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