Blame view
lib/percpu_counter.c
5.82 KB
b24413180 License cleanup: ... |
1 |
// SPDX-License-Identifier: GPL-2.0 |
3cbc56402 [PATCH] percpu_co... |
2 3 4 5 6 |
/* * Fast batching percpu counters. */ #include <linux/percpu_counter.h> |
c67ad917c percpu_counters()... |
7 8 9 |
#include <linux/mutex.h> #include <linux/init.h> #include <linux/cpu.h> |
3cbc56402 [PATCH] percpu_co... |
10 |
#include <linux/module.h> |
e2852ae82 percpu_counter: a... |
11 |
#include <linux/debugobjects.h> |
3cbc56402 [PATCH] percpu_co... |
12 |
|
3a8495c73 lib/percpu_counte... |
13 |
#ifdef CONFIG_HOTPLUG_CPU |
c67ad917c percpu_counters()... |
14 |
static LIST_HEAD(percpu_counters); |
d87aae2f3 switch the protec... |
15 |
static DEFINE_SPINLOCK(percpu_counters_lock); |
3a8495c73 lib/percpu_counte... |
16 |
#endif |
c67ad917c percpu_counters()... |
17 |
|
e2852ae82 percpu_counter: a... |
18 19 20 |
#ifdef CONFIG_DEBUG_OBJECTS_PERCPU_COUNTER static struct debug_obj_descr percpu_counter_debug_descr; |
d99b1d891 percpu_counter: u... |
21 |
static bool percpu_counter_fixup_free(void *addr, enum debug_obj_state state) |
e2852ae82 percpu_counter: a... |
22 23 24 25 26 27 28 |
{ struct percpu_counter *fbc = addr; switch (state) { case ODEBUG_STATE_ACTIVE: percpu_counter_destroy(fbc); debug_object_free(fbc, &percpu_counter_debug_descr); |
d99b1d891 percpu_counter: u... |
29 |
return true; |
e2852ae82 percpu_counter: a... |
30 |
default: |
d99b1d891 percpu_counter: u... |
31 |
return false; |
e2852ae82 percpu_counter: a... |
32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 |
} } static struct debug_obj_descr percpu_counter_debug_descr = { .name = "percpu_counter", .fixup_free = percpu_counter_fixup_free, }; static inline void debug_percpu_counter_activate(struct percpu_counter *fbc) { debug_object_init(fbc, &percpu_counter_debug_descr); debug_object_activate(fbc, &percpu_counter_debug_descr); } static inline void debug_percpu_counter_deactivate(struct percpu_counter *fbc) { debug_object_deactivate(fbc, &percpu_counter_debug_descr); debug_object_free(fbc, &percpu_counter_debug_descr); } #else /* CONFIG_DEBUG_OBJECTS_PERCPU_COUNTER */ static inline void debug_percpu_counter_activate(struct percpu_counter *fbc) { } static inline void debug_percpu_counter_deactivate(struct percpu_counter *fbc) { } #endif /* CONFIG_DEBUG_OBJECTS_PERCPU_COUNTER */ |
3a587f47b lib: percpu_count... |
58 59 60 |
void percpu_counter_set(struct percpu_counter *fbc, s64 amount) { int cpu; |
098faf580 percpu_counter: m... |
61 |
unsigned long flags; |
3a587f47b lib: percpu_count... |
62 |
|
098faf580 percpu_counter: m... |
63 |
raw_spin_lock_irqsave(&fbc->lock, flags); |
3a587f47b lib: percpu_count... |
64 65 66 67 68 |
for_each_possible_cpu(cpu) { s32 *pcount = per_cpu_ptr(fbc->counters, cpu); *pcount = 0; } fbc->count = amount; |
098faf580 percpu_counter: m... |
69 |
raw_spin_unlock_irqrestore(&fbc->lock, flags); |
3a587f47b lib: percpu_count... |
70 71 |
} EXPORT_SYMBOL(percpu_counter_set); |
3e8f399da writeback: rework... |
72 73 74 75 76 77 78 |
/** * This function is both preempt and irq safe. The former is due to explicit * preemption disable. The latter is guaranteed by the fact that the slow path * is explicitly protected by an irq-safe spinlock whereas the fast patch uses * this_cpu_add which is irq-safe by definition. Hence there is no need muck * with irq state before calling this one */ |
104b4e513 percpu_counter: R... |
79 |
void percpu_counter_add_batch(struct percpu_counter *fbc, s64 amount, s32 batch) |
3cbc56402 [PATCH] percpu_co... |
80 |
{ |
20e897670 lib: make percpu_... |
81 |
s64 count; |
3cbc56402 [PATCH] percpu_co... |
82 |
|
ea00c30b5 percpu_counter: u... |
83 |
preempt_disable(); |
819a72af8 percpucounter: Op... |
84 |
count = __this_cpu_read(*fbc->counters) + amount; |
252e0ba6b lib: percpu_count... |
85 |
if (count >= batch || count <= -batch) { |
098faf580 percpu_counter: m... |
86 87 |
unsigned long flags; raw_spin_lock_irqsave(&fbc->lock, flags); |
3cbc56402 [PATCH] percpu_co... |
88 |
fbc->count += count; |
d1969a84d percpu_counter: u... |
89 |
__this_cpu_sub(*fbc->counters, count - amount); |
098faf580 percpu_counter: m... |
90 |
raw_spin_unlock_irqrestore(&fbc->lock, flags); |
3cbc56402 [PATCH] percpu_co... |
91 |
} else { |
74e72f894 lib/percpu_counte... |
92 |
this_cpu_add(*fbc->counters, amount); |
3cbc56402 [PATCH] percpu_co... |
93 |
} |
ea00c30b5 percpu_counter: u... |
94 |
preempt_enable(); |
3cbc56402 [PATCH] percpu_co... |
95 |
} |
104b4e513 percpu_counter: R... |
96 |
EXPORT_SYMBOL(percpu_counter_add_batch); |
3cbc56402 [PATCH] percpu_co... |
97 98 99 100 101 |
/* * Add up all the per-cpu counts, return the result. This is a more accurate * but much slower version of percpu_counter_read_positive() */ |
02d211688 revert "percpu_co... |
102 |
s64 __percpu_counter_sum(struct percpu_counter *fbc) |
3cbc56402 [PATCH] percpu_co... |
103 |
{ |
0216bfcff [PATCH] percpu co... |
104 |
s64 ret; |
3cbc56402 [PATCH] percpu_co... |
105 |
int cpu; |
098faf580 percpu_counter: m... |
106 |
unsigned long flags; |
3cbc56402 [PATCH] percpu_co... |
107 |
|
098faf580 percpu_counter: m... |
108 |
raw_spin_lock_irqsave(&fbc->lock, flags); |
3cbc56402 [PATCH] percpu_co... |
109 |
ret = fbc->count; |
b4ef0296f percpu_counters: ... |
110 |
for_each_online_cpu(cpu) { |
0216bfcff [PATCH] percpu co... |
111 |
s32 *pcount = per_cpu_ptr(fbc->counters, cpu); |
3cbc56402 [PATCH] percpu_co... |
112 113 |
ret += *pcount; } |
098faf580 percpu_counter: m... |
114 |
raw_spin_unlock_irqrestore(&fbc->lock, flags); |
bf1d89c81 lib: percpu_count... |
115 |
return ret; |
3cbc56402 [PATCH] percpu_co... |
116 |
} |
bf1d89c81 lib: percpu_count... |
117 |
EXPORT_SYMBOL(__percpu_counter_sum); |
c67ad917c percpu_counters()... |
118 |
|
908c7f194 percpu_counter: a... |
119 |
int __percpu_counter_init(struct percpu_counter *fbc, s64 amount, gfp_t gfp, |
ea319518b locking, percpu c... |
120 |
struct lock_class_key *key) |
c67ad917c percpu_counters()... |
121 |
{ |
ebd8fef30 percpu_counter: m... |
122 |
unsigned long flags __maybe_unused; |
f032a4508 locking, percpu_c... |
123 |
raw_spin_lock_init(&fbc->lock); |
ea319518b locking, percpu c... |
124 |
lockdep_set_class(&fbc->lock, key); |
c67ad917c percpu_counters()... |
125 |
fbc->count = amount; |
908c7f194 percpu_counter: a... |
126 |
fbc->counters = alloc_percpu_gfp(s32, gfp); |
833f4077b lib: percpu_count... |
127 128 |
if (!fbc->counters) return -ENOMEM; |
e2852ae82 percpu_counter: a... |
129 130 |
debug_percpu_counter_activate(fbc); |
c67ad917c percpu_counters()... |
131 |
#ifdef CONFIG_HOTPLUG_CPU |
8474b591f percpu: fix list_... |
132 |
INIT_LIST_HEAD(&fbc->list); |
ebd8fef30 percpu_counter: m... |
133 |
spin_lock_irqsave(&percpu_counters_lock, flags); |
c67ad917c percpu_counters()... |
134 |
list_add(&fbc->list, &percpu_counters); |
ebd8fef30 percpu_counter: m... |
135 |
spin_unlock_irqrestore(&percpu_counters_lock, flags); |
c67ad917c percpu_counters()... |
136 |
#endif |
833f4077b lib: percpu_count... |
137 |
return 0; |
c67ad917c percpu_counters()... |
138 |
} |
ea319518b locking, percpu c... |
139 |
EXPORT_SYMBOL(__percpu_counter_init); |
c67ad917c percpu_counters()... |
140 141 142 |
void percpu_counter_destroy(struct percpu_counter *fbc) { |
ebd8fef30 percpu_counter: m... |
143 |
unsigned long flags __maybe_unused; |
833f4077b lib: percpu_count... |
144 145 |
if (!fbc->counters) return; |
e2852ae82 percpu_counter: a... |
146 |
debug_percpu_counter_deactivate(fbc); |
c67ad917c percpu_counters()... |
147 |
#ifdef CONFIG_HOTPLUG_CPU |
ebd8fef30 percpu_counter: m... |
148 |
spin_lock_irqsave(&percpu_counters_lock, flags); |
c67ad917c percpu_counters()... |
149 |
list_del(&fbc->list); |
ebd8fef30 percpu_counter: m... |
150 |
spin_unlock_irqrestore(&percpu_counters_lock, flags); |
c67ad917c percpu_counters()... |
151 |
#endif |
fd3d664fe percpu_counter: f... |
152 153 |
free_percpu(fbc->counters); fbc->counters = NULL; |
c67ad917c percpu_counters()... |
154 155 |
} EXPORT_SYMBOL(percpu_counter_destroy); |
179f7ebff percpu_counter: F... |
156 157 |
int percpu_counter_batch __read_mostly = 32; EXPORT_SYMBOL(percpu_counter_batch); |
5588f5afb lib/percpu_counte... |
158 |
static int compute_batch_value(unsigned int cpu) |
179f7ebff percpu_counter: F... |
159 160 161 162 |
{ int nr = num_online_cpus(); percpu_counter_batch = max(32, nr*2); |
5588f5afb lib/percpu_counte... |
163 |
return 0; |
179f7ebff percpu_counter: F... |
164 |
} |
5588f5afb lib/percpu_counte... |
165 |
static int percpu_counter_cpu_dead(unsigned int cpu) |
c67ad917c percpu_counters()... |
166 |
{ |
179f7ebff percpu_counter: F... |
167 |
#ifdef CONFIG_HOTPLUG_CPU |
c67ad917c percpu_counters()... |
168 |
struct percpu_counter *fbc; |
5588f5afb lib/percpu_counte... |
169 |
compute_batch_value(cpu); |
c67ad917c percpu_counters()... |
170 |
|
ebd8fef30 percpu_counter: m... |
171 |
spin_lock_irq(&percpu_counters_lock); |
c67ad917c percpu_counters()... |
172 173 |
list_for_each_entry(fbc, &percpu_counters, list) { s32 *pcount; |
aaf0f2fa6 percpu_counter: p... |
174 |
raw_spin_lock(&fbc->lock); |
c67ad917c percpu_counters()... |
175 176 177 |
pcount = per_cpu_ptr(fbc->counters, cpu); fbc->count += *pcount; *pcount = 0; |
aaf0f2fa6 percpu_counter: p... |
178 |
raw_spin_unlock(&fbc->lock); |
c67ad917c percpu_counters()... |
179 |
} |
ebd8fef30 percpu_counter: m... |
180 |
spin_unlock_irq(&percpu_counters_lock); |
179f7ebff percpu_counter: F... |
181 |
#endif |
5588f5afb lib/percpu_counte... |
182 |
return 0; |
c67ad917c percpu_counters()... |
183 |
} |
27f5e0f69 tmpfs: add accura... |
184 185 186 187 |
/* * Compare counter against given value. * Return 1 if greater, 0 if equal and -1 if less */ |
80188b0d7 percpu_counter: b... |
188 |
int __percpu_counter_compare(struct percpu_counter *fbc, s64 rhs, s32 batch) |
27f5e0f69 tmpfs: add accura... |
189 190 191 192 193 |
{ s64 count; count = percpu_counter_read(fbc); /* Check to see if rough count will be sufficient for comparison */ |
80188b0d7 percpu_counter: b... |
194 |
if (abs(count - rhs) > (batch * num_online_cpus())) { |
27f5e0f69 tmpfs: add accura... |
195 196 197 198 199 200 201 202 203 204 205 206 207 208 |
if (count > rhs) return 1; else return -1; } /* Need to use precise count */ count = percpu_counter_sum(fbc); if (count > rhs) return 1; else if (count < rhs) return -1; else return 0; } |
80188b0d7 percpu_counter: b... |
209 |
EXPORT_SYMBOL(__percpu_counter_compare); |
27f5e0f69 tmpfs: add accura... |
210 |
|
c67ad917c percpu_counters()... |
211 212 |
static int __init percpu_counter_startup(void) { |
5588f5afb lib/percpu_counte... |
213 214 215 216 217 218 219 220 221 |
int ret; ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "lib/percpu_cnt:online", compute_batch_value, NULL); WARN_ON(ret < 0); ret = cpuhp_setup_state_nocalls(CPUHP_PERCPU_CNT_DEAD, "lib/percpu_cnt:dead", NULL, percpu_counter_cpu_dead); WARN_ON(ret < 0); |
c67ad917c percpu_counters()... |
222 223 224 |
return 0; } module_init(percpu_counter_startup); |