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