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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * kernel/cpuset.c | |
3 | * | |
4 | * Processor and Memory placement constraints for sets of tasks. | |
5 | * | |
6 | * Copyright (C) 2003 BULL SA. | |
029190c5 | 7 | * Copyright (C) 2004-2007 Silicon Graphics, Inc. |
8793d854 | 8 | * Copyright (C) 2006 Google, Inc |
1da177e4 LT |
9 | * |
10 | * Portions derived from Patrick Mochel's sysfs code. | |
11 | * sysfs is Copyright (c) 2001-3 Patrick Mochel | |
1da177e4 | 12 | * |
825a46af | 13 | * 2003-10-10 Written by Simon Derr. |
1da177e4 | 14 | * 2003-10-22 Updates by Stephen Hemminger. |
825a46af | 15 | * 2004 May-July Rework by Paul Jackson. |
8793d854 | 16 | * 2006 Rework by Paul Menage to use generic cgroups |
cf417141 MK |
17 | * 2008 Rework of the scheduler domains and CPU hotplug handling |
18 | * by Max Krasnyansky | |
1da177e4 LT |
19 | * |
20 | * This file is subject to the terms and conditions of the GNU General Public | |
21 | * License. See the file COPYING in the main directory of the Linux | |
22 | * distribution for more details. | |
23 | */ | |
24 | ||
1da177e4 LT |
25 | #include <linux/cpu.h> |
26 | #include <linux/cpumask.h> | |
27 | #include <linux/cpuset.h> | |
28 | #include <linux/err.h> | |
29 | #include <linux/errno.h> | |
30 | #include <linux/file.h> | |
31 | #include <linux/fs.h> | |
32 | #include <linux/init.h> | |
33 | #include <linux/interrupt.h> | |
34 | #include <linux/kernel.h> | |
35 | #include <linux/kmod.h> | |
36 | #include <linux/list.h> | |
68860ec1 | 37 | #include <linux/mempolicy.h> |
1da177e4 | 38 | #include <linux/mm.h> |
f481891f | 39 | #include <linux/memory.h> |
9984de1a | 40 | #include <linux/export.h> |
1da177e4 LT |
41 | #include <linux/mount.h> |
42 | #include <linux/namei.h> | |
43 | #include <linux/pagemap.h> | |
44 | #include <linux/proc_fs.h> | |
6b9c2603 | 45 | #include <linux/rcupdate.h> |
1da177e4 LT |
46 | #include <linux/sched.h> |
47 | #include <linux/seq_file.h> | |
22fb52dd | 48 | #include <linux/security.h> |
1da177e4 | 49 | #include <linux/slab.h> |
1da177e4 LT |
50 | #include <linux/spinlock.h> |
51 | #include <linux/stat.h> | |
52 | #include <linux/string.h> | |
53 | #include <linux/time.h> | |
54 | #include <linux/backing-dev.h> | |
55 | #include <linux/sort.h> | |
56 | ||
57 | #include <asm/uaccess.h> | |
60063497 | 58 | #include <linux/atomic.h> |
3d3f26a7 | 59 | #include <linux/mutex.h> |
956db3ca CW |
60 | #include <linux/workqueue.h> |
61 | #include <linux/cgroup.h> | |
e44193d3 | 62 | #include <linux/wait.h> |
1da177e4 | 63 | |
664eedde | 64 | struct static_key cpusets_enabled_key __read_mostly = STATIC_KEY_INIT_FALSE; |
202f72d5 | 65 | |
3e0d98b9 PJ |
66 | /* See "Frequency meter" comments, below. */ |
67 | ||
68 | struct fmeter { | |
69 | int cnt; /* unprocessed events count */ | |
70 | int val; /* most recent output value */ | |
71 | time_t time; /* clock (secs) when val computed */ | |
72 | spinlock_t lock; /* guards read or write of above */ | |
73 | }; | |
74 | ||
1da177e4 | 75 | struct cpuset { |
8793d854 PM |
76 | struct cgroup_subsys_state css; |
77 | ||
1da177e4 | 78 | unsigned long flags; /* "unsigned long" so bitops work */ |
300ed6cb | 79 | cpumask_var_t cpus_allowed; /* CPUs allowed to tasks in cpuset */ |
1da177e4 LT |
80 | nodemask_t mems_allowed; /* Memory Nodes allowed to tasks */ |
81 | ||
33ad801d LZ |
82 | /* |
83 | * This is old Memory Nodes tasks took on. | |
84 | * | |
85 | * - top_cpuset.old_mems_allowed is initialized to mems_allowed. | |
86 | * - A new cpuset's old_mems_allowed is initialized when some | |
87 | * task is moved into it. | |
88 | * - old_mems_allowed is used in cpuset_migrate_mm() when we change | |
89 | * cpuset.mems_allowed and have tasks' nodemask updated, and | |
90 | * then old_mems_allowed is updated to mems_allowed. | |
91 | */ | |
92 | nodemask_t old_mems_allowed; | |
93 | ||
3e0d98b9 | 94 | struct fmeter fmeter; /* memory_pressure filter */ |
029190c5 | 95 | |
452477fa TH |
96 | /* |
97 | * Tasks are being attached to this cpuset. Used to prevent | |
98 | * zeroing cpus/mems_allowed between ->can_attach() and ->attach(). | |
99 | */ | |
100 | int attach_in_progress; | |
101 | ||
029190c5 PJ |
102 | /* partition number for rebuild_sched_domains() */ |
103 | int pn; | |
956db3ca | 104 | |
1d3504fc HS |
105 | /* for custom sched domain */ |
106 | int relax_domain_level; | |
1da177e4 LT |
107 | }; |
108 | ||
a7c6d554 | 109 | static inline struct cpuset *css_cs(struct cgroup_subsys_state *css) |
8793d854 | 110 | { |
a7c6d554 | 111 | return css ? container_of(css, struct cpuset, css) : NULL; |
8793d854 PM |
112 | } |
113 | ||
114 | /* Retrieve the cpuset for a task */ | |
115 | static inline struct cpuset *task_cs(struct task_struct *task) | |
116 | { | |
073219e9 | 117 | return css_cs(task_css(task, cpuset_cgrp_id)); |
8793d854 | 118 | } |
8793d854 | 119 | |
c9710d80 | 120 | static inline struct cpuset *parent_cs(struct cpuset *cs) |
c431069f | 121 | { |
5c9d535b | 122 | return css_cs(cs->css.parent); |
c431069f TH |
123 | } |
124 | ||
b246272e DR |
125 | #ifdef CONFIG_NUMA |
126 | static inline bool task_has_mempolicy(struct task_struct *task) | |
127 | { | |
128 | return task->mempolicy; | |
129 | } | |
130 | #else | |
131 | static inline bool task_has_mempolicy(struct task_struct *task) | |
132 | { | |
133 | return false; | |
134 | } | |
135 | #endif | |
136 | ||
137 | ||
1da177e4 LT |
138 | /* bits in struct cpuset flags field */ |
139 | typedef enum { | |
efeb77b2 | 140 | CS_ONLINE, |
1da177e4 LT |
141 | CS_CPU_EXCLUSIVE, |
142 | CS_MEM_EXCLUSIVE, | |
78608366 | 143 | CS_MEM_HARDWALL, |
45b07ef3 | 144 | CS_MEMORY_MIGRATE, |
029190c5 | 145 | CS_SCHED_LOAD_BALANCE, |
825a46af PJ |
146 | CS_SPREAD_PAGE, |
147 | CS_SPREAD_SLAB, | |
1da177e4 LT |
148 | } cpuset_flagbits_t; |
149 | ||
150 | /* convenient tests for these bits */ | |
efeb77b2 TH |
151 | static inline bool is_cpuset_online(const struct cpuset *cs) |
152 | { | |
153 | return test_bit(CS_ONLINE, &cs->flags); | |
154 | } | |
155 | ||
1da177e4 LT |
156 | static inline int is_cpu_exclusive(const struct cpuset *cs) |
157 | { | |
7b5b9ef0 | 158 | return test_bit(CS_CPU_EXCLUSIVE, &cs->flags); |
1da177e4 LT |
159 | } |
160 | ||
161 | static inline int is_mem_exclusive(const struct cpuset *cs) | |
162 | { | |
7b5b9ef0 | 163 | return test_bit(CS_MEM_EXCLUSIVE, &cs->flags); |
1da177e4 LT |
164 | } |
165 | ||
78608366 PM |
166 | static inline int is_mem_hardwall(const struct cpuset *cs) |
167 | { | |
168 | return test_bit(CS_MEM_HARDWALL, &cs->flags); | |
169 | } | |
170 | ||
029190c5 PJ |
171 | static inline int is_sched_load_balance(const struct cpuset *cs) |
172 | { | |
173 | return test_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); | |
174 | } | |
175 | ||
45b07ef3 PJ |
176 | static inline int is_memory_migrate(const struct cpuset *cs) |
177 | { | |
7b5b9ef0 | 178 | return test_bit(CS_MEMORY_MIGRATE, &cs->flags); |
45b07ef3 PJ |
179 | } |
180 | ||
825a46af PJ |
181 | static inline int is_spread_page(const struct cpuset *cs) |
182 | { | |
183 | return test_bit(CS_SPREAD_PAGE, &cs->flags); | |
184 | } | |
185 | ||
186 | static inline int is_spread_slab(const struct cpuset *cs) | |
187 | { | |
188 | return test_bit(CS_SPREAD_SLAB, &cs->flags); | |
189 | } | |
190 | ||
1da177e4 | 191 | static struct cpuset top_cpuset = { |
efeb77b2 TH |
192 | .flags = ((1 << CS_ONLINE) | (1 << CS_CPU_EXCLUSIVE) | |
193 | (1 << CS_MEM_EXCLUSIVE)), | |
1da177e4 LT |
194 | }; |
195 | ||
ae8086ce TH |
196 | /** |
197 | * cpuset_for_each_child - traverse online children of a cpuset | |
198 | * @child_cs: loop cursor pointing to the current child | |
492eb21b | 199 | * @pos_css: used for iteration |
ae8086ce TH |
200 | * @parent_cs: target cpuset to walk children of |
201 | * | |
202 | * Walk @child_cs through the online children of @parent_cs. Must be used | |
203 | * with RCU read locked. | |
204 | */ | |
492eb21b TH |
205 | #define cpuset_for_each_child(child_cs, pos_css, parent_cs) \ |
206 | css_for_each_child((pos_css), &(parent_cs)->css) \ | |
207 | if (is_cpuset_online(((child_cs) = css_cs((pos_css))))) | |
ae8086ce | 208 | |
fc560a26 TH |
209 | /** |
210 | * cpuset_for_each_descendant_pre - pre-order walk of a cpuset's descendants | |
211 | * @des_cs: loop cursor pointing to the current descendant | |
492eb21b | 212 | * @pos_css: used for iteration |
fc560a26 TH |
213 | * @root_cs: target cpuset to walk ancestor of |
214 | * | |
215 | * Walk @des_cs through the online descendants of @root_cs. Must be used | |
492eb21b | 216 | * with RCU read locked. The caller may modify @pos_css by calling |
bd8815a6 TH |
217 | * css_rightmost_descendant() to skip subtree. @root_cs is included in the |
218 | * iteration and the first node to be visited. | |
fc560a26 | 219 | */ |
492eb21b TH |
220 | #define cpuset_for_each_descendant_pre(des_cs, pos_css, root_cs) \ |
221 | css_for_each_descendant_pre((pos_css), &(root_cs)->css) \ | |
222 | if (is_cpuset_online(((des_cs) = css_cs((pos_css))))) | |
fc560a26 | 223 | |
1da177e4 | 224 | /* |
5d21cc2d TH |
225 | * There are two global mutexes guarding cpuset structures - cpuset_mutex |
226 | * and callback_mutex. The latter may nest inside the former. We also | |
227 | * require taking task_lock() when dereferencing a task's cpuset pointer. | |
228 | * See "The task_lock() exception", at the end of this comment. | |
229 | * | |
230 | * A task must hold both mutexes to modify cpusets. If a task holds | |
231 | * cpuset_mutex, then it blocks others wanting that mutex, ensuring that it | |
232 | * is the only task able to also acquire callback_mutex and be able to | |
233 | * modify cpusets. It can perform various checks on the cpuset structure | |
234 | * first, knowing nothing will change. It can also allocate memory while | |
235 | * just holding cpuset_mutex. While it is performing these checks, various | |
236 | * callback routines can briefly acquire callback_mutex to query cpusets. | |
237 | * Once it is ready to make the changes, it takes callback_mutex, blocking | |
238 | * everyone else. | |
053199ed PJ |
239 | * |
240 | * Calls to the kernel memory allocator can not be made while holding | |
3d3f26a7 | 241 | * callback_mutex, as that would risk double tripping on callback_mutex |
053199ed PJ |
242 | * from one of the callbacks into the cpuset code from within |
243 | * __alloc_pages(). | |
244 | * | |
3d3f26a7 | 245 | * If a task is only holding callback_mutex, then it has read-only |
053199ed PJ |
246 | * access to cpusets. |
247 | * | |
58568d2a MX |
248 | * Now, the task_struct fields mems_allowed and mempolicy may be changed |
249 | * by other task, we use alloc_lock in the task_struct fields to protect | |
250 | * them. | |
053199ed | 251 | * |
3d3f26a7 | 252 | * The cpuset_common_file_read() handlers only hold callback_mutex across |
053199ed PJ |
253 | * small pieces of code, such as when reading out possibly multi-word |
254 | * cpumasks and nodemasks. | |
255 | * | |
2df167a3 PM |
256 | * Accessing a task's cpuset should be done in accordance with the |
257 | * guidelines for accessing subsystem state in kernel/cgroup.c | |
1da177e4 LT |
258 | */ |
259 | ||
5d21cc2d | 260 | static DEFINE_MUTEX(cpuset_mutex); |
3d3f26a7 | 261 | static DEFINE_MUTEX(callback_mutex); |
4247bdc6 | 262 | |
3a5a6d0c TH |
263 | /* |
264 | * CPU / memory hotplug is handled asynchronously. | |
265 | */ | |
266 | static void cpuset_hotplug_workfn(struct work_struct *work); | |
3a5a6d0c TH |
267 | static DECLARE_WORK(cpuset_hotplug_work, cpuset_hotplug_workfn); |
268 | ||
e44193d3 LZ |
269 | static DECLARE_WAIT_QUEUE_HEAD(cpuset_attach_wq); |
270 | ||
cf417141 MK |
271 | /* |
272 | * This is ugly, but preserves the userspace API for existing cpuset | |
8793d854 | 273 | * users. If someone tries to mount the "cpuset" filesystem, we |
cf417141 MK |
274 | * silently switch it to mount "cgroup" instead |
275 | */ | |
f7e83571 AV |
276 | static struct dentry *cpuset_mount(struct file_system_type *fs_type, |
277 | int flags, const char *unused_dev_name, void *data) | |
1da177e4 | 278 | { |
8793d854 | 279 | struct file_system_type *cgroup_fs = get_fs_type("cgroup"); |
f7e83571 | 280 | struct dentry *ret = ERR_PTR(-ENODEV); |
8793d854 PM |
281 | if (cgroup_fs) { |
282 | char mountopts[] = | |
283 | "cpuset,noprefix," | |
284 | "release_agent=/sbin/cpuset_release_agent"; | |
f7e83571 AV |
285 | ret = cgroup_fs->mount(cgroup_fs, flags, |
286 | unused_dev_name, mountopts); | |
8793d854 PM |
287 | put_filesystem(cgroup_fs); |
288 | } | |
289 | return ret; | |
1da177e4 LT |
290 | } |
291 | ||
292 | static struct file_system_type cpuset_fs_type = { | |
293 | .name = "cpuset", | |
f7e83571 | 294 | .mount = cpuset_mount, |
1da177e4 LT |
295 | }; |
296 | ||
1da177e4 | 297 | /* |
300ed6cb | 298 | * Return in pmask the portion of a cpusets's cpus_allowed that |
1da177e4 | 299 | * are online. If none are online, walk up the cpuset hierarchy |
40df2deb LZ |
300 | * until we find one that does have some online cpus. The top |
301 | * cpuset always has some cpus online. | |
1da177e4 LT |
302 | * |
303 | * One way or another, we guarantee to return some non-empty subset | |
5f054e31 | 304 | * of cpu_online_mask. |
1da177e4 | 305 | * |
3d3f26a7 | 306 | * Call with callback_mutex held. |
1da177e4 | 307 | */ |
c9710d80 | 308 | static void guarantee_online_cpus(struct cpuset *cs, struct cpumask *pmask) |
1da177e4 | 309 | { |
40df2deb | 310 | while (!cpumask_intersects(cs->cpus_allowed, cpu_online_mask)) |
c431069f | 311 | cs = parent_cs(cs); |
40df2deb | 312 | cpumask_and(pmask, cs->cpus_allowed, cpu_online_mask); |
1da177e4 LT |
313 | } |
314 | ||
315 | /* | |
316 | * Return in *pmask the portion of a cpusets's mems_allowed that | |
0e1e7c7a CL |
317 | * are online, with memory. If none are online with memory, walk |
318 | * up the cpuset hierarchy until we find one that does have some | |
40df2deb | 319 | * online mems. The top cpuset always has some mems online. |
1da177e4 LT |
320 | * |
321 | * One way or another, we guarantee to return some non-empty subset | |
38d7bee9 | 322 | * of node_states[N_MEMORY]. |
1da177e4 | 323 | * |
3d3f26a7 | 324 | * Call with callback_mutex held. |
1da177e4 | 325 | */ |
c9710d80 | 326 | static void guarantee_online_mems(struct cpuset *cs, nodemask_t *pmask) |
1da177e4 | 327 | { |
40df2deb | 328 | while (!nodes_intersects(cs->mems_allowed, node_states[N_MEMORY])) |
c431069f | 329 | cs = parent_cs(cs); |
40df2deb | 330 | nodes_and(*pmask, cs->mems_allowed, node_states[N_MEMORY]); |
1da177e4 LT |
331 | } |
332 | ||
f3b39d47 MX |
333 | /* |
334 | * update task's spread flag if cpuset's page/slab spread flag is set | |
335 | * | |
5d21cc2d | 336 | * Called with callback_mutex/cpuset_mutex held |
f3b39d47 MX |
337 | */ |
338 | static void cpuset_update_task_spread_flag(struct cpuset *cs, | |
339 | struct task_struct *tsk) | |
340 | { | |
341 | if (is_spread_page(cs)) | |
342 | tsk->flags |= PF_SPREAD_PAGE; | |
343 | else | |
344 | tsk->flags &= ~PF_SPREAD_PAGE; | |
345 | if (is_spread_slab(cs)) | |
346 | tsk->flags |= PF_SPREAD_SLAB; | |
347 | else | |
348 | tsk->flags &= ~PF_SPREAD_SLAB; | |
349 | } | |
350 | ||
1da177e4 LT |
351 | /* |
352 | * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q? | |
353 | * | |
354 | * One cpuset is a subset of another if all its allowed CPUs and | |
355 | * Memory Nodes are a subset of the other, and its exclusive flags | |
5d21cc2d | 356 | * are only set if the other's are set. Call holding cpuset_mutex. |
1da177e4 LT |
357 | */ |
358 | ||
359 | static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q) | |
360 | { | |
300ed6cb | 361 | return cpumask_subset(p->cpus_allowed, q->cpus_allowed) && |
1da177e4 LT |
362 | nodes_subset(p->mems_allowed, q->mems_allowed) && |
363 | is_cpu_exclusive(p) <= is_cpu_exclusive(q) && | |
364 | is_mem_exclusive(p) <= is_mem_exclusive(q); | |
365 | } | |
366 | ||
645fcc9d LZ |
367 | /** |
368 | * alloc_trial_cpuset - allocate a trial cpuset | |
369 | * @cs: the cpuset that the trial cpuset duplicates | |
370 | */ | |
c9710d80 | 371 | static struct cpuset *alloc_trial_cpuset(struct cpuset *cs) |
645fcc9d | 372 | { |
300ed6cb LZ |
373 | struct cpuset *trial; |
374 | ||
375 | trial = kmemdup(cs, sizeof(*cs), GFP_KERNEL); | |
376 | if (!trial) | |
377 | return NULL; | |
378 | ||
379 | if (!alloc_cpumask_var(&trial->cpus_allowed, GFP_KERNEL)) { | |
380 | kfree(trial); | |
381 | return NULL; | |
382 | } | |
383 | cpumask_copy(trial->cpus_allowed, cs->cpus_allowed); | |
384 | ||
385 | return trial; | |
645fcc9d LZ |
386 | } |
387 | ||
388 | /** | |
389 | * free_trial_cpuset - free the trial cpuset | |
390 | * @trial: the trial cpuset to be freed | |
391 | */ | |
392 | static void free_trial_cpuset(struct cpuset *trial) | |
393 | { | |
300ed6cb | 394 | free_cpumask_var(trial->cpus_allowed); |
645fcc9d LZ |
395 | kfree(trial); |
396 | } | |
397 | ||
1da177e4 LT |
398 | /* |
399 | * validate_change() - Used to validate that any proposed cpuset change | |
400 | * follows the structural rules for cpusets. | |
401 | * | |
402 | * If we replaced the flag and mask values of the current cpuset | |
403 | * (cur) with those values in the trial cpuset (trial), would | |
404 | * our various subset and exclusive rules still be valid? Presumes | |
5d21cc2d | 405 | * cpuset_mutex held. |
1da177e4 LT |
406 | * |
407 | * 'cur' is the address of an actual, in-use cpuset. Operations | |
408 | * such as list traversal that depend on the actual address of the | |
409 | * cpuset in the list must use cur below, not trial. | |
410 | * | |
411 | * 'trial' is the address of bulk structure copy of cur, with | |
412 | * perhaps one or more of the fields cpus_allowed, mems_allowed, | |
413 | * or flags changed to new, trial values. | |
414 | * | |
415 | * Return 0 if valid, -errno if not. | |
416 | */ | |
417 | ||
c9710d80 | 418 | static int validate_change(struct cpuset *cur, struct cpuset *trial) |
1da177e4 | 419 | { |
492eb21b | 420 | struct cgroup_subsys_state *css; |
1da177e4 | 421 | struct cpuset *c, *par; |
ae8086ce TH |
422 | int ret; |
423 | ||
424 | rcu_read_lock(); | |
1da177e4 LT |
425 | |
426 | /* Each of our child cpusets must be a subset of us */ | |
ae8086ce | 427 | ret = -EBUSY; |
492eb21b | 428 | cpuset_for_each_child(c, css, cur) |
ae8086ce TH |
429 | if (!is_cpuset_subset(c, trial)) |
430 | goto out; | |
1da177e4 LT |
431 | |
432 | /* Remaining checks don't apply to root cpuset */ | |
ae8086ce | 433 | ret = 0; |
69604067 | 434 | if (cur == &top_cpuset) |
ae8086ce | 435 | goto out; |
1da177e4 | 436 | |
c431069f | 437 | par = parent_cs(cur); |
69604067 | 438 | |
1da177e4 | 439 | /* We must be a subset of our parent cpuset */ |
ae8086ce | 440 | ret = -EACCES; |
1da177e4 | 441 | if (!is_cpuset_subset(trial, par)) |
ae8086ce | 442 | goto out; |
1da177e4 | 443 | |
2df167a3 PM |
444 | /* |
445 | * If either I or some sibling (!= me) is exclusive, we can't | |
446 | * overlap | |
447 | */ | |
ae8086ce | 448 | ret = -EINVAL; |
492eb21b | 449 | cpuset_for_each_child(c, css, par) { |
1da177e4 LT |
450 | if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) && |
451 | c != cur && | |
300ed6cb | 452 | cpumask_intersects(trial->cpus_allowed, c->cpus_allowed)) |
ae8086ce | 453 | goto out; |
1da177e4 LT |
454 | if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) && |
455 | c != cur && | |
456 | nodes_intersects(trial->mems_allowed, c->mems_allowed)) | |
ae8086ce | 457 | goto out; |
1da177e4 LT |
458 | } |
459 | ||
452477fa TH |
460 | /* |
461 | * Cpusets with tasks - existing or newly being attached - can't | |
1c09b195 | 462 | * be changed to have empty cpus_allowed or mems_allowed. |
452477fa | 463 | */ |
ae8086ce | 464 | ret = -ENOSPC; |
07bc356e | 465 | if ((cgroup_has_tasks(cur->css.cgroup) || cur->attach_in_progress)) { |
1c09b195 LZ |
466 | if (!cpumask_empty(cur->cpus_allowed) && |
467 | cpumask_empty(trial->cpus_allowed)) | |
468 | goto out; | |
469 | if (!nodes_empty(cur->mems_allowed) && | |
470 | nodes_empty(trial->mems_allowed)) | |
471 | goto out; | |
472 | } | |
020958b6 | 473 | |
ae8086ce TH |
474 | ret = 0; |
475 | out: | |
476 | rcu_read_unlock(); | |
477 | return ret; | |
1da177e4 LT |
478 | } |
479 | ||
db7f47cf | 480 | #ifdef CONFIG_SMP |
029190c5 | 481 | /* |
cf417141 | 482 | * Helper routine for generate_sched_domains(). |
029190c5 PJ |
483 | * Do cpusets a, b have overlapping cpus_allowed masks? |
484 | */ | |
029190c5 PJ |
485 | static int cpusets_overlap(struct cpuset *a, struct cpuset *b) |
486 | { | |
300ed6cb | 487 | return cpumask_intersects(a->cpus_allowed, b->cpus_allowed); |
029190c5 PJ |
488 | } |
489 | ||
1d3504fc HS |
490 | static void |
491 | update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c) | |
492 | { | |
1d3504fc HS |
493 | if (dattr->relax_domain_level < c->relax_domain_level) |
494 | dattr->relax_domain_level = c->relax_domain_level; | |
495 | return; | |
496 | } | |
497 | ||
fc560a26 TH |
498 | static void update_domain_attr_tree(struct sched_domain_attr *dattr, |
499 | struct cpuset *root_cs) | |
f5393693 | 500 | { |
fc560a26 | 501 | struct cpuset *cp; |
492eb21b | 502 | struct cgroup_subsys_state *pos_css; |
f5393693 | 503 | |
fc560a26 | 504 | rcu_read_lock(); |
492eb21b | 505 | cpuset_for_each_descendant_pre(cp, pos_css, root_cs) { |
bd8815a6 TH |
506 | if (cp == root_cs) |
507 | continue; | |
508 | ||
fc560a26 TH |
509 | /* skip the whole subtree if @cp doesn't have any CPU */ |
510 | if (cpumask_empty(cp->cpus_allowed)) { | |
492eb21b | 511 | pos_css = css_rightmost_descendant(pos_css); |
f5393693 | 512 | continue; |
fc560a26 | 513 | } |
f5393693 LJ |
514 | |
515 | if (is_sched_load_balance(cp)) | |
516 | update_domain_attr(dattr, cp); | |
f5393693 | 517 | } |
fc560a26 | 518 | rcu_read_unlock(); |
f5393693 LJ |
519 | } |
520 | ||
029190c5 | 521 | /* |
cf417141 MK |
522 | * generate_sched_domains() |
523 | * | |
524 | * This function builds a partial partition of the systems CPUs | |
525 | * A 'partial partition' is a set of non-overlapping subsets whose | |
526 | * union is a subset of that set. | |
0a0fca9d | 527 | * The output of this function needs to be passed to kernel/sched/core.c |
cf417141 MK |
528 | * partition_sched_domains() routine, which will rebuild the scheduler's |
529 | * load balancing domains (sched domains) as specified by that partial | |
530 | * partition. | |
029190c5 | 531 | * |
45ce80fb | 532 | * See "What is sched_load_balance" in Documentation/cgroups/cpusets.txt |
029190c5 PJ |
533 | * for a background explanation of this. |
534 | * | |
535 | * Does not return errors, on the theory that the callers of this | |
536 | * routine would rather not worry about failures to rebuild sched | |
537 | * domains when operating in the severe memory shortage situations | |
538 | * that could cause allocation failures below. | |
539 | * | |
5d21cc2d | 540 | * Must be called with cpuset_mutex held. |
029190c5 PJ |
541 | * |
542 | * The three key local variables below are: | |
aeed6824 | 543 | * q - a linked-list queue of cpuset pointers, used to implement a |
029190c5 PJ |
544 | * top-down scan of all cpusets. This scan loads a pointer |
545 | * to each cpuset marked is_sched_load_balance into the | |
546 | * array 'csa'. For our purposes, rebuilding the schedulers | |
547 | * sched domains, we can ignore !is_sched_load_balance cpusets. | |
548 | * csa - (for CpuSet Array) Array of pointers to all the cpusets | |
549 | * that need to be load balanced, for convenient iterative | |
550 | * access by the subsequent code that finds the best partition, | |
551 | * i.e the set of domains (subsets) of CPUs such that the | |
552 | * cpus_allowed of every cpuset marked is_sched_load_balance | |
553 | * is a subset of one of these domains, while there are as | |
554 | * many such domains as possible, each as small as possible. | |
555 | * doms - Conversion of 'csa' to an array of cpumasks, for passing to | |
0a0fca9d | 556 | * the kernel/sched/core.c routine partition_sched_domains() in a |
029190c5 PJ |
557 | * convenient format, that can be easily compared to the prior |
558 | * value to determine what partition elements (sched domains) | |
559 | * were changed (added or removed.) | |
560 | * | |
561 | * Finding the best partition (set of domains): | |
562 | * The triple nested loops below over i, j, k scan over the | |
563 | * load balanced cpusets (using the array of cpuset pointers in | |
564 | * csa[]) looking for pairs of cpusets that have overlapping | |
565 | * cpus_allowed, but which don't have the same 'pn' partition | |
566 | * number and gives them in the same partition number. It keeps | |
567 | * looping on the 'restart' label until it can no longer find | |
568 | * any such pairs. | |
569 | * | |
570 | * The union of the cpus_allowed masks from the set of | |
571 | * all cpusets having the same 'pn' value then form the one | |
572 | * element of the partition (one sched domain) to be passed to | |
573 | * partition_sched_domains(). | |
574 | */ | |
acc3f5d7 | 575 | static int generate_sched_domains(cpumask_var_t **domains, |
cf417141 | 576 | struct sched_domain_attr **attributes) |
029190c5 | 577 | { |
029190c5 PJ |
578 | struct cpuset *cp; /* scans q */ |
579 | struct cpuset **csa; /* array of all cpuset ptrs */ | |
580 | int csn; /* how many cpuset ptrs in csa so far */ | |
581 | int i, j, k; /* indices for partition finding loops */ | |
acc3f5d7 | 582 | cpumask_var_t *doms; /* resulting partition; i.e. sched domains */ |
1d3504fc | 583 | struct sched_domain_attr *dattr; /* attributes for custom domains */ |
1583715d | 584 | int ndoms = 0; /* number of sched domains in result */ |
6af866af | 585 | int nslot; /* next empty doms[] struct cpumask slot */ |
492eb21b | 586 | struct cgroup_subsys_state *pos_css; |
029190c5 | 587 | |
029190c5 | 588 | doms = NULL; |
1d3504fc | 589 | dattr = NULL; |
cf417141 | 590 | csa = NULL; |
029190c5 PJ |
591 | |
592 | /* Special case for the 99% of systems with one, full, sched domain */ | |
593 | if (is_sched_load_balance(&top_cpuset)) { | |
acc3f5d7 RR |
594 | ndoms = 1; |
595 | doms = alloc_sched_domains(ndoms); | |
029190c5 | 596 | if (!doms) |
cf417141 MK |
597 | goto done; |
598 | ||
1d3504fc HS |
599 | dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL); |
600 | if (dattr) { | |
601 | *dattr = SD_ATTR_INIT; | |
93a65575 | 602 | update_domain_attr_tree(dattr, &top_cpuset); |
1d3504fc | 603 | } |
acc3f5d7 | 604 | cpumask_copy(doms[0], top_cpuset.cpus_allowed); |
cf417141 | 605 | |
cf417141 | 606 | goto done; |
029190c5 PJ |
607 | } |
608 | ||
664eedde | 609 | csa = kmalloc(nr_cpusets() * sizeof(cp), GFP_KERNEL); |
029190c5 PJ |
610 | if (!csa) |
611 | goto done; | |
612 | csn = 0; | |
613 | ||
fc560a26 | 614 | rcu_read_lock(); |
492eb21b | 615 | cpuset_for_each_descendant_pre(cp, pos_css, &top_cpuset) { |
bd8815a6 TH |
616 | if (cp == &top_cpuset) |
617 | continue; | |
f5393693 | 618 | /* |
fc560a26 TH |
619 | * Continue traversing beyond @cp iff @cp has some CPUs and |
620 | * isn't load balancing. The former is obvious. The | |
621 | * latter: All child cpusets contain a subset of the | |
622 | * parent's cpus, so just skip them, and then we call | |
623 | * update_domain_attr_tree() to calc relax_domain_level of | |
624 | * the corresponding sched domain. | |
f5393693 | 625 | */ |
fc560a26 TH |
626 | if (!cpumask_empty(cp->cpus_allowed) && |
627 | !is_sched_load_balance(cp)) | |
f5393693 | 628 | continue; |
489a5393 | 629 | |
fc560a26 TH |
630 | if (is_sched_load_balance(cp)) |
631 | csa[csn++] = cp; | |
632 | ||
633 | /* skip @cp's subtree */ | |
492eb21b | 634 | pos_css = css_rightmost_descendant(pos_css); |
fc560a26 TH |
635 | } |
636 | rcu_read_unlock(); | |
029190c5 PJ |
637 | |
638 | for (i = 0; i < csn; i++) | |
639 | csa[i]->pn = i; | |
640 | ndoms = csn; | |
641 | ||
642 | restart: | |
643 | /* Find the best partition (set of sched domains) */ | |
644 | for (i = 0; i < csn; i++) { | |
645 | struct cpuset *a = csa[i]; | |
646 | int apn = a->pn; | |
647 | ||
648 | for (j = 0; j < csn; j++) { | |
649 | struct cpuset *b = csa[j]; | |
650 | int bpn = b->pn; | |
651 | ||
652 | if (apn != bpn && cpusets_overlap(a, b)) { | |
653 | for (k = 0; k < csn; k++) { | |
654 | struct cpuset *c = csa[k]; | |
655 | ||
656 | if (c->pn == bpn) | |
657 | c->pn = apn; | |
658 | } | |
659 | ndoms--; /* one less element */ | |
660 | goto restart; | |
661 | } | |
662 | } | |
663 | } | |
664 | ||
cf417141 MK |
665 | /* |
666 | * Now we know how many domains to create. | |
667 | * Convert <csn, csa> to <ndoms, doms> and populate cpu masks. | |
668 | */ | |
acc3f5d7 | 669 | doms = alloc_sched_domains(ndoms); |
700018e0 | 670 | if (!doms) |
cf417141 | 671 | goto done; |
cf417141 MK |
672 | |
673 | /* | |
674 | * The rest of the code, including the scheduler, can deal with | |
675 | * dattr==NULL case. No need to abort if alloc fails. | |
676 | */ | |
1d3504fc | 677 | dattr = kmalloc(ndoms * sizeof(struct sched_domain_attr), GFP_KERNEL); |
029190c5 PJ |
678 | |
679 | for (nslot = 0, i = 0; i < csn; i++) { | |
680 | struct cpuset *a = csa[i]; | |
6af866af | 681 | struct cpumask *dp; |
029190c5 PJ |
682 | int apn = a->pn; |
683 | ||
cf417141 MK |
684 | if (apn < 0) { |
685 | /* Skip completed partitions */ | |
686 | continue; | |
687 | } | |
688 | ||
acc3f5d7 | 689 | dp = doms[nslot]; |
cf417141 MK |
690 | |
691 | if (nslot == ndoms) { | |
692 | static int warnings = 10; | |
693 | if (warnings) { | |
12d3089c FF |
694 | pr_warn("rebuild_sched_domains confused: nslot %d, ndoms %d, csn %d, i %d, apn %d\n", |
695 | nslot, ndoms, csn, i, apn); | |
cf417141 | 696 | warnings--; |
029190c5 | 697 | } |
cf417141 MK |
698 | continue; |
699 | } | |
029190c5 | 700 | |
6af866af | 701 | cpumask_clear(dp); |
cf417141 MK |
702 | if (dattr) |
703 | *(dattr + nslot) = SD_ATTR_INIT; | |
704 | for (j = i; j < csn; j++) { | |
705 | struct cpuset *b = csa[j]; | |
706 | ||
707 | if (apn == b->pn) { | |
300ed6cb | 708 | cpumask_or(dp, dp, b->cpus_allowed); |
cf417141 MK |
709 | if (dattr) |
710 | update_domain_attr_tree(dattr + nslot, b); | |
711 | ||
712 | /* Done with this partition */ | |
713 | b->pn = -1; | |
029190c5 | 714 | } |
029190c5 | 715 | } |
cf417141 | 716 | nslot++; |
029190c5 PJ |
717 | } |
718 | BUG_ON(nslot != ndoms); | |
719 | ||
cf417141 MK |
720 | done: |
721 | kfree(csa); | |
722 | ||
700018e0 LZ |
723 | /* |
724 | * Fallback to the default domain if kmalloc() failed. | |
725 | * See comments in partition_sched_domains(). | |
726 | */ | |
727 | if (doms == NULL) | |
728 | ndoms = 1; | |
729 | ||
cf417141 MK |
730 | *domains = doms; |
731 | *attributes = dattr; | |
732 | return ndoms; | |
733 | } | |
734 | ||
735 | /* | |
736 | * Rebuild scheduler domains. | |
737 | * | |
699140ba TH |
738 | * If the flag 'sched_load_balance' of any cpuset with non-empty |
739 | * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset | |
740 | * which has that flag enabled, or if any cpuset with a non-empty | |
741 | * 'cpus' is removed, then call this routine to rebuild the | |
742 | * scheduler's dynamic sched domains. | |
cf417141 | 743 | * |
5d21cc2d | 744 | * Call with cpuset_mutex held. Takes get_online_cpus(). |
cf417141 | 745 | */ |
699140ba | 746 | static void rebuild_sched_domains_locked(void) |
cf417141 MK |
747 | { |
748 | struct sched_domain_attr *attr; | |
acc3f5d7 | 749 | cpumask_var_t *doms; |
cf417141 MK |
750 | int ndoms; |
751 | ||
5d21cc2d | 752 | lockdep_assert_held(&cpuset_mutex); |
86ef5c9a | 753 | get_online_cpus(); |
cf417141 | 754 | |
5b16c2a4 LZ |
755 | /* |
756 | * We have raced with CPU hotplug. Don't do anything to avoid | |
757 | * passing doms with offlined cpu to partition_sched_domains(). | |
758 | * Anyways, hotplug work item will rebuild sched domains. | |
759 | */ | |
760 | if (!cpumask_equal(top_cpuset.cpus_allowed, cpu_active_mask)) | |
761 | goto out; | |
762 | ||
cf417141 | 763 | /* Generate domain masks and attrs */ |
cf417141 | 764 | ndoms = generate_sched_domains(&doms, &attr); |
cf417141 MK |
765 | |
766 | /* Have scheduler rebuild the domains */ | |
767 | partition_sched_domains(ndoms, doms, attr); | |
5b16c2a4 | 768 | out: |
86ef5c9a | 769 | put_online_cpus(); |
cf417141 | 770 | } |
db7f47cf | 771 | #else /* !CONFIG_SMP */ |
699140ba | 772 | static void rebuild_sched_domains_locked(void) |
db7f47cf PM |
773 | { |
774 | } | |
db7f47cf | 775 | #endif /* CONFIG_SMP */ |
029190c5 | 776 | |
cf417141 MK |
777 | void rebuild_sched_domains(void) |
778 | { | |
5d21cc2d | 779 | mutex_lock(&cpuset_mutex); |
699140ba | 780 | rebuild_sched_domains_locked(); |
5d21cc2d | 781 | mutex_unlock(&cpuset_mutex); |
029190c5 PJ |
782 | } |
783 | ||
070b57fc LZ |
784 | /* |
785 | * effective_cpumask_cpuset - return nearest ancestor with non-empty cpus | |
786 | * @cs: the cpuset in interest | |
58f4790b | 787 | * |
070b57fc LZ |
788 | * A cpuset's effective cpumask is the cpumask of the nearest ancestor |
789 | * with non-empty cpus. We use effective cpumask whenever: | |
790 | * - we update tasks' cpus_allowed. (they take on the ancestor's cpumask | |
791 | * if the cpuset they reside in has no cpus) | |
792 | * - we want to retrieve task_cs(tsk)'s cpus_allowed. | |
793 | * | |
794 | * Called with cpuset_mutex held. cpuset_cpus_allowed_fallback() is an | |
795 | * exception. See comments there. | |
796 | */ | |
797 | static struct cpuset *effective_cpumask_cpuset(struct cpuset *cs) | |
798 | { | |
799 | while (cpumask_empty(cs->cpus_allowed)) | |
800 | cs = parent_cs(cs); | |
801 | return cs; | |
802 | } | |
803 | ||
804 | /* | |
805 | * effective_nodemask_cpuset - return nearest ancestor with non-empty mems | |
806 | * @cs: the cpuset in interest | |
807 | * | |
808 | * A cpuset's effective nodemask is the nodemask of the nearest ancestor | |
809 | * with non-empty memss. We use effective nodemask whenever: | |
810 | * - we update tasks' mems_allowed. (they take on the ancestor's nodemask | |
811 | * if the cpuset they reside in has no mems) | |
812 | * - we want to retrieve task_cs(tsk)'s mems_allowed. | |
813 | * | |
814 | * Called with cpuset_mutex held. | |
053199ed | 815 | */ |
070b57fc | 816 | static struct cpuset *effective_nodemask_cpuset(struct cpuset *cs) |
58f4790b | 817 | { |
070b57fc LZ |
818 | while (nodes_empty(cs->mems_allowed)) |
819 | cs = parent_cs(cs); | |
820 | return cs; | |
58f4790b | 821 | } |
053199ed | 822 | |
0b2f630a MX |
823 | /** |
824 | * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset. | |
825 | * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed | |
0b2f630a | 826 | * |
d66393e5 TH |
827 | * Iterate through each task of @cs updating its cpus_allowed to the |
828 | * effective cpuset's. As this function is called with cpuset_mutex held, | |
829 | * cpuset membership stays stable. | |
0b2f630a | 830 | */ |
d66393e5 | 831 | static void update_tasks_cpumask(struct cpuset *cs) |
0b2f630a | 832 | { |
d66393e5 TH |
833 | struct cpuset *cpus_cs = effective_cpumask_cpuset(cs); |
834 | struct css_task_iter it; | |
835 | struct task_struct *task; | |
836 | ||
837 | css_task_iter_start(&cs->css, &it); | |
838 | while ((task = css_task_iter_next(&it))) | |
839 | set_cpus_allowed_ptr(task, cpus_cs->cpus_allowed); | |
840 | css_task_iter_end(&it); | |
0b2f630a MX |
841 | } |
842 | ||
5c5cc623 LZ |
843 | /* |
844 | * update_tasks_cpumask_hier - Update the cpumasks of tasks in the hierarchy. | |
845 | * @root_cs: the root cpuset of the hierarchy | |
846 | * @update_root: update root cpuset or not? | |
5c5cc623 LZ |
847 | * |
848 | * This will update cpumasks of tasks in @root_cs and all other empty cpusets | |
849 | * which take on cpumask of @root_cs. | |
850 | * | |
851 | * Called with cpuset_mutex held | |
852 | */ | |
d66393e5 | 853 | static void update_tasks_cpumask_hier(struct cpuset *root_cs, bool update_root) |
5c5cc623 LZ |
854 | { |
855 | struct cpuset *cp; | |
492eb21b | 856 | struct cgroup_subsys_state *pos_css; |
5c5cc623 LZ |
857 | |
858 | rcu_read_lock(); | |
492eb21b | 859 | cpuset_for_each_descendant_pre(cp, pos_css, root_cs) { |
bd8815a6 TH |
860 | if (cp == root_cs) { |
861 | if (!update_root) | |
862 | continue; | |
863 | } else { | |
864 | /* skip the whole subtree if @cp have some CPU */ | |
865 | if (!cpumask_empty(cp->cpus_allowed)) { | |
866 | pos_css = css_rightmost_descendant(pos_css); | |
867 | continue; | |
868 | } | |
5c5cc623 | 869 | } |
ec903c0c | 870 | if (!css_tryget_online(&cp->css)) |
5c5cc623 LZ |
871 | continue; |
872 | rcu_read_unlock(); | |
873 | ||
d66393e5 | 874 | update_tasks_cpumask(cp); |
5c5cc623 LZ |
875 | |
876 | rcu_read_lock(); | |
877 | css_put(&cp->css); | |
878 | } | |
879 | rcu_read_unlock(); | |
880 | } | |
881 | ||
58f4790b CW |
882 | /** |
883 | * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it | |
884 | * @cs: the cpuset to consider | |
fc34ac1d | 885 | * @trialcs: trial cpuset |
58f4790b CW |
886 | * @buf: buffer of cpu numbers written to this cpuset |
887 | */ | |
645fcc9d LZ |
888 | static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, |
889 | const char *buf) | |
1da177e4 | 890 | { |
58f4790b CW |
891 | int retval; |
892 | int is_load_balanced; | |
1da177e4 | 893 | |
5f054e31 | 894 | /* top_cpuset.cpus_allowed tracks cpu_online_mask; it's read-only */ |
4c4d50f7 PJ |
895 | if (cs == &top_cpuset) |
896 | return -EACCES; | |
897 | ||
6f7f02e7 | 898 | /* |
c8d9c90c | 899 | * An empty cpus_allowed is ok only if the cpuset has no tasks. |
020958b6 PJ |
900 | * Since cpulist_parse() fails on an empty mask, we special case |
901 | * that parsing. The validate_change() call ensures that cpusets | |
902 | * with tasks have cpus. | |
6f7f02e7 | 903 | */ |
020958b6 | 904 | if (!*buf) { |
300ed6cb | 905 | cpumask_clear(trialcs->cpus_allowed); |
6f7f02e7 | 906 | } else { |
300ed6cb | 907 | retval = cpulist_parse(buf, trialcs->cpus_allowed); |
6f7f02e7 DR |
908 | if (retval < 0) |
909 | return retval; | |
37340746 | 910 | |
6ad4c188 | 911 | if (!cpumask_subset(trialcs->cpus_allowed, cpu_active_mask)) |
37340746 | 912 | return -EINVAL; |
6f7f02e7 | 913 | } |
029190c5 | 914 | |
8707d8b8 | 915 | /* Nothing to do if the cpus didn't change */ |
300ed6cb | 916 | if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed)) |
8707d8b8 | 917 | return 0; |
58f4790b | 918 | |
a73456f3 LZ |
919 | retval = validate_change(cs, trialcs); |
920 | if (retval < 0) | |
921 | return retval; | |
922 | ||
645fcc9d | 923 | is_load_balanced = is_sched_load_balance(trialcs); |
029190c5 | 924 | |
3d3f26a7 | 925 | mutex_lock(&callback_mutex); |
300ed6cb | 926 | cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed); |
3d3f26a7 | 927 | mutex_unlock(&callback_mutex); |
029190c5 | 928 | |
d66393e5 | 929 | update_tasks_cpumask_hier(cs, true); |
58f4790b | 930 | |
8707d8b8 | 931 | if (is_load_balanced) |
699140ba | 932 | rebuild_sched_domains_locked(); |
85d7b949 | 933 | return 0; |
1da177e4 LT |
934 | } |
935 | ||
e4e364e8 PJ |
936 | /* |
937 | * cpuset_migrate_mm | |
938 | * | |
939 | * Migrate memory region from one set of nodes to another. | |
940 | * | |
941 | * Temporarilly set tasks mems_allowed to target nodes of migration, | |
942 | * so that the migration code can allocate pages on these nodes. | |
943 | * | |
e4e364e8 PJ |
944 | * While the mm_struct we are migrating is typically from some |
945 | * other task, the task_struct mems_allowed that we are hacking | |
946 | * is for our current task, which must allocate new pages for that | |
947 | * migrating memory region. | |
e4e364e8 PJ |
948 | */ |
949 | ||
950 | static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from, | |
951 | const nodemask_t *to) | |
952 | { | |
953 | struct task_struct *tsk = current; | |
070b57fc | 954 | struct cpuset *mems_cs; |
e4e364e8 | 955 | |
e4e364e8 | 956 | tsk->mems_allowed = *to; |
e4e364e8 PJ |
957 | |
958 | do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL); | |
959 | ||
47295830 | 960 | rcu_read_lock(); |
070b57fc LZ |
961 | mems_cs = effective_nodemask_cpuset(task_cs(tsk)); |
962 | guarantee_online_mems(mems_cs, &tsk->mems_allowed); | |
47295830 | 963 | rcu_read_unlock(); |
e4e364e8 PJ |
964 | } |
965 | ||
3b6766fe | 966 | /* |
58568d2a MX |
967 | * cpuset_change_task_nodemask - change task's mems_allowed and mempolicy |
968 | * @tsk: the task to change | |
969 | * @newmems: new nodes that the task will be set | |
970 | * | |
971 | * In order to avoid seeing no nodes if the old and new nodes are disjoint, | |
972 | * we structure updates as setting all new allowed nodes, then clearing newly | |
973 | * disallowed ones. | |
58568d2a MX |
974 | */ |
975 | static void cpuset_change_task_nodemask(struct task_struct *tsk, | |
976 | nodemask_t *newmems) | |
977 | { | |
b246272e | 978 | bool need_loop; |
89e8a244 | 979 | |
c0ff7453 MX |
980 | /* |
981 | * Allow tasks that have access to memory reserves because they have | |
982 | * been OOM killed to get memory anywhere. | |
983 | */ | |
984 | if (unlikely(test_thread_flag(TIF_MEMDIE))) | |
985 | return; | |
986 | if (current->flags & PF_EXITING) /* Let dying task have memory */ | |
987 | return; | |
988 | ||
989 | task_lock(tsk); | |
b246272e DR |
990 | /* |
991 | * Determine if a loop is necessary if another thread is doing | |
d26914d1 | 992 | * read_mems_allowed_begin(). If at least one node remains unchanged and |
b246272e DR |
993 | * tsk does not have a mempolicy, then an empty nodemask will not be |
994 | * possible when mems_allowed is larger than a word. | |
995 | */ | |
996 | need_loop = task_has_mempolicy(tsk) || | |
997 | !nodes_intersects(*newmems, tsk->mems_allowed); | |
c0ff7453 | 998 | |
0fc0287c PZ |
999 | if (need_loop) { |
1000 | local_irq_disable(); | |
cc9a6c87 | 1001 | write_seqcount_begin(&tsk->mems_allowed_seq); |
0fc0287c | 1002 | } |
c0ff7453 | 1003 | |
cc9a6c87 MG |
1004 | nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems); |
1005 | mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP1); | |
c0ff7453 MX |
1006 | |
1007 | mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP2); | |
58568d2a | 1008 | tsk->mems_allowed = *newmems; |
cc9a6c87 | 1009 | |
0fc0287c | 1010 | if (need_loop) { |
cc9a6c87 | 1011 | write_seqcount_end(&tsk->mems_allowed_seq); |
0fc0287c PZ |
1012 | local_irq_enable(); |
1013 | } | |
cc9a6c87 | 1014 | |
c0ff7453 | 1015 | task_unlock(tsk); |
58568d2a MX |
1016 | } |
1017 | ||
8793d854 PM |
1018 | static void *cpuset_being_rebound; |
1019 | ||
0b2f630a MX |
1020 | /** |
1021 | * update_tasks_nodemask - Update the nodemasks of tasks in the cpuset. | |
1022 | * @cs: the cpuset in which each task's mems_allowed mask needs to be changed | |
0b2f630a | 1023 | * |
d66393e5 TH |
1024 | * Iterate through each task of @cs updating its mems_allowed to the |
1025 | * effective cpuset's. As this function is called with cpuset_mutex held, | |
1026 | * cpuset membership stays stable. | |
0b2f630a | 1027 | */ |
d66393e5 | 1028 | static void update_tasks_nodemask(struct cpuset *cs) |
1da177e4 | 1029 | { |
33ad801d | 1030 | static nodemask_t newmems; /* protected by cpuset_mutex */ |
070b57fc | 1031 | struct cpuset *mems_cs = effective_nodemask_cpuset(cs); |
d66393e5 TH |
1032 | struct css_task_iter it; |
1033 | struct task_struct *task; | |
59dac16f | 1034 | |
846a16bf | 1035 | cpuset_being_rebound = cs; /* causes mpol_dup() rebind */ |
4225399a | 1036 | |
070b57fc | 1037 | guarantee_online_mems(mems_cs, &newmems); |
33ad801d | 1038 | |
4225399a | 1039 | /* |
3b6766fe LZ |
1040 | * The mpol_rebind_mm() call takes mmap_sem, which we couldn't |
1041 | * take while holding tasklist_lock. Forks can happen - the | |
1042 | * mpol_dup() cpuset_being_rebound check will catch such forks, | |
1043 | * and rebind their vma mempolicies too. Because we still hold | |
5d21cc2d | 1044 | * the global cpuset_mutex, we know that no other rebind effort |
3b6766fe | 1045 | * will be contending for the global variable cpuset_being_rebound. |
4225399a | 1046 | * It's ok if we rebind the same mm twice; mpol_rebind_mm() |
04c19fa6 | 1047 | * is idempotent. Also migrate pages in each mm to new nodes. |
4225399a | 1048 | */ |
d66393e5 TH |
1049 | css_task_iter_start(&cs->css, &it); |
1050 | while ((task = css_task_iter_next(&it))) { | |
1051 | struct mm_struct *mm; | |
1052 | bool migrate; | |
1053 | ||
1054 | cpuset_change_task_nodemask(task, &newmems); | |
1055 | ||
1056 | mm = get_task_mm(task); | |
1057 | if (!mm) | |
1058 | continue; | |
1059 | ||
1060 | migrate = is_memory_migrate(cs); | |
1061 | ||
1062 | mpol_rebind_mm(mm, &cs->mems_allowed); | |
1063 | if (migrate) | |
1064 | cpuset_migrate_mm(mm, &cs->old_mems_allowed, &newmems); | |
1065 | mmput(mm); | |
1066 | } | |
1067 | css_task_iter_end(&it); | |
4225399a | 1068 | |
33ad801d LZ |
1069 | /* |
1070 | * All the tasks' nodemasks have been updated, update | |
1071 | * cs->old_mems_allowed. | |
1072 | */ | |
1073 | cs->old_mems_allowed = newmems; | |
1074 | ||
2df167a3 | 1075 | /* We're done rebinding vmas to this cpuset's new mems_allowed. */ |
8793d854 | 1076 | cpuset_being_rebound = NULL; |
1da177e4 LT |
1077 | } |
1078 | ||
5c5cc623 LZ |
1079 | /* |
1080 | * update_tasks_nodemask_hier - Update the nodemasks of tasks in the hierarchy. | |
1081 | * @cs: the root cpuset of the hierarchy | |
1082 | * @update_root: update the root cpuset or not? | |
5c5cc623 LZ |
1083 | * |
1084 | * This will update nodemasks of tasks in @root_cs and all other empty cpusets | |
1085 | * which take on nodemask of @root_cs. | |
1086 | * | |
1087 | * Called with cpuset_mutex held | |
1088 | */ | |
d66393e5 | 1089 | static void update_tasks_nodemask_hier(struct cpuset *root_cs, bool update_root) |
5c5cc623 LZ |
1090 | { |
1091 | struct cpuset *cp; | |
492eb21b | 1092 | struct cgroup_subsys_state *pos_css; |
5c5cc623 LZ |
1093 | |
1094 | rcu_read_lock(); | |
492eb21b | 1095 | cpuset_for_each_descendant_pre(cp, pos_css, root_cs) { |
bd8815a6 TH |
1096 | if (cp == root_cs) { |
1097 | if (!update_root) | |
1098 | continue; | |
1099 | } else { | |
1100 | /* skip the whole subtree if @cp have some CPU */ | |
1101 | if (!nodes_empty(cp->mems_allowed)) { | |
1102 | pos_css = css_rightmost_descendant(pos_css); | |
1103 | continue; | |
1104 | } | |
5c5cc623 | 1105 | } |
ec903c0c | 1106 | if (!css_tryget_online(&cp->css)) |
5c5cc623 LZ |
1107 | continue; |
1108 | rcu_read_unlock(); | |
1109 | ||
d66393e5 | 1110 | update_tasks_nodemask(cp); |
5c5cc623 LZ |
1111 | |
1112 | rcu_read_lock(); | |
1113 | css_put(&cp->css); | |
1114 | } | |
1115 | rcu_read_unlock(); | |
1116 | } | |
1117 | ||
0b2f630a MX |
1118 | /* |
1119 | * Handle user request to change the 'mems' memory placement | |
1120 | * of a cpuset. Needs to validate the request, update the | |
58568d2a MX |
1121 | * cpusets mems_allowed, and for each task in the cpuset, |
1122 | * update mems_allowed and rebind task's mempolicy and any vma | |
1123 | * mempolicies and if the cpuset is marked 'memory_migrate', | |
1124 | * migrate the tasks pages to the new memory. | |
0b2f630a | 1125 | * |
5d21cc2d | 1126 | * Call with cpuset_mutex held. May take callback_mutex during call. |
0b2f630a MX |
1127 | * Will take tasklist_lock, scan tasklist for tasks in cpuset cs, |
1128 | * lock each such tasks mm->mmap_sem, scan its vma's and rebind | |
1129 | * their mempolicies to the cpusets new mems_allowed. | |
1130 | */ | |
645fcc9d LZ |
1131 | static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs, |
1132 | const char *buf) | |
0b2f630a | 1133 | { |
0b2f630a MX |
1134 | int retval; |
1135 | ||
1136 | /* | |
38d7bee9 | 1137 | * top_cpuset.mems_allowed tracks node_stats[N_MEMORY]; |
0b2f630a MX |
1138 | * it's read-only |
1139 | */ | |
53feb297 MX |
1140 | if (cs == &top_cpuset) { |
1141 | retval = -EACCES; | |
1142 | goto done; | |
1143 | } | |
0b2f630a | 1144 | |
0b2f630a MX |
1145 | /* |
1146 | * An empty mems_allowed is ok iff there are no tasks in the cpuset. | |
1147 | * Since nodelist_parse() fails on an empty mask, we special case | |
1148 | * that parsing. The validate_change() call ensures that cpusets | |
1149 | * with tasks have memory. | |
1150 | */ | |
1151 | if (!*buf) { | |
645fcc9d | 1152 | nodes_clear(trialcs->mems_allowed); |
0b2f630a | 1153 | } else { |
645fcc9d | 1154 | retval = nodelist_parse(buf, trialcs->mems_allowed); |
0b2f630a MX |
1155 | if (retval < 0) |
1156 | goto done; | |
1157 | ||
645fcc9d | 1158 | if (!nodes_subset(trialcs->mems_allowed, |
38d7bee9 | 1159 | node_states[N_MEMORY])) { |
53feb297 MX |
1160 | retval = -EINVAL; |
1161 | goto done; | |
1162 | } | |
0b2f630a | 1163 | } |
33ad801d LZ |
1164 | |
1165 | if (nodes_equal(cs->mems_allowed, trialcs->mems_allowed)) { | |
0b2f630a MX |
1166 | retval = 0; /* Too easy - nothing to do */ |
1167 | goto done; | |
1168 | } | |
645fcc9d | 1169 | retval = validate_change(cs, trialcs); |
0b2f630a MX |
1170 | if (retval < 0) |
1171 | goto done; | |
1172 | ||
1173 | mutex_lock(&callback_mutex); | |
645fcc9d | 1174 | cs->mems_allowed = trialcs->mems_allowed; |
0b2f630a MX |
1175 | mutex_unlock(&callback_mutex); |
1176 | ||
d66393e5 | 1177 | update_tasks_nodemask_hier(cs, true); |
0b2f630a MX |
1178 | done: |
1179 | return retval; | |
1180 | } | |
1181 | ||
8793d854 PM |
1182 | int current_cpuset_is_being_rebound(void) |
1183 | { | |
391acf97 GZ |
1184 | int ret; |
1185 | ||
1186 | rcu_read_lock(); | |
1187 | ret = task_cs(current) == cpuset_being_rebound; | |
1188 | rcu_read_unlock(); | |
1189 | ||
1190 | return ret; | |
8793d854 PM |
1191 | } |
1192 | ||
5be7a479 | 1193 | static int update_relax_domain_level(struct cpuset *cs, s64 val) |
1d3504fc | 1194 | { |
db7f47cf | 1195 | #ifdef CONFIG_SMP |
60495e77 | 1196 | if (val < -1 || val >= sched_domain_level_max) |
30e0e178 | 1197 | return -EINVAL; |
db7f47cf | 1198 | #endif |
1d3504fc HS |
1199 | |
1200 | if (val != cs->relax_domain_level) { | |
1201 | cs->relax_domain_level = val; | |
300ed6cb LZ |
1202 | if (!cpumask_empty(cs->cpus_allowed) && |
1203 | is_sched_load_balance(cs)) | |
699140ba | 1204 | rebuild_sched_domains_locked(); |
1d3504fc HS |
1205 | } |
1206 | ||
1207 | return 0; | |
1208 | } | |
1209 | ||
72ec7029 | 1210 | /** |
950592f7 MX |
1211 | * update_tasks_flags - update the spread flags of tasks in the cpuset. |
1212 | * @cs: the cpuset in which each task's spread flags needs to be changed | |
950592f7 | 1213 | * |
d66393e5 TH |
1214 | * Iterate through each task of @cs updating its spread flags. As this |
1215 | * function is called with cpuset_mutex held, cpuset membership stays | |
1216 | * stable. | |
950592f7 | 1217 | */ |
d66393e5 | 1218 | static void update_tasks_flags(struct cpuset *cs) |
950592f7 | 1219 | { |
d66393e5 TH |
1220 | struct css_task_iter it; |
1221 | struct task_struct *task; | |
1222 | ||
1223 | css_task_iter_start(&cs->css, &it); | |
1224 | while ((task = css_task_iter_next(&it))) | |
1225 | cpuset_update_task_spread_flag(cs, task); | |
1226 | css_task_iter_end(&it); | |
950592f7 MX |
1227 | } |
1228 | ||
1da177e4 LT |
1229 | /* |
1230 | * update_flag - read a 0 or a 1 in a file and update associated flag | |
78608366 PM |
1231 | * bit: the bit to update (see cpuset_flagbits_t) |
1232 | * cs: the cpuset to update | |
1233 | * turning_on: whether the flag is being set or cleared | |
053199ed | 1234 | * |
5d21cc2d | 1235 | * Call with cpuset_mutex held. |
1da177e4 LT |
1236 | */ |
1237 | ||
700fe1ab PM |
1238 | static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, |
1239 | int turning_on) | |
1da177e4 | 1240 | { |
645fcc9d | 1241 | struct cpuset *trialcs; |
40b6a762 | 1242 | int balance_flag_changed; |
950592f7 | 1243 | int spread_flag_changed; |
950592f7 | 1244 | int err; |
1da177e4 | 1245 | |
645fcc9d LZ |
1246 | trialcs = alloc_trial_cpuset(cs); |
1247 | if (!trialcs) | |
1248 | return -ENOMEM; | |
1249 | ||
1da177e4 | 1250 | if (turning_on) |
645fcc9d | 1251 | set_bit(bit, &trialcs->flags); |
1da177e4 | 1252 | else |
645fcc9d | 1253 | clear_bit(bit, &trialcs->flags); |
1da177e4 | 1254 | |
645fcc9d | 1255 | err = validate_change(cs, trialcs); |
85d7b949 | 1256 | if (err < 0) |
645fcc9d | 1257 | goto out; |
029190c5 | 1258 | |
029190c5 | 1259 | balance_flag_changed = (is_sched_load_balance(cs) != |
645fcc9d | 1260 | is_sched_load_balance(trialcs)); |
029190c5 | 1261 | |
950592f7 MX |
1262 | spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs)) |
1263 | || (is_spread_page(cs) != is_spread_page(trialcs))); | |
1264 | ||
3d3f26a7 | 1265 | mutex_lock(&callback_mutex); |
645fcc9d | 1266 | cs->flags = trialcs->flags; |
3d3f26a7 | 1267 | mutex_unlock(&callback_mutex); |
85d7b949 | 1268 | |
300ed6cb | 1269 | if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed) |
699140ba | 1270 | rebuild_sched_domains_locked(); |
029190c5 | 1271 | |
950592f7 | 1272 | if (spread_flag_changed) |
d66393e5 | 1273 | update_tasks_flags(cs); |
645fcc9d LZ |
1274 | out: |
1275 | free_trial_cpuset(trialcs); | |
1276 | return err; | |
1da177e4 LT |
1277 | } |
1278 | ||
3e0d98b9 | 1279 | /* |
80f7228b | 1280 | * Frequency meter - How fast is some event occurring? |
3e0d98b9 PJ |
1281 | * |
1282 | * These routines manage a digitally filtered, constant time based, | |
1283 | * event frequency meter. There are four routines: | |
1284 | * fmeter_init() - initialize a frequency meter. | |
1285 | * fmeter_markevent() - called each time the event happens. | |
1286 | * fmeter_getrate() - returns the recent rate of such events. | |
1287 | * fmeter_update() - internal routine used to update fmeter. | |
1288 | * | |
1289 | * A common data structure is passed to each of these routines, | |
1290 | * which is used to keep track of the state required to manage the | |
1291 | * frequency meter and its digital filter. | |
1292 | * | |
1293 | * The filter works on the number of events marked per unit time. | |
1294 | * The filter is single-pole low-pass recursive (IIR). The time unit | |
1295 | * is 1 second. Arithmetic is done using 32-bit integers scaled to | |
1296 | * simulate 3 decimal digits of precision (multiplied by 1000). | |
1297 | * | |
1298 | * With an FM_COEF of 933, and a time base of 1 second, the filter | |
1299 | * has a half-life of 10 seconds, meaning that if the events quit | |
1300 | * happening, then the rate returned from the fmeter_getrate() | |
1301 | * will be cut in half each 10 seconds, until it converges to zero. | |
1302 | * | |
1303 | * It is not worth doing a real infinitely recursive filter. If more | |
1304 | * than FM_MAXTICKS ticks have elapsed since the last filter event, | |
1305 | * just compute FM_MAXTICKS ticks worth, by which point the level | |
1306 | * will be stable. | |
1307 | * | |
1308 | * Limit the count of unprocessed events to FM_MAXCNT, so as to avoid | |
1309 | * arithmetic overflow in the fmeter_update() routine. | |
1310 | * | |
1311 | * Given the simple 32 bit integer arithmetic used, this meter works | |
1312 | * best for reporting rates between one per millisecond (msec) and | |
1313 | * one per 32 (approx) seconds. At constant rates faster than one | |
1314 | * per msec it maxes out at values just under 1,000,000. At constant | |
1315 | * rates between one per msec, and one per second it will stabilize | |
1316 | * to a value N*1000, where N is the rate of events per second. | |
1317 | * At constant rates between one per second and one per 32 seconds, | |
1318 | * it will be choppy, moving up on the seconds that have an event, | |
1319 | * and then decaying until the next event. At rates slower than | |
1320 | * about one in 32 seconds, it decays all the way back to zero between | |
1321 | * each event. | |
1322 | */ | |
1323 | ||
1324 | #define FM_COEF 933 /* coefficient for half-life of 10 secs */ | |
1325 | #define FM_MAXTICKS ((time_t)99) /* useless computing more ticks than this */ | |
1326 | #define FM_MAXCNT 1000000 /* limit cnt to avoid overflow */ | |
1327 | #define FM_SCALE 1000 /* faux fixed point scale */ | |
1328 | ||
1329 | /* Initialize a frequency meter */ | |
1330 | static void fmeter_init(struct fmeter *fmp) | |
1331 | { | |
1332 | fmp->cnt = 0; | |
1333 | fmp->val = 0; | |
1334 | fmp->time = 0; | |
1335 | spin_lock_init(&fmp->lock); | |
1336 | } | |
1337 | ||
1338 | /* Internal meter update - process cnt events and update value */ | |
1339 | static void fmeter_update(struct fmeter *fmp) | |
1340 | { | |
1341 | time_t now = get_seconds(); | |
1342 | time_t ticks = now - fmp->time; | |
1343 | ||
1344 | if (ticks == 0) | |
1345 | return; | |
1346 | ||
1347 | ticks = min(FM_MAXTICKS, ticks); | |
1348 | while (ticks-- > 0) | |
1349 | fmp->val = (FM_COEF * fmp->val) / FM_SCALE; | |
1350 | fmp->time = now; | |
1351 | ||
1352 | fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE; | |
1353 | fmp->cnt = 0; | |
1354 | } | |
1355 | ||
1356 | /* Process any previous ticks, then bump cnt by one (times scale). */ | |
1357 | static void fmeter_markevent(struct fmeter *fmp) | |
1358 | { | |
1359 | spin_lock(&fmp->lock); | |
1360 | fmeter_update(fmp); | |
1361 | fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE); | |
1362 | spin_unlock(&fmp->lock); | |
1363 | } | |
1364 | ||
1365 | /* Process any previous ticks, then return current value. */ | |
1366 | static int fmeter_getrate(struct fmeter *fmp) | |
1367 | { | |
1368 | int val; | |
1369 | ||
1370 | spin_lock(&fmp->lock); | |
1371 | fmeter_update(fmp); | |
1372 | val = fmp->val; | |
1373 | spin_unlock(&fmp->lock); | |
1374 | return val; | |
1375 | } | |
1376 | ||
57fce0a6 TH |
1377 | static struct cpuset *cpuset_attach_old_cs; |
1378 | ||
5d21cc2d | 1379 | /* Called by cgroups to determine if a cpuset is usable; cpuset_mutex held */ |
eb95419b TH |
1380 | static int cpuset_can_attach(struct cgroup_subsys_state *css, |
1381 | struct cgroup_taskset *tset) | |
f780bdb7 | 1382 | { |
eb95419b | 1383 | struct cpuset *cs = css_cs(css); |
bb9d97b6 TH |
1384 | struct task_struct *task; |
1385 | int ret; | |
1da177e4 | 1386 | |
57fce0a6 TH |
1387 | /* used later by cpuset_attach() */ |
1388 | cpuset_attach_old_cs = task_cs(cgroup_taskset_first(tset)); | |
1389 | ||
5d21cc2d TH |
1390 | mutex_lock(&cpuset_mutex); |
1391 | ||
88fa523b LZ |
1392 | /* |
1393 | * We allow to move tasks into an empty cpuset if sane_behavior | |
1394 | * flag is set. | |
1395 | */ | |
5d21cc2d | 1396 | ret = -ENOSPC; |
eb95419b | 1397 | if (!cgroup_sane_behavior(css->cgroup) && |
88fa523b | 1398 | (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))) |
5d21cc2d | 1399 | goto out_unlock; |
9985b0ba | 1400 | |
924f0d9a | 1401 | cgroup_taskset_for_each(task, tset) { |
bb9d97b6 | 1402 | /* |
14a40ffc TH |
1403 | * Kthreads which disallow setaffinity shouldn't be moved |
1404 | * to a new cpuset; we don't want to change their cpu | |
1405 | * affinity and isolating such threads by their set of | |
1406 | * allowed nodes is unnecessary. Thus, cpusets are not | |
1407 | * applicable for such threads. This prevents checking for | |
1408 | * success of set_cpus_allowed_ptr() on all attached tasks | |
1409 | * before cpus_allowed may be changed. | |
bb9d97b6 | 1410 | */ |
5d21cc2d | 1411 | ret = -EINVAL; |
14a40ffc | 1412 | if (task->flags & PF_NO_SETAFFINITY) |
5d21cc2d TH |
1413 | goto out_unlock; |
1414 | ret = security_task_setscheduler(task); | |
1415 | if (ret) | |
1416 | goto out_unlock; | |
bb9d97b6 | 1417 | } |
f780bdb7 | 1418 | |
452477fa TH |
1419 | /* |
1420 | * Mark attach is in progress. This makes validate_change() fail | |
1421 | * changes which zero cpus/mems_allowed. | |
1422 | */ | |
1423 | cs->attach_in_progress++; | |
5d21cc2d TH |
1424 | ret = 0; |
1425 | out_unlock: | |
1426 | mutex_unlock(&cpuset_mutex); | |
1427 | return ret; | |
8793d854 | 1428 | } |
f780bdb7 | 1429 | |
eb95419b | 1430 | static void cpuset_cancel_attach(struct cgroup_subsys_state *css, |
452477fa TH |
1431 | struct cgroup_taskset *tset) |
1432 | { | |
5d21cc2d | 1433 | mutex_lock(&cpuset_mutex); |
eb95419b | 1434 | css_cs(css)->attach_in_progress--; |
5d21cc2d | 1435 | mutex_unlock(&cpuset_mutex); |
8793d854 | 1436 | } |
1da177e4 | 1437 | |
4e4c9a14 | 1438 | /* |
5d21cc2d | 1439 | * Protected by cpuset_mutex. cpus_attach is used only by cpuset_attach() |
4e4c9a14 TH |
1440 | * but we can't allocate it dynamically there. Define it global and |
1441 | * allocate from cpuset_init(). | |
1442 | */ | |
1443 | static cpumask_var_t cpus_attach; | |
1444 | ||
eb95419b TH |
1445 | static void cpuset_attach(struct cgroup_subsys_state *css, |
1446 | struct cgroup_taskset *tset) | |
8793d854 | 1447 | { |
67bd2c59 | 1448 | /* static buf protected by cpuset_mutex */ |
4e4c9a14 | 1449 | static nodemask_t cpuset_attach_nodemask_to; |
8793d854 | 1450 | struct mm_struct *mm; |
bb9d97b6 TH |
1451 | struct task_struct *task; |
1452 | struct task_struct *leader = cgroup_taskset_first(tset); | |
eb95419b | 1453 | struct cpuset *cs = css_cs(css); |
57fce0a6 | 1454 | struct cpuset *oldcs = cpuset_attach_old_cs; |
070b57fc LZ |
1455 | struct cpuset *cpus_cs = effective_cpumask_cpuset(cs); |
1456 | struct cpuset *mems_cs = effective_nodemask_cpuset(cs); | |
22fb52dd | 1457 | |
5d21cc2d TH |
1458 | mutex_lock(&cpuset_mutex); |
1459 | ||
4e4c9a14 TH |
1460 | /* prepare for attach */ |
1461 | if (cs == &top_cpuset) | |
1462 | cpumask_copy(cpus_attach, cpu_possible_mask); | |
1463 | else | |
070b57fc | 1464 | guarantee_online_cpus(cpus_cs, cpus_attach); |
4e4c9a14 | 1465 | |
070b57fc | 1466 | guarantee_online_mems(mems_cs, &cpuset_attach_nodemask_to); |
4e4c9a14 | 1467 | |
924f0d9a | 1468 | cgroup_taskset_for_each(task, tset) { |
bb9d97b6 TH |
1469 | /* |
1470 | * can_attach beforehand should guarantee that this doesn't | |
1471 | * fail. TODO: have a better way to handle failure here | |
1472 | */ | |
1473 | WARN_ON_ONCE(set_cpus_allowed_ptr(task, cpus_attach)); | |
1474 | ||
1475 | cpuset_change_task_nodemask(task, &cpuset_attach_nodemask_to); | |
1476 | cpuset_update_task_spread_flag(cs, task); | |
1477 | } | |
22fb52dd | 1478 | |
f780bdb7 BB |
1479 | /* |
1480 | * Change mm, possibly for multiple threads in a threadgroup. This is | |
1481 | * expensive and may sleep. | |
1482 | */ | |
f780bdb7 | 1483 | cpuset_attach_nodemask_to = cs->mems_allowed; |
bb9d97b6 | 1484 | mm = get_task_mm(leader); |
4225399a | 1485 | if (mm) { |
070b57fc LZ |
1486 | struct cpuset *mems_oldcs = effective_nodemask_cpuset(oldcs); |
1487 | ||
f780bdb7 | 1488 | mpol_rebind_mm(mm, &cpuset_attach_nodemask_to); |
f047cecf LZ |
1489 | |
1490 | /* | |
1491 | * old_mems_allowed is the same with mems_allowed here, except | |
1492 | * if this task is being moved automatically due to hotplug. | |
1493 | * In that case @mems_allowed has been updated and is empty, | |
1494 | * so @old_mems_allowed is the right nodesets that we migrate | |
1495 | * mm from. | |
1496 | */ | |
1497 | if (is_memory_migrate(cs)) { | |
1498 | cpuset_migrate_mm(mm, &mems_oldcs->old_mems_allowed, | |
f780bdb7 | 1499 | &cpuset_attach_nodemask_to); |
f047cecf | 1500 | } |
4225399a PJ |
1501 | mmput(mm); |
1502 | } | |
452477fa | 1503 | |
33ad801d | 1504 | cs->old_mems_allowed = cpuset_attach_nodemask_to; |
02bb5863 | 1505 | |
452477fa | 1506 | cs->attach_in_progress--; |
e44193d3 LZ |
1507 | if (!cs->attach_in_progress) |
1508 | wake_up(&cpuset_attach_wq); | |
5d21cc2d TH |
1509 | |
1510 | mutex_unlock(&cpuset_mutex); | |
1da177e4 LT |
1511 | } |
1512 | ||
1513 | /* The various types of files and directories in a cpuset file system */ | |
1514 | ||
1515 | typedef enum { | |
45b07ef3 | 1516 | FILE_MEMORY_MIGRATE, |
1da177e4 LT |
1517 | FILE_CPULIST, |
1518 | FILE_MEMLIST, | |
1519 | FILE_CPU_EXCLUSIVE, | |
1520 | FILE_MEM_EXCLUSIVE, | |
78608366 | 1521 | FILE_MEM_HARDWALL, |
029190c5 | 1522 | FILE_SCHED_LOAD_BALANCE, |
1d3504fc | 1523 | FILE_SCHED_RELAX_DOMAIN_LEVEL, |
3e0d98b9 PJ |
1524 | FILE_MEMORY_PRESSURE_ENABLED, |
1525 | FILE_MEMORY_PRESSURE, | |
825a46af PJ |
1526 | FILE_SPREAD_PAGE, |
1527 | FILE_SPREAD_SLAB, | |
1da177e4 LT |
1528 | } cpuset_filetype_t; |
1529 | ||
182446d0 TH |
1530 | static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft, |
1531 | u64 val) | |
700fe1ab | 1532 | { |
182446d0 | 1533 | struct cpuset *cs = css_cs(css); |
700fe1ab | 1534 | cpuset_filetype_t type = cft->private; |
a903f086 | 1535 | int retval = 0; |
700fe1ab | 1536 | |
5d21cc2d | 1537 | mutex_lock(&cpuset_mutex); |
a903f086 LZ |
1538 | if (!is_cpuset_online(cs)) { |
1539 | retval = -ENODEV; | |
5d21cc2d | 1540 | goto out_unlock; |
a903f086 | 1541 | } |
700fe1ab PM |
1542 | |
1543 | switch (type) { | |
1da177e4 | 1544 | case FILE_CPU_EXCLUSIVE: |
700fe1ab | 1545 | retval = update_flag(CS_CPU_EXCLUSIVE, cs, val); |
1da177e4 LT |
1546 | break; |
1547 | case FILE_MEM_EXCLUSIVE: | |
700fe1ab | 1548 | retval = update_flag(CS_MEM_EXCLUSIVE, cs, val); |
1da177e4 | 1549 | break; |
78608366 PM |
1550 | case FILE_MEM_HARDWALL: |
1551 | retval = update_flag(CS_MEM_HARDWALL, cs, val); | |
1552 | break; | |
029190c5 | 1553 | case FILE_SCHED_LOAD_BALANCE: |
700fe1ab | 1554 | retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, val); |
1d3504fc | 1555 | break; |
45b07ef3 | 1556 | case FILE_MEMORY_MIGRATE: |
700fe1ab | 1557 | retval = update_flag(CS_MEMORY_MIGRATE, cs, val); |
45b07ef3 | 1558 | break; |
3e0d98b9 | 1559 | case FILE_MEMORY_PRESSURE_ENABLED: |
700fe1ab | 1560 | cpuset_memory_pressure_enabled = !!val; |
3e0d98b9 PJ |
1561 | break; |
1562 | case FILE_MEMORY_PRESSURE: | |
1563 | retval = -EACCES; | |
1564 | break; | |
825a46af | 1565 | case FILE_SPREAD_PAGE: |
700fe1ab | 1566 | retval = update_flag(CS_SPREAD_PAGE, cs, val); |
825a46af PJ |
1567 | break; |
1568 | case FILE_SPREAD_SLAB: | |
700fe1ab | 1569 | retval = update_flag(CS_SPREAD_SLAB, cs, val); |
825a46af | 1570 | break; |
1da177e4 LT |
1571 | default: |
1572 | retval = -EINVAL; | |
700fe1ab | 1573 | break; |
1da177e4 | 1574 | } |
5d21cc2d TH |
1575 | out_unlock: |
1576 | mutex_unlock(&cpuset_mutex); | |
1da177e4 LT |
1577 | return retval; |
1578 | } | |
1579 | ||
182446d0 TH |
1580 | static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft, |
1581 | s64 val) | |
5be7a479 | 1582 | { |
182446d0 | 1583 | struct cpuset *cs = css_cs(css); |
5be7a479 | 1584 | cpuset_filetype_t type = cft->private; |
5d21cc2d | 1585 | int retval = -ENODEV; |
5be7a479 | 1586 | |
5d21cc2d TH |
1587 | mutex_lock(&cpuset_mutex); |
1588 | if (!is_cpuset_online(cs)) | |
1589 | goto out_unlock; | |
e3712395 | 1590 | |
5be7a479 PM |
1591 | switch (type) { |
1592 | case FILE_SCHED_RELAX_DOMAIN_LEVEL: | |
1593 | retval = update_relax_domain_level(cs, val); | |
1594 | break; | |
1595 | default: | |
1596 | retval = -EINVAL; | |
1597 | break; | |
1598 | } | |
5d21cc2d TH |
1599 | out_unlock: |
1600 | mutex_unlock(&cpuset_mutex); | |
5be7a479 PM |
1601 | return retval; |
1602 | } | |
1603 | ||
e3712395 PM |
1604 | /* |
1605 | * Common handling for a write to a "cpus" or "mems" file. | |
1606 | */ | |
451af504 TH |
1607 | static ssize_t cpuset_write_resmask(struct kernfs_open_file *of, |
1608 | char *buf, size_t nbytes, loff_t off) | |
e3712395 | 1609 | { |
451af504 | 1610 | struct cpuset *cs = css_cs(of_css(of)); |
645fcc9d | 1611 | struct cpuset *trialcs; |
5d21cc2d | 1612 | int retval = -ENODEV; |
e3712395 | 1613 | |
451af504 TH |
1614 | buf = strstrip(buf); |
1615 | ||
3a5a6d0c TH |
1616 | /* |
1617 | * CPU or memory hotunplug may leave @cs w/o any execution | |
1618 | * resources, in which case the hotplug code asynchronously updates | |
1619 | * configuration and transfers all tasks to the nearest ancestor | |
1620 | * which can execute. | |
1621 | * | |
1622 | * As writes to "cpus" or "mems" may restore @cs's execution | |
1623 | * resources, wait for the previously scheduled operations before | |
1624 | * proceeding, so that we don't end up keep removing tasks added | |
1625 | * after execution capability is restored. | |
76bb5ab8 TH |
1626 | * |
1627 | * cpuset_hotplug_work calls back into cgroup core via | |
1628 | * cgroup_transfer_tasks() and waiting for it from a cgroupfs | |
1629 | * operation like this one can lead to a deadlock through kernfs | |
1630 | * active_ref protection. Let's break the protection. Losing the | |
1631 | * protection is okay as we check whether @cs is online after | |
1632 | * grabbing cpuset_mutex anyway. This only happens on the legacy | |
1633 | * hierarchies. | |
3a5a6d0c | 1634 | */ |
76bb5ab8 TH |
1635 | css_get(&cs->css); |
1636 | kernfs_break_active_protection(of->kn); | |
3a5a6d0c TH |
1637 | flush_work(&cpuset_hotplug_work); |
1638 | ||
5d21cc2d TH |
1639 | mutex_lock(&cpuset_mutex); |
1640 | if (!is_cpuset_online(cs)) | |
1641 | goto out_unlock; | |
e3712395 | 1642 | |
645fcc9d | 1643 | trialcs = alloc_trial_cpuset(cs); |
b75f38d6 LZ |
1644 | if (!trialcs) { |
1645 | retval = -ENOMEM; | |
5d21cc2d | 1646 | goto out_unlock; |
b75f38d6 | 1647 | } |
645fcc9d | 1648 | |
451af504 | 1649 | switch (of_cft(of)->private) { |
e3712395 | 1650 | case FILE_CPULIST: |
645fcc9d | 1651 | retval = update_cpumask(cs, trialcs, buf); |
e3712395 PM |
1652 | break; |
1653 | case FILE_MEMLIST: | |
645fcc9d | 1654 | retval = update_nodemask(cs, trialcs, buf); |
e3712395 PM |
1655 | break; |
1656 | default: | |
1657 | retval = -EINVAL; | |
1658 | break; | |
1659 | } | |
645fcc9d LZ |
1660 | |
1661 | free_trial_cpuset(trialcs); | |
5d21cc2d TH |
1662 | out_unlock: |
1663 | mutex_unlock(&cpuset_mutex); | |
76bb5ab8 TH |
1664 | kernfs_unbreak_active_protection(of->kn); |
1665 | css_put(&cs->css); | |
451af504 | 1666 | return retval ?: nbytes; |
e3712395 PM |
1667 | } |
1668 | ||
1da177e4 LT |
1669 | /* |
1670 | * These ascii lists should be read in a single call, by using a user | |
1671 | * buffer large enough to hold the entire map. If read in smaller | |
1672 | * chunks, there is no guarantee of atomicity. Since the display format | |
1673 | * used, list of ranges of sequential numbers, is variable length, | |
1674 | * and since these maps can change value dynamically, one could read | |
1675 | * gibberish by doing partial reads while a list was changing. | |
1da177e4 | 1676 | */ |
2da8ca82 | 1677 | static int cpuset_common_seq_show(struct seq_file *sf, void *v) |
1da177e4 | 1678 | { |
2da8ca82 TH |
1679 | struct cpuset *cs = css_cs(seq_css(sf)); |
1680 | cpuset_filetype_t type = seq_cft(sf)->private; | |
51ffe411 TH |
1681 | ssize_t count; |
1682 | char *buf, *s; | |
1683 | int ret = 0; | |
1da177e4 | 1684 | |
51ffe411 TH |
1685 | count = seq_get_buf(sf, &buf); |
1686 | s = buf; | |
1da177e4 | 1687 | |
51ffe411 | 1688 | mutex_lock(&callback_mutex); |
1da177e4 LT |
1689 | |
1690 | switch (type) { | |
1691 | case FILE_CPULIST: | |
51ffe411 | 1692 | s += cpulist_scnprintf(s, count, cs->cpus_allowed); |
1da177e4 LT |
1693 | break; |
1694 | case FILE_MEMLIST: | |
51ffe411 | 1695 | s += nodelist_scnprintf(s, count, cs->mems_allowed); |
1da177e4 | 1696 | break; |
1da177e4 | 1697 | default: |
51ffe411 TH |
1698 | ret = -EINVAL; |
1699 | goto out_unlock; | |
1da177e4 | 1700 | } |
1da177e4 | 1701 | |
51ffe411 TH |
1702 | if (s < buf + count - 1) { |
1703 | *s++ = '\n'; | |
1704 | seq_commit(sf, s - buf); | |
1705 | } else { | |
1706 | seq_commit(sf, -1); | |
1707 | } | |
1708 | out_unlock: | |
1709 | mutex_unlock(&callback_mutex); | |
1710 | return ret; | |
1da177e4 LT |
1711 | } |
1712 | ||
182446d0 | 1713 | static u64 cpuset_read_u64(struct cgroup_subsys_state *css, struct cftype *cft) |
700fe1ab | 1714 | { |
182446d0 | 1715 | struct cpuset *cs = css_cs(css); |
700fe1ab PM |
1716 | cpuset_filetype_t type = cft->private; |
1717 | switch (type) { | |
1718 | case FILE_CPU_EXCLUSIVE: | |
1719 | return is_cpu_exclusive(cs); | |
1720 | case FILE_MEM_EXCLUSIVE: | |
1721 | return is_mem_exclusive(cs); | |
78608366 PM |
1722 | case FILE_MEM_HARDWALL: |
1723 | return is_mem_hardwall(cs); | |
700fe1ab PM |
1724 | case FILE_SCHED_LOAD_BALANCE: |
1725 | return is_sched_load_balance(cs); | |
1726 | case FILE_MEMORY_MIGRATE: | |
1727 | return is_memory_migrate(cs); | |
1728 | case FILE_MEMORY_PRESSURE_ENABLED: | |
1729 | return cpuset_memory_pressure_enabled; | |
1730 | case FILE_MEMORY_PRESSURE: | |
1731 | return fmeter_getrate(&cs->fmeter); | |
1732 | case FILE_SPREAD_PAGE: | |
1733 | return is_spread_page(cs); | |
1734 | case FILE_SPREAD_SLAB: | |
1735 | return is_spread_slab(cs); | |
1736 | default: | |
1737 | BUG(); | |
1738 | } | |
cf417141 MK |
1739 | |
1740 | /* Unreachable but makes gcc happy */ | |
1741 | return 0; | |
700fe1ab | 1742 | } |
1da177e4 | 1743 | |
182446d0 | 1744 | static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft) |
5be7a479 | 1745 | { |
182446d0 | 1746 | struct cpuset *cs = css_cs(css); |
5be7a479 PM |
1747 | cpuset_filetype_t type = cft->private; |
1748 | switch (type) { | |
1749 | case FILE_SCHED_RELAX_DOMAIN_LEVEL: | |
1750 | return cs->relax_domain_level; | |
1751 | default: | |
1752 | BUG(); | |
1753 | } | |
cf417141 MK |
1754 | |
1755 | /* Unrechable but makes gcc happy */ | |
1756 | return 0; | |
5be7a479 PM |
1757 | } |
1758 | ||
1da177e4 LT |
1759 | |
1760 | /* | |
1761 | * for the common functions, 'private' gives the type of file | |
1762 | */ | |
1763 | ||
addf2c73 PM |
1764 | static struct cftype files[] = { |
1765 | { | |
1766 | .name = "cpus", | |
2da8ca82 | 1767 | .seq_show = cpuset_common_seq_show, |
451af504 | 1768 | .write = cpuset_write_resmask, |
e3712395 | 1769 | .max_write_len = (100U + 6 * NR_CPUS), |
addf2c73 PM |
1770 | .private = FILE_CPULIST, |
1771 | }, | |
1772 | ||
1773 | { | |
1774 | .name = "mems", | |
2da8ca82 | 1775 | .seq_show = cpuset_common_seq_show, |
451af504 | 1776 | .write = cpuset_write_resmask, |
e3712395 | 1777 | .max_write_len = (100U + 6 * MAX_NUMNODES), |
addf2c73 PM |
1778 | .private = FILE_MEMLIST, |
1779 | }, | |
1780 | ||
1781 | { | |
1782 | .name = "cpu_exclusive", | |
1783 | .read_u64 = cpuset_read_u64, | |
1784 | .write_u64 = cpuset_write_u64, | |
1785 | .private = FILE_CPU_EXCLUSIVE, | |
1786 | }, | |
1787 | ||
1788 | { | |
1789 | .name = "mem_exclusive", | |
1790 | .read_u64 = cpuset_read_u64, | |
1791 | .write_u64 = cpuset_write_u64, | |
1792 | .private = FILE_MEM_EXCLUSIVE, | |
1793 | }, | |
1794 | ||
78608366 PM |
1795 | { |
1796 | .name = "mem_hardwall", | |
1797 | .read_u64 = cpuset_read_u64, | |
1798 | .write_u64 = cpuset_write_u64, | |
1799 | .private = FILE_MEM_HARDWALL, | |
1800 | }, | |
1801 | ||
addf2c73 PM |
1802 | { |
1803 | .name = "sched_load_balance", | |
1804 | .read_u64 = cpuset_read_u64, | |
1805 | .write_u64 = cpuset_write_u64, | |
1806 | .private = FILE_SCHED_LOAD_BALANCE, | |
1807 | }, | |
1808 | ||
1809 | { | |
1810 | .name = "sched_relax_domain_level", | |
5be7a479 PM |
1811 | .read_s64 = cpuset_read_s64, |
1812 | .write_s64 = cpuset_write_s64, | |
addf2c73 PM |
1813 | .private = FILE_SCHED_RELAX_DOMAIN_LEVEL, |
1814 | }, | |
1815 | ||
1816 | { | |
1817 | .name = "memory_migrate", | |
1818 | .read_u64 = cpuset_read_u64, | |
1819 | .write_u64 = cpuset_write_u64, | |
1820 | .private = FILE_MEMORY_MIGRATE, | |
1821 | }, | |
1822 | ||
1823 | { | |
1824 | .name = "memory_pressure", | |
1825 | .read_u64 = cpuset_read_u64, | |
1826 | .write_u64 = cpuset_write_u64, | |
1827 | .private = FILE_MEMORY_PRESSURE, | |
099fca32 | 1828 | .mode = S_IRUGO, |
addf2c73 PM |
1829 | }, |
1830 | ||
1831 | { | |
1832 | .name = "memory_spread_page", | |
1833 | .read_u64 = cpuset_read_u64, | |
1834 | .write_u64 = cpuset_write_u64, | |
1835 | .private = FILE_SPREAD_PAGE, | |
1836 | }, | |
1837 | ||
1838 | { | |
1839 | .name = "memory_spread_slab", | |
1840 | .read_u64 = cpuset_read_u64, | |
1841 | .write_u64 = cpuset_write_u64, | |
1842 | .private = FILE_SPREAD_SLAB, | |
1843 | }, | |
3e0d98b9 | 1844 | |
4baf6e33 TH |
1845 | { |
1846 | .name = "memory_pressure_enabled", | |
1847 | .flags = CFTYPE_ONLY_ON_ROOT, | |
1848 | .read_u64 = cpuset_read_u64, | |
1849 | .write_u64 = cpuset_write_u64, | |
1850 | .private = FILE_MEMORY_PRESSURE_ENABLED, | |
1851 | }, | |
1da177e4 | 1852 | |
4baf6e33 TH |
1853 | { } /* terminate */ |
1854 | }; | |
1da177e4 LT |
1855 | |
1856 | /* | |
92fb9748 | 1857 | * cpuset_css_alloc - allocate a cpuset css |
c9e5fe66 | 1858 | * cgrp: control group that the new cpuset will be part of |
1da177e4 LT |
1859 | */ |
1860 | ||
eb95419b TH |
1861 | static struct cgroup_subsys_state * |
1862 | cpuset_css_alloc(struct cgroup_subsys_state *parent_css) | |
1da177e4 | 1863 | { |
c8f699bb | 1864 | struct cpuset *cs; |
1da177e4 | 1865 | |
eb95419b | 1866 | if (!parent_css) |
8793d854 | 1867 | return &top_cpuset.css; |
033fa1c5 | 1868 | |
c8f699bb | 1869 | cs = kzalloc(sizeof(*cs), GFP_KERNEL); |
1da177e4 | 1870 | if (!cs) |
8793d854 | 1871 | return ERR_PTR(-ENOMEM); |
300ed6cb LZ |
1872 | if (!alloc_cpumask_var(&cs->cpus_allowed, GFP_KERNEL)) { |
1873 | kfree(cs); | |
1874 | return ERR_PTR(-ENOMEM); | |
1875 | } | |
1da177e4 | 1876 | |
029190c5 | 1877 | set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); |
300ed6cb | 1878 | cpumask_clear(cs->cpus_allowed); |
f9a86fcb | 1879 | nodes_clear(cs->mems_allowed); |
3e0d98b9 | 1880 | fmeter_init(&cs->fmeter); |
1d3504fc | 1881 | cs->relax_domain_level = -1; |
1da177e4 | 1882 | |
c8f699bb TH |
1883 | return &cs->css; |
1884 | } | |
1885 | ||
eb95419b | 1886 | static int cpuset_css_online(struct cgroup_subsys_state *css) |
c8f699bb | 1887 | { |
eb95419b | 1888 | struct cpuset *cs = css_cs(css); |
c431069f | 1889 | struct cpuset *parent = parent_cs(cs); |
ae8086ce | 1890 | struct cpuset *tmp_cs; |
492eb21b | 1891 | struct cgroup_subsys_state *pos_css; |
c8f699bb TH |
1892 | |
1893 | if (!parent) | |
1894 | return 0; | |
1895 | ||
5d21cc2d TH |
1896 | mutex_lock(&cpuset_mutex); |
1897 | ||
efeb77b2 | 1898 | set_bit(CS_ONLINE, &cs->flags); |
c8f699bb TH |
1899 | if (is_spread_page(parent)) |
1900 | set_bit(CS_SPREAD_PAGE, &cs->flags); | |
1901 | if (is_spread_slab(parent)) | |
1902 | set_bit(CS_SPREAD_SLAB, &cs->flags); | |
1da177e4 | 1903 | |
664eedde | 1904 | cpuset_inc(); |
033fa1c5 | 1905 | |
eb95419b | 1906 | if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags)) |
5d21cc2d | 1907 | goto out_unlock; |
033fa1c5 TH |
1908 | |
1909 | /* | |
1910 | * Clone @parent's configuration if CGRP_CPUSET_CLONE_CHILDREN is | |
1911 | * set. This flag handling is implemented in cgroup core for | |
1912 | * histrical reasons - the flag may be specified during mount. | |
1913 | * | |
1914 | * Currently, if any sibling cpusets have exclusive cpus or mem, we | |
1915 | * refuse to clone the configuration - thereby refusing the task to | |
1916 | * be entered, and as a result refusing the sys_unshare() or | |
1917 | * clone() which initiated it. If this becomes a problem for some | |
1918 | * users who wish to allow that scenario, then this could be | |
1919 | * changed to grant parent->cpus_allowed-sibling_cpus_exclusive | |
1920 | * (and likewise for mems) to the new cgroup. | |
1921 | */ | |
ae8086ce | 1922 | rcu_read_lock(); |
492eb21b | 1923 | cpuset_for_each_child(tmp_cs, pos_css, parent) { |
ae8086ce TH |
1924 | if (is_mem_exclusive(tmp_cs) || is_cpu_exclusive(tmp_cs)) { |
1925 | rcu_read_unlock(); | |
5d21cc2d | 1926 | goto out_unlock; |
ae8086ce | 1927 | } |
033fa1c5 | 1928 | } |
ae8086ce | 1929 | rcu_read_unlock(); |
033fa1c5 TH |
1930 | |
1931 | mutex_lock(&callback_mutex); | |
1932 | cs->mems_allowed = parent->mems_allowed; | |
1933 | cpumask_copy(cs->cpus_allowed, parent->cpus_allowed); | |
1934 | mutex_unlock(&callback_mutex); | |
5d21cc2d TH |
1935 | out_unlock: |
1936 | mutex_unlock(&cpuset_mutex); | |
c8f699bb TH |
1937 | return 0; |
1938 | } | |
1939 | ||
0b9e6965 ZH |
1940 | /* |
1941 | * If the cpuset being removed has its flag 'sched_load_balance' | |
1942 | * enabled, then simulate turning sched_load_balance off, which | |
1943 | * will call rebuild_sched_domains_locked(). | |
1944 | */ | |
1945 | ||
eb95419b | 1946 | static void cpuset_css_offline(struct cgroup_subsys_state *css) |
c8f699bb | 1947 | { |
eb95419b | 1948 | struct cpuset *cs = css_cs(css); |
c8f699bb | 1949 | |
5d21cc2d | 1950 | mutex_lock(&cpuset_mutex); |
c8f699bb TH |
1951 | |
1952 | if (is_sched_load_balance(cs)) | |
1953 | update_flag(CS_SCHED_LOAD_BALANCE, cs, 0); | |
1954 | ||
664eedde | 1955 | cpuset_dec(); |
efeb77b2 | 1956 | clear_bit(CS_ONLINE, &cs->flags); |
c8f699bb | 1957 | |
5d21cc2d | 1958 | mutex_unlock(&cpuset_mutex); |
1da177e4 LT |
1959 | } |
1960 | ||
eb95419b | 1961 | static void cpuset_css_free(struct cgroup_subsys_state *css) |
1da177e4 | 1962 | { |
eb95419b | 1963 | struct cpuset *cs = css_cs(css); |
1da177e4 | 1964 | |
300ed6cb | 1965 | free_cpumask_var(cs->cpus_allowed); |
8793d854 | 1966 | kfree(cs); |
1da177e4 LT |
1967 | } |
1968 | ||
073219e9 | 1969 | struct cgroup_subsys cpuset_cgrp_subsys = { |
92fb9748 | 1970 | .css_alloc = cpuset_css_alloc, |
c8f699bb TH |
1971 | .css_online = cpuset_css_online, |
1972 | .css_offline = cpuset_css_offline, | |
92fb9748 | 1973 | .css_free = cpuset_css_free, |
8793d854 | 1974 | .can_attach = cpuset_can_attach, |
452477fa | 1975 | .cancel_attach = cpuset_cancel_attach, |
8793d854 | 1976 | .attach = cpuset_attach, |
4baf6e33 | 1977 | .base_cftypes = files, |
8793d854 PM |
1978 | .early_init = 1, |
1979 | }; | |
1980 | ||
1da177e4 LT |
1981 | /** |
1982 | * cpuset_init - initialize cpusets at system boot | |
1983 | * | |
1984 | * Description: Initialize top_cpuset and the cpuset internal file system, | |
1985 | **/ | |
1986 | ||
1987 | int __init cpuset_init(void) | |
1988 | { | |
8793d854 | 1989 | int err = 0; |
1da177e4 | 1990 | |
58568d2a MX |
1991 | if (!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL)) |
1992 | BUG(); | |
1993 | ||
300ed6cb | 1994 | cpumask_setall(top_cpuset.cpus_allowed); |
f9a86fcb | 1995 | nodes_setall(top_cpuset.mems_allowed); |
1da177e4 | 1996 | |
3e0d98b9 | 1997 | fmeter_init(&top_cpuset.fmeter); |
029190c5 | 1998 | set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags); |
1d3504fc | 1999 | top_cpuset.relax_domain_level = -1; |
1da177e4 | 2000 | |
1da177e4 LT |
2001 | err = register_filesystem(&cpuset_fs_type); |
2002 | if (err < 0) | |
8793d854 PM |
2003 | return err; |
2004 | ||
2341d1b6 LZ |
2005 | if (!alloc_cpumask_var(&cpus_attach, GFP_KERNEL)) |
2006 | BUG(); | |
2007 | ||
8793d854 | 2008 | return 0; |
1da177e4 LT |
2009 | } |
2010 | ||
b1aac8bb | 2011 | /* |
cf417141 | 2012 | * If CPU and/or memory hotplug handlers, below, unplug any CPUs |
b1aac8bb PJ |
2013 | * or memory nodes, we need to walk over the cpuset hierarchy, |
2014 | * removing that CPU or node from all cpusets. If this removes the | |
956db3ca CW |
2015 | * last CPU or node from a cpuset, then move the tasks in the empty |
2016 | * cpuset to its next-highest non-empty parent. | |
b1aac8bb | 2017 | */ |
956db3ca CW |
2018 | static void remove_tasks_in_empty_cpuset(struct cpuset *cs) |
2019 | { | |
2020 | struct cpuset *parent; | |
2021 | ||
956db3ca CW |
2022 | /* |
2023 | * Find its next-highest non-empty parent, (top cpuset | |
2024 | * has online cpus, so can't be empty). | |
2025 | */ | |
c431069f | 2026 | parent = parent_cs(cs); |
300ed6cb | 2027 | while (cpumask_empty(parent->cpus_allowed) || |
b4501295 | 2028 | nodes_empty(parent->mems_allowed)) |
c431069f | 2029 | parent = parent_cs(parent); |
956db3ca | 2030 | |
8cc99345 | 2031 | if (cgroup_transfer_tasks(parent->css.cgroup, cs->css.cgroup)) { |
12d3089c | 2032 | pr_err("cpuset: failed to transfer tasks out of empty cpuset "); |
e61734c5 TH |
2033 | pr_cont_cgroup_name(cs->css.cgroup); |
2034 | pr_cont("\n"); | |
8cc99345 | 2035 | } |
956db3ca CW |
2036 | } |
2037 | ||
deb7aa30 | 2038 | /** |
388afd85 | 2039 | * cpuset_hotplug_update_tasks - update tasks in a cpuset for hotunplug |
deb7aa30 | 2040 | * @cs: cpuset in interest |
956db3ca | 2041 | * |
deb7aa30 TH |
2042 | * Compare @cs's cpu and mem masks against top_cpuset and if some have gone |
2043 | * offline, update @cs accordingly. If @cs ends up with no CPU or memory, | |
2044 | * all its tasks are moved to the nearest ancestor with both resources. | |
80d1fa64 | 2045 | */ |
388afd85 | 2046 | static void cpuset_hotplug_update_tasks(struct cpuset *cs) |
80d1fa64 | 2047 | { |
deb7aa30 | 2048 | static cpumask_t off_cpus; |
33ad801d | 2049 | static nodemask_t off_mems; |
5d21cc2d | 2050 | bool is_empty; |
5c5cc623 | 2051 | bool sane = cgroup_sane_behavior(cs->css.cgroup); |
80d1fa64 | 2052 | |
e44193d3 LZ |
2053 | retry: |
2054 | wait_event(cpuset_attach_wq, cs->attach_in_progress == 0); | |
80d1fa64 | 2055 | |
5d21cc2d | 2056 | mutex_lock(&cpuset_mutex); |
7ddf96b0 | 2057 | |
e44193d3 LZ |
2058 | /* |
2059 | * We have raced with task attaching. We wait until attaching | |
2060 | * is finished, so we won't attach a task to an empty cpuset. | |
2061 | */ | |
2062 | if (cs->attach_in_progress) { | |
2063 | mutex_unlock(&cpuset_mutex); | |
2064 | goto retry; | |
2065 | } | |
2066 | ||
deb7aa30 TH |
2067 | cpumask_andnot(&off_cpus, cs->cpus_allowed, top_cpuset.cpus_allowed); |
2068 | nodes_andnot(off_mems, cs->mems_allowed, top_cpuset.mems_allowed); | |
80d1fa64 | 2069 | |
5c5cc623 LZ |
2070 | mutex_lock(&callback_mutex); |
2071 | cpumask_andnot(cs->cpus_allowed, cs->cpus_allowed, &off_cpus); | |
2072 | mutex_unlock(&callback_mutex); | |
2073 | ||
2074 | /* | |
2075 | * If sane_behavior flag is set, we need to update tasks' cpumask | |
f047cecf LZ |
2076 | * for empty cpuset to take on ancestor's cpumask. Otherwise, don't |
2077 | * call update_tasks_cpumask() if the cpuset becomes empty, as | |
2078 | * the tasks in it will be migrated to an ancestor. | |
5c5cc623 LZ |
2079 | */ |
2080 | if ((sane && cpumask_empty(cs->cpus_allowed)) || | |
f047cecf | 2081 | (!cpumask_empty(&off_cpus) && !cpumask_empty(cs->cpus_allowed))) |
d66393e5 | 2082 | update_tasks_cpumask(cs); |
80d1fa64 | 2083 | |
5c5cc623 LZ |
2084 | mutex_lock(&callback_mutex); |
2085 | nodes_andnot(cs->mems_allowed, cs->mems_allowed, off_mems); | |
2086 | mutex_unlock(&callback_mutex); | |
2087 | ||
2088 | /* | |
2089 | * If sane_behavior flag is set, we need to update tasks' nodemask | |
f047cecf LZ |
2090 | * for empty cpuset to take on ancestor's nodemask. Otherwise, don't |
2091 | * call update_tasks_nodemask() if the cpuset becomes empty, as | |
2092 | * the tasks in it will be migratd to an ancestor. | |
5c5cc623 LZ |
2093 | */ |
2094 | if ((sane && nodes_empty(cs->mems_allowed)) || | |
f047cecf | 2095 | (!nodes_empty(off_mems) && !nodes_empty(cs->mems_allowed))) |
d66393e5 | 2096 | update_tasks_nodemask(cs); |
deb7aa30 | 2097 | |
5d21cc2d TH |
2098 | is_empty = cpumask_empty(cs->cpus_allowed) || |
2099 | nodes_empty(cs->mems_allowed); | |
8d033948 | 2100 | |
5d21cc2d TH |
2101 | mutex_unlock(&cpuset_mutex); |
2102 | ||
2103 | /* | |
5c5cc623 LZ |
2104 | * If sane_behavior flag is set, we'll keep tasks in empty cpusets. |
2105 | * | |
2106 | * Otherwise move tasks to the nearest ancestor with execution | |
2107 | * resources. This is full cgroup operation which will | |
5d21cc2d TH |
2108 | * also call back into cpuset. Should be done outside any lock. |
2109 | */ | |
5c5cc623 | 2110 | if (!sane && is_empty) |
5d21cc2d | 2111 | remove_tasks_in_empty_cpuset(cs); |
b1aac8bb PJ |
2112 | } |
2113 | ||
deb7aa30 | 2114 | /** |
3a5a6d0c | 2115 | * cpuset_hotplug_workfn - handle CPU/memory hotunplug for a cpuset |
956db3ca | 2116 | * |
deb7aa30 TH |
2117 | * This function is called after either CPU or memory configuration has |
2118 | * changed and updates cpuset accordingly. The top_cpuset is always | |
2119 | * synchronized to cpu_active_mask and N_MEMORY, which is necessary in | |
2120 | * order to make cpusets transparent (of no affect) on systems that are | |
2121 | * actively using CPU hotplug but making no active use of cpusets. | |
956db3ca | 2122 | * |
deb7aa30 | 2123 | * Non-root cpusets are only affected by offlining. If any CPUs or memory |
388afd85 LZ |
2124 | * nodes have been taken down, cpuset_hotplug_update_tasks() is invoked on |
2125 | * all descendants. | |
956db3ca | 2126 | * |
deb7aa30 TH |
2127 | * Note that CPU offlining during suspend is ignored. We don't modify |
2128 | * cpusets across suspend/resume cycles at all. | |
956db3ca | 2129 | */ |
3a5a6d0c | 2130 | static void cpuset_hotplug_workfn(struct work_struct *work) |
b1aac8bb | 2131 | { |
5c5cc623 LZ |
2132 | static cpumask_t new_cpus; |
2133 | static nodemask_t new_mems; | |
deb7aa30 | 2134 | bool cpus_updated, mems_updated; |
b1aac8bb | 2135 | |
5d21cc2d | 2136 | mutex_lock(&cpuset_mutex); |
956db3ca | 2137 | |
deb7aa30 TH |
2138 | /* fetch the available cpus/mems and find out which changed how */ |
2139 | cpumask_copy(&new_cpus, cpu_active_mask); | |
2140 | new_mems = node_states[N_MEMORY]; | |
7ddf96b0 | 2141 | |
deb7aa30 | 2142 | cpus_updated = !cpumask_equal(top_cpuset.cpus_allowed, &new_cpus); |
deb7aa30 | 2143 | mems_updated = !nodes_equal(top_cpuset.mems_allowed, new_mems); |
7ddf96b0 | 2144 | |
deb7aa30 TH |
2145 | /* synchronize cpus_allowed to cpu_active_mask */ |
2146 | if (cpus_updated) { | |
2147 | mutex_lock(&callback_mutex); | |
2148 | cpumask_copy(top_cpuset.cpus_allowed, &new_cpus); | |
2149 | mutex_unlock(&callback_mutex); | |
2150 | /* we don't mess with cpumasks of tasks in top_cpuset */ | |
2151 | } | |
b4501295 | 2152 | |
deb7aa30 TH |
2153 | /* synchronize mems_allowed to N_MEMORY */ |
2154 | if (mems_updated) { | |
deb7aa30 TH |
2155 | mutex_lock(&callback_mutex); |
2156 | top_cpuset.mems_allowed = new_mems; | |
2157 | mutex_unlock(&callback_mutex); | |
d66393e5 | 2158 | update_tasks_nodemask(&top_cpuset); |
deb7aa30 | 2159 | } |
b4501295 | 2160 | |
388afd85 LZ |
2161 | mutex_unlock(&cpuset_mutex); |
2162 | ||
5c5cc623 LZ |
2163 | /* if cpus or mems changed, we need to propagate to descendants */ |
2164 | if (cpus_updated || mems_updated) { | |
deb7aa30 | 2165 | struct cpuset *cs; |
492eb21b | 2166 | struct cgroup_subsys_state *pos_css; |
f9b4fb8d | 2167 | |
fc560a26 | 2168 | rcu_read_lock(); |
492eb21b | 2169 | cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) { |
ec903c0c | 2170 | if (cs == &top_cpuset || !css_tryget_online(&cs->css)) |
388afd85 LZ |
2171 | continue; |
2172 | rcu_read_unlock(); | |
7ddf96b0 | 2173 | |
388afd85 | 2174 | cpuset_hotplug_update_tasks(cs); |
b4501295 | 2175 | |
388afd85 LZ |
2176 | rcu_read_lock(); |
2177 | css_put(&cs->css); | |
2178 | } | |
2179 | rcu_read_unlock(); | |
2180 | } | |
8d033948 | 2181 | |
deb7aa30 | 2182 | /* rebuild sched domains if cpus_allowed has changed */ |
e0e80a02 LZ |
2183 | if (cpus_updated) |
2184 | rebuild_sched_domains(); | |
b1aac8bb PJ |
2185 | } |
2186 | ||
7ddf96b0 | 2187 | void cpuset_update_active_cpus(bool cpu_online) |
4c4d50f7 | 2188 | { |
3a5a6d0c TH |
2189 | /* |
2190 | * We're inside cpu hotplug critical region which usually nests | |
2191 | * inside cgroup synchronization. Bounce actual hotplug processing | |
2192 | * to a work item to avoid reverse locking order. | |
2193 | * | |
2194 | * We still need to do partition_sched_domains() synchronously; | |
2195 | * otherwise, the scheduler will get confused and put tasks to the | |
2196 | * dead CPU. Fall back to the default single domain. | |
2197 | * cpuset_hotplug_workfn() will rebuild it as necessary. | |
2198 | */ | |
2199 | partition_sched_domains(1, NULL, NULL); | |
2200 | schedule_work(&cpuset_hotplug_work); | |
4c4d50f7 | 2201 | } |
4c4d50f7 | 2202 | |
38837fc7 | 2203 | /* |
38d7bee9 LJ |
2204 | * Keep top_cpuset.mems_allowed tracking node_states[N_MEMORY]. |
2205 | * Call this routine anytime after node_states[N_MEMORY] changes. | |
a1cd2b13 | 2206 | * See cpuset_update_active_cpus() for CPU hotplug handling. |
38837fc7 | 2207 | */ |
f481891f MX |
2208 | static int cpuset_track_online_nodes(struct notifier_block *self, |
2209 | unsigned long action, void *arg) | |
38837fc7 | 2210 | { |
3a5a6d0c | 2211 | schedule_work(&cpuset_hotplug_work); |
f481891f | 2212 | return NOTIFY_OK; |
38837fc7 | 2213 | } |
d8f10cb3 AM |
2214 | |
2215 | static struct notifier_block cpuset_track_online_nodes_nb = { | |
2216 | .notifier_call = cpuset_track_online_nodes, | |
2217 | .priority = 10, /* ??! */ | |
2218 | }; | |
38837fc7 | 2219 | |
1da177e4 LT |
2220 | /** |
2221 | * cpuset_init_smp - initialize cpus_allowed | |
2222 | * | |
2223 | * Description: Finish top cpuset after cpu, node maps are initialized | |
d8f10cb3 | 2224 | */ |
1da177e4 LT |
2225 | void __init cpuset_init_smp(void) |
2226 | { | |
6ad4c188 | 2227 | cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask); |
38d7bee9 | 2228 | top_cpuset.mems_allowed = node_states[N_MEMORY]; |
33ad801d | 2229 | top_cpuset.old_mems_allowed = top_cpuset.mems_allowed; |
4c4d50f7 | 2230 | |
d8f10cb3 | 2231 | register_hotmemory_notifier(&cpuset_track_online_nodes_nb); |
1da177e4 LT |
2232 | } |
2233 | ||
2234 | /** | |
1da177e4 LT |
2235 | * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset. |
2236 | * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed. | |
6af866af | 2237 | * @pmask: pointer to struct cpumask variable to receive cpus_allowed set. |
1da177e4 | 2238 | * |
300ed6cb | 2239 | * Description: Returns the cpumask_var_t cpus_allowed of the cpuset |
1da177e4 | 2240 | * attached to the specified @tsk. Guaranteed to return some non-empty |
5f054e31 | 2241 | * subset of cpu_online_mask, even if this means going outside the |
1da177e4 LT |
2242 | * tasks cpuset. |
2243 | **/ | |
2244 | ||
6af866af | 2245 | void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask) |
1da177e4 | 2246 | { |
070b57fc LZ |
2247 | struct cpuset *cpus_cs; |
2248 | ||
3d3f26a7 | 2249 | mutex_lock(&callback_mutex); |
b8dadcb5 | 2250 | rcu_read_lock(); |
070b57fc LZ |
2251 | cpus_cs = effective_cpumask_cpuset(task_cs(tsk)); |
2252 | guarantee_online_cpus(cpus_cs, pmask); | |
b8dadcb5 | 2253 | rcu_read_unlock(); |
897f0b3c | 2254 | mutex_unlock(&callback_mutex); |
1da177e4 LT |
2255 | } |
2256 | ||
2baab4e9 | 2257 | void cpuset_cpus_allowed_fallback(struct task_struct *tsk) |
9084bb82 | 2258 | { |
c9710d80 | 2259 | struct cpuset *cpus_cs; |
9084bb82 ON |
2260 | |
2261 | rcu_read_lock(); | |
070b57fc LZ |
2262 | cpus_cs = effective_cpumask_cpuset(task_cs(tsk)); |
2263 | do_set_cpus_allowed(tsk, cpus_cs->cpus_allowed); | |
9084bb82 ON |
2264 | rcu_read_unlock(); |
2265 | ||
2266 | /* | |
2267 | * We own tsk->cpus_allowed, nobody can change it under us. | |
2268 | * | |
2269 | * But we used cs && cs->cpus_allowed lockless and thus can | |
2270 | * race with cgroup_attach_task() or update_cpumask() and get | |
2271 | * the wrong tsk->cpus_allowed. However, both cases imply the | |
2272 | * subsequent cpuset_change_cpumask()->set_cpus_allowed_ptr() | |
2273 | * which takes task_rq_lock(). | |
2274 | * | |
2275 | * If we are called after it dropped the lock we must see all | |
2276 | * changes in tsk_cs()->cpus_allowed. Otherwise we can temporary | |
2277 | * set any mask even if it is not right from task_cs() pov, | |
2278 | * the pending set_cpus_allowed_ptr() will fix things. | |
2baab4e9 PZ |
2279 | * |
2280 | * select_fallback_rq() will fix things ups and set cpu_possible_mask | |
2281 | * if required. | |
9084bb82 | 2282 | */ |
9084bb82 ON |
2283 | } |
2284 | ||
1da177e4 LT |
2285 | void cpuset_init_current_mems_allowed(void) |
2286 | { | |
f9a86fcb | 2287 | nodes_setall(current->mems_allowed); |
1da177e4 LT |
2288 | } |
2289 | ||
909d75a3 PJ |
2290 | /** |
2291 | * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset. | |
2292 | * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed. | |
2293 | * | |
2294 | * Description: Returns the nodemask_t mems_allowed of the cpuset | |
2295 | * attached to the specified @tsk. Guaranteed to return some non-empty | |
38d7bee9 | 2296 | * subset of node_states[N_MEMORY], even if this means going outside the |
909d75a3 PJ |
2297 | * tasks cpuset. |
2298 | **/ | |
2299 | ||
2300 | nodemask_t cpuset_mems_allowed(struct task_struct *tsk) | |
2301 | { | |
070b57fc | 2302 | struct cpuset *mems_cs; |
909d75a3 PJ |
2303 | nodemask_t mask; |
2304 | ||
3d3f26a7 | 2305 | mutex_lock(&callback_mutex); |
b8dadcb5 | 2306 | rcu_read_lock(); |
070b57fc LZ |
2307 | mems_cs = effective_nodemask_cpuset(task_cs(tsk)); |
2308 | guarantee_online_mems(mems_cs, &mask); | |
b8dadcb5 | 2309 | rcu_read_unlock(); |
3d3f26a7 | 2310 | mutex_unlock(&callback_mutex); |
909d75a3 PJ |
2311 | |
2312 | return mask; | |
2313 | } | |
2314 | ||
d9fd8a6d | 2315 | /** |
19770b32 MG |
2316 | * cpuset_nodemask_valid_mems_allowed - check nodemask vs. curremt mems_allowed |
2317 | * @nodemask: the nodemask to be checked | |
d9fd8a6d | 2318 | * |
19770b32 | 2319 | * Are any of the nodes in the nodemask allowed in current->mems_allowed? |
1da177e4 | 2320 | */ |
19770b32 | 2321 | int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask) |
1da177e4 | 2322 | { |
19770b32 | 2323 | return nodes_intersects(*nodemask, current->mems_allowed); |
1da177e4 LT |
2324 | } |
2325 | ||
9bf2229f | 2326 | /* |
78608366 PM |
2327 | * nearest_hardwall_ancestor() - Returns the nearest mem_exclusive or |
2328 | * mem_hardwall ancestor to the specified cpuset. Call holding | |
2329 | * callback_mutex. If no ancestor is mem_exclusive or mem_hardwall | |
2330 | * (an unusual configuration), then returns the root cpuset. | |
9bf2229f | 2331 | */ |
c9710d80 | 2332 | static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs) |
9bf2229f | 2333 | { |
c431069f TH |
2334 | while (!(is_mem_exclusive(cs) || is_mem_hardwall(cs)) && parent_cs(cs)) |
2335 | cs = parent_cs(cs); | |
9bf2229f PJ |
2336 | return cs; |
2337 | } | |
2338 | ||
d9fd8a6d | 2339 | /** |
a1bc5a4e DR |
2340 | * cpuset_node_allowed_softwall - Can we allocate on a memory node? |
2341 | * @node: is this an allowed node? | |
02a0e53d | 2342 | * @gfp_mask: memory allocation flags |
d9fd8a6d | 2343 | * |
a1bc5a4e DR |
2344 | * If we're in interrupt, yes, we can always allocate. If __GFP_THISNODE is |
2345 | * set, yes, we can always allocate. If node is in our task's mems_allowed, | |
2346 | * yes. If it's not a __GFP_HARDWALL request and this node is in the nearest | |
2347 | * hardwalled cpuset ancestor to this task's cpuset, yes. If the task has been | |
2348 | * OOM killed and has access to memory reserves as specified by the TIF_MEMDIE | |
2349 | * flag, yes. | |
9bf2229f PJ |
2350 | * Otherwise, no. |
2351 | * | |
a1bc5a4e DR |
2352 | * If __GFP_HARDWALL is set, cpuset_node_allowed_softwall() reduces to |
2353 | * cpuset_node_allowed_hardwall(). Otherwise, cpuset_node_allowed_softwall() | |
2354 | * might sleep, and might allow a node from an enclosing cpuset. | |
02a0e53d | 2355 | * |
a1bc5a4e DR |
2356 | * cpuset_node_allowed_hardwall() only handles the simpler case of hardwall |
2357 | * cpusets, and never sleeps. | |
02a0e53d PJ |
2358 | * |
2359 | * The __GFP_THISNODE placement logic is really handled elsewhere, | |
2360 | * by forcibly using a zonelist starting at a specified node, and by | |
2361 | * (in get_page_from_freelist()) refusing to consider the zones for | |
2362 | * any node on the zonelist except the first. By the time any such | |
2363 | * calls get to this routine, we should just shut up and say 'yes'. | |
2364 | * | |
9bf2229f | 2365 | * GFP_USER allocations are marked with the __GFP_HARDWALL bit, |
c596d9f3 DR |
2366 | * and do not allow allocations outside the current tasks cpuset |
2367 | * unless the task has been OOM killed as is marked TIF_MEMDIE. | |
9bf2229f | 2368 | * GFP_KERNEL allocations are not so marked, so can escape to the |
78608366 | 2369 | * nearest enclosing hardwalled ancestor cpuset. |
9bf2229f | 2370 | * |
02a0e53d PJ |
2371 | * Scanning up parent cpusets requires callback_mutex. The |
2372 | * __alloc_pages() routine only calls here with __GFP_HARDWALL bit | |
2373 | * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the | |
2374 | * current tasks mems_allowed came up empty on the first pass over | |
2375 | * the zonelist. So only GFP_KERNEL allocations, if all nodes in the | |
2376 | * cpuset are short of memory, might require taking the callback_mutex | |
2377 | * mutex. | |
9bf2229f | 2378 | * |
36be57ff | 2379 | * The first call here from mm/page_alloc:get_page_from_freelist() |
02a0e53d PJ |
2380 | * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets, |
2381 | * so no allocation on a node outside the cpuset is allowed (unless | |
2382 | * in interrupt, of course). | |
36be57ff PJ |
2383 | * |
2384 | * The second pass through get_page_from_freelist() doesn't even call | |
2385 | * here for GFP_ATOMIC calls. For those calls, the __alloc_pages() | |
2386 | * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set | |
2387 | * in alloc_flags. That logic and the checks below have the combined | |
2388 | * affect that: | |
9bf2229f PJ |
2389 | * in_interrupt - any node ok (current task context irrelevant) |
2390 | * GFP_ATOMIC - any node ok | |
c596d9f3 | 2391 | * TIF_MEMDIE - any node ok |
78608366 | 2392 | * GFP_KERNEL - any node in enclosing hardwalled cpuset ok |
9bf2229f | 2393 | * GFP_USER - only nodes in current tasks mems allowed ok. |
36be57ff PJ |
2394 | * |
2395 | * Rule: | |
a1bc5a4e | 2396 | * Don't call cpuset_node_allowed_softwall if you can't sleep, unless you |
36be57ff PJ |
2397 | * pass in the __GFP_HARDWALL flag set in gfp_flag, which disables |
2398 | * the code that might scan up ancestor cpusets and sleep. | |
02a0e53d | 2399 | */ |
a1bc5a4e | 2400 | int __cpuset_node_allowed_softwall(int node, gfp_t gfp_mask) |
1da177e4 | 2401 | { |
c9710d80 | 2402 | struct cpuset *cs; /* current cpuset ancestors */ |
29afd49b | 2403 | int allowed; /* is allocation in zone z allowed? */ |
9bf2229f | 2404 | |
9b819d20 | 2405 | if (in_interrupt() || (gfp_mask & __GFP_THISNODE)) |
9bf2229f | 2406 | return 1; |
92d1dbd2 | 2407 | might_sleep_if(!(gfp_mask & __GFP_HARDWALL)); |
9bf2229f PJ |
2408 | if (node_isset(node, current->mems_allowed)) |
2409 | return 1; | |
c596d9f3 DR |
2410 | /* |
2411 | * Allow tasks that have access to memory reserves because they have | |
2412 | * been OOM killed to get memory anywhere. | |
2413 | */ | |
2414 | if (unlikely(test_thread_flag(TIF_MEMDIE))) | |
2415 | return 1; | |
9bf2229f PJ |
2416 | if (gfp_mask & __GFP_HARDWALL) /* If hardwall request, stop here */ |
2417 | return 0; | |
2418 | ||
5563e770 BP |
2419 | if (current->flags & PF_EXITING) /* Let dying task have memory */ |
2420 | return 1; | |
2421 | ||
9bf2229f | 2422 | /* Not hardwall and node outside mems_allowed: scan up cpusets */ |
3d3f26a7 | 2423 | mutex_lock(&callback_mutex); |
053199ed | 2424 | |
b8dadcb5 | 2425 | rcu_read_lock(); |
78608366 | 2426 | cs = nearest_hardwall_ancestor(task_cs(current)); |
99afb0fd | 2427 | allowed = node_isset(node, cs->mems_allowed); |
b8dadcb5 | 2428 | rcu_read_unlock(); |
053199ed | 2429 | |
3d3f26a7 | 2430 | mutex_unlock(&callback_mutex); |
9bf2229f | 2431 | return allowed; |
1da177e4 LT |
2432 | } |
2433 | ||
02a0e53d | 2434 | /* |
a1bc5a4e DR |
2435 | * cpuset_node_allowed_hardwall - Can we allocate on a memory node? |
2436 | * @node: is this an allowed node? | |
02a0e53d PJ |
2437 | * @gfp_mask: memory allocation flags |
2438 | * | |
a1bc5a4e DR |
2439 | * If we're in interrupt, yes, we can always allocate. If __GFP_THISNODE is |
2440 | * set, yes, we can always allocate. If node is in our task's mems_allowed, | |
2441 | * yes. If the task has been OOM killed and has access to memory reserves as | |
2442 | * specified by the TIF_MEMDIE flag, yes. | |
2443 | * Otherwise, no. | |
02a0e53d PJ |
2444 | * |
2445 | * The __GFP_THISNODE placement logic is really handled elsewhere, | |
2446 | * by forcibly using a zonelist starting at a specified node, and by | |
2447 | * (in get_page_from_freelist()) refusing to consider the zones for | |
2448 | * any node on the zonelist except the first. By the time any such | |
2449 | * calls get to this routine, we should just shut up and say 'yes'. | |
2450 | * | |
a1bc5a4e DR |
2451 | * Unlike the cpuset_node_allowed_softwall() variant, above, |
2452 | * this variant requires that the node be in the current task's | |
02a0e53d PJ |
2453 | * mems_allowed or that we're in interrupt. It does not scan up the |
2454 | * cpuset hierarchy for the nearest enclosing mem_exclusive cpuset. | |
2455 | * It never sleeps. | |
2456 | */ | |
a1bc5a4e | 2457 | int __cpuset_node_allowed_hardwall(int node, gfp_t gfp_mask) |
02a0e53d | 2458 | { |
02a0e53d PJ |
2459 | if (in_interrupt() || (gfp_mask & __GFP_THISNODE)) |
2460 | return 1; | |
02a0e53d PJ |
2461 | if (node_isset(node, current->mems_allowed)) |
2462 | return 1; | |
dedf8b79 DW |
2463 | /* |
2464 | * Allow tasks that have access to memory reserves because they have | |
2465 | * been OOM killed to get memory anywhere. | |
2466 | */ | |
2467 | if (unlikely(test_thread_flag(TIF_MEMDIE))) | |
2468 | return 1; | |
02a0e53d PJ |
2469 | return 0; |
2470 | } | |
2471 | ||
825a46af | 2472 | /** |
6adef3eb JS |
2473 | * cpuset_mem_spread_node() - On which node to begin search for a file page |
2474 | * cpuset_slab_spread_node() - On which node to begin search for a slab page | |
825a46af PJ |
2475 | * |
2476 | * If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for | |
2477 | * tasks in a cpuset with is_spread_page or is_spread_slab set), | |
2478 | * and if the memory allocation used cpuset_mem_spread_node() | |
2479 | * to determine on which node to start looking, as it will for | |
2480 | * certain page cache or slab cache pages such as used for file | |
2481 | * system buffers and inode caches, then instead of starting on the | |
2482 | * local node to look for a free page, rather spread the starting | |
2483 | * node around the tasks mems_allowed nodes. | |
2484 | * | |
2485 | * We don't have to worry about the returned node being offline | |
2486 | * because "it can't happen", and even if it did, it would be ok. | |
2487 | * | |
2488 | * The routines calling guarantee_online_mems() are careful to | |
2489 | * only set nodes in task->mems_allowed that are online. So it | |
2490 | * should not be possible for the following code to return an | |
2491 | * offline node. But if it did, that would be ok, as this routine | |
2492 | * is not returning the node where the allocation must be, only | |
2493 | * the node where the search should start. The zonelist passed to | |
2494 | * __alloc_pages() will include all nodes. If the slab allocator | |
2495 | * is passed an offline node, it will fall back to the local node. | |
2496 | * See kmem_cache_alloc_node(). | |
2497 | */ | |
2498 | ||
6adef3eb | 2499 | static int cpuset_spread_node(int *rotor) |
825a46af PJ |
2500 | { |
2501 | int node; | |
2502 | ||
6adef3eb | 2503 | node = next_node(*rotor, current->mems_allowed); |
825a46af PJ |
2504 | if (node == MAX_NUMNODES) |
2505 | node = first_node(current->mems_allowed); | |
6adef3eb | 2506 | *rotor = node; |
825a46af PJ |
2507 | return node; |
2508 | } | |
6adef3eb JS |
2509 | |
2510 | int cpuset_mem_spread_node(void) | |
2511 | { | |
778d3b0f MH |
2512 | if (current->cpuset_mem_spread_rotor == NUMA_NO_NODE) |
2513 | current->cpuset_mem_spread_rotor = | |
2514 | node_random(¤t->mems_allowed); | |
2515 | ||
6adef3eb JS |
2516 | return cpuset_spread_node(¤t->cpuset_mem_spread_rotor); |
2517 | } | |
2518 | ||
2519 | int cpuset_slab_spread_node(void) | |
2520 | { | |
778d3b0f MH |
2521 | if (current->cpuset_slab_spread_rotor == NUMA_NO_NODE) |
2522 | current->cpuset_slab_spread_rotor = | |
2523 | node_random(¤t->mems_allowed); | |
2524 | ||
6adef3eb JS |
2525 | return cpuset_spread_node(¤t->cpuset_slab_spread_rotor); |
2526 | } | |
2527 | ||
825a46af PJ |
2528 | EXPORT_SYMBOL_GPL(cpuset_mem_spread_node); |
2529 | ||
ef08e3b4 | 2530 | /** |
bbe373f2 DR |
2531 | * cpuset_mems_allowed_intersects - Does @tsk1's mems_allowed intersect @tsk2's? |
2532 | * @tsk1: pointer to task_struct of some task. | |
2533 | * @tsk2: pointer to task_struct of some other task. | |
2534 | * | |
2535 | * Description: Return true if @tsk1's mems_allowed intersects the | |
2536 | * mems_allowed of @tsk2. Used by the OOM killer to determine if | |
2537 | * one of the task's memory usage might impact the memory available | |
2538 | * to the other. | |
ef08e3b4 PJ |
2539 | **/ |
2540 | ||
bbe373f2 DR |
2541 | int cpuset_mems_allowed_intersects(const struct task_struct *tsk1, |
2542 | const struct task_struct *tsk2) | |
ef08e3b4 | 2543 | { |
bbe373f2 | 2544 | return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed); |
ef08e3b4 PJ |
2545 | } |
2546 | ||
f440d98f LZ |
2547 | #define CPUSET_NODELIST_LEN (256) |
2548 | ||
75aa1994 DR |
2549 | /** |
2550 | * cpuset_print_task_mems_allowed - prints task's cpuset and mems_allowed | |
fc34ac1d | 2551 | * @tsk: pointer to task_struct of some task. |
75aa1994 DR |
2552 | * |
2553 | * Description: Prints @task's name, cpuset name, and cached copy of its | |
b8dadcb5 | 2554 | * mems_allowed to the kernel log. |
75aa1994 DR |
2555 | */ |
2556 | void cpuset_print_task_mems_allowed(struct task_struct *tsk) | |
2557 | { | |
f440d98f LZ |
2558 | /* Statically allocated to prevent using excess stack. */ |
2559 | static char cpuset_nodelist[CPUSET_NODELIST_LEN]; | |
2560 | static DEFINE_SPINLOCK(cpuset_buffer_lock); | |
b8dadcb5 | 2561 | struct cgroup *cgrp; |
75aa1994 | 2562 | |
f440d98f | 2563 | spin_lock(&cpuset_buffer_lock); |
b8dadcb5 | 2564 | rcu_read_lock(); |
63f43f55 | 2565 | |
b8dadcb5 | 2566 | cgrp = task_cs(tsk)->css.cgroup; |
75aa1994 DR |
2567 | nodelist_scnprintf(cpuset_nodelist, CPUSET_NODELIST_LEN, |
2568 | tsk->mems_allowed); | |
12d3089c | 2569 | pr_info("%s cpuset=", tsk->comm); |
e61734c5 TH |
2570 | pr_cont_cgroup_name(cgrp); |
2571 | pr_cont(" mems_allowed=%s\n", cpuset_nodelist); | |
f440d98f | 2572 | |
cfb5966b | 2573 | rcu_read_unlock(); |
75aa1994 DR |
2574 | spin_unlock(&cpuset_buffer_lock); |
2575 | } | |
2576 | ||
3e0d98b9 PJ |
2577 | /* |
2578 | * Collection of memory_pressure is suppressed unless | |
2579 | * this flag is enabled by writing "1" to the special | |
2580 | * cpuset file 'memory_pressure_enabled' in the root cpuset. | |
2581 | */ | |
2582 | ||
c5b2aff8 | 2583 | int cpuset_memory_pressure_enabled __read_mostly; |
3e0d98b9 PJ |
2584 | |
2585 | /** | |
2586 | * cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims. | |
2587 | * | |
2588 | * Keep a running average of the rate of synchronous (direct) | |
2589 | * page reclaim efforts initiated by tasks in each cpuset. | |
2590 | * | |
2591 | * This represents the rate at which some task in the cpuset | |
2592 | * ran low on memory on all nodes it was allowed to use, and | |
2593 | * had to enter the kernels page reclaim code in an effort to | |
2594 | * create more free memory by tossing clean pages or swapping | |
2595 | * or writing dirty pages. | |
2596 | * | |
2597 | * Display to user space in the per-cpuset read-only file | |
2598 | * "memory_pressure". Value displayed is an integer | |
2599 | * representing the recent rate of entry into the synchronous | |
2600 | * (direct) page reclaim by any task attached to the cpuset. | |
2601 | **/ | |
2602 | ||
2603 | void __cpuset_memory_pressure_bump(void) | |
2604 | { | |
b8dadcb5 | 2605 | rcu_read_lock(); |
8793d854 | 2606 | fmeter_markevent(&task_cs(current)->fmeter); |
b8dadcb5 | 2607 | rcu_read_unlock(); |
3e0d98b9 PJ |
2608 | } |
2609 | ||
8793d854 | 2610 | #ifdef CONFIG_PROC_PID_CPUSET |
1da177e4 LT |
2611 | /* |
2612 | * proc_cpuset_show() | |
2613 | * - Print tasks cpuset path into seq_file. | |
2614 | * - Used for /proc/<pid>/cpuset. | |
053199ed PJ |
2615 | * - No need to task_lock(tsk) on this tsk->cpuset reference, as it |
2616 | * doesn't really matter if tsk->cpuset changes after we read it, | |
5d21cc2d | 2617 | * and we take cpuset_mutex, keeping cpuset_attach() from changing it |
2df167a3 | 2618 | * anyway. |
1da177e4 | 2619 | */ |
8d8b97ba | 2620 | int proc_cpuset_show(struct seq_file *m, void *unused_v) |
1da177e4 | 2621 | { |
13b41b09 | 2622 | struct pid *pid; |
1da177e4 | 2623 | struct task_struct *tsk; |
e61734c5 | 2624 | char *buf, *p; |
8793d854 | 2625 | struct cgroup_subsys_state *css; |
99f89551 | 2626 | int retval; |
1da177e4 | 2627 | |
99f89551 | 2628 | retval = -ENOMEM; |
e61734c5 | 2629 | buf = kmalloc(PATH_MAX, GFP_KERNEL); |
1da177e4 | 2630 | if (!buf) |
99f89551 EB |
2631 | goto out; |
2632 | ||
2633 | retval = -ESRCH; | |
13b41b09 EB |
2634 | pid = m->private; |
2635 | tsk = get_pid_task(pid, PIDTYPE_PID); | |
99f89551 EB |
2636 | if (!tsk) |
2637 | goto out_free; | |
1da177e4 | 2638 | |
e61734c5 | 2639 | retval = -ENAMETOOLONG; |
27e89ae5 | 2640 | rcu_read_lock(); |
073219e9 | 2641 | css = task_css(tsk, cpuset_cgrp_id); |
e61734c5 | 2642 | p = cgroup_path(css->cgroup, buf, PATH_MAX); |
27e89ae5 | 2643 | rcu_read_unlock(); |
e61734c5 | 2644 | if (!p) |
27e89ae5 | 2645 | goto out_put_task; |
e61734c5 | 2646 | seq_puts(m, p); |
1da177e4 | 2647 | seq_putc(m, '\n'); |
e61734c5 | 2648 | retval = 0; |
27e89ae5 | 2649 | out_put_task: |
99f89551 EB |
2650 | put_task_struct(tsk); |
2651 | out_free: | |
1da177e4 | 2652 | kfree(buf); |
99f89551 | 2653 | out: |
1da177e4 LT |
2654 | return retval; |
2655 | } | |
8793d854 | 2656 | #endif /* CONFIG_PROC_PID_CPUSET */ |
1da177e4 | 2657 | |
d01d4827 | 2658 | /* Display task mems_allowed in /proc/<pid>/status file. */ |
df5f8314 EB |
2659 | void cpuset_task_status_allowed(struct seq_file *m, struct task_struct *task) |
2660 | { | |
fc34ac1d | 2661 | seq_puts(m, "Mems_allowed:\t"); |
30e8e136 | 2662 | seq_nodemask(m, &task->mems_allowed); |
fc34ac1d FF |
2663 | seq_puts(m, "\n"); |
2664 | seq_puts(m, "Mems_allowed_list:\t"); | |
30e8e136 | 2665 | seq_nodemask_list(m, &task->mems_allowed); |
fc34ac1d | 2666 | seq_puts(m, "\n"); |
1da177e4 | 2667 | } |