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Commit 5361471437a97cf493c2aa7d881bbedc9c248415

Authored by James Hogan
Committed by Paul E. McKenney
1 parent c34ac00cae
Exists in smarc-imx_3.14.28_1.0.0_ga and in 1 other branch imx_3.14.28_1.0.0_ga

rcu: Select IRQ_WORK from TREE_PREEMPT_RCU 

TREE_RCU and TREE_PREEMPT_RCU both cause kernel/rcutree.c to be built,
but only TREE_RCU selects IRQ_WORK, which can result in an undefined
reference to irq_work_queue for some (random) configs:

kernel/built-in.o In function `rcu_start_gp_advanced':
kernel/rcutree.c:1564: undefined reference to `irq_work_queue'

Select IRQ_WORK from TREE_PREEMPT_RCU too to fix this.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

Showing 1 changed file with 1 additions and 0 deletions Inline Diff

1 config ARCH 1 config ARCH
2 string 2 string
3 option env="ARCH" 3 option env="ARCH"
4 4
5 config KERNELVERSION 5 config KERNELVERSION
6 string 6 string
7 option env="KERNELVERSION" 7 option env="KERNELVERSION"
8 8
9 config DEFCONFIG_LIST 9 config DEFCONFIG_LIST
10 string 10 string
11 depends on !UML 11 depends on !UML
12 option defconfig_list 12 option defconfig_list
13 default "/lib/modules/$UNAME_RELEASE/.config" 13 default "/lib/modules/$UNAME_RELEASE/.config"
14 default "/etc/kernel-config" 14 default "/etc/kernel-config"
15 default "/boot/config-$UNAME_RELEASE" 15 default "/boot/config-$UNAME_RELEASE"
16 default "$ARCH_DEFCONFIG" 16 default "$ARCH_DEFCONFIG"
17 default "arch/$ARCH/defconfig" 17 default "arch/$ARCH/defconfig"
18 18
19 config CONSTRUCTORS 19 config CONSTRUCTORS
20 bool 20 bool
21 depends on !UML 21 depends on !UML
22 22
23 config IRQ_WORK 23 config IRQ_WORK
24 bool 24 bool
25 25
26 config BUILDTIME_EXTABLE_SORT 26 config BUILDTIME_EXTABLE_SORT
27 bool 27 bool
28 28
29 menu "General setup" 29 menu "General setup"
30 30
31 config BROKEN 31 config BROKEN
32 bool 32 bool
33 33
34 config BROKEN_ON_SMP 34 config BROKEN_ON_SMP
35 bool 35 bool
36 depends on BROKEN || !SMP 36 depends on BROKEN || !SMP
37 default y 37 default y
38 38
39 config INIT_ENV_ARG_LIMIT 39 config INIT_ENV_ARG_LIMIT
40 int 40 int
41 default 32 if !UML 41 default 32 if !UML
42 default 128 if UML 42 default 128 if UML
43 help 43 help
44 Maximum of each of the number of arguments and environment 44 Maximum of each of the number of arguments and environment
45 variables passed to init from the kernel command line. 45 variables passed to init from the kernel command line.
46 46
47 47
48 config CROSS_COMPILE 48 config CROSS_COMPILE
49 string "Cross-compiler tool prefix" 49 string "Cross-compiler tool prefix"
50 help 50 help
51 Same as running 'make CROSS_COMPILE=prefix-' but stored for 51 Same as running 'make CROSS_COMPILE=prefix-' but stored for
52 default make runs in this kernel build directory. You don't 52 default make runs in this kernel build directory. You don't
53 need to set this unless you want the configured kernel build 53 need to set this unless you want the configured kernel build
54 directory to select the cross-compiler automatically. 54 directory to select the cross-compiler automatically.
55 55
56 config COMPILE_TEST 56 config COMPILE_TEST
57 bool "Compile also drivers which will not load" 57 bool "Compile also drivers which will not load"
58 default n 58 default n
59 help 59 help
60 Some drivers can be compiled on a different platform than they are 60 Some drivers can be compiled on a different platform than they are
61 intended to be run on. Despite they cannot be loaded there (or even 61 intended to be run on. Despite they cannot be loaded there (or even
62 when they load they cannot be used due to missing HW support), 62 when they load they cannot be used due to missing HW support),
63 developers still, opposing to distributors, might want to build such 63 developers still, opposing to distributors, might want to build such
64 drivers to compile-test them. 64 drivers to compile-test them.
65 65
66 If you are a developer and want to build everything available, say Y 66 If you are a developer and want to build everything available, say Y
67 here. If you are a user/distributor, say N here to exclude useless 67 here. If you are a user/distributor, say N here to exclude useless
68 drivers to be distributed. 68 drivers to be distributed.
69 69
70 config LOCALVERSION 70 config LOCALVERSION
71 string "Local version - append to kernel release" 71 string "Local version - append to kernel release"
72 help 72 help
73 Append an extra string to the end of your kernel version. 73 Append an extra string to the end of your kernel version.
74 This will show up when you type uname, for example. 74 This will show up when you type uname, for example.
75 The string you set here will be appended after the contents of 75 The string you set here will be appended after the contents of
76 any files with a filename matching localversion* in your 76 any files with a filename matching localversion* in your
77 object and source tree, in that order. Your total string can 77 object and source tree, in that order. Your total string can
78 be a maximum of 64 characters. 78 be a maximum of 64 characters.
79 79
80 config LOCALVERSION_AUTO 80 config LOCALVERSION_AUTO
81 bool "Automatically append version information to the version string" 81 bool "Automatically append version information to the version string"
82 default y 82 default y
83 help 83 help
84 This will try to automatically determine if the current tree is a 84 This will try to automatically determine if the current tree is a
85 release tree by looking for git tags that belong to the current 85 release tree by looking for git tags that belong to the current
86 top of tree revision. 86 top of tree revision.
87 87
88 A string of the format -gxxxxxxxx will be added to the localversion 88 A string of the format -gxxxxxxxx will be added to the localversion
89 if a git-based tree is found. The string generated by this will be 89 if a git-based tree is found. The string generated by this will be
90 appended after any matching localversion* files, and after the value 90 appended after any matching localversion* files, and after the value
91 set in CONFIG_LOCALVERSION. 91 set in CONFIG_LOCALVERSION.
92 92
93 (The actual string used here is the first eight characters produced 93 (The actual string used here is the first eight characters produced
94 by running the command: 94 by running the command:
95 95
96 $ git rev-parse --verify HEAD 96 $ git rev-parse --verify HEAD
97 97
98 which is done within the script "scripts/setlocalversion".) 98 which is done within the script "scripts/setlocalversion".)
99 99
100 config HAVE_KERNEL_GZIP 100 config HAVE_KERNEL_GZIP
101 bool 101 bool
102 102
103 config HAVE_KERNEL_BZIP2 103 config HAVE_KERNEL_BZIP2
104 bool 104 bool
105 105
106 config HAVE_KERNEL_LZMA 106 config HAVE_KERNEL_LZMA
107 bool 107 bool
108 108
109 config HAVE_KERNEL_XZ 109 config HAVE_KERNEL_XZ
110 bool 110 bool
111 111
112 config HAVE_KERNEL_LZO 112 config HAVE_KERNEL_LZO
113 bool 113 bool
114 114
115 config HAVE_KERNEL_LZ4 115 config HAVE_KERNEL_LZ4
116 bool 116 bool
117 117
118 choice 118 choice
119 prompt "Kernel compression mode" 119 prompt "Kernel compression mode"
120 default KERNEL_GZIP 120 default KERNEL_GZIP
121 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4 121 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4
122 help 122 help
123 The linux kernel is a kind of self-extracting executable. 123 The linux kernel is a kind of self-extracting executable.
124 Several compression algorithms are available, which differ 124 Several compression algorithms are available, which differ
125 in efficiency, compression and decompression speed. 125 in efficiency, compression and decompression speed.
126 Compression speed is only relevant when building a kernel. 126 Compression speed is only relevant when building a kernel.
127 Decompression speed is relevant at each boot. 127 Decompression speed is relevant at each boot.
128 128
129 If you have any problems with bzip2 or lzma compressed 129 If you have any problems with bzip2 or lzma compressed
130 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older 130 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
131 version of this functionality (bzip2 only), for 2.4, was 131 version of this functionality (bzip2 only), for 2.4, was
132 supplied by Christian Ludwig) 132 supplied by Christian Ludwig)
133 133
134 High compression options are mostly useful for users, who 134 High compression options are mostly useful for users, who
135 are low on disk space (embedded systems), but for whom ram 135 are low on disk space (embedded systems), but for whom ram
136 size matters less. 136 size matters less.
137 137
138 If in doubt, select 'gzip' 138 If in doubt, select 'gzip'
139 139
140 config KERNEL_GZIP 140 config KERNEL_GZIP
141 bool "Gzip" 141 bool "Gzip"
142 depends on HAVE_KERNEL_GZIP 142 depends on HAVE_KERNEL_GZIP
143 help 143 help
144 The old and tried gzip compression. It provides a good balance 144 The old and tried gzip compression. It provides a good balance
145 between compression ratio and decompression speed. 145 between compression ratio and decompression speed.
146 146
147 config KERNEL_BZIP2 147 config KERNEL_BZIP2
148 bool "Bzip2" 148 bool "Bzip2"
149 depends on HAVE_KERNEL_BZIP2 149 depends on HAVE_KERNEL_BZIP2
150 help 150 help
151 Its compression ratio and speed is intermediate. 151 Its compression ratio and speed is intermediate.
152 Decompression speed is slowest among the choices. The kernel 152 Decompression speed is slowest among the choices. The kernel
153 size is about 10% smaller with bzip2, in comparison to gzip. 153 size is about 10% smaller with bzip2, in comparison to gzip.
154 Bzip2 uses a large amount of memory. For modern kernels you 154 Bzip2 uses a large amount of memory. For modern kernels you
155 will need at least 8MB RAM or more for booting. 155 will need at least 8MB RAM or more for booting.
156 156
157 config KERNEL_LZMA 157 config KERNEL_LZMA
158 bool "LZMA" 158 bool "LZMA"
159 depends on HAVE_KERNEL_LZMA 159 depends on HAVE_KERNEL_LZMA
160 help 160 help
161 This compression algorithm's ratio is best. Decompression speed 161 This compression algorithm's ratio is best. Decompression speed
162 is between gzip and bzip2. Compression is slowest. 162 is between gzip and bzip2. Compression is slowest.
163 The kernel size is about 33% smaller with LZMA in comparison to gzip. 163 The kernel size is about 33% smaller with LZMA in comparison to gzip.
164 164
165 config KERNEL_XZ 165 config KERNEL_XZ
166 bool "XZ" 166 bool "XZ"
167 depends on HAVE_KERNEL_XZ 167 depends on HAVE_KERNEL_XZ
168 help 168 help
169 XZ uses the LZMA2 algorithm and instruction set specific 169 XZ uses the LZMA2 algorithm and instruction set specific
170 BCJ filters which can improve compression ratio of executable 170 BCJ filters which can improve compression ratio of executable
171 code. The size of the kernel is about 30% smaller with XZ in 171 code. The size of the kernel is about 30% smaller with XZ in
172 comparison to gzip. On architectures for which there is a BCJ 172 comparison to gzip. On architectures for which there is a BCJ
173 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ 173 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
174 will create a few percent smaller kernel than plain LZMA. 174 will create a few percent smaller kernel than plain LZMA.
175 175
176 The speed is about the same as with LZMA: The decompression 176 The speed is about the same as with LZMA: The decompression
177 speed of XZ is better than that of bzip2 but worse than gzip 177 speed of XZ is better than that of bzip2 but worse than gzip
178 and LZO. Compression is slow. 178 and LZO. Compression is slow.
179 179
180 config KERNEL_LZO 180 config KERNEL_LZO
181 bool "LZO" 181 bool "LZO"
182 depends on HAVE_KERNEL_LZO 182 depends on HAVE_KERNEL_LZO
183 help 183 help
184 Its compression ratio is the poorest among the choices. The kernel 184 Its compression ratio is the poorest among the choices. The kernel
185 size is about 10% bigger than gzip; however its speed 185 size is about 10% bigger than gzip; however its speed
186 (both compression and decompression) is the fastest. 186 (both compression and decompression) is the fastest.
187 187
188 config KERNEL_LZ4 188 config KERNEL_LZ4
189 bool "LZ4" 189 bool "LZ4"
190 depends on HAVE_KERNEL_LZ4 190 depends on HAVE_KERNEL_LZ4
191 help 191 help
192 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding. 192 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
193 A preliminary version of LZ4 de/compression tool is available at 193 A preliminary version of LZ4 de/compression tool is available at
194 <https://code.google.com/p/lz4/>. 194 <https://code.google.com/p/lz4/>.
195 195
196 Its compression ratio is worse than LZO. The size of the kernel 196 Its compression ratio is worse than LZO. The size of the kernel
197 is about 8% bigger than LZO. But the decompression speed is 197 is about 8% bigger than LZO. But the decompression speed is
198 faster than LZO. 198 faster than LZO.
199 199
200 endchoice 200 endchoice
201 201
202 config DEFAULT_HOSTNAME 202 config DEFAULT_HOSTNAME
203 string "Default hostname" 203 string "Default hostname"
204 default "(none)" 204 default "(none)"
205 help 205 help
206 This option determines the default system hostname before userspace 206 This option determines the default system hostname before userspace
207 calls sethostname(2). The kernel traditionally uses "(none)" here, 207 calls sethostname(2). The kernel traditionally uses "(none)" here,
208 but you may wish to use a different default here to make a minimal 208 but you may wish to use a different default here to make a minimal
209 system more usable with less configuration. 209 system more usable with less configuration.
210 210
211 config SWAP 211 config SWAP
212 bool "Support for paging of anonymous memory (swap)" 212 bool "Support for paging of anonymous memory (swap)"
213 depends on MMU && BLOCK 213 depends on MMU && BLOCK
214 default y 214 default y
215 help 215 help
216 This option allows you to choose whether you want to have support 216 This option allows you to choose whether you want to have support
217 for so called swap devices or swap files in your kernel that are 217 for so called swap devices or swap files in your kernel that are
218 used to provide more virtual memory than the actual RAM present 218 used to provide more virtual memory than the actual RAM present
219 in your computer. If unsure say Y. 219 in your computer. If unsure say Y.
220 220
221 config SYSVIPC 221 config SYSVIPC
222 bool "System V IPC" 222 bool "System V IPC"
223 ---help--- 223 ---help---
224 Inter Process Communication is a suite of library functions and 224 Inter Process Communication is a suite of library functions and
225 system calls which let processes (running programs) synchronize and 225 system calls which let processes (running programs) synchronize and
226 exchange information. It is generally considered to be a good thing, 226 exchange information. It is generally considered to be a good thing,
227 and some programs won't run unless you say Y here. In particular, if 227 and some programs won't run unless you say Y here. In particular, if
228 you want to run the DOS emulator dosemu under Linux (read the 228 you want to run the DOS emulator dosemu under Linux (read the
229 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 229 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
230 you'll need to say Y here. 230 you'll need to say Y here.
231 231
232 You can find documentation about IPC with "info ipc" and also in 232 You can find documentation about IPC with "info ipc" and also in
233 section 6.4 of the Linux Programmer's Guide, available from 233 section 6.4 of the Linux Programmer's Guide, available from
234 <http://www.tldp.org/guides.html>. 234 <http://www.tldp.org/guides.html>.
235 235
236 config SYSVIPC_SYSCTL 236 config SYSVIPC_SYSCTL
237 bool 237 bool
238 depends on SYSVIPC 238 depends on SYSVIPC
239 depends on SYSCTL 239 depends on SYSCTL
240 default y 240 default y
241 241
242 config POSIX_MQUEUE 242 config POSIX_MQUEUE
243 bool "POSIX Message Queues" 243 bool "POSIX Message Queues"
244 depends on NET 244 depends on NET
245 ---help--- 245 ---help---
246 POSIX variant of message queues is a part of IPC. In POSIX message 246 POSIX variant of message queues is a part of IPC. In POSIX message
247 queues every message has a priority which decides about succession 247 queues every message has a priority which decides about succession
248 of receiving it by a process. If you want to compile and run 248 of receiving it by a process. If you want to compile and run
249 programs written e.g. for Solaris with use of its POSIX message 249 programs written e.g. for Solaris with use of its POSIX message
250 queues (functions mq_*) say Y here. 250 queues (functions mq_*) say Y here.
251 251
252 POSIX message queues are visible as a filesystem called 'mqueue' 252 POSIX message queues are visible as a filesystem called 'mqueue'
253 and can be mounted somewhere if you want to do filesystem 253 and can be mounted somewhere if you want to do filesystem
254 operations on message queues. 254 operations on message queues.
255 255
256 If unsure, say Y. 256 If unsure, say Y.
257 257
258 config POSIX_MQUEUE_SYSCTL 258 config POSIX_MQUEUE_SYSCTL
259 bool 259 bool
260 depends on POSIX_MQUEUE 260 depends on POSIX_MQUEUE
261 depends on SYSCTL 261 depends on SYSCTL
262 default y 262 default y
263 263
264 config FHANDLE 264 config FHANDLE
265 bool "open by fhandle syscalls" 265 bool "open by fhandle syscalls"
266 select EXPORTFS 266 select EXPORTFS
267 help 267 help
268 If you say Y here, a user level program will be able to map 268 If you say Y here, a user level program will be able to map
269 file names to handle and then later use the handle for 269 file names to handle and then later use the handle for
270 different file system operations. This is useful in implementing 270 different file system operations. This is useful in implementing
271 userspace file servers, which now track files using handles instead 271 userspace file servers, which now track files using handles instead
272 of names. The handle would remain the same even if file names 272 of names. The handle would remain the same even if file names
273 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 273 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
274 syscalls. 274 syscalls.
275 275
276 config AUDIT 276 config AUDIT
277 bool "Auditing support" 277 bool "Auditing support"
278 depends on NET 278 depends on NET
279 help 279 help
280 Enable auditing infrastructure that can be used with another 280 Enable auditing infrastructure that can be used with another
281 kernel subsystem, such as SELinux (which requires this for 281 kernel subsystem, such as SELinux (which requires this for
282 logging of avc messages output). Does not do system-call 282 logging of avc messages output). Does not do system-call
283 auditing without CONFIG_AUDITSYSCALL. 283 auditing without CONFIG_AUDITSYSCALL.
284 284
285 config AUDITSYSCALL 285 config AUDITSYSCALL
286 bool "Enable system-call auditing support" 286 bool "Enable system-call auditing support"
287 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT)) 287 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT))
288 default y if SECURITY_SELINUX 288 default y if SECURITY_SELINUX
289 help 289 help
290 Enable low-overhead system-call auditing infrastructure that 290 Enable low-overhead system-call auditing infrastructure that
291 can be used independently or with another kernel subsystem, 291 can be used independently or with another kernel subsystem,
292 such as SELinux. 292 such as SELinux.
293 293
294 config AUDIT_WATCH 294 config AUDIT_WATCH
295 def_bool y 295 def_bool y
296 depends on AUDITSYSCALL 296 depends on AUDITSYSCALL
297 select FSNOTIFY 297 select FSNOTIFY
298 298
299 config AUDIT_TREE 299 config AUDIT_TREE
300 def_bool y 300 def_bool y
301 depends on AUDITSYSCALL 301 depends on AUDITSYSCALL
302 select FSNOTIFY 302 select FSNOTIFY
303 303
304 config AUDIT_LOGINUID_IMMUTABLE 304 config AUDIT_LOGINUID_IMMUTABLE
305 bool "Make audit loginuid immutable" 305 bool "Make audit loginuid immutable"
306 depends on AUDIT 306 depends on AUDIT
307 help 307 help
308 The config option toggles if a task setting its loginuid requires 308 The config option toggles if a task setting its loginuid requires
309 CAP_SYS_AUDITCONTROL or if that task should require no special permissions 309 CAP_SYS_AUDITCONTROL or if that task should require no special permissions
310 but should instead only allow setting its loginuid if it was never 310 but should instead only allow setting its loginuid if it was never
311 previously set. On systems which use systemd or a similar central 311 previously set. On systems which use systemd or a similar central
312 process to restart login services this should be set to true. On older 312 process to restart login services this should be set to true. On older
313 systems in which an admin would typically have to directly stop and 313 systems in which an admin would typically have to directly stop and
314 start processes this should be set to false. Setting this to true allows 314 start processes this should be set to false. Setting this to true allows
315 one to drop potentially dangerous capabilites from the login tasks, 315 one to drop potentially dangerous capabilites from the login tasks,
316 but may not be backwards compatible with older init systems. 316 but may not be backwards compatible with older init systems.
317 317
318 source "kernel/irq/Kconfig" 318 source "kernel/irq/Kconfig"
319 source "kernel/time/Kconfig" 319 source "kernel/time/Kconfig"
320 320
321 menu "CPU/Task time and stats accounting" 321 menu "CPU/Task time and stats accounting"
322 322
323 config VIRT_CPU_ACCOUNTING 323 config VIRT_CPU_ACCOUNTING
324 bool 324 bool
325 325
326 choice 326 choice
327 prompt "Cputime accounting" 327 prompt "Cputime accounting"
328 default TICK_CPU_ACCOUNTING if !PPC64 328 default TICK_CPU_ACCOUNTING if !PPC64
329 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64 329 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
330 330
331 # Kind of a stub config for the pure tick based cputime accounting 331 # Kind of a stub config for the pure tick based cputime accounting
332 config TICK_CPU_ACCOUNTING 332 config TICK_CPU_ACCOUNTING
333 bool "Simple tick based cputime accounting" 333 bool "Simple tick based cputime accounting"
334 depends on !S390 && !NO_HZ_FULL 334 depends on !S390 && !NO_HZ_FULL
335 help 335 help
336 This is the basic tick based cputime accounting that maintains 336 This is the basic tick based cputime accounting that maintains
337 statistics about user, system and idle time spent on per jiffies 337 statistics about user, system and idle time spent on per jiffies
338 granularity. 338 granularity.
339 339
340 If unsure, say Y. 340 If unsure, say Y.
341 341
342 config VIRT_CPU_ACCOUNTING_NATIVE 342 config VIRT_CPU_ACCOUNTING_NATIVE
343 bool "Deterministic task and CPU time accounting" 343 bool "Deterministic task and CPU time accounting"
344 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL 344 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
345 select VIRT_CPU_ACCOUNTING 345 select VIRT_CPU_ACCOUNTING
346 help 346 help
347 Select this option to enable more accurate task and CPU time 347 Select this option to enable more accurate task and CPU time
348 accounting. This is done by reading a CPU counter on each 348 accounting. This is done by reading a CPU counter on each
349 kernel entry and exit and on transitions within the kernel 349 kernel entry and exit and on transitions within the kernel
350 between system, softirq and hardirq state, so there is a 350 between system, softirq and hardirq state, so there is a
351 small performance impact. In the case of s390 or IBM POWER > 5, 351 small performance impact. In the case of s390 or IBM POWER > 5,
352 this also enables accounting of stolen time on logically-partitioned 352 this also enables accounting of stolen time on logically-partitioned
353 systems. 353 systems.
354 354
355 config VIRT_CPU_ACCOUNTING_GEN 355 config VIRT_CPU_ACCOUNTING_GEN
356 bool "Full dynticks CPU time accounting" 356 bool "Full dynticks CPU time accounting"
357 depends on HAVE_CONTEXT_TRACKING && 64BIT 357 depends on HAVE_CONTEXT_TRACKING && 64BIT
358 select VIRT_CPU_ACCOUNTING 358 select VIRT_CPU_ACCOUNTING
359 select CONTEXT_TRACKING 359 select CONTEXT_TRACKING
360 help 360 help
361 Select this option to enable task and CPU time accounting on full 361 Select this option to enable task and CPU time accounting on full
362 dynticks systems. This accounting is implemented by watching every 362 dynticks systems. This accounting is implemented by watching every
363 kernel-user boundaries using the context tracking subsystem. 363 kernel-user boundaries using the context tracking subsystem.
364 The accounting is thus performed at the expense of some significant 364 The accounting is thus performed at the expense of some significant
365 overhead. 365 overhead.
366 366
367 For now this is only useful if you are working on the full 367 For now this is only useful if you are working on the full
368 dynticks subsystem development. 368 dynticks subsystem development.
369 369
370 If unsure, say N. 370 If unsure, say N.
371 371
372 config IRQ_TIME_ACCOUNTING 372 config IRQ_TIME_ACCOUNTING
373 bool "Fine granularity task level IRQ time accounting" 373 bool "Fine granularity task level IRQ time accounting"
374 depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL 374 depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL
375 help 375 help
376 Select this option to enable fine granularity task irq time 376 Select this option to enable fine granularity task irq time
377 accounting. This is done by reading a timestamp on each 377 accounting. This is done by reading a timestamp on each
378 transitions between softirq and hardirq state, so there can be a 378 transitions between softirq and hardirq state, so there can be a
379 small performance impact. 379 small performance impact.
380 380
381 If in doubt, say N here. 381 If in doubt, say N here.
382 382
383 endchoice 383 endchoice
384 384
385 config BSD_PROCESS_ACCT 385 config BSD_PROCESS_ACCT
386 bool "BSD Process Accounting" 386 bool "BSD Process Accounting"
387 help 387 help
388 If you say Y here, a user level program will be able to instruct the 388 If you say Y here, a user level program will be able to instruct the
389 kernel (via a special system call) to write process accounting 389 kernel (via a special system call) to write process accounting
390 information to a file: whenever a process exits, information about 390 information to a file: whenever a process exits, information about
391 that process will be appended to the file by the kernel. The 391 that process will be appended to the file by the kernel. The
392 information includes things such as creation time, owning user, 392 information includes things such as creation time, owning user,
393 command name, memory usage, controlling terminal etc. (the complete 393 command name, memory usage, controlling terminal etc. (the complete
394 list is in the struct acct in <file:include/linux/acct.h>). It is 394 list is in the struct acct in <file:include/linux/acct.h>). It is
395 up to the user level program to do useful things with this 395 up to the user level program to do useful things with this
396 information. This is generally a good idea, so say Y. 396 information. This is generally a good idea, so say Y.
397 397
398 config BSD_PROCESS_ACCT_V3 398 config BSD_PROCESS_ACCT_V3
399 bool "BSD Process Accounting version 3 file format" 399 bool "BSD Process Accounting version 3 file format"
400 depends on BSD_PROCESS_ACCT 400 depends on BSD_PROCESS_ACCT
401 default n 401 default n
402 help 402 help
403 If you say Y here, the process accounting information is written 403 If you say Y here, the process accounting information is written
404 in a new file format that also logs the process IDs of each 404 in a new file format that also logs the process IDs of each
405 process and it's parent. Note that this file format is incompatible 405 process and it's parent. Note that this file format is incompatible
406 with previous v0/v1/v2 file formats, so you will need updated tools 406 with previous v0/v1/v2 file formats, so you will need updated tools
407 for processing it. A preliminary version of these tools is available 407 for processing it. A preliminary version of these tools is available
408 at <http://www.gnu.org/software/acct/>. 408 at <http://www.gnu.org/software/acct/>.
409 409
410 config TASKSTATS 410 config TASKSTATS
411 bool "Export task/process statistics through netlink" 411 bool "Export task/process statistics through netlink"
412 depends on NET 412 depends on NET
413 default n 413 default n
414 help 414 help
415 Export selected statistics for tasks/processes through the 415 Export selected statistics for tasks/processes through the
416 generic netlink interface. Unlike BSD process accounting, the 416 generic netlink interface. Unlike BSD process accounting, the
417 statistics are available during the lifetime of tasks/processes as 417 statistics are available during the lifetime of tasks/processes as
418 responses to commands. Like BSD accounting, they are sent to user 418 responses to commands. Like BSD accounting, they are sent to user
419 space on task exit. 419 space on task exit.
420 420
421 Say N if unsure. 421 Say N if unsure.
422 422
423 config TASK_DELAY_ACCT 423 config TASK_DELAY_ACCT
424 bool "Enable per-task delay accounting" 424 bool "Enable per-task delay accounting"
425 depends on TASKSTATS 425 depends on TASKSTATS
426 help 426 help
427 Collect information on time spent by a task waiting for system 427 Collect information on time spent by a task waiting for system
428 resources like cpu, synchronous block I/O completion and swapping 428 resources like cpu, synchronous block I/O completion and swapping
429 in pages. Such statistics can help in setting a task's priorities 429 in pages. Such statistics can help in setting a task's priorities
430 relative to other tasks for cpu, io, rss limits etc. 430 relative to other tasks for cpu, io, rss limits etc.
431 431
432 Say N if unsure. 432 Say N if unsure.
433 433
434 config TASK_XACCT 434 config TASK_XACCT
435 bool "Enable extended accounting over taskstats" 435 bool "Enable extended accounting over taskstats"
436 depends on TASKSTATS 436 depends on TASKSTATS
437 help 437 help
438 Collect extended task accounting data and send the data 438 Collect extended task accounting data and send the data
439 to userland for processing over the taskstats interface. 439 to userland for processing over the taskstats interface.
440 440
441 Say N if unsure. 441 Say N if unsure.
442 442
443 config TASK_IO_ACCOUNTING 443 config TASK_IO_ACCOUNTING
444 bool "Enable per-task storage I/O accounting" 444 bool "Enable per-task storage I/O accounting"
445 depends on TASK_XACCT 445 depends on TASK_XACCT
446 help 446 help
447 Collect information on the number of bytes of storage I/O which this 447 Collect information on the number of bytes of storage I/O which this
448 task has caused. 448 task has caused.
449 449
450 Say N if unsure. 450 Say N if unsure.
451 451
452 endmenu # "CPU/Task time and stats accounting" 452 endmenu # "CPU/Task time and stats accounting"
453 453
454 menu "RCU Subsystem" 454 menu "RCU Subsystem"
455 455
456 choice 456 choice
457 prompt "RCU Implementation" 457 prompt "RCU Implementation"
458 default TREE_RCU 458 default TREE_RCU
459 459
460 config TREE_RCU 460 config TREE_RCU
461 bool "Tree-based hierarchical RCU" 461 bool "Tree-based hierarchical RCU"
462 depends on !PREEMPT && SMP 462 depends on !PREEMPT && SMP
463 select IRQ_WORK 463 select IRQ_WORK
464 help 464 help
465 This option selects the RCU implementation that is 465 This option selects the RCU implementation that is
466 designed for very large SMP system with hundreds or 466 designed for very large SMP system with hundreds or
467 thousands of CPUs. It also scales down nicely to 467 thousands of CPUs. It also scales down nicely to
468 smaller systems. 468 smaller systems.
469 469
470 config TREE_PREEMPT_RCU 470 config TREE_PREEMPT_RCU
471 bool "Preemptible tree-based hierarchical RCU" 471 bool "Preemptible tree-based hierarchical RCU"
472 depends on PREEMPT 472 depends on PREEMPT
473 select IRQ_WORK
473 help 474 help
474 This option selects the RCU implementation that is 475 This option selects the RCU implementation that is
475 designed for very large SMP systems with hundreds or 476 designed for very large SMP systems with hundreds or
476 thousands of CPUs, but for which real-time response 477 thousands of CPUs, but for which real-time response
477 is also required. It also scales down nicely to 478 is also required. It also scales down nicely to
478 smaller systems. 479 smaller systems.
479 480
480 Select this option if you are unsure. 481 Select this option if you are unsure.
481 482
482 config TINY_RCU 483 config TINY_RCU
483 bool "UP-only small-memory-footprint RCU" 484 bool "UP-only small-memory-footprint RCU"
484 depends on !PREEMPT && !SMP 485 depends on !PREEMPT && !SMP
485 help 486 help
486 This option selects the RCU implementation that is 487 This option selects the RCU implementation that is
487 designed for UP systems from which real-time response 488 designed for UP systems from which real-time response
488 is not required. This option greatly reduces the 489 is not required. This option greatly reduces the
489 memory footprint of RCU. 490 memory footprint of RCU.
490 491
491 endchoice 492 endchoice
492 493
493 config PREEMPT_RCU 494 config PREEMPT_RCU
494 def_bool TREE_PREEMPT_RCU 495 def_bool TREE_PREEMPT_RCU
495 help 496 help
496 This option enables preemptible-RCU code that is common between 497 This option enables preemptible-RCU code that is common between
497 the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations. 498 the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
498 499
499 config RCU_STALL_COMMON 500 config RCU_STALL_COMMON
500 def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE ) 501 def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE )
501 help 502 help
502 This option enables RCU CPU stall code that is common between 503 This option enables RCU CPU stall code that is common between
503 the TINY and TREE variants of RCU. The purpose is to allow 504 the TINY and TREE variants of RCU. The purpose is to allow
504 the tiny variants to disable RCU CPU stall warnings, while 505 the tiny variants to disable RCU CPU stall warnings, while
505 making these warnings mandatory for the tree variants. 506 making these warnings mandatory for the tree variants.
506 507
507 config CONTEXT_TRACKING 508 config CONTEXT_TRACKING
508 bool 509 bool
509 510
510 config RCU_USER_QS 511 config RCU_USER_QS
511 bool "Consider userspace as in RCU extended quiescent state" 512 bool "Consider userspace as in RCU extended quiescent state"
512 depends on HAVE_CONTEXT_TRACKING && SMP 513 depends on HAVE_CONTEXT_TRACKING && SMP
513 select CONTEXT_TRACKING 514 select CONTEXT_TRACKING
514 help 515 help
515 This option sets hooks on kernel / userspace boundaries and 516 This option sets hooks on kernel / userspace boundaries and
516 puts RCU in extended quiescent state when the CPU runs in 517 puts RCU in extended quiescent state when the CPU runs in
517 userspace. It means that when a CPU runs in userspace, it is 518 userspace. It means that when a CPU runs in userspace, it is
518 excluded from the global RCU state machine and thus doesn't 519 excluded from the global RCU state machine and thus doesn't
519 try to keep the timer tick on for RCU. 520 try to keep the timer tick on for RCU.
520 521
521 Unless you want to hack and help the development of the full 522 Unless you want to hack and help the development of the full
522 dynticks mode, you shouldn't enable this option. It also 523 dynticks mode, you shouldn't enable this option. It also
523 adds unnecessary overhead. 524 adds unnecessary overhead.
524 525
525 If unsure say N 526 If unsure say N
526 527
527 config CONTEXT_TRACKING_FORCE 528 config CONTEXT_TRACKING_FORCE
528 bool "Force context tracking" 529 bool "Force context tracking"
529 depends on CONTEXT_TRACKING 530 depends on CONTEXT_TRACKING
530 default CONTEXT_TRACKING 531 default CONTEXT_TRACKING
531 help 532 help
532 Probe on user/kernel boundaries by default in order to 533 Probe on user/kernel boundaries by default in order to
533 test the features that rely on it such as userspace RCU extended 534 test the features that rely on it such as userspace RCU extended
534 quiescent states. 535 quiescent states.
535 This test is there for debugging until we have a real user like the 536 This test is there for debugging until we have a real user like the
536 full dynticks mode. 537 full dynticks mode.
537 538
538 config RCU_FANOUT 539 config RCU_FANOUT
539 int "Tree-based hierarchical RCU fanout value" 540 int "Tree-based hierarchical RCU fanout value"
540 range 2 64 if 64BIT 541 range 2 64 if 64BIT
541 range 2 32 if !64BIT 542 range 2 32 if !64BIT
542 depends on TREE_RCU || TREE_PREEMPT_RCU 543 depends on TREE_RCU || TREE_PREEMPT_RCU
543 default 64 if 64BIT 544 default 64 if 64BIT
544 default 32 if !64BIT 545 default 32 if !64BIT
545 help 546 help
546 This option controls the fanout of hierarchical implementations 547 This option controls the fanout of hierarchical implementations
547 of RCU, allowing RCU to work efficiently on machines with 548 of RCU, allowing RCU to work efficiently on machines with
548 large numbers of CPUs. This value must be at least the fourth 549 large numbers of CPUs. This value must be at least the fourth
549 root of NR_CPUS, which allows NR_CPUS to be insanely large. 550 root of NR_CPUS, which allows NR_CPUS to be insanely large.
550 The default value of RCU_FANOUT should be used for production 551 The default value of RCU_FANOUT should be used for production
551 systems, but if you are stress-testing the RCU implementation 552 systems, but if you are stress-testing the RCU implementation
552 itself, small RCU_FANOUT values allow you to test large-system 553 itself, small RCU_FANOUT values allow you to test large-system
553 code paths on small(er) systems. 554 code paths on small(er) systems.
554 555
555 Select a specific number if testing RCU itself. 556 Select a specific number if testing RCU itself.
556 Take the default if unsure. 557 Take the default if unsure.
557 558
558 config RCU_FANOUT_LEAF 559 config RCU_FANOUT_LEAF
559 int "Tree-based hierarchical RCU leaf-level fanout value" 560 int "Tree-based hierarchical RCU leaf-level fanout value"
560 range 2 RCU_FANOUT if 64BIT 561 range 2 RCU_FANOUT if 64BIT
561 range 2 RCU_FANOUT if !64BIT 562 range 2 RCU_FANOUT if !64BIT
562 depends on TREE_RCU || TREE_PREEMPT_RCU 563 depends on TREE_RCU || TREE_PREEMPT_RCU
563 default 16 564 default 16
564 help 565 help
565 This option controls the leaf-level fanout of hierarchical 566 This option controls the leaf-level fanout of hierarchical
566 implementations of RCU, and allows trading off cache misses 567 implementations of RCU, and allows trading off cache misses
567 against lock contention. Systems that synchronize their 568 against lock contention. Systems that synchronize their
568 scheduling-clock interrupts for energy-efficiency reasons will 569 scheduling-clock interrupts for energy-efficiency reasons will
569 want the default because the smaller leaf-level fanout keeps 570 want the default because the smaller leaf-level fanout keeps
570 lock contention levels acceptably low. Very large systems 571 lock contention levels acceptably low. Very large systems
571 (hundreds or thousands of CPUs) will instead want to set this 572 (hundreds or thousands of CPUs) will instead want to set this
572 value to the maximum value possible in order to reduce the 573 value to the maximum value possible in order to reduce the
573 number of cache misses incurred during RCU's grace-period 574 number of cache misses incurred during RCU's grace-period
574 initialization. These systems tend to run CPU-bound, and thus 575 initialization. These systems tend to run CPU-bound, and thus
575 are not helped by synchronized interrupts, and thus tend to 576 are not helped by synchronized interrupts, and thus tend to
576 skew them, which reduces lock contention enough that large 577 skew them, which reduces lock contention enough that large
577 leaf-level fanouts work well. 578 leaf-level fanouts work well.
578 579
579 Select a specific number if testing RCU itself. 580 Select a specific number if testing RCU itself.
580 581
581 Select the maximum permissible value for large systems. 582 Select the maximum permissible value for large systems.
582 583
583 Take the default if unsure. 584 Take the default if unsure.
584 585
585 config RCU_FANOUT_EXACT 586 config RCU_FANOUT_EXACT
586 bool "Disable tree-based hierarchical RCU auto-balancing" 587 bool "Disable tree-based hierarchical RCU auto-balancing"
587 depends on TREE_RCU || TREE_PREEMPT_RCU 588 depends on TREE_RCU || TREE_PREEMPT_RCU
588 default n 589 default n
589 help 590 help
590 This option forces use of the exact RCU_FANOUT value specified, 591 This option forces use of the exact RCU_FANOUT value specified,
591 regardless of imbalances in the hierarchy. This is useful for 592 regardless of imbalances in the hierarchy. This is useful for
592 testing RCU itself, and might one day be useful on systems with 593 testing RCU itself, and might one day be useful on systems with
593 strong NUMA behavior. 594 strong NUMA behavior.
594 595
595 Without RCU_FANOUT_EXACT, the code will balance the hierarchy. 596 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
596 597
597 Say N if unsure. 598 Say N if unsure.
598 599
599 config RCU_FAST_NO_HZ 600 config RCU_FAST_NO_HZ
600 bool "Accelerate last non-dyntick-idle CPU's grace periods" 601 bool "Accelerate last non-dyntick-idle CPU's grace periods"
601 depends on NO_HZ_COMMON && SMP 602 depends on NO_HZ_COMMON && SMP
602 default n 603 default n
603 help 604 help
604 This option permits CPUs to enter dynticks-idle state even if 605 This option permits CPUs to enter dynticks-idle state even if
605 they have RCU callbacks queued, and prevents RCU from waking 606 they have RCU callbacks queued, and prevents RCU from waking
606 these CPUs up more than roughly once every four jiffies (by 607 these CPUs up more than roughly once every four jiffies (by
607 default, you can adjust this using the rcutree.rcu_idle_gp_delay 608 default, you can adjust this using the rcutree.rcu_idle_gp_delay
608 parameter), thus improving energy efficiency. On the other 609 parameter), thus improving energy efficiency. On the other
609 hand, this option increases the duration of RCU grace periods, 610 hand, this option increases the duration of RCU grace periods,
610 for example, slowing down synchronize_rcu(). 611 for example, slowing down synchronize_rcu().
611 612
612 Say Y if energy efficiency is critically important, and you 613 Say Y if energy efficiency is critically important, and you
613 don't care about increased grace-period durations. 614 don't care about increased grace-period durations.
614 615
615 Say N if you are unsure. 616 Say N if you are unsure.
616 617
617 config TREE_RCU_TRACE 618 config TREE_RCU_TRACE
618 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU ) 619 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
619 select DEBUG_FS 620 select DEBUG_FS
620 help 621 help
621 This option provides tracing for the TREE_RCU and 622 This option provides tracing for the TREE_RCU and
622 TREE_PREEMPT_RCU implementations, permitting Makefile to 623 TREE_PREEMPT_RCU implementations, permitting Makefile to
623 trivially select kernel/rcutree_trace.c. 624 trivially select kernel/rcutree_trace.c.
624 625
625 config RCU_BOOST 626 config RCU_BOOST
626 bool "Enable RCU priority boosting" 627 bool "Enable RCU priority boosting"
627 depends on RT_MUTEXES && PREEMPT_RCU 628 depends on RT_MUTEXES && PREEMPT_RCU
628 default n 629 default n
629 help 630 help
630 This option boosts the priority of preempted RCU readers that 631 This option boosts the priority of preempted RCU readers that
631 block the current preemptible RCU grace period for too long. 632 block the current preemptible RCU grace period for too long.
632 This option also prevents heavy loads from blocking RCU 633 This option also prevents heavy loads from blocking RCU
633 callback invocation for all flavors of RCU. 634 callback invocation for all flavors of RCU.
634 635
635 Say Y here if you are working with real-time apps or heavy loads 636 Say Y here if you are working with real-time apps or heavy loads
636 Say N here if you are unsure. 637 Say N here if you are unsure.
637 638
638 config RCU_BOOST_PRIO 639 config RCU_BOOST_PRIO
639 int "Real-time priority to boost RCU readers to" 640 int "Real-time priority to boost RCU readers to"
640 range 1 99 641 range 1 99
641 depends on RCU_BOOST 642 depends on RCU_BOOST
642 default 1 643 default 1
643 help 644 help
644 This option specifies the real-time priority to which long-term 645 This option specifies the real-time priority to which long-term
645 preempted RCU readers are to be boosted. If you are working 646 preempted RCU readers are to be boosted. If you are working
646 with a real-time application that has one or more CPU-bound 647 with a real-time application that has one or more CPU-bound
647 threads running at a real-time priority level, you should set 648 threads running at a real-time priority level, you should set
648 RCU_BOOST_PRIO to a priority higher then the highest-priority 649 RCU_BOOST_PRIO to a priority higher then the highest-priority
649 real-time CPU-bound thread. The default RCU_BOOST_PRIO value 650 real-time CPU-bound thread. The default RCU_BOOST_PRIO value
650 of 1 is appropriate in the common case, which is real-time 651 of 1 is appropriate in the common case, which is real-time
651 applications that do not have any CPU-bound threads. 652 applications that do not have any CPU-bound threads.
652 653
653 Some real-time applications might not have a single real-time 654 Some real-time applications might not have a single real-time
654 thread that saturates a given CPU, but instead might have 655 thread that saturates a given CPU, but instead might have
655 multiple real-time threads that, taken together, fully utilize 656 multiple real-time threads that, taken together, fully utilize
656 that CPU. In this case, you should set RCU_BOOST_PRIO to 657 that CPU. In this case, you should set RCU_BOOST_PRIO to
657 a priority higher than the lowest-priority thread that is 658 a priority higher than the lowest-priority thread that is
658 conspiring to prevent the CPU from running any non-real-time 659 conspiring to prevent the CPU from running any non-real-time
659 tasks. For example, if one thread at priority 10 and another 660 tasks. For example, if one thread at priority 10 and another
660 thread at priority 5 are between themselves fully consuming 661 thread at priority 5 are between themselves fully consuming
661 the CPU time on a given CPU, then RCU_BOOST_PRIO should be 662 the CPU time on a given CPU, then RCU_BOOST_PRIO should be
662 set to priority 6 or higher. 663 set to priority 6 or higher.
663 664
664 Specify the real-time priority, or take the default if unsure. 665 Specify the real-time priority, or take the default if unsure.
665 666
666 config RCU_BOOST_DELAY 667 config RCU_BOOST_DELAY
667 int "Milliseconds to delay boosting after RCU grace-period start" 668 int "Milliseconds to delay boosting after RCU grace-period start"
668 range 0 3000 669 range 0 3000
669 depends on RCU_BOOST 670 depends on RCU_BOOST
670 default 500 671 default 500
671 help 672 help
672 This option specifies the time to wait after the beginning of 673 This option specifies the time to wait after the beginning of
673 a given grace period before priority-boosting preempted RCU 674 a given grace period before priority-boosting preempted RCU
674 readers blocking that grace period. Note that any RCU reader 675 readers blocking that grace period. Note that any RCU reader
675 blocking an expedited RCU grace period is boosted immediately. 676 blocking an expedited RCU grace period is boosted immediately.
676 677
677 Accept the default if unsure. 678 Accept the default if unsure.
678 679
679 config RCU_NOCB_CPU 680 config RCU_NOCB_CPU
680 bool "Offload RCU callback processing from boot-selected CPUs" 681 bool "Offload RCU callback processing from boot-selected CPUs"
681 depends on TREE_RCU || TREE_PREEMPT_RCU 682 depends on TREE_RCU || TREE_PREEMPT_RCU
682 default n 683 default n
683 help 684 help
684 Use this option to reduce OS jitter for aggressive HPC or 685 Use this option to reduce OS jitter for aggressive HPC or
685 real-time workloads. It can also be used to offload RCU 686 real-time workloads. It can also be used to offload RCU
686 callback invocation to energy-efficient CPUs in battery-powered 687 callback invocation to energy-efficient CPUs in battery-powered
687 asymmetric multiprocessors. 688 asymmetric multiprocessors.
688 689
689 This option offloads callback invocation from the set of 690 This option offloads callback invocation from the set of
690 CPUs specified at boot time by the rcu_nocbs parameter. 691 CPUs specified at boot time by the rcu_nocbs parameter.
691 For each such CPU, a kthread ("rcuox/N") will be created to 692 For each such CPU, a kthread ("rcuox/N") will be created to
692 invoke callbacks, where the "N" is the CPU being offloaded, 693 invoke callbacks, where the "N" is the CPU being offloaded,
693 and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and 694 and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
694 "s" for RCU-sched. Nothing prevents this kthread from running 695 "s" for RCU-sched. Nothing prevents this kthread from running
695 on the specified CPUs, but (1) the kthreads may be preempted 696 on the specified CPUs, but (1) the kthreads may be preempted
696 between each callback, and (2) affinity or cgroups can be used 697 between each callback, and (2) affinity or cgroups can be used
697 to force the kthreads to run on whatever set of CPUs is desired. 698 to force the kthreads to run on whatever set of CPUs is desired.
698 699
699 Say Y here if you want to help to debug reduced OS jitter. 700 Say Y here if you want to help to debug reduced OS jitter.
700 Say N here if you are unsure. 701 Say N here if you are unsure.
701 702
702 choice 703 choice
703 prompt "Build-forced no-CBs CPUs" 704 prompt "Build-forced no-CBs CPUs"
704 default RCU_NOCB_CPU_NONE 705 default RCU_NOCB_CPU_NONE
705 help 706 help
706 This option allows no-CBs CPUs (whose RCU callbacks are invoked 707 This option allows no-CBs CPUs (whose RCU callbacks are invoked
707 from kthreads rather than from softirq context) to be specified 708 from kthreads rather than from softirq context) to be specified
708 at build time. Additional no-CBs CPUs may be specified by 709 at build time. Additional no-CBs CPUs may be specified by
709 the rcu_nocbs= boot parameter. 710 the rcu_nocbs= boot parameter.
710 711
711 config RCU_NOCB_CPU_NONE 712 config RCU_NOCB_CPU_NONE
712 bool "No build_forced no-CBs CPUs" 713 bool "No build_forced no-CBs CPUs"
713 depends on RCU_NOCB_CPU && !NO_HZ_FULL 714 depends on RCU_NOCB_CPU && !NO_HZ_FULL
714 help 715 help
715 This option does not force any of the CPUs to be no-CBs CPUs. 716 This option does not force any of the CPUs to be no-CBs CPUs.
716 Only CPUs designated by the rcu_nocbs= boot parameter will be 717 Only CPUs designated by the rcu_nocbs= boot parameter will be
717 no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU 718 no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
718 kthreads whose names begin with "rcuo". All other CPUs will 719 kthreads whose names begin with "rcuo". All other CPUs will
719 invoke their own RCU callbacks in softirq context. 720 invoke their own RCU callbacks in softirq context.
720 721
721 Select this option if you want to choose no-CBs CPUs at 722 Select this option if you want to choose no-CBs CPUs at
722 boot time, for example, to allow testing of different no-CBs 723 boot time, for example, to allow testing of different no-CBs
723 configurations without having to rebuild the kernel each time. 724 configurations without having to rebuild the kernel each time.
724 725
725 config RCU_NOCB_CPU_ZERO 726 config RCU_NOCB_CPU_ZERO
726 bool "CPU 0 is a build_forced no-CBs CPU" 727 bool "CPU 0 is a build_forced no-CBs CPU"
727 depends on RCU_NOCB_CPU && !NO_HZ_FULL 728 depends on RCU_NOCB_CPU && !NO_HZ_FULL
728 help 729 help
729 This option forces CPU 0 to be a no-CBs CPU, so that its RCU 730 This option forces CPU 0 to be a no-CBs CPU, so that its RCU
730 callbacks are invoked by a per-CPU kthread whose name begins 731 callbacks are invoked by a per-CPU kthread whose name begins
731 with "rcuo". Additional CPUs may be designated as no-CBs 732 with "rcuo". Additional CPUs may be designated as no-CBs
732 CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs. 733 CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
733 All other CPUs will invoke their own RCU callbacks in softirq 734 All other CPUs will invoke their own RCU callbacks in softirq
734 context. 735 context.
735 736
736 Select this if CPU 0 needs to be a no-CBs CPU for real-time 737 Select this if CPU 0 needs to be a no-CBs CPU for real-time
737 or energy-efficiency reasons, but the real reason it exists 738 or energy-efficiency reasons, but the real reason it exists
738 is to ensure that randconfig testing covers mixed systems. 739 is to ensure that randconfig testing covers mixed systems.
739 740
740 config RCU_NOCB_CPU_ALL 741 config RCU_NOCB_CPU_ALL
741 bool "All CPUs are build_forced no-CBs CPUs" 742 bool "All CPUs are build_forced no-CBs CPUs"
742 depends on RCU_NOCB_CPU 743 depends on RCU_NOCB_CPU
743 help 744 help
744 This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs= 745 This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
745 boot parameter will be ignored. All CPUs' RCU callbacks will 746 boot parameter will be ignored. All CPUs' RCU callbacks will
746 be executed in the context of per-CPU rcuo kthreads created for 747 be executed in the context of per-CPU rcuo kthreads created for
747 this purpose. Assuming that the kthreads whose names start with 748 this purpose. Assuming that the kthreads whose names start with
748 "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter 749 "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
749 on the remaining CPUs, but might decrease memory locality during 750 on the remaining CPUs, but might decrease memory locality during
750 RCU-callback invocation, thus potentially degrading throughput. 751 RCU-callback invocation, thus potentially degrading throughput.
751 752
752 Select this if all CPUs need to be no-CBs CPUs for real-time 753 Select this if all CPUs need to be no-CBs CPUs for real-time
753 or energy-efficiency reasons. 754 or energy-efficiency reasons.
754 755
755 endchoice 756 endchoice
756 757
757 endmenu # "RCU Subsystem" 758 endmenu # "RCU Subsystem"
758 759
759 config IKCONFIG 760 config IKCONFIG
760 tristate "Kernel .config support" 761 tristate "Kernel .config support"
761 ---help--- 762 ---help---
762 This option enables the complete Linux kernel ".config" file 763 This option enables the complete Linux kernel ".config" file
763 contents to be saved in the kernel. It provides documentation 764 contents to be saved in the kernel. It provides documentation
764 of which kernel options are used in a running kernel or in an 765 of which kernel options are used in a running kernel or in an
765 on-disk kernel. This information can be extracted from the kernel 766 on-disk kernel. This information can be extracted from the kernel
766 image file with the script scripts/extract-ikconfig and used as 767 image file with the script scripts/extract-ikconfig and used as
767 input to rebuild the current kernel or to build another kernel. 768 input to rebuild the current kernel or to build another kernel.
768 It can also be extracted from a running kernel by reading 769 It can also be extracted from a running kernel by reading
769 /proc/config.gz if enabled (below). 770 /proc/config.gz if enabled (below).
770 771
771 config IKCONFIG_PROC 772 config IKCONFIG_PROC
772 bool "Enable access to .config through /proc/config.gz" 773 bool "Enable access to .config through /proc/config.gz"
773 depends on IKCONFIG && PROC_FS 774 depends on IKCONFIG && PROC_FS
774 ---help--- 775 ---help---
775 This option enables access to the kernel configuration file 776 This option enables access to the kernel configuration file
776 through /proc/config.gz. 777 through /proc/config.gz.
777 778
778 config LOG_BUF_SHIFT 779 config LOG_BUF_SHIFT
779 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 780 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
780 range 12 21 781 range 12 21
781 default 17 782 default 17
782 help 783 help
783 Select kernel log buffer size as a power of 2. 784 Select kernel log buffer size as a power of 2.
784 Examples: 785 Examples:
785 17 => 128 KB 786 17 => 128 KB
786 16 => 64 KB 787 16 => 64 KB
787 15 => 32 KB 788 15 => 32 KB
788 14 => 16 KB 789 14 => 16 KB
789 13 => 8 KB 790 13 => 8 KB
790 12 => 4 KB 791 12 => 4 KB
791 792
792 # 793 #
793 # Architectures with an unreliable sched_clock() should select this: 794 # Architectures with an unreliable sched_clock() should select this:
794 # 795 #
795 config HAVE_UNSTABLE_SCHED_CLOCK 796 config HAVE_UNSTABLE_SCHED_CLOCK
796 bool 797 bool
797 798
798 config GENERIC_SCHED_CLOCK 799 config GENERIC_SCHED_CLOCK
799 bool 800 bool
800 801
801 # 802 #
802 # For architectures that want to enable the support for NUMA-affine scheduler 803 # For architectures that want to enable the support for NUMA-affine scheduler
803 # balancing logic: 804 # balancing logic:
804 # 805 #
805 config ARCH_SUPPORTS_NUMA_BALANCING 806 config ARCH_SUPPORTS_NUMA_BALANCING
806 bool 807 bool
807 808
808 # For architectures that (ab)use NUMA to represent different memory regions 809 # For architectures that (ab)use NUMA to represent different memory regions
809 # all cpu-local but of different latencies, such as SuperH. 810 # all cpu-local but of different latencies, such as SuperH.
810 # 811 #
811 config ARCH_WANT_NUMA_VARIABLE_LOCALITY 812 config ARCH_WANT_NUMA_VARIABLE_LOCALITY
812 bool 813 bool
813 814
814 # 815 #
815 # For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE 816 # For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE
816 config ARCH_WANTS_PROT_NUMA_PROT_NONE 817 config ARCH_WANTS_PROT_NUMA_PROT_NONE
817 bool 818 bool
818 819
819 config ARCH_USES_NUMA_PROT_NONE 820 config ARCH_USES_NUMA_PROT_NONE
820 bool 821 bool
821 default y 822 default y
822 depends on ARCH_WANTS_PROT_NUMA_PROT_NONE 823 depends on ARCH_WANTS_PROT_NUMA_PROT_NONE
823 depends on NUMA_BALANCING 824 depends on NUMA_BALANCING
824 825
825 config NUMA_BALANCING_DEFAULT_ENABLED 826 config NUMA_BALANCING_DEFAULT_ENABLED
826 bool "Automatically enable NUMA aware memory/task placement" 827 bool "Automatically enable NUMA aware memory/task placement"
827 default y 828 default y
828 depends on NUMA_BALANCING 829 depends on NUMA_BALANCING
829 help 830 help
830 If set, autonumic NUMA balancing will be enabled if running on a NUMA 831 If set, autonumic NUMA balancing will be enabled if running on a NUMA
831 machine. 832 machine.
832 833
833 config NUMA_BALANCING 834 config NUMA_BALANCING
834 bool "Memory placement aware NUMA scheduler" 835 bool "Memory placement aware NUMA scheduler"
835 depends on ARCH_SUPPORTS_NUMA_BALANCING 836 depends on ARCH_SUPPORTS_NUMA_BALANCING
836 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY 837 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
837 depends on SMP && NUMA && MIGRATION 838 depends on SMP && NUMA && MIGRATION
838 help 839 help
839 This option adds support for automatic NUMA aware memory/task placement. 840 This option adds support for automatic NUMA aware memory/task placement.
840 The mechanism is quite primitive and is based on migrating memory when 841 The mechanism is quite primitive and is based on migrating memory when
841 it is references to the node the task is running on. 842 it is references to the node the task is running on.
842 843
843 This system will be inactive on UMA systems. 844 This system will be inactive on UMA systems.
844 845
845 menuconfig CGROUPS 846 menuconfig CGROUPS
846 boolean "Control Group support" 847 boolean "Control Group support"
847 depends on EVENTFD 848 depends on EVENTFD
848 help 849 help
849 This option adds support for grouping sets of processes together, for 850 This option adds support for grouping sets of processes together, for
850 use with process control subsystems such as Cpusets, CFS, memory 851 use with process control subsystems such as Cpusets, CFS, memory
851 controls or device isolation. 852 controls or device isolation.
852 See 853 See
853 - Documentation/scheduler/sched-design-CFS.txt (CFS) 854 - Documentation/scheduler/sched-design-CFS.txt (CFS)
854 - Documentation/cgroups/ (features for grouping, isolation 855 - Documentation/cgroups/ (features for grouping, isolation
855 and resource control) 856 and resource control)
856 857
857 Say N if unsure. 858 Say N if unsure.
858 859
859 if CGROUPS 860 if CGROUPS
860 861
861 config CGROUP_DEBUG 862 config CGROUP_DEBUG
862 bool "Example debug cgroup subsystem" 863 bool "Example debug cgroup subsystem"
863 default n 864 default n
864 help 865 help
865 This option enables a simple cgroup subsystem that 866 This option enables a simple cgroup subsystem that
866 exports useful debugging information about the cgroups 867 exports useful debugging information about the cgroups
867 framework. 868 framework.
868 869
869 Say N if unsure. 870 Say N if unsure.
870 871
871 config CGROUP_FREEZER 872 config CGROUP_FREEZER
872 bool "Freezer cgroup subsystem" 873 bool "Freezer cgroup subsystem"
873 help 874 help
874 Provides a way to freeze and unfreeze all tasks in a 875 Provides a way to freeze and unfreeze all tasks in a
875 cgroup. 876 cgroup.
876 877
877 config CGROUP_DEVICE 878 config CGROUP_DEVICE
878 bool "Device controller for cgroups" 879 bool "Device controller for cgroups"
879 help 880 help
880 Provides a cgroup implementing whitelists for devices which 881 Provides a cgroup implementing whitelists for devices which
881 a process in the cgroup can mknod or open. 882 a process in the cgroup can mknod or open.
882 883
883 config CPUSETS 884 config CPUSETS
884 bool "Cpuset support" 885 bool "Cpuset support"
885 help 886 help
886 This option will let you create and manage CPUSETs which 887 This option will let you create and manage CPUSETs which
887 allow dynamically partitioning a system into sets of CPUs and 888 allow dynamically partitioning a system into sets of CPUs and
888 Memory Nodes and assigning tasks to run only within those sets. 889 Memory Nodes and assigning tasks to run only within those sets.
889 This is primarily useful on large SMP or NUMA systems. 890 This is primarily useful on large SMP or NUMA systems.
890 891
891 Say N if unsure. 892 Say N if unsure.
892 893
893 config PROC_PID_CPUSET 894 config PROC_PID_CPUSET
894 bool "Include legacy /proc/<pid>/cpuset file" 895 bool "Include legacy /proc/<pid>/cpuset file"
895 depends on CPUSETS 896 depends on CPUSETS
896 default y 897 default y
897 898
898 config CGROUP_CPUACCT 899 config CGROUP_CPUACCT
899 bool "Simple CPU accounting cgroup subsystem" 900 bool "Simple CPU accounting cgroup subsystem"
900 help 901 help
901 Provides a simple Resource Controller for monitoring the 902 Provides a simple Resource Controller for monitoring the
902 total CPU consumed by the tasks in a cgroup. 903 total CPU consumed by the tasks in a cgroup.
903 904
904 config RESOURCE_COUNTERS 905 config RESOURCE_COUNTERS
905 bool "Resource counters" 906 bool "Resource counters"
906 help 907 help
907 This option enables controller independent resource accounting 908 This option enables controller independent resource accounting
908 infrastructure that works with cgroups. 909 infrastructure that works with cgroups.
909 910
910 config MEMCG 911 config MEMCG
911 bool "Memory Resource Controller for Control Groups" 912 bool "Memory Resource Controller for Control Groups"
912 depends on RESOURCE_COUNTERS 913 depends on RESOURCE_COUNTERS
913 select MM_OWNER 914 select MM_OWNER
914 help 915 help
915 Provides a memory resource controller that manages both anonymous 916 Provides a memory resource controller that manages both anonymous
916 memory and page cache. (See Documentation/cgroups/memory.txt) 917 memory and page cache. (See Documentation/cgroups/memory.txt)
917 918
918 Note that setting this option increases fixed memory overhead 919 Note that setting this option increases fixed memory overhead
919 associated with each page of memory in the system. By this, 920 associated with each page of memory in the system. By this,
920 8(16)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory 921 8(16)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
921 usage tracking struct at boot. Total amount of this is printed out 922 usage tracking struct at boot. Total amount of this is printed out
922 at boot. 923 at boot.
923 924
924 Only enable when you're ok with these trade offs and really 925 Only enable when you're ok with these trade offs and really
925 sure you need the memory resource controller. Even when you enable 926 sure you need the memory resource controller. Even when you enable
926 this, you can set "cgroup_disable=memory" at your boot option to 927 this, you can set "cgroup_disable=memory" at your boot option to
927 disable memory resource controller and you can avoid overheads. 928 disable memory resource controller and you can avoid overheads.
928 (and lose benefits of memory resource controller) 929 (and lose benefits of memory resource controller)
929 930
930 This config option also selects MM_OWNER config option, which 931 This config option also selects MM_OWNER config option, which
931 could in turn add some fork/exit overhead. 932 could in turn add some fork/exit overhead.
932 933
933 config MEMCG_SWAP 934 config MEMCG_SWAP
934 bool "Memory Resource Controller Swap Extension" 935 bool "Memory Resource Controller Swap Extension"
935 depends on MEMCG && SWAP 936 depends on MEMCG && SWAP
936 help 937 help
937 Add swap management feature to memory resource controller. When you 938 Add swap management feature to memory resource controller. When you
938 enable this, you can limit mem+swap usage per cgroup. In other words, 939 enable this, you can limit mem+swap usage per cgroup. In other words,
939 when you disable this, memory resource controller has no cares to 940 when you disable this, memory resource controller has no cares to
940 usage of swap...a process can exhaust all of the swap. This extension 941 usage of swap...a process can exhaust all of the swap. This extension
941 is useful when you want to avoid exhaustion swap but this itself 942 is useful when you want to avoid exhaustion swap but this itself
942 adds more overheads and consumes memory for remembering information. 943 adds more overheads and consumes memory for remembering information.
943 Especially if you use 32bit system or small memory system, please 944 Especially if you use 32bit system or small memory system, please
944 be careful about enabling this. When memory resource controller 945 be careful about enabling this. When memory resource controller
945 is disabled by boot option, this will be automatically disabled and 946 is disabled by boot option, this will be automatically disabled and
946 there will be no overhead from this. Even when you set this config=y, 947 there will be no overhead from this. Even when you set this config=y,
947 if boot option "swapaccount=0" is set, swap will not be accounted. 948 if boot option "swapaccount=0" is set, swap will not be accounted.
948 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page 949 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
949 size is 4096bytes, 512k per 1Gbytes of swap. 950 size is 4096bytes, 512k per 1Gbytes of swap.
950 config MEMCG_SWAP_ENABLED 951 config MEMCG_SWAP_ENABLED
951 bool "Memory Resource Controller Swap Extension enabled by default" 952 bool "Memory Resource Controller Swap Extension enabled by default"
952 depends on MEMCG_SWAP 953 depends on MEMCG_SWAP
953 default y 954 default y
954 help 955 help
955 Memory Resource Controller Swap Extension comes with its price in 956 Memory Resource Controller Swap Extension comes with its price in
956 a bigger memory consumption. General purpose distribution kernels 957 a bigger memory consumption. General purpose distribution kernels
957 which want to enable the feature but keep it disabled by default 958 which want to enable the feature but keep it disabled by default
958 and let the user enable it by swapaccount boot command line 959 and let the user enable it by swapaccount boot command line
959 parameter should have this option unselected. 960 parameter should have this option unselected.
960 For those who want to have the feature enabled by default should 961 For those who want to have the feature enabled by default should
961 select this option (if, for some reason, they need to disable it 962 select this option (if, for some reason, they need to disable it
962 then swapaccount=0 does the trick). 963 then swapaccount=0 does the trick).
963 config MEMCG_KMEM 964 config MEMCG_KMEM
964 bool "Memory Resource Controller Kernel Memory accounting" 965 bool "Memory Resource Controller Kernel Memory accounting"
965 depends on MEMCG 966 depends on MEMCG
966 depends on SLUB || SLAB 967 depends on SLUB || SLAB
967 help 968 help
968 The Kernel Memory extension for Memory Resource Controller can limit 969 The Kernel Memory extension for Memory Resource Controller can limit
969 the amount of memory used by kernel objects in the system. Those are 970 the amount of memory used by kernel objects in the system. Those are
970 fundamentally different from the entities handled by the standard 971 fundamentally different from the entities handled by the standard
971 Memory Controller, which are page-based, and can be swapped. Users of 972 Memory Controller, which are page-based, and can be swapped. Users of
972 the kmem extension can use it to guarantee that no group of processes 973 the kmem extension can use it to guarantee that no group of processes
973 will ever exhaust kernel resources alone. 974 will ever exhaust kernel resources alone.
974 975
975 config CGROUP_HUGETLB 976 config CGROUP_HUGETLB
976 bool "HugeTLB Resource Controller for Control Groups" 977 bool "HugeTLB Resource Controller for Control Groups"
977 depends on RESOURCE_COUNTERS && HUGETLB_PAGE 978 depends on RESOURCE_COUNTERS && HUGETLB_PAGE
978 default n 979 default n
979 help 980 help
980 Provides a cgroup Resource Controller for HugeTLB pages. 981 Provides a cgroup Resource Controller for HugeTLB pages.
981 When you enable this, you can put a per cgroup limit on HugeTLB usage. 982 When you enable this, you can put a per cgroup limit on HugeTLB usage.
982 The limit is enforced during page fault. Since HugeTLB doesn't 983 The limit is enforced during page fault. Since HugeTLB doesn't
983 support page reclaim, enforcing the limit at page fault time implies 984 support page reclaim, enforcing the limit at page fault time implies
984 that, the application will get SIGBUS signal if it tries to access 985 that, the application will get SIGBUS signal if it tries to access
985 HugeTLB pages beyond its limit. This requires the application to know 986 HugeTLB pages beyond its limit. This requires the application to know
986 beforehand how much HugeTLB pages it would require for its use. The 987 beforehand how much HugeTLB pages it would require for its use. The
987 control group is tracked in the third page lru pointer. This means 988 control group is tracked in the third page lru pointer. This means
988 that we cannot use the controller with huge page less than 3 pages. 989 that we cannot use the controller with huge page less than 3 pages.
989 990
990 config CGROUP_PERF 991 config CGROUP_PERF
991 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring" 992 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
992 depends on PERF_EVENTS && CGROUPS 993 depends on PERF_EVENTS && CGROUPS
993 help 994 help
994 This option extends the per-cpu mode to restrict monitoring to 995 This option extends the per-cpu mode to restrict monitoring to
995 threads which belong to the cgroup specified and run on the 996 threads which belong to the cgroup specified and run on the
996 designated cpu. 997 designated cpu.
997 998
998 Say N if unsure. 999 Say N if unsure.
999 1000
1000 menuconfig CGROUP_SCHED 1001 menuconfig CGROUP_SCHED
1001 bool "Group CPU scheduler" 1002 bool "Group CPU scheduler"
1002 default n 1003 default n
1003 help 1004 help
1004 This feature lets CPU scheduler recognize task groups and control CPU 1005 This feature lets CPU scheduler recognize task groups and control CPU
1005 bandwidth allocation to such task groups. It uses cgroups to group 1006 bandwidth allocation to such task groups. It uses cgroups to group
1006 tasks. 1007 tasks.
1007 1008
1008 if CGROUP_SCHED 1009 if CGROUP_SCHED
1009 config FAIR_GROUP_SCHED 1010 config FAIR_GROUP_SCHED
1010 bool "Group scheduling for SCHED_OTHER" 1011 bool "Group scheduling for SCHED_OTHER"
1011 depends on CGROUP_SCHED 1012 depends on CGROUP_SCHED
1012 default CGROUP_SCHED 1013 default CGROUP_SCHED
1013 1014
1014 config CFS_BANDWIDTH 1015 config CFS_BANDWIDTH
1015 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" 1016 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
1016 depends on FAIR_GROUP_SCHED 1017 depends on FAIR_GROUP_SCHED
1017 default n 1018 default n
1018 help 1019 help
1019 This option allows users to define CPU bandwidth rates (limits) for 1020 This option allows users to define CPU bandwidth rates (limits) for
1020 tasks running within the fair group scheduler. Groups with no limit 1021 tasks running within the fair group scheduler. Groups with no limit
1021 set are considered to be unconstrained and will run with no 1022 set are considered to be unconstrained and will run with no
1022 restriction. 1023 restriction.
1023 See tip/Documentation/scheduler/sched-bwc.txt for more information. 1024 See tip/Documentation/scheduler/sched-bwc.txt for more information.
1024 1025
1025 config RT_GROUP_SCHED 1026 config RT_GROUP_SCHED
1026 bool "Group scheduling for SCHED_RR/FIFO" 1027 bool "Group scheduling for SCHED_RR/FIFO"
1027 depends on CGROUP_SCHED 1028 depends on CGROUP_SCHED
1028 default n 1029 default n
1029 help 1030 help
1030 This feature lets you explicitly allocate real CPU bandwidth 1031 This feature lets you explicitly allocate real CPU bandwidth
1031 to task groups. If enabled, it will also make it impossible to 1032 to task groups. If enabled, it will also make it impossible to
1032 schedule realtime tasks for non-root users until you allocate 1033 schedule realtime tasks for non-root users until you allocate
1033 realtime bandwidth for them. 1034 realtime bandwidth for them.
1034 See Documentation/scheduler/sched-rt-group.txt for more information. 1035 See Documentation/scheduler/sched-rt-group.txt for more information.
1035 1036
1036 endif #CGROUP_SCHED 1037 endif #CGROUP_SCHED
1037 1038
1038 config BLK_CGROUP 1039 config BLK_CGROUP
1039 bool "Block IO controller" 1040 bool "Block IO controller"
1040 depends on BLOCK 1041 depends on BLOCK
1041 default n 1042 default n
1042 ---help--- 1043 ---help---
1043 Generic block IO controller cgroup interface. This is the common 1044 Generic block IO controller cgroup interface. This is the common
1044 cgroup interface which should be used by various IO controlling 1045 cgroup interface which should be used by various IO controlling
1045 policies. 1046 policies.
1046 1047
1047 Currently, CFQ IO scheduler uses it to recognize task groups and 1048 Currently, CFQ IO scheduler uses it to recognize task groups and
1048 control disk bandwidth allocation (proportional time slice allocation) 1049 control disk bandwidth allocation (proportional time slice allocation)
1049 to such task groups. It is also used by bio throttling logic in 1050 to such task groups. It is also used by bio throttling logic in
1050 block layer to implement upper limit in IO rates on a device. 1051 block layer to implement upper limit in IO rates on a device.
1051 1052
1052 This option only enables generic Block IO controller infrastructure. 1053 This option only enables generic Block IO controller infrastructure.
1053 One needs to also enable actual IO controlling logic/policy. For 1054 One needs to also enable actual IO controlling logic/policy. For
1054 enabling proportional weight division of disk bandwidth in CFQ, set 1055 enabling proportional weight division of disk bandwidth in CFQ, set
1055 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set 1056 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
1056 CONFIG_BLK_DEV_THROTTLING=y. 1057 CONFIG_BLK_DEV_THROTTLING=y.
1057 1058
1058 See Documentation/cgroups/blkio-controller.txt for more information. 1059 See Documentation/cgroups/blkio-controller.txt for more information.
1059 1060
1060 config DEBUG_BLK_CGROUP 1061 config DEBUG_BLK_CGROUP
1061 bool "Enable Block IO controller debugging" 1062 bool "Enable Block IO controller debugging"
1062 depends on BLK_CGROUP 1063 depends on BLK_CGROUP
1063 default n 1064 default n
1064 ---help--- 1065 ---help---
1065 Enable some debugging help. Currently it exports additional stat 1066 Enable some debugging help. Currently it exports additional stat
1066 files in a cgroup which can be useful for debugging. 1067 files in a cgroup which can be useful for debugging.
1067 1068
1068 endif # CGROUPS 1069 endif # CGROUPS
1069 1070
1070 config CHECKPOINT_RESTORE 1071 config CHECKPOINT_RESTORE
1071 bool "Checkpoint/restore support" if EXPERT 1072 bool "Checkpoint/restore support" if EXPERT
1072 default n 1073 default n
1073 help 1074 help
1074 Enables additional kernel features in a sake of checkpoint/restore. 1075 Enables additional kernel features in a sake of checkpoint/restore.
1075 In particular it adds auxiliary prctl codes to setup process text, 1076 In particular it adds auxiliary prctl codes to setup process text,
1076 data and heap segment sizes, and a few additional /proc filesystem 1077 data and heap segment sizes, and a few additional /proc filesystem
1077 entries. 1078 entries.
1078 1079
1079 If unsure, say N here. 1080 If unsure, say N here.
1080 1081
1081 menuconfig NAMESPACES 1082 menuconfig NAMESPACES
1082 bool "Namespaces support" if EXPERT 1083 bool "Namespaces support" if EXPERT
1083 default !EXPERT 1084 default !EXPERT
1084 help 1085 help
1085 Provides the way to make tasks work with different objects using 1086 Provides the way to make tasks work with different objects using
1086 the same id. For example same IPC id may refer to different objects 1087 the same id. For example same IPC id may refer to different objects
1087 or same user id or pid may refer to different tasks when used in 1088 or same user id or pid may refer to different tasks when used in
1088 different namespaces. 1089 different namespaces.
1089 1090
1090 if NAMESPACES 1091 if NAMESPACES
1091 1092
1092 config UTS_NS 1093 config UTS_NS
1093 bool "UTS namespace" 1094 bool "UTS namespace"
1094 default y 1095 default y
1095 help 1096 help
1096 In this namespace tasks see different info provided with the 1097 In this namespace tasks see different info provided with the
1097 uname() system call 1098 uname() system call
1098 1099
1099 config IPC_NS 1100 config IPC_NS
1100 bool "IPC namespace" 1101 bool "IPC namespace"
1101 depends on (SYSVIPC || POSIX_MQUEUE) 1102 depends on (SYSVIPC || POSIX_MQUEUE)
1102 default y 1103 default y
1103 help 1104 help
1104 In this namespace tasks work with IPC ids which correspond to 1105 In this namespace tasks work with IPC ids which correspond to
1105 different IPC objects in different namespaces. 1106 different IPC objects in different namespaces.
1106 1107
1107 config USER_NS 1108 config USER_NS
1108 bool "User namespace" 1109 bool "User namespace"
1109 depends on UIDGID_CONVERTED 1110 depends on UIDGID_CONVERTED
1110 select UIDGID_STRICT_TYPE_CHECKS 1111 select UIDGID_STRICT_TYPE_CHECKS
1111 1112
1112 default n 1113 default n
1113 help 1114 help
1114 This allows containers, i.e. vservers, to use user namespaces 1115 This allows containers, i.e. vservers, to use user namespaces
1115 to provide different user info for different servers. 1116 to provide different user info for different servers.
1116 1117
1117 When user namespaces are enabled in the kernel it is 1118 When user namespaces are enabled in the kernel it is
1118 recommended that the MEMCG and MEMCG_KMEM options also be 1119 recommended that the MEMCG and MEMCG_KMEM options also be
1119 enabled and that user-space use the memory control groups to 1120 enabled and that user-space use the memory control groups to
1120 limit the amount of memory a memory unprivileged users can 1121 limit the amount of memory a memory unprivileged users can
1121 use. 1122 use.
1122 1123
1123 If unsure, say N. 1124 If unsure, say N.
1124 1125
1125 config PID_NS 1126 config PID_NS
1126 bool "PID Namespaces" 1127 bool "PID Namespaces"
1127 default y 1128 default y
1128 help 1129 help
1129 Support process id namespaces. This allows having multiple 1130 Support process id namespaces. This allows having multiple
1130 processes with the same pid as long as they are in different 1131 processes with the same pid as long as they are in different
1131 pid namespaces. This is a building block of containers. 1132 pid namespaces. This is a building block of containers.
1132 1133
1133 config NET_NS 1134 config NET_NS
1134 bool "Network namespace" 1135 bool "Network namespace"
1135 depends on NET 1136 depends on NET
1136 default y 1137 default y
1137 help 1138 help
1138 Allow user space to create what appear to be multiple instances 1139 Allow user space to create what appear to be multiple instances
1139 of the network stack. 1140 of the network stack.
1140 1141
1141 endif # NAMESPACES 1142 endif # NAMESPACES
1142 1143
1143 config UIDGID_CONVERTED 1144 config UIDGID_CONVERTED
1144 # True if all of the selected software conmponents are known 1145 # True if all of the selected software conmponents are known
1145 # to have uid_t and gid_t converted to kuid_t and kgid_t 1146 # to have uid_t and gid_t converted to kuid_t and kgid_t
1146 # where appropriate and are otherwise safe to use with 1147 # where appropriate and are otherwise safe to use with
1147 # the user namespace. 1148 # the user namespace.
1148 bool 1149 bool
1149 default y 1150 default y
1150 1151
1151 # Filesystems 1152 # Filesystems
1152 depends on XFS_FS = n 1153 depends on XFS_FS = n
1153 1154
1154 config UIDGID_STRICT_TYPE_CHECKS 1155 config UIDGID_STRICT_TYPE_CHECKS
1155 bool "Require conversions between uid/gids and their internal representation" 1156 bool "Require conversions between uid/gids and their internal representation"
1156 depends on UIDGID_CONVERTED 1157 depends on UIDGID_CONVERTED
1157 default n 1158 default n
1158 help 1159 help
1159 While the nececessary conversions are being added to all subsystems this option allows 1160 While the nececessary conversions are being added to all subsystems this option allows
1160 the code to continue to build for unconverted subsystems. 1161 the code to continue to build for unconverted subsystems.
1161 1162
1162 Say Y here if you want the strict type checking enabled 1163 Say Y here if you want the strict type checking enabled
1163 1164
1164 config SCHED_AUTOGROUP 1165 config SCHED_AUTOGROUP
1165 bool "Automatic process group scheduling" 1166 bool "Automatic process group scheduling"
1166 select EVENTFD 1167 select EVENTFD
1167 select CGROUPS 1168 select CGROUPS
1168 select CGROUP_SCHED 1169 select CGROUP_SCHED
1169 select FAIR_GROUP_SCHED 1170 select FAIR_GROUP_SCHED
1170 help 1171 help
1171 This option optimizes the scheduler for common desktop workloads by 1172 This option optimizes the scheduler for common desktop workloads by
1172 automatically creating and populating task groups. This separation 1173 automatically creating and populating task groups. This separation
1173 of workloads isolates aggressive CPU burners (like build jobs) from 1174 of workloads isolates aggressive CPU burners (like build jobs) from
1174 desktop applications. Task group autogeneration is currently based 1175 desktop applications. Task group autogeneration is currently based
1175 upon task session. 1176 upon task session.
1176 1177
1177 config MM_OWNER 1178 config MM_OWNER
1178 bool 1179 bool
1179 1180
1180 config SYSFS_DEPRECATED 1181 config SYSFS_DEPRECATED
1181 bool "Enable deprecated sysfs features to support old userspace tools" 1182 bool "Enable deprecated sysfs features to support old userspace tools"
1182 depends on SYSFS 1183 depends on SYSFS
1183 default n 1184 default n
1184 help 1185 help
1185 This option adds code that switches the layout of the "block" class 1186 This option adds code that switches the layout of the "block" class
1186 devices, to not show up in /sys/class/block/, but only in 1187 devices, to not show up in /sys/class/block/, but only in
1187 /sys/block/. 1188 /sys/block/.
1188 1189
1189 This switch is only active when the sysfs.deprecated=1 boot option is 1190 This switch is only active when the sysfs.deprecated=1 boot option is
1190 passed or the SYSFS_DEPRECATED_V2 option is set. 1191 passed or the SYSFS_DEPRECATED_V2 option is set.
1191 1192
1192 This option allows new kernels to run on old distributions and tools, 1193 This option allows new kernels to run on old distributions and tools,
1193 which might get confused by /sys/class/block/. Since 2007/2008 all 1194 which might get confused by /sys/class/block/. Since 2007/2008 all
1194 major distributions and tools handle this just fine. 1195 major distributions and tools handle this just fine.
1195 1196
1196 Recent distributions and userspace tools after 2009/2010 depend on 1197 Recent distributions and userspace tools after 2009/2010 depend on
1197 the existence of /sys/class/block/, and will not work with this 1198 the existence of /sys/class/block/, and will not work with this
1198 option enabled. 1199 option enabled.
1199 1200
1200 Only if you are using a new kernel on an old distribution, you might 1201 Only if you are using a new kernel on an old distribution, you might
1201 need to say Y here. 1202 need to say Y here.
1202 1203
1203 config SYSFS_DEPRECATED_V2 1204 config SYSFS_DEPRECATED_V2
1204 bool "Enable deprecated sysfs features by default" 1205 bool "Enable deprecated sysfs features by default"
1205 default n 1206 default n
1206 depends on SYSFS 1207 depends on SYSFS
1207 depends on SYSFS_DEPRECATED 1208 depends on SYSFS_DEPRECATED
1208 help 1209 help
1209 Enable deprecated sysfs by default. 1210 Enable deprecated sysfs by default.
1210 1211
1211 See the CONFIG_SYSFS_DEPRECATED option for more details about this 1212 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1212 option. 1213 option.
1213 1214
1214 Only if you are using a new kernel on an old distribution, you might 1215 Only if you are using a new kernel on an old distribution, you might
1215 need to say Y here. Even then, odds are you would not need it 1216 need to say Y here. Even then, odds are you would not need it
1216 enabled, you can always pass the boot option if absolutely necessary. 1217 enabled, you can always pass the boot option if absolutely necessary.
1217 1218
1218 config RELAY 1219 config RELAY
1219 bool "Kernel->user space relay support (formerly relayfs)" 1220 bool "Kernel->user space relay support (formerly relayfs)"
1220 help 1221 help
1221 This option enables support for relay interface support in 1222 This option enables support for relay interface support in
1222 certain file systems (such as debugfs). 1223 certain file systems (such as debugfs).
1223 It is designed to provide an efficient mechanism for tools and 1224 It is designed to provide an efficient mechanism for tools and
1224 facilities to relay large amounts of data from kernel space to 1225 facilities to relay large amounts of data from kernel space to
1225 user space. 1226 user space.
1226 1227
1227 If unsure, say N. 1228 If unsure, say N.
1228 1229
1229 config BLK_DEV_INITRD 1230 config BLK_DEV_INITRD
1230 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1231 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1231 depends on BROKEN || !FRV 1232 depends on BROKEN || !FRV
1232 help 1233 help
1233 The initial RAM filesystem is a ramfs which is loaded by the 1234 The initial RAM filesystem is a ramfs which is loaded by the
1234 boot loader (loadlin or lilo) and that is mounted as root 1235 boot loader (loadlin or lilo) and that is mounted as root
1235 before the normal boot procedure. It is typically used to 1236 before the normal boot procedure. It is typically used to
1236 load modules needed to mount the "real" root file system, 1237 load modules needed to mount the "real" root file system,
1237 etc. See <file:Documentation/initrd.txt> for details. 1238 etc. See <file:Documentation/initrd.txt> for details.
1238 1239
1239 If RAM disk support (BLK_DEV_RAM) is also included, this 1240 If RAM disk support (BLK_DEV_RAM) is also included, this
1240 also enables initial RAM disk (initrd) support and adds 1241 also enables initial RAM disk (initrd) support and adds
1241 15 Kbytes (more on some other architectures) to the kernel size. 1242 15 Kbytes (more on some other architectures) to the kernel size.
1242 1243
1243 If unsure say Y. 1244 If unsure say Y.
1244 1245
1245 if BLK_DEV_INITRD 1246 if BLK_DEV_INITRD
1246 1247
1247 source "usr/Kconfig" 1248 source "usr/Kconfig"
1248 1249
1249 endif 1250 endif
1250 1251
1251 config CC_OPTIMIZE_FOR_SIZE 1252 config CC_OPTIMIZE_FOR_SIZE
1252 bool "Optimize for size" 1253 bool "Optimize for size"
1253 help 1254 help
1254 Enabling this option will pass "-Os" instead of "-O2" to gcc 1255 Enabling this option will pass "-Os" instead of "-O2" to gcc
1255 resulting in a smaller kernel. 1256 resulting in a smaller kernel.
1256 1257
1257 If unsure, say N. 1258 If unsure, say N.
1258 1259
1259 config SYSCTL 1260 config SYSCTL
1260 bool 1261 bool
1261 1262
1262 config ANON_INODES 1263 config ANON_INODES
1263 bool 1264 bool
1264 1265
1265 config HAVE_UID16 1266 config HAVE_UID16
1266 bool 1267 bool
1267 1268
1268 config SYSCTL_EXCEPTION_TRACE 1269 config SYSCTL_EXCEPTION_TRACE
1269 bool 1270 bool
1270 help 1271 help
1271 Enable support for /proc/sys/debug/exception-trace. 1272 Enable support for /proc/sys/debug/exception-trace.
1272 1273
1273 config SYSCTL_ARCH_UNALIGN_NO_WARN 1274 config SYSCTL_ARCH_UNALIGN_NO_WARN
1274 bool 1275 bool
1275 help 1276 help
1276 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap 1277 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1277 Allows arch to define/use @no_unaligned_warning to possibly warn 1278 Allows arch to define/use @no_unaligned_warning to possibly warn
1278 about unaligned access emulation going on under the hood. 1279 about unaligned access emulation going on under the hood.
1279 1280
1280 config SYSCTL_ARCH_UNALIGN_ALLOW 1281 config SYSCTL_ARCH_UNALIGN_ALLOW
1281 bool 1282 bool
1282 help 1283 help
1283 Enable support for /proc/sys/kernel/unaligned-trap 1284 Enable support for /proc/sys/kernel/unaligned-trap
1284 Allows arches to define/use @unaligned_enabled to runtime toggle 1285 Allows arches to define/use @unaligned_enabled to runtime toggle
1285 the unaligned access emulation. 1286 the unaligned access emulation.
1286 see arch/parisc/kernel/unaligned.c for reference 1287 see arch/parisc/kernel/unaligned.c for reference
1287 1288
1288 config HAVE_PCSPKR_PLATFORM 1289 config HAVE_PCSPKR_PLATFORM
1289 bool 1290 bool
1290 1291
1291 menuconfig EXPERT 1292 menuconfig EXPERT
1292 bool "Configure standard kernel features (expert users)" 1293 bool "Configure standard kernel features (expert users)"
1293 # Unhide debug options, to make the on-by-default options visible 1294 # Unhide debug options, to make the on-by-default options visible
1294 select DEBUG_KERNEL 1295 select DEBUG_KERNEL
1295 help 1296 help
1296 This option allows certain base kernel options and settings 1297 This option allows certain base kernel options and settings
1297 to be disabled or tweaked. This is for specialized 1298 to be disabled or tweaked. This is for specialized
1298 environments which can tolerate a "non-standard" kernel. 1299 environments which can tolerate a "non-standard" kernel.
1299 Only use this if you really know what you are doing. 1300 Only use this if you really know what you are doing.
1300 1301
1301 config UID16 1302 config UID16
1302 bool "Enable 16-bit UID system calls" if EXPERT 1303 bool "Enable 16-bit UID system calls" if EXPERT
1303 depends on HAVE_UID16 1304 depends on HAVE_UID16
1304 default y 1305 default y
1305 help 1306 help
1306 This enables the legacy 16-bit UID syscall wrappers. 1307 This enables the legacy 16-bit UID syscall wrappers.
1307 1308
1308 config SYSCTL_SYSCALL 1309 config SYSCTL_SYSCALL
1309 bool "Sysctl syscall support" if EXPERT 1310 bool "Sysctl syscall support" if EXPERT
1310 depends on PROC_SYSCTL 1311 depends on PROC_SYSCTL
1311 default n 1312 default n
1312 select SYSCTL 1313 select SYSCTL
1313 ---help--- 1314 ---help---
1314 sys_sysctl uses binary paths that have been found challenging 1315 sys_sysctl uses binary paths that have been found challenging
1315 to properly maintain and use. The interface in /proc/sys 1316 to properly maintain and use. The interface in /proc/sys
1316 using paths with ascii names is now the primary path to this 1317 using paths with ascii names is now the primary path to this
1317 information. 1318 information.
1318 1319
1319 Almost nothing using the binary sysctl interface so if you are 1320 Almost nothing using the binary sysctl interface so if you are
1320 trying to save some space it is probably safe to disable this, 1321 trying to save some space it is probably safe to disable this,
1321 making your kernel marginally smaller. 1322 making your kernel marginally smaller.
1322 1323
1323 If unsure say N here. 1324 If unsure say N here.
1324 1325
1325 config KALLSYMS 1326 config KALLSYMS
1326 bool "Load all symbols for debugging/ksymoops" if EXPERT 1327 bool "Load all symbols for debugging/ksymoops" if EXPERT
1327 default y 1328 default y
1328 help 1329 help
1329 Say Y here to let the kernel print out symbolic crash information and 1330 Say Y here to let the kernel print out symbolic crash information and
1330 symbolic stack backtraces. This increases the size of the kernel 1331 symbolic stack backtraces. This increases the size of the kernel
1331 somewhat, as all symbols have to be loaded into the kernel image. 1332 somewhat, as all symbols have to be loaded into the kernel image.
1332 1333
1333 config KALLSYMS_ALL 1334 config KALLSYMS_ALL
1334 bool "Include all symbols in kallsyms" 1335 bool "Include all symbols in kallsyms"
1335 depends on DEBUG_KERNEL && KALLSYMS 1336 depends on DEBUG_KERNEL && KALLSYMS
1336 help 1337 help
1337 Normally kallsyms only contains the symbols of functions for nicer 1338 Normally kallsyms only contains the symbols of functions for nicer
1338 OOPS messages and backtraces (i.e., symbols from the text and inittext 1339 OOPS messages and backtraces (i.e., symbols from the text and inittext
1339 sections). This is sufficient for most cases. And only in very rare 1340 sections). This is sufficient for most cases. And only in very rare
1340 cases (e.g., when a debugger is used) all symbols are required (e.g., 1341 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1341 names of variables from the data sections, etc). 1342 names of variables from the data sections, etc).
1342 1343
1343 This option makes sure that all symbols are loaded into the kernel 1344 This option makes sure that all symbols are loaded into the kernel
1344 image (i.e., symbols from all sections) in cost of increased kernel 1345 image (i.e., symbols from all sections) in cost of increased kernel
1345 size (depending on the kernel configuration, it may be 300KiB or 1346 size (depending on the kernel configuration, it may be 300KiB or
1346 something like this). 1347 something like this).
1347 1348
1348 Say N unless you really need all symbols. 1349 Say N unless you really need all symbols.
1349 1350
1350 config PRINTK 1351 config PRINTK
1351 default y 1352 default y
1352 bool "Enable support for printk" if EXPERT 1353 bool "Enable support for printk" if EXPERT
1353 select IRQ_WORK 1354 select IRQ_WORK
1354 help 1355 help
1355 This option enables normal printk support. Removing it 1356 This option enables normal printk support. Removing it
1356 eliminates most of the message strings from the kernel image 1357 eliminates most of the message strings from the kernel image
1357 and makes the kernel more or less silent. As this makes it 1358 and makes the kernel more or less silent. As this makes it
1358 very difficult to diagnose system problems, saying N here is 1359 very difficult to diagnose system problems, saying N here is
1359 strongly discouraged. 1360 strongly discouraged.
1360 1361
1361 config BUG 1362 config BUG
1362 bool "BUG() support" if EXPERT 1363 bool "BUG() support" if EXPERT
1363 default y 1364 default y
1364 help 1365 help
1365 Disabling this option eliminates support for BUG and WARN, reducing 1366 Disabling this option eliminates support for BUG and WARN, reducing
1366 the size of your kernel image and potentially quietly ignoring 1367 the size of your kernel image and potentially quietly ignoring
1367 numerous fatal conditions. You should only consider disabling this 1368 numerous fatal conditions. You should only consider disabling this
1368 option for embedded systems with no facilities for reporting errors. 1369 option for embedded systems with no facilities for reporting errors.
1369 Just say Y. 1370 Just say Y.
1370 1371
1371 config ELF_CORE 1372 config ELF_CORE
1372 depends on COREDUMP 1373 depends on COREDUMP
1373 default y 1374 default y
1374 bool "Enable ELF core dumps" if EXPERT 1375 bool "Enable ELF core dumps" if EXPERT
1375 help 1376 help
1376 Enable support for generating core dumps. Disabling saves about 4k. 1377 Enable support for generating core dumps. Disabling saves about 4k.
1377 1378
1378 1379
1379 config PCSPKR_PLATFORM 1380 config PCSPKR_PLATFORM
1380 bool "Enable PC-Speaker support" if EXPERT 1381 bool "Enable PC-Speaker support" if EXPERT
1381 depends on HAVE_PCSPKR_PLATFORM 1382 depends on HAVE_PCSPKR_PLATFORM
1382 select I8253_LOCK 1383 select I8253_LOCK
1383 default y 1384 default y
1384 help 1385 help
1385 This option allows to disable the internal PC-Speaker 1386 This option allows to disable the internal PC-Speaker
1386 support, saving some memory. 1387 support, saving some memory.
1387 1388
1388 config BASE_FULL 1389 config BASE_FULL
1389 default y 1390 default y
1390 bool "Enable full-sized data structures for core" if EXPERT 1391 bool "Enable full-sized data structures for core" if EXPERT
1391 help 1392 help
1392 Disabling this option reduces the size of miscellaneous core 1393 Disabling this option reduces the size of miscellaneous core
1393 kernel data structures. This saves memory on small machines, 1394 kernel data structures. This saves memory on small machines,
1394 but may reduce performance. 1395 but may reduce performance.
1395 1396
1396 config FUTEX 1397 config FUTEX
1397 bool "Enable futex support" if EXPERT 1398 bool "Enable futex support" if EXPERT
1398 default y 1399 default y
1399 select RT_MUTEXES 1400 select RT_MUTEXES
1400 help 1401 help
1401 Disabling this option will cause the kernel to be built without 1402 Disabling this option will cause the kernel to be built without
1402 support for "fast userspace mutexes". The resulting kernel may not 1403 support for "fast userspace mutexes". The resulting kernel may not
1403 run glibc-based applications correctly. 1404 run glibc-based applications correctly.
1404 1405
1405 config EPOLL 1406 config EPOLL
1406 bool "Enable eventpoll support" if EXPERT 1407 bool "Enable eventpoll support" if EXPERT
1407 default y 1408 default y
1408 select ANON_INODES 1409 select ANON_INODES
1409 help 1410 help
1410 Disabling this option will cause the kernel to be built without 1411 Disabling this option will cause the kernel to be built without
1411 support for epoll family of system calls. 1412 support for epoll family of system calls.
1412 1413
1413 config SIGNALFD 1414 config SIGNALFD
1414 bool "Enable signalfd() system call" if EXPERT 1415 bool "Enable signalfd() system call" if EXPERT
1415 select ANON_INODES 1416 select ANON_INODES
1416 default y 1417 default y
1417 help 1418 help
1418 Enable the signalfd() system call that allows to receive signals 1419 Enable the signalfd() system call that allows to receive signals
1419 on a file descriptor. 1420 on a file descriptor.
1420 1421
1421 If unsure, say Y. 1422 If unsure, say Y.
1422 1423
1423 config TIMERFD 1424 config TIMERFD
1424 bool "Enable timerfd() system call" if EXPERT 1425 bool "Enable timerfd() system call" if EXPERT
1425 select ANON_INODES 1426 select ANON_INODES
1426 default y 1427 default y
1427 help 1428 help
1428 Enable the timerfd() system call that allows to receive timer 1429 Enable the timerfd() system call that allows to receive timer
1429 events on a file descriptor. 1430 events on a file descriptor.
1430 1431
1431 If unsure, say Y. 1432 If unsure, say Y.
1432 1433
1433 config EVENTFD 1434 config EVENTFD
1434 bool "Enable eventfd() system call" if EXPERT 1435 bool "Enable eventfd() system call" if EXPERT
1435 select ANON_INODES 1436 select ANON_INODES
1436 default y 1437 default y
1437 help 1438 help
1438 Enable the eventfd() system call that allows to receive both 1439 Enable the eventfd() system call that allows to receive both
1439 kernel notification (ie. KAIO) or userspace notifications. 1440 kernel notification (ie. KAIO) or userspace notifications.
1440 1441
1441 If unsure, say Y. 1442 If unsure, say Y.
1442 1443
1443 config SHMEM 1444 config SHMEM
1444 bool "Use full shmem filesystem" if EXPERT 1445 bool "Use full shmem filesystem" if EXPERT
1445 default y 1446 default y
1446 depends on MMU 1447 depends on MMU
1447 help 1448 help
1448 The shmem is an internal filesystem used to manage shared memory. 1449 The shmem is an internal filesystem used to manage shared memory.
1449 It is backed by swap and manages resource limits. It is also exported 1450 It is backed by swap and manages resource limits. It is also exported
1450 to userspace as tmpfs if TMPFS is enabled. Disabling this 1451 to userspace as tmpfs if TMPFS is enabled. Disabling this
1451 option replaces shmem and tmpfs with the much simpler ramfs code, 1452 option replaces shmem and tmpfs with the much simpler ramfs code,
1452 which may be appropriate on small systems without swap. 1453 which may be appropriate on small systems without swap.
1453 1454
1454 config AIO 1455 config AIO
1455 bool "Enable AIO support" if EXPERT 1456 bool "Enable AIO support" if EXPERT
1456 default y 1457 default y
1457 help 1458 help
1458 This option enables POSIX asynchronous I/O which may by used 1459 This option enables POSIX asynchronous I/O which may by used
1459 by some high performance threaded applications. Disabling 1460 by some high performance threaded applications. Disabling
1460 this option saves about 7k. 1461 this option saves about 7k.
1461 1462
1462 config PCI_QUIRKS 1463 config PCI_QUIRKS
1463 default y 1464 default y
1464 bool "Enable PCI quirk workarounds" if EXPERT 1465 bool "Enable PCI quirk workarounds" if EXPERT
1465 depends on PCI 1466 depends on PCI
1466 help 1467 help
1467 This enables workarounds for various PCI chipset 1468 This enables workarounds for various PCI chipset
1468 bugs/quirks. Disable this only if your target machine is 1469 bugs/quirks. Disable this only if your target machine is
1469 unaffected by PCI quirks. 1470 unaffected by PCI quirks.
1470 1471
1471 config EMBEDDED 1472 config EMBEDDED
1472 bool "Embedded system" 1473 bool "Embedded system"
1473 select EXPERT 1474 select EXPERT
1474 help 1475 help
1475 This option should be enabled if compiling the kernel for 1476 This option should be enabled if compiling the kernel for
1476 an embedded system so certain expert options are available 1477 an embedded system so certain expert options are available
1477 for configuration. 1478 for configuration.
1478 1479
1479 config HAVE_PERF_EVENTS 1480 config HAVE_PERF_EVENTS
1480 bool 1481 bool
1481 help 1482 help
1482 See tools/perf/design.txt for details. 1483 See tools/perf/design.txt for details.
1483 1484
1484 config PERF_USE_VMALLOC 1485 config PERF_USE_VMALLOC
1485 bool 1486 bool
1486 help 1487 help
1487 See tools/perf/design.txt for details 1488 See tools/perf/design.txt for details
1488 1489
1489 menu "Kernel Performance Events And Counters" 1490 menu "Kernel Performance Events And Counters"
1490 1491
1491 config PERF_EVENTS 1492 config PERF_EVENTS
1492 bool "Kernel performance events and counters" 1493 bool "Kernel performance events and counters"
1493 default y if PROFILING 1494 default y if PROFILING
1494 depends on HAVE_PERF_EVENTS 1495 depends on HAVE_PERF_EVENTS
1495 select ANON_INODES 1496 select ANON_INODES
1496 select IRQ_WORK 1497 select IRQ_WORK
1497 help 1498 help
1498 Enable kernel support for various performance events provided 1499 Enable kernel support for various performance events provided
1499 by software and hardware. 1500 by software and hardware.
1500 1501
1501 Software events are supported either built-in or via the 1502 Software events are supported either built-in or via the
1502 use of generic tracepoints. 1503 use of generic tracepoints.
1503 1504
1504 Most modern CPUs support performance events via performance 1505 Most modern CPUs support performance events via performance
1505 counter registers. These registers count the number of certain 1506 counter registers. These registers count the number of certain
1506 types of hw events: such as instructions executed, cachemisses 1507 types of hw events: such as instructions executed, cachemisses
1507 suffered, or branches mis-predicted - without slowing down the 1508 suffered, or branches mis-predicted - without slowing down the
1508 kernel or applications. These registers can also trigger interrupts 1509 kernel or applications. These registers can also trigger interrupts
1509 when a threshold number of events have passed - and can thus be 1510 when a threshold number of events have passed - and can thus be
1510 used to profile the code that runs on that CPU. 1511 used to profile the code that runs on that CPU.
1511 1512
1512 The Linux Performance Event subsystem provides an abstraction of 1513 The Linux Performance Event subsystem provides an abstraction of
1513 these software and hardware event capabilities, available via a 1514 these software and hardware event capabilities, available via a
1514 system call and used by the "perf" utility in tools/perf/. It 1515 system call and used by the "perf" utility in tools/perf/. It
1515 provides per task and per CPU counters, and it provides event 1516 provides per task and per CPU counters, and it provides event
1516 capabilities on top of those. 1517 capabilities on top of those.
1517 1518
1518 Say Y if unsure. 1519 Say Y if unsure.
1519 1520
1520 config DEBUG_PERF_USE_VMALLOC 1521 config DEBUG_PERF_USE_VMALLOC
1521 default n 1522 default n
1522 bool "Debug: use vmalloc to back perf mmap() buffers" 1523 bool "Debug: use vmalloc to back perf mmap() buffers"
1523 depends on PERF_EVENTS && DEBUG_KERNEL 1524 depends on PERF_EVENTS && DEBUG_KERNEL
1524 select PERF_USE_VMALLOC 1525 select PERF_USE_VMALLOC
1525 help 1526 help
1526 Use vmalloc memory to back perf mmap() buffers. 1527 Use vmalloc memory to back perf mmap() buffers.
1527 1528
1528 Mostly useful for debugging the vmalloc code on platforms 1529 Mostly useful for debugging the vmalloc code on platforms
1529 that don't require it. 1530 that don't require it.
1530 1531
1531 Say N if unsure. 1532 Say N if unsure.
1532 1533
1533 endmenu 1534 endmenu
1534 1535
1535 config VM_EVENT_COUNTERS 1536 config VM_EVENT_COUNTERS
1536 default y 1537 default y
1537 bool "Enable VM event counters for /proc/vmstat" if EXPERT 1538 bool "Enable VM event counters for /proc/vmstat" if EXPERT
1538 help 1539 help
1539 VM event counters are needed for event counts to be shown. 1540 VM event counters are needed for event counts to be shown.
1540 This option allows the disabling of the VM event counters 1541 This option allows the disabling of the VM event counters
1541 on EXPERT systems. /proc/vmstat will only show page counts 1542 on EXPERT systems. /proc/vmstat will only show page counts
1542 if VM event counters are disabled. 1543 if VM event counters are disabled.
1543 1544
1544 config SLUB_DEBUG 1545 config SLUB_DEBUG
1545 default y 1546 default y
1546 bool "Enable SLUB debugging support" if EXPERT 1547 bool "Enable SLUB debugging support" if EXPERT
1547 depends on SLUB && SYSFS 1548 depends on SLUB && SYSFS
1548 help 1549 help
1549 SLUB has extensive debug support features. Disabling these can 1550 SLUB has extensive debug support features. Disabling these can
1550 result in significant savings in code size. This also disables 1551 result in significant savings in code size. This also disables
1551 SLUB sysfs support. /sys/slab will not exist and there will be 1552 SLUB sysfs support. /sys/slab will not exist and there will be
1552 no support for cache validation etc. 1553 no support for cache validation etc.
1553 1554
1554 config COMPAT_BRK 1555 config COMPAT_BRK
1555 bool "Disable heap randomization" 1556 bool "Disable heap randomization"
1556 default y 1557 default y
1557 help 1558 help
1558 Randomizing heap placement makes heap exploits harder, but it 1559 Randomizing heap placement makes heap exploits harder, but it
1559 also breaks ancient binaries (including anything libc5 based). 1560 also breaks ancient binaries (including anything libc5 based).
1560 This option changes the bootup default to heap randomization 1561 This option changes the bootup default to heap randomization
1561 disabled, and can be overridden at runtime by setting 1562 disabled, and can be overridden at runtime by setting
1562 /proc/sys/kernel/randomize_va_space to 2. 1563 /proc/sys/kernel/randomize_va_space to 2.
1563 1564
1564 On non-ancient distros (post-2000 ones) N is usually a safe choice. 1565 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1565 1566
1566 choice 1567 choice
1567 prompt "Choose SLAB allocator" 1568 prompt "Choose SLAB allocator"
1568 default SLUB 1569 default SLUB
1569 help 1570 help
1570 This option allows to select a slab allocator. 1571 This option allows to select a slab allocator.
1571 1572
1572 config SLAB 1573 config SLAB
1573 bool "SLAB" 1574 bool "SLAB"
1574 help 1575 help
1575 The regular slab allocator that is established and known to work 1576 The regular slab allocator that is established and known to work
1576 well in all environments. It organizes cache hot objects in 1577 well in all environments. It organizes cache hot objects in
1577 per cpu and per node queues. 1578 per cpu and per node queues.
1578 1579
1579 config SLUB 1580 config SLUB
1580 bool "SLUB (Unqueued Allocator)" 1581 bool "SLUB (Unqueued Allocator)"
1581 help 1582 help
1582 SLUB is a slab allocator that minimizes cache line usage 1583 SLUB is a slab allocator that minimizes cache line usage
1583 instead of managing queues of cached objects (SLAB approach). 1584 instead of managing queues of cached objects (SLAB approach).
1584 Per cpu caching is realized using slabs of objects instead 1585 Per cpu caching is realized using slabs of objects instead
1585 of queues of objects. SLUB can use memory efficiently 1586 of queues of objects. SLUB can use memory efficiently
1586 and has enhanced diagnostics. SLUB is the default choice for 1587 and has enhanced diagnostics. SLUB is the default choice for
1587 a slab allocator. 1588 a slab allocator.
1588 1589
1589 config SLOB 1590 config SLOB
1590 depends on EXPERT 1591 depends on EXPERT
1591 bool "SLOB (Simple Allocator)" 1592 bool "SLOB (Simple Allocator)"
1592 help 1593 help
1593 SLOB replaces the stock allocator with a drastically simpler 1594 SLOB replaces the stock allocator with a drastically simpler
1594 allocator. SLOB is generally more space efficient but 1595 allocator. SLOB is generally more space efficient but
1595 does not perform as well on large systems. 1596 does not perform as well on large systems.
1596 1597
1597 endchoice 1598 endchoice
1598 1599
1599 config SLUB_CPU_PARTIAL 1600 config SLUB_CPU_PARTIAL
1600 default y 1601 default y
1601 depends on SLUB 1602 depends on SLUB
1602 bool "SLUB per cpu partial cache" 1603 bool "SLUB per cpu partial cache"
1603 help 1604 help
1604 Per cpu partial caches accellerate objects allocation and freeing 1605 Per cpu partial caches accellerate objects allocation and freeing
1605 that is local to a processor at the price of more indeterminism 1606 that is local to a processor at the price of more indeterminism
1606 in the latency of the free. On overflow these caches will be cleared 1607 in the latency of the free. On overflow these caches will be cleared
1607 which requires the taking of locks that may cause latency spikes. 1608 which requires the taking of locks that may cause latency spikes.
1608 Typically one would choose no for a realtime system. 1609 Typically one would choose no for a realtime system.
1609 1610
1610 config MMAP_ALLOW_UNINITIALIZED 1611 config MMAP_ALLOW_UNINITIALIZED
1611 bool "Allow mmapped anonymous memory to be uninitialized" 1612 bool "Allow mmapped anonymous memory to be uninitialized"
1612 depends on EXPERT && !MMU 1613 depends on EXPERT && !MMU
1613 default n 1614 default n
1614 help 1615 help
1615 Normally, and according to the Linux spec, anonymous memory obtained 1616 Normally, and according to the Linux spec, anonymous memory obtained
1616 from mmap() has it's contents cleared before it is passed to 1617 from mmap() has it's contents cleared before it is passed to
1617 userspace. Enabling this config option allows you to request that 1618 userspace. Enabling this config option allows you to request that
1618 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus 1619 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1619 providing a huge performance boost. If this option is not enabled, 1620 providing a huge performance boost. If this option is not enabled,
1620 then the flag will be ignored. 1621 then the flag will be ignored.
1621 1622
1622 This is taken advantage of by uClibc's malloc(), and also by 1623 This is taken advantage of by uClibc's malloc(), and also by
1623 ELF-FDPIC binfmt's brk and stack allocator. 1624 ELF-FDPIC binfmt's brk and stack allocator.
1624 1625
1625 Because of the obvious security issues, this option should only be 1626 Because of the obvious security issues, this option should only be
1626 enabled on embedded devices where you control what is run in 1627 enabled on embedded devices where you control what is run in
1627 userspace. Since that isn't generally a problem on no-MMU systems, 1628 userspace. Since that isn't generally a problem on no-MMU systems,
1628 it is normally safe to say Y here. 1629 it is normally safe to say Y here.
1629 1630
1630 See Documentation/nommu-mmap.txt for more information. 1631 See Documentation/nommu-mmap.txt for more information.
1631 1632
1632 config PROFILING 1633 config PROFILING
1633 bool "Profiling support" 1634 bool "Profiling support"
1634 help 1635 help
1635 Say Y here to enable the extended profiling support mechanisms used 1636 Say Y here to enable the extended profiling support mechanisms used
1636 by profilers such as OProfile. 1637 by profilers such as OProfile.
1637 1638
1638 # 1639 #
1639 # Place an empty function call at each tracepoint site. Can be 1640 # Place an empty function call at each tracepoint site. Can be
1640 # dynamically changed for a probe function. 1641 # dynamically changed for a probe function.
1641 # 1642 #
1642 config TRACEPOINTS 1643 config TRACEPOINTS
1643 bool 1644 bool
1644 1645
1645 source "arch/Kconfig" 1646 source "arch/Kconfig"
1646 1647
1647 endmenu # General setup 1648 endmenu # General setup
1648 1649
1649 config HAVE_GENERIC_DMA_COHERENT 1650 config HAVE_GENERIC_DMA_COHERENT
1650 bool 1651 bool
1651 default n 1652 default n
1652 1653
1653 config SLABINFO 1654 config SLABINFO
1654 bool 1655 bool
1655 depends on PROC_FS 1656 depends on PROC_FS
1656 depends on SLAB || SLUB_DEBUG 1657 depends on SLAB || SLUB_DEBUG
1657 default y 1658 default y
1658 1659
1659 config RT_MUTEXES 1660 config RT_MUTEXES
1660 boolean 1661 boolean
1661 1662
1662 config BASE_SMALL 1663 config BASE_SMALL
1663 int 1664 int
1664 default 0 if BASE_FULL 1665 default 0 if BASE_FULL
1665 default 1 if !BASE_FULL 1666 default 1 if !BASE_FULL
1666 1667
1667 menuconfig MODULES 1668 menuconfig MODULES
1668 bool "Enable loadable module support" 1669 bool "Enable loadable module support"
1669 help 1670 help
1670 Kernel modules are small pieces of compiled code which can 1671 Kernel modules are small pieces of compiled code which can
1671 be inserted in the running kernel, rather than being 1672 be inserted in the running kernel, rather than being
1672 permanently built into the kernel. You use the "modprobe" 1673 permanently built into the kernel. You use the "modprobe"
1673 tool to add (and sometimes remove) them. If you say Y here, 1674 tool to add (and sometimes remove) them. If you say Y here,
1674 many parts of the kernel can be built as modules (by 1675 many parts of the kernel can be built as modules (by
1675 answering M instead of Y where indicated): this is most 1676 answering M instead of Y where indicated): this is most
1676 useful for infrequently used options which are not required 1677 useful for infrequently used options which are not required
1677 for booting. For more information, see the man pages for 1678 for booting. For more information, see the man pages for
1678 modprobe, lsmod, modinfo, insmod and rmmod. 1679 modprobe, lsmod, modinfo, insmod and rmmod.
1679 1680
1680 If you say Y here, you will need to run "make 1681 If you say Y here, you will need to run "make
1681 modules_install" to put the modules under /lib/modules/ 1682 modules_install" to put the modules under /lib/modules/
1682 where modprobe can find them (you may need to be root to do 1683 where modprobe can find them (you may need to be root to do
1683 this). 1684 this).
1684 1685
1685 If unsure, say Y. 1686 If unsure, say Y.
1686 1687
1687 if MODULES 1688 if MODULES
1688 1689
1689 config MODULE_FORCE_LOAD 1690 config MODULE_FORCE_LOAD
1690 bool "Forced module loading" 1691 bool "Forced module loading"
1691 default n 1692 default n
1692 help 1693 help
1693 Allow loading of modules without version information (ie. modprobe 1694 Allow loading of modules without version information (ie. modprobe
1694 --force). Forced module loading sets the 'F' (forced) taint flag and 1695 --force). Forced module loading sets the 'F' (forced) taint flag and
1695 is usually a really bad idea. 1696 is usually a really bad idea.
1696 1697
1697 config MODULE_UNLOAD 1698 config MODULE_UNLOAD
1698 bool "Module unloading" 1699 bool "Module unloading"
1699 help 1700 help
1700 Without this option you will not be able to unload any 1701 Without this option you will not be able to unload any
1701 modules (note that some modules may not be unloadable 1702 modules (note that some modules may not be unloadable
1702 anyway), which makes your kernel smaller, faster 1703 anyway), which makes your kernel smaller, faster
1703 and simpler. If unsure, say Y. 1704 and simpler. If unsure, say Y.
1704 1705
1705 config MODULE_FORCE_UNLOAD 1706 config MODULE_FORCE_UNLOAD
1706 bool "Forced module unloading" 1707 bool "Forced module unloading"
1707 depends on MODULE_UNLOAD 1708 depends on MODULE_UNLOAD
1708 help 1709 help
1709 This option allows you to force a module to unload, even if the 1710 This option allows you to force a module to unload, even if the
1710 kernel believes it is unsafe: the kernel will remove the module 1711 kernel believes it is unsafe: the kernel will remove the module
1711 without waiting for anyone to stop using it (using the -f option to 1712 without waiting for anyone to stop using it (using the -f option to
1712 rmmod). This is mainly for kernel developers and desperate users. 1713 rmmod). This is mainly for kernel developers and desperate users.
1713 If unsure, say N. 1714 If unsure, say N.
1714 1715
1715 config MODVERSIONS 1716 config MODVERSIONS
1716 bool "Module versioning support" 1717 bool "Module versioning support"
1717 help 1718 help
1718 Usually, you have to use modules compiled with your kernel. 1719 Usually, you have to use modules compiled with your kernel.
1719 Saying Y here makes it sometimes possible to use modules 1720 Saying Y here makes it sometimes possible to use modules
1720 compiled for different kernels, by adding enough information 1721 compiled for different kernels, by adding enough information
1721 to the modules to (hopefully) spot any changes which would 1722 to the modules to (hopefully) spot any changes which would
1722 make them incompatible with the kernel you are running. If 1723 make them incompatible with the kernel you are running. If
1723 unsure, say N. 1724 unsure, say N.
1724 1725
1725 config MODULE_SRCVERSION_ALL 1726 config MODULE_SRCVERSION_ALL
1726 bool "Source checksum for all modules" 1727 bool "Source checksum for all modules"
1727 help 1728 help
1728 Modules which contain a MODULE_VERSION get an extra "srcversion" 1729 Modules which contain a MODULE_VERSION get an extra "srcversion"
1729 field inserted into their modinfo section, which contains a 1730 field inserted into their modinfo section, which contains a
1730 sum of the source files which made it. This helps maintainers 1731 sum of the source files which made it. This helps maintainers
1731 see exactly which source was used to build a module (since 1732 see exactly which source was used to build a module (since
1732 others sometimes change the module source without updating 1733 others sometimes change the module source without updating
1733 the version). With this option, such a "srcversion" field 1734 the version). With this option, such a "srcversion" field
1734 will be created for all modules. If unsure, say N. 1735 will be created for all modules. If unsure, say N.
1735 1736
1736 config MODULE_SIG 1737 config MODULE_SIG
1737 bool "Module signature verification" 1738 bool "Module signature verification"
1738 depends on MODULES 1739 depends on MODULES
1739 select KEYS 1740 select KEYS
1740 select CRYPTO 1741 select CRYPTO
1741 select ASYMMETRIC_KEY_TYPE 1742 select ASYMMETRIC_KEY_TYPE
1742 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 1743 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1743 select PUBLIC_KEY_ALGO_RSA 1744 select PUBLIC_KEY_ALGO_RSA
1744 select ASN1 1745 select ASN1
1745 select OID_REGISTRY 1746 select OID_REGISTRY
1746 select X509_CERTIFICATE_PARSER 1747 select X509_CERTIFICATE_PARSER
1747 help 1748 help
1748 Check modules for valid signatures upon load: the signature 1749 Check modules for valid signatures upon load: the signature
1749 is simply appended to the module. For more information see 1750 is simply appended to the module. For more information see
1750 Documentation/module-signing.txt. 1751 Documentation/module-signing.txt.
1751 1752
1752 !!!WARNING!!! If you enable this option, you MUST make sure that the 1753 !!!WARNING!!! If you enable this option, you MUST make sure that the
1753 module DOES NOT get stripped after being signed. This includes the 1754 module DOES NOT get stripped after being signed. This includes the
1754 debuginfo strip done by some packagers (such as rpmbuild) and 1755 debuginfo strip done by some packagers (such as rpmbuild) and
1755 inclusion into an initramfs that wants the module size reduced. 1756 inclusion into an initramfs that wants the module size reduced.
1756 1757
1757 config MODULE_SIG_FORCE 1758 config MODULE_SIG_FORCE
1758 bool "Require modules to be validly signed" 1759 bool "Require modules to be validly signed"
1759 depends on MODULE_SIG 1760 depends on MODULE_SIG
1760 help 1761 help
1761 Reject unsigned modules or signed modules for which we don't have a 1762 Reject unsigned modules or signed modules for which we don't have a
1762 key. Without this, such modules will simply taint the kernel. 1763 key. Without this, such modules will simply taint the kernel.
1763 1764
1764 config MODULE_SIG_ALL 1765 config MODULE_SIG_ALL
1765 bool "Automatically sign all modules" 1766 bool "Automatically sign all modules"
1766 default y 1767 default y
1767 depends on MODULE_SIG 1768 depends on MODULE_SIG
1768 help 1769 help
1769 Sign all modules during make modules_install. Without this option, 1770 Sign all modules during make modules_install. Without this option,
1770 modules must be signed manually, using the scripts/sign-file tool. 1771 modules must be signed manually, using the scripts/sign-file tool.
1771 1772
1772 comment "Do not forget to sign required modules with scripts/sign-file" 1773 comment "Do not forget to sign required modules with scripts/sign-file"
1773 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL 1774 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1774 1775
1775 choice 1776 choice
1776 prompt "Which hash algorithm should modules be signed with?" 1777 prompt "Which hash algorithm should modules be signed with?"
1777 depends on MODULE_SIG 1778 depends on MODULE_SIG
1778 help 1779 help
1779 This determines which sort of hashing algorithm will be used during 1780 This determines which sort of hashing algorithm will be used during
1780 signature generation. This algorithm _must_ be built into the kernel 1781 signature generation. This algorithm _must_ be built into the kernel
1781 directly so that signature verification can take place. It is not 1782 directly so that signature verification can take place. It is not
1782 possible to load a signed module containing the algorithm to check 1783 possible to load a signed module containing the algorithm to check
1783 the signature on that module. 1784 the signature on that module.
1784 1785
1785 config MODULE_SIG_SHA1 1786 config MODULE_SIG_SHA1
1786 bool "Sign modules with SHA-1" 1787 bool "Sign modules with SHA-1"
1787 select CRYPTO_SHA1 1788 select CRYPTO_SHA1
1788 1789
1789 config MODULE_SIG_SHA224 1790 config MODULE_SIG_SHA224
1790 bool "Sign modules with SHA-224" 1791 bool "Sign modules with SHA-224"
1791 select CRYPTO_SHA256 1792 select CRYPTO_SHA256
1792 1793
1793 config MODULE_SIG_SHA256 1794 config MODULE_SIG_SHA256
1794 bool "Sign modules with SHA-256" 1795 bool "Sign modules with SHA-256"
1795 select CRYPTO_SHA256 1796 select CRYPTO_SHA256
1796 1797
1797 config MODULE_SIG_SHA384 1798 config MODULE_SIG_SHA384
1798 bool "Sign modules with SHA-384" 1799 bool "Sign modules with SHA-384"
1799 select CRYPTO_SHA512 1800 select CRYPTO_SHA512
1800 1801
1801 config MODULE_SIG_SHA512 1802 config MODULE_SIG_SHA512
1802 bool "Sign modules with SHA-512" 1803 bool "Sign modules with SHA-512"
1803 select CRYPTO_SHA512 1804 select CRYPTO_SHA512
1804 1805
1805 endchoice 1806 endchoice
1806 1807
1807 config MODULE_SIG_HASH 1808 config MODULE_SIG_HASH
1808 string 1809 string
1809 depends on MODULE_SIG 1810 depends on MODULE_SIG
1810 default "sha1" if MODULE_SIG_SHA1 1811 default "sha1" if MODULE_SIG_SHA1
1811 default "sha224" if MODULE_SIG_SHA224 1812 default "sha224" if MODULE_SIG_SHA224
1812 default "sha256" if MODULE_SIG_SHA256 1813 default "sha256" if MODULE_SIG_SHA256
1813 default "sha384" if MODULE_SIG_SHA384 1814 default "sha384" if MODULE_SIG_SHA384
1814 default "sha512" if MODULE_SIG_SHA512 1815 default "sha512" if MODULE_SIG_SHA512
1815 1816
1816 endif # MODULES 1817 endif # MODULES
1817 1818
1818 config INIT_ALL_POSSIBLE 1819 config INIT_ALL_POSSIBLE
1819 bool 1820 bool
1820 help 1821 help
1821 Back when each arch used to define their own cpu_online_mask and 1822 Back when each arch used to define their own cpu_online_mask and
1822 cpu_possible_mask, some of them chose to initialize cpu_possible_mask 1823 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
1823 with all 1s, and others with all 0s. When they were centralised, 1824 with all 1s, and others with all 0s. When they were centralised,
1824 it was better to provide this option than to break all the archs 1825 it was better to provide this option than to break all the archs
1825 and have several arch maintainers pursuing me down dark alleys. 1826 and have several arch maintainers pursuing me down dark alleys.
1826 1827
1827 config STOP_MACHINE 1828 config STOP_MACHINE
1828 bool 1829 bool
1829 default y 1830 default y
1830 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 1831 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1831 help 1832 help
1832 Need stop_machine() primitive. 1833 Need stop_machine() primitive.
1833 1834
1834 source "block/Kconfig" 1835 source "block/Kconfig"
1835 1836
1836 config PREEMPT_NOTIFIERS 1837 config PREEMPT_NOTIFIERS
1837 bool 1838 bool
1838 1839
1839 config PADATA 1840 config PADATA
1840 depends on SMP 1841 depends on SMP
1841 bool 1842 bool
1842 1843
1843 # Can be selected by architectures with broken toolchains 1844 # Can be selected by architectures with broken toolchains
1844 # that get confused by correct const<->read_only section 1845 # that get confused by correct const<->read_only section
1845 # mappings 1846 # mappings
1846 config BROKEN_RODATA 1847 config BROKEN_RODATA
1847 bool 1848 bool
1848 1849
1849 config ASN1 1850 config ASN1
1850 tristate 1851 tristate
1851 help 1852 help
1852 Build a simple ASN.1 grammar compiler that produces a bytecode output 1853 Build a simple ASN.1 grammar compiler that produces a bytecode output
1853 that can be interpreted by the ASN.1 stream decoder and used to 1854 that can be interpreted by the ASN.1 stream decoder and used to
1854 inform it as to what tags are to be expected in a stream and what 1855 inform it as to what tags are to be expected in a stream and what
1855 functions to call on what tags. 1856 functions to call on what tags.
1856 1857
1857 source "kernel/Kconfig.locks" 1858 source "kernel/Kconfig.locks"
1858 1859