parameter. |
64db4cfff "Tree RCU": scala... |
3913 |
*/ |
199977bff rcu: Remove unnec... |
3914 |
static void __init rcu_init_levelspread(int *levelspread, const int *levelcnt) |
64db4cfff "Tree RCU": scala... |
3915 |
{ |
64db4cfff "Tree RCU": scala... |
3916 |
int i; |
7fa270010 rcu: Convert CONF... |
3917 |
if (rcu_fanout_exact) { |
199977bff rcu: Remove unnec... |
3918 |
levelspread[rcu_num_lvls - 1] = rcu_fanout_leaf; |
662924057 rcu: Use IS_ENABL... |
3919 |
for (i = rcu_num_lvls - 2; i >= 0; i--) |
199977bff rcu: Remove unnec... |
3920 |
levelspread[i] = RCU_FANOUT; |
662924057 rcu: Use IS_ENABL... |
3921 3922 3923 3924 3925 3926 |
} else { int ccur; int cprv; cprv = nr_cpu_ids; for (i = rcu_num_lvls - 1; i >= 0; i--) { |
199977bff rcu: Remove unnec... |
3927 3928 |
ccur = levelcnt[i]; levelspread[i] = (cprv + ccur - 1) / ccur; |
662924057 rcu: Use IS_ENABL... |
3929 3930 |
cprv = ccur; } |
64db4cfff "Tree RCU": scala... |
3931 3932 |
} } |
64db4cfff "Tree RCU": scala... |
3933 3934 3935 3936 |
/* * Helper function for rcu_init() that initializes one rcu_state structure. */ |
a87f203e2 rcu: Eliminate un... |
3937 |
static void __init rcu_init_one(struct rcu_state *rsp) |
64db4cfff "Tree RCU": scala... |
3938 |
{ |
cb0071023 rcu: Limit count ... |
3939 3940 |
static const char * const buf[] = RCU_NODE_NAME_INIT; static const char * const fqs[] = RCU_FQS_NAME_INIT; |
3dc5dbe9a rcu: Move lock_cl... |
3941 3942 |
static struct lock_class_key rcu_node_class[RCU_NUM_LVLS]; static struct lock_class_key rcu_fqs_class[RCU_NUM_LVLS]; |
4a81e8328 rcu: Reduce overh... |
3943 |
static u8 fl_mask = 0x1; |
199977bff rcu: Remove unnec... |
3944 3945 3946 |
int levelcnt[RCU_NUM_LVLS]; /* # nodes in each level. */ int levelspread[RCU_NUM_LVLS]; /* kids/node in each level. */ |
64db4cfff "Tree RCU": scala... |
3947 3948 3949 3950 |
int cpustride = 1; int i; int j; struct rcu_node *rnp; |
05b84aec4 rcu: Limit rcu_ca... |
3951 |
BUILD_BUG_ON(RCU_NUM_LVLS > ARRAY_SIZE(buf)); /* Fix buf[] init! */ |
b6407e863 rcu: Give differe... |
3952 |
|
3eaaaf6cd rcu: Shut up spur... |
3953 3954 3955 |
/* Silence gcc 4.8 false positive about array index out of range. */ if (rcu_num_lvls <= 0 || rcu_num_lvls > RCU_NUM_LVLS) panic("rcu_init_one: rcu_num_lvls out of range"); |
4930521ae rcu: Silence comp... |
3956 |
|
64db4cfff "Tree RCU": scala... |
3957 |
/* Initialize the level-tracking arrays. */ |
f885b7f2b rcu: Control RCU_... |
3958 |
for (i = 0; i < rcu_num_lvls; i++) |
199977bff rcu: Remove unnec... |
3959 |
levelcnt[i] = num_rcu_lvl[i]; |
f885b7f2b rcu: Control RCU_... |
3960 |
for (i = 1; i < rcu_num_lvls; i++) |
199977bff rcu: Remove unnec... |
3961 3962 |
rsp->level[i] = rsp->level[i - 1] + levelcnt[i - 1]; rcu_init_levelspread(levelspread, levelcnt); |
4a81e8328 rcu: Reduce overh... |
3963 3964 |
rsp->flavor_mask = fl_mask; fl_mask <<= 1; |
64db4cfff "Tree RCU": scala... |
3965 3966 |
/* Initialize the elements themselves, starting from the leaves. */ |
f885b7f2b rcu: Control RCU_... |
3967 |
for (i = rcu_num_lvls - 1; i >= 0; i--) { |
199977bff rcu: Remove unnec... |
3968 |
cpustride *= levelspread[i]; |
64db4cfff "Tree RCU": scala... |
3969 |
rnp = rsp->level[i]; |
199977bff rcu: Remove unnec... |
3970 |
for (j = 0; j < levelcnt[i]; j++, rnp++) { |
67c583a7d RCU: Privatize rc... |
3971 3972 |
raw_spin_lock_init(&ACCESS_PRIVATE(rnp, lock)); lockdep_set_class_and_name(&ACCESS_PRIVATE(rnp, lock), |
b6407e863 rcu: Give differe... |
3973 |
&rcu_node_class[i], buf[i]); |
394f2769a rcu: Prevent forc... |
3974 3975 3976 |
raw_spin_lock_init(&rnp->fqslock); lockdep_set_class_and_name(&rnp->fqslock, &rcu_fqs_class[i], fqs[i]); |
25d30cf42 rcu: Adjust for u... |
3977 3978 |
rnp->gpnum = rsp->gpnum; rnp->completed = rsp->completed; |
64db4cfff "Tree RCU": scala... |
3979 3980 3981 3982 |
rnp->qsmask = 0; rnp->qsmaskinit = 0; rnp->grplo = j * cpustride; rnp->grphi = (j + 1) * cpustride - 1; |
595f3900f rcu: Replace NR_C... |
3983 3984 |
if (rnp->grphi >= nr_cpu_ids) rnp->grphi = nr_cpu_ids - 1; |
64db4cfff "Tree RCU": scala... |
3985 3986 3987 3988 3989 |
if (i == 0) { rnp->grpnum = 0; rnp->grpmask = 0; rnp->parent = NULL; } else { |
199977bff rcu: Remove unnec... |
3990 |
rnp->grpnum = j % levelspread[i - 1]; |
64db4cfff "Tree RCU": scala... |
3991 3992 |
rnp->grpmask = 1UL << rnp->grpnum; rnp->parent = rsp->level[i - 1] + |
199977bff rcu: Remove unnec... |
3993 |
j / levelspread[i - 1]; |
64db4cfff "Tree RCU": scala... |
3994 3995 |
} rnp->level = i; |
12f5f524c rcu: merge TREE_P... |
3996 |
INIT_LIST_HEAD(&rnp->blkd_tasks); |
dae6e64d2 rcu: Introduce pr... |
3997 |
rcu_init_one_nocb(rnp); |
f6a12f34a rcu: Enforce expe... |
3998 3999 |
init_waitqueue_head(&rnp->exp_wq[0]); init_waitqueue_head(&rnp->exp_wq[1]); |
3b5f668e7 rcu: Overlap wake... |
4000 4001 |
init_waitqueue_head(&rnp->exp_wq[2]); init_waitqueue_head(&rnp->exp_wq[3]); |
f6a12f34a rcu: Enforce expe... |
4002 |
spin_lock_init(&rnp->exp_lock); |
64db4cfff "Tree RCU": scala... |
4003 4004 |
} } |
0c34029ab rcu: move some co... |
4005 |
|
abedf8e24 rcu: Use simple w... |
4006 4007 |
init_swait_queue_head(&rsp->gp_wq); init_swait_queue_head(&rsp->expedited_wq); |
f885b7f2b rcu: Control RCU_... |
4008 |
rnp = rsp->level[rcu_num_lvls - 1]; |
0c34029ab rcu: move some co... |
4009 |
for_each_possible_cpu(i) { |
4a90a0681 rcu: permit disco... |
4010 |
while (i > rnp->grphi) |
0c34029ab rcu: move some co... |
4011 |
rnp++; |
394f99a90 rcu: simplify the... |
4012 |
per_cpu_ptr(rsp->rda, i)->mynode = rnp; |
0c34029ab rcu: move some co... |
4013 4014 |
rcu_boot_init_percpu_data(i, rsp); } |
6ce75a232 rcu: Introduce fo... |
4015 |
list_add(&rsp->flavors, &rcu_struct_flavors); |
64db4cfff "Tree RCU": scala... |
4016 |
} |
f885b7f2b rcu: Control RCU_... |
4017 4018 |
/* * Compute the rcu_node tree geometry from kernel parameters. This cannot |
4102adab9 rcu: Move RCU-rel... |
4019 |
* replace the definitions in tree.h because those are needed to size |
f885b7f2b rcu: Control RCU_... |
4020 4021 4022 4023 |
* the ->node array in the rcu_state structure. */ static void __init rcu_init_geometry(void) { |
026ad2835 rcu: Drive quiesc... |
4024 |
ulong d; |
f885b7f2b rcu: Control RCU_... |
4025 |
int i; |
05b84aec4 rcu: Limit rcu_ca... |
4026 |
int rcu_capacity[RCU_NUM_LVLS]; |
f885b7f2b rcu: Control RCU_... |
4027 |
|
026ad2835 rcu: Drive quiesc... |
4028 4029 4030 4031 4032 4033 4034 4035 4036 4037 4038 4039 |
/* * Initialize any unspecified boot parameters. * The default values of jiffies_till_first_fqs and * jiffies_till_next_fqs are set to the RCU_JIFFIES_TILL_FORCE_QS * value, which is a function of HZ, then adding one for each * RCU_JIFFIES_FQS_DIV CPUs that might be on the system. */ d = RCU_JIFFIES_TILL_FORCE_QS + nr_cpu_ids / RCU_JIFFIES_FQS_DIV; if (jiffies_till_first_fqs == ULONG_MAX) jiffies_till_first_fqs = d; if (jiffies_till_next_fqs == ULONG_MAX) jiffies_till_next_fqs = d; |
f885b7f2b rcu: Control RCU_... |
4040 |
/* If the compile-time values are accurate, just leave. */ |
47d631af5 rcu: Make RCU abl... |
4041 |
if (rcu_fanout_leaf == RCU_FANOUT_LEAF && |
b17c7035f rcu: Shrink RCU b... |
4042 |
nr_cpu_ids == NR_CPUS) |
f885b7f2b rcu: Control RCU_... |
4043 |
return; |
394790981 rcu: Let the worl... |
4044 4045 4046 |
pr_info("RCU: Adjusting geometry for rcu_fanout_leaf=%d, nr_cpu_ids=%d ", rcu_fanout_leaf, nr_cpu_ids); |
f885b7f2b rcu: Control RCU_... |
4047 4048 |
/* |
ee968ac61 rcu: Eliminate pa... |
4049 4050 4051 4052 |
* The boot-time rcu_fanout_leaf parameter must be at least two * and cannot exceed the number of bits in the rcu_node masks. * Complain and fall back to the compile-time values if this * limit is exceeded. |
f885b7f2b rcu: Control RCU_... |
4053 |
*/ |
ee968ac61 rcu: Eliminate pa... |
4054 |
if (rcu_fanout_leaf < 2 || |
75cf15a4c rcu: Panic if RCU... |
4055 |
rcu_fanout_leaf > sizeof(unsigned long) * 8) { |
13bd64947 rcu: Reset rcu_fa... |
4056 |
rcu_fanout_leaf = RCU_FANOUT_LEAF; |
f885b7f2b rcu: Control RCU_... |
4057 4058 4059 |
WARN_ON(1); return; } |
75cf15a4c rcu: Panic if RCU... |
4060 |
/* |
f885b7f2b rcu: Control RCU_... |
4061 |
* Compute number of nodes that can be handled an rcu_node tree |
9618138b0 rcu: Simplify rcu... |
4062 |
* with the given number of levels. |
f885b7f2b rcu: Control RCU_... |
4063 |
*/ |
9618138b0 rcu: Simplify rcu... |
4064 |
rcu_capacity[0] = rcu_fanout_leaf; |
05b84aec4 rcu: Limit rcu_ca... |
4065 |
for (i = 1; i < RCU_NUM_LVLS; i++) |
05c5df31a rcu: Make RCU abl... |
4066 |
rcu_capacity[i] = rcu_capacity[i - 1] * RCU_FANOUT; |
f885b7f2b rcu: Control RCU_... |
4067 4068 |
/* |
75cf15a4c rcu: Panic if RCU... |
4069 |
* The tree must be able to accommodate the configured number of CPUs. |
ee968ac61 rcu: Eliminate pa... |
4070 |
* If this limit is exceeded, fall back to the compile-time values. |
f885b7f2b rcu: Control RCU_... |
4071 |
*/ |
ee968ac61 rcu: Eliminate pa... |
4072 4073 4074 4075 4076 |
if (nr_cpu_ids > rcu_capacity[RCU_NUM_LVLS - 1]) { rcu_fanout_leaf = RCU_FANOUT_LEAF; WARN_ON(1); return; } |
f885b7f2b rcu: Control RCU_... |
4077 |
|
679f9858b rcu: Cleanup rcu_... |
4078 |
/* Calculate the number of levels in the tree. */ |
9618138b0 rcu: Simplify rcu... |
4079 |
for (i = 0; nr_cpu_ids > rcu_capacity[i]; i++) { |
679f9858b rcu: Cleanup rcu_... |
4080 |
} |
9618138b0 rcu: Simplify rcu... |
4081 |
rcu_num_lvls = i + 1; |
679f9858b rcu: Cleanup rcu_... |
4082 |
|
f885b7f2b rcu: Control RCU_... |
4083 |
/* Calculate the number of rcu_nodes at each level of the tree. */ |
679f9858b rcu: Cleanup rcu_... |
4084 |
for (i = 0; i < rcu_num_lvls; i++) { |
9618138b0 rcu: Simplify rcu... |
4085 |
int cap = rcu_capacity[(rcu_num_lvls - 1) - i]; |
679f9858b rcu: Cleanup rcu_... |
4086 4087 |
num_rcu_lvl[i] = DIV_ROUND_UP(nr_cpu_ids, cap); } |
f885b7f2b rcu: Control RCU_... |
4088 4089 4090 |
/* Calculate the total number of rcu_node structures. */ rcu_num_nodes = 0; |
679f9858b rcu: Cleanup rcu_... |
4091 |
for (i = 0; i < rcu_num_lvls; i++) |
f885b7f2b rcu: Control RCU_... |
4092 |
rcu_num_nodes += num_rcu_lvl[i]; |
f885b7f2b rcu: Control RCU_... |
4093 |
} |
a3dc2948c rcu: Enable diagn... |
4094 4095 4096 4097 4098 4099 4100 4101 4102 4103 4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117 |
/* * Dump out the structure of the rcu_node combining tree associated * with the rcu_state structure referenced by rsp. */ static void __init rcu_dump_rcu_node_tree(struct rcu_state *rsp) { int level = 0; struct rcu_node *rnp; pr_info("rcu_node tree layout dump "); pr_info(" "); rcu_for_each_node_breadth_first(rsp, rnp) { if (rnp->level != level) { pr_cont(" "); pr_info(" "); level = rnp->level; } pr_cont("%d:%d ^%d ", rnp->grplo, rnp->grphi, rnp->grpnum); } pr_cont(" "); } |
9f680ab41 rcu: Eliminate un... |
4118 |
void __init rcu_init(void) |
64db4cfff "Tree RCU": scala... |
4119 |
{ |
017c42613 rcu: Fix sparse w... |
4120 |
int cpu; |
9f680ab41 rcu: Eliminate un... |
4121 |
|
476276781 rcu: Move early b... |
4122 |
rcu_early_boot_tests(); |
f41d911f8 rcu: Merge preemp... |
4123 |
rcu_bootup_announce(); |
f885b7f2b rcu: Control RCU_... |
4124 |
rcu_init_geometry(); |
a87f203e2 rcu: Eliminate un... |
4125 4126 |
rcu_init_one(&rcu_bh_state); rcu_init_one(&rcu_sched_state); |
a3dc2948c rcu: Enable diagn... |
4127 4128 |
if (dump_tree) rcu_dump_rcu_node_tree(&rcu_sched_state); |
f41d911f8 rcu: Merge preemp... |
4129 |
__rcu_init_preempt(); |
b5b393601 rcu: Fix spacing ... |
4130 |
open_softirq(RCU_SOFTIRQ, rcu_process_callbacks); |
9f680ab41 rcu: Eliminate un... |
4131 4132 4133 4134 4135 4136 |
/* * We don't need protection against CPU-hotplug here because * this is called early in boot, before either interrupts * or the scheduler are operational. */ |
d1d74d14e rcu: Expedite gra... |
4137 |
pm_notifier(rcu_pm_notify, 0); |
7ec99de36 rcu: Provide exac... |
4138 |
for_each_online_cpu(cpu) { |
4df837425 rcu: Convert rcut... |
4139 |
rcutree_prepare_cpu(cpu); |
7ec99de36 rcu: Provide exac... |
4140 4141 |
rcu_cpu_starting(cpu); } |
64db4cfff "Tree RCU": scala... |
4142 |
} |
3549c2bc2 rcu: Move expedit... |
4143 |
#include "tree_exp.h" |
4102adab9 rcu: Move RCU-rel... |
4144 |
#include "tree_plugin.h" |