| 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/time64.h>
|
| 55 | #include <linux/backing-dev.h>
|
| 56 | #include <linux/sort.h>
|
| 57 |
|
| 58 | #include <asm/uaccess.h>
|
| 59 | #include <linux/atomic.h>
|
| 60 | #include <linux/mutex.h>
|
| 61 | #include <linux/cgroup.h>
|
| 62 | #include <linux/wait.h>
|
| 63 |
|
| 64 | DEFINE_STATIC_KEY_FALSE(cpusets_enabled_key);
|
| 65 |
|
| 66 |
|
| 67 |
|
| 68 | struct fmeter {
|
| 69 | int cnt;
|
| 70 | int val;
|
| 71 | time64_t time;
|
| 72 | spinlock_t lock;
|
| 73 | };
|
| 74 |
|
| 75 | struct cpuset {
|
| 76 | struct cgroup_subsys_state css;
|
| 77 |
|
| 78 | unsigned long flags;
|
| 79 |
|
| 80 | |
| 81 | * On default hierarchy:
|
| 82 | *
|
| 83 | * The user-configured masks can only be changed by writing to
|
| 84 | * cpuset.cpus and cpuset.mems, and won't be limited by the
|
| 85 | * parent masks.
|
| 86 | *
|
| 87 | * The effective masks is the real masks that apply to the tasks
|
| 88 | * in the cpuset. They may be changed if the configured masks are
|
| 89 | * changed or hotplug happens.
|
| 90 | *
|
| 91 | * effective_mask == configured_mask & parent's effective_mask,
|
| 92 | * and if it ends up empty, it will inherit the parent's mask.
|
| 93 | *
|
| 94 | *
|
| 95 | * On legacy hierachy:
|
| 96 | *
|
| 97 | * The user-configured masks are always the same with effective masks.
|
| 98 |
|
| 99 |
|
| 100 |
|
| 101 | cpumask_var_t cpus_allowed;
|
| 102 | nodemask_t mems_allowed;
|
| 103 |
|
| 104 |
|
| 105 | cpumask_var_t effective_cpus;
|
| 106 | nodemask_t effective_mems;
|
| 107 |
|
| 108 | |
| 109 | * This is old Memory Nodes tasks took on.
|
| 110 | *
|
| 111 | * - top_cpuset.old_mems_allowed is initialized to mems_allowed.
|
| 112 | * - A new cpuset's old_mems_allowed is initialized when some
|
| 113 | * task is moved into it.
|
| 114 | * - old_mems_allowed is used in cpuset_migrate_mm() when we change
|
| 115 | * cpuset.mems_allowed and have tasks' nodemask updated, and
|
| 116 | * then old_mems_allowed is updated to mems_allowed.
|
| 117 |
|
| 118 | nodemask_t old_mems_allowed;
|
| 119 |
|
| 120 | struct fmeter fmeter;
|
| 121 |
|
| 122 | |
| 123 | * Tasks are being attached to this cpuset. Used to prevent
|
| 124 | * zeroing cpus/mems_allowed between ->can_attach() and ->attach().
|
| 125 |
|
| 126 | int attach_in_progress;
|
| 127 |
|
| 128 |
|
| 129 | int pn;
|
| 130 |
|
| 131 |
|
| 132 | int relax_domain_level;
|
| 133 | };
|
| 134 |
|
| 135 | static inline struct cpuset *css_cs(struct cgroup_subsys_state *css)
|
| 136 | {
|
| 137 | return css ? container_of(css, struct cpuset, css) : NULL;
|
| 138 | }
|
| 139 |
|
| 140 |
|
| 141 | static inline struct cpuset *task_cs(struct task_struct *task)
|
| 142 | {
|
| 143 | return css_cs(task_css(task, cpuset_cgrp_id));
|
| 144 | }
|
| 145 |
|
| 146 | static inline struct cpuset *parent_cs(struct cpuset *cs)
|
| 147 | {
|
| 148 | return css_cs(cs->css.parent);
|
| 149 | }
|
| 150 |
|
| 151 | #ifdef CONFIG_NUMA
|
| 152 | static inline bool task_has_mempolicy(struct task_struct *task)
|
| 153 | {
|
| 154 | return task->mempolicy;
|
| 155 | }
|
| 156 | #else
|
| 157 | static inline bool task_has_mempolicy(struct task_struct *task)
|
| 158 | {
|
| 159 | return false;
|
| 160 | }
|
| 161 | #endif
|
| 162 |
|
| 163 |
|
| 164 |
|
| 165 | typedef enum {
|
| 166 | CS_ONLINE,
|
| 167 | CS_CPU_EXCLUSIVE,
|
| 168 | CS_MEM_EXCLUSIVE,
|
| 169 | CS_MEM_HARDWALL,
|
| 170 | CS_MEMORY_MIGRATE,
|
| 171 | CS_SCHED_LOAD_BALANCE,
|
| 172 | CS_SPREAD_PAGE,
|
| 173 | CS_SPREAD_SLAB,
|
| 174 | } cpuset_flagbits_t;
|
| 175 |
|
| 176 |
|
| 177 | static inline bool is_cpuset_online(const struct cpuset *cs)
|
| 178 | {
|
| 179 | return test_bit(CS_ONLINE, &cs->flags);
|
| 180 | }
|
| 181 |
|
| 182 | static inline int is_cpu_exclusive(const struct cpuset *cs)
|
| 183 | {
|
| 184 | return test_bit(CS_CPU_EXCLUSIVE, &cs->flags);
|
| 185 | }
|
| 186 |
|
| 187 | static inline int is_mem_exclusive(const struct cpuset *cs)
|
| 188 | {
|
| 189 | return test_bit(CS_MEM_EXCLUSIVE, &cs->flags);
|
| 190 | }
|
| 191 |
|
| 192 | static inline int is_mem_hardwall(const struct cpuset *cs)
|
| 193 | {
|
| 194 | return test_bit(CS_MEM_HARDWALL, &cs->flags);
|
| 195 | }
|
| 196 |
|
| 197 | static inline int is_sched_load_balance(const struct cpuset *cs)
|
| 198 | {
|
| 199 | return test_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
|
| 200 | }
|
| 201 |
|
| 202 | static inline int is_memory_migrate(const struct cpuset *cs)
|
| 203 | {
|
| 204 | return test_bit(CS_MEMORY_MIGRATE, &cs->flags);
|
| 205 | }
|
| 206 |
|
| 207 | static inline int is_spread_page(const struct cpuset *cs)
|
| 208 | {
|
| 209 | return test_bit(CS_SPREAD_PAGE, &cs->flags);
|
| 210 | }
|
| 211 |
|
| 212 | static inline int is_spread_slab(const struct cpuset *cs)
|
| 213 | {
|
| 214 | return test_bit(CS_SPREAD_SLAB, &cs->flags);
|
| 215 | }
|
| 216 |
|
| 217 | static struct cpuset top_cpuset = {
|
| 218 | .flags = ((1 << CS_ONLINE) | (1 << CS_CPU_EXCLUSIVE) |
|
| 219 | (1 << CS_MEM_EXCLUSIVE)),
|
| 220 | };
|
| 221 |
|
| 222 | |
| 223 | * cpuset_for_each_child - traverse online children of a cpuset
|
| 224 | * @child_cs: loop cursor pointing to the current child
|
| 225 | * @pos_css: used for iteration
|
| 226 | * @parent_cs: target cpuset to walk children of
|
| 227 | *
|
| 228 | * Walk @child_cs through the online children of @parent_cs. Must be used
|
| 229 | * with RCU read locked.
|
| 230 |
|
| 231 | #define cpuset_for_each_child(child_cs, pos_css, parent_cs) \
|
| 232 | css_for_each_child((pos_css), &(parent_cs)->css) \
|
| 233 | if (is_cpuset_online(((child_cs) = css_cs((pos_css)))))
|
| 234 |
|
| 235 | |
| 236 | * cpuset_for_each_descendant_pre - pre-order walk of a cpuset's descendants
|
| 237 | * @des_cs: loop cursor pointing to the current descendant
|
| 238 | * @pos_css: used for iteration
|
| 239 | * @root_cs: target cpuset to walk ancestor of
|
| 240 | *
|
| 241 | * Walk @des_cs through the online descendants of @root_cs. Must be used
|
| 242 | * with RCU read locked. The caller may modify @pos_css by calling
|
| 243 | * css_rightmost_descendant() to skip subtree. @root_cs is included in the
|
| 244 | * iteration and the first node to be visited.
|
| 245 |
|
| 246 | #define cpuset_for_each_descendant_pre(des_cs, pos_css, root_cs) \
|
| 247 | css_for_each_descendant_pre((pos_css), &(root_cs)->css) \
|
| 248 | if (is_cpuset_online(((des_cs) = css_cs((pos_css)))))
|
| 249 |
|
| 250 | |
| 251 | * There are two global locks guarding cpuset structures - cpuset_mutex and
|
| 252 | * callback_lock. We also require taking task_lock() when dereferencing a
|
| 253 | * task's cpuset pointer. See "The task_lock() exception", at the end of this
|
| 254 | * comment.
|
| 255 | *
|
| 256 | * A task must hold both locks to modify cpusets. If a task holds
|
| 257 | * cpuset_mutex, then it blocks others wanting that mutex, ensuring that it
|
| 258 | * is the only task able to also acquire callback_lock and be able to
|
| 259 | * modify cpusets. It can perform various checks on the cpuset structure
|
| 260 | * first, knowing nothing will change. It can also allocate memory while
|
| 261 | * just holding cpuset_mutex. While it is performing these checks, various
|
| 262 | * callback routines can briefly acquire callback_lock to query cpusets.
|
| 263 | * Once it is ready to make the changes, it takes callback_lock, blocking
|
| 264 | * everyone else.
|
| 265 | *
|
| 266 | * Calls to the kernel memory allocator can not be made while holding
|
| 267 | * callback_lock, as that would risk double tripping on callback_lock
|
| 268 | * from one of the callbacks into the cpuset code from within
|
| 269 | * __alloc_pages().
|
| 270 | *
|
| 271 | * If a task is only holding callback_lock, then it has read-only
|
| 272 | * access to cpusets.
|
| 273 | *
|
| 274 | * Now, the task_struct fields mems_allowed and mempolicy may be changed
|
| 275 | * by other task, we use alloc_lock in the task_struct fields to protect
|
| 276 | * them.
|
| 277 | *
|
| 278 | * The cpuset_common_file_read() handlers only hold callback_lock across
|
| 279 | * small pieces of code, such as when reading out possibly multi-word
|
| 280 | * cpumasks and nodemasks.
|
| 281 | *
|
| 282 | * Accessing a task's cpuset should be done in accordance with the
|
| 283 | * guidelines for accessing subsystem state in kernel/cgroup.c
|
| 284 |
|
| 285 |
|
| 286 | static DEFINE_MUTEX(cpuset_mutex);
|
| 287 | static DEFINE_SPINLOCK(callback_lock);
|
| 288 |
|
| 289 | static struct workqueue_struct *cpuset_migrate_mm_wq;
|
| 290 |
|
| 291 | |
| 292 | * CPU / memory hotplug is handled asynchronously.
|
| 293 |
|
| 294 | static void cpuset_hotplug_workfn(struct work_struct *work);
|
| 295 | static DECLARE_WORK(cpuset_hotplug_work, cpuset_hotplug_workfn);
|
| 296 |
|
| 297 | static DECLARE_WAIT_QUEUE_HEAD(cpuset_attach_wq);
|
| 298 |
|
| 299 | |
| 300 | * This is ugly, but preserves the userspace API for existing cpuset
|
| 301 | * users. If someone tries to mount the "cpuset" filesystem, we
|
| 302 | * silently switch it to mount "cgroup" instead
|
| 303 |
|
| 304 | static struct dentry *cpuset_mount(struct file_system_type *fs_type,
|
| 305 | int flags, const char *unused_dev_name, void *data)
|
| 306 | {
|
| 307 | struct file_system_type *cgroup_fs = get_fs_type("cgroup");
|
| 308 | struct dentry *ret = ERR_PTR(-ENODEV);
|
| 309 | if (cgroup_fs) {
|
| 310 | char mountopts[] =
|
| 311 | "cpuset,noprefix,"
|
| 312 | "release_agent=/sbin/cpuset_release_agent";
|
| 313 | ret = cgroup_fs->mount(cgroup_fs, flags,
|
| 314 | unused_dev_name, mountopts);
|
| 315 | put_filesystem(cgroup_fs);
|
| 316 | }
|
| 317 | return ret;
|
| 318 | }
|
| 319 |
|
| 320 | static struct file_system_type cpuset_fs_type = {
|
| 321 | .name = "cpuset",
|
| 322 | .mount = cpuset_mount,
|
| 323 | };
|
| 324 |
|
| 325 | |
| 326 | * Return in pmask the portion of a cpusets's cpus_allowed that
|
| 327 | * are online. If none are online, walk up the cpuset hierarchy
|
| 328 | * until we find one that does have some online cpus.
|
| 329 | *
|
| 330 | * One way or another, we guarantee to return some non-empty subset
|
| 331 | * of cpu_online_mask.
|
| 332 | *
|
| 333 | * Call with callback_lock or cpuset_mutex held.
|
| 334 |
|
| 335 | static void guarantee_online_cpus(struct cpuset *cs, struct cpumask *pmask)
|
| 336 | {
|
| 337 | while (!cpumask_intersects(cs->effective_cpus, cpu_online_mask)) {
|
| 338 | cs = parent_cs(cs);
|
| 339 | if (unlikely(!cs)) {
|
| 340 | |
| 341 | * The top cpuset doesn't have any online cpu as a
|
| 342 | * consequence of a race between cpuset_hotplug_work
|
| 343 | * and cpu hotplug notifier. But we know the top
|
| 344 | * cpuset's effective_cpus is on its way to to be
|
| 345 | * identical to cpu_online_mask.
|
| 346 |
|
| 347 | cpumask_copy(pmask, cpu_online_mask);
|
| 348 | return;
|
| 349 | }
|
| 350 | }
|
| 351 | cpumask_and(pmask, cs->effective_cpus, cpu_online_mask);
|
| 352 | }
|
| 353 |
|
| 354 | |
| 355 | * Return in *pmask the portion of a cpusets's mems_allowed that
|
| 356 | * are online, with memory. If none are online with memory, walk
|
| 357 | * up the cpuset hierarchy until we find one that does have some
|
| 358 | * online mems. The top cpuset always has some mems online.
|
| 359 | *
|
| 360 | * One way or another, we guarantee to return some non-empty subset
|
| 361 | * of node_states[N_MEMORY].
|
| 362 | *
|
| 363 | * Call with callback_lock or cpuset_mutex held.
|
| 364 |
|
| 365 | static void guarantee_online_mems(struct cpuset *cs, nodemask_t *pmask)
|
| 366 | {
|
| 367 | while (!nodes_intersects(cs->effective_mems, node_states[N_MEMORY]))
|
| 368 | cs = parent_cs(cs);
|
| 369 | nodes_and(*pmask, cs->effective_mems, node_states[N_MEMORY]);
|
| 370 | }
|
| 371 |
|
| 372 | |
| 373 | * update task's spread flag if cpuset's page/slab spread flag is set
|
| 374 | *
|
| 375 | * Call with callback_lock or cpuset_mutex held.
|
| 376 |
|
| 377 | static void cpuset_update_task_spread_flag(struct cpuset *cs,
|
| 378 | struct task_struct *tsk)
|
| 379 | {
|
| 380 | if (is_spread_page(cs))
|
| 381 | task_set_spread_page(tsk);
|
| 382 | else
|
| 383 | task_clear_spread_page(tsk);
|
| 384 |
|
| 385 | if (is_spread_slab(cs))
|
| 386 | task_set_spread_slab(tsk);
|
| 387 | else
|
| 388 | task_clear_spread_slab(tsk);
|
| 389 | }
|
| 390 |
|
| 391 | |
| 392 | * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q?
|
| 393 | *
|
| 394 | * One cpuset is a subset of another if all its allowed CPUs and
|
| 395 | * Memory Nodes are a subset of the other, and its exclusive flags
|
| 396 | * are only set if the other's are set. Call holding cpuset_mutex.
|
| 397 |
|
| 398 |
|
| 399 | static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
|
| 400 | {
|
| 401 | return cpumask_subset(p->cpus_allowed, q->cpus_allowed) &&
|
| 402 | nodes_subset(p->mems_allowed, q->mems_allowed) &&
|
| 403 | is_cpu_exclusive(p) <= is_cpu_exclusive(q) &&
|
| 404 | is_mem_exclusive(p) <= is_mem_exclusive(q);
|
| 405 | }
|
| 406 |
|
| 407 | |
| 408 | * alloc_trial_cpuset - allocate a trial cpuset
|
| 409 | * @cs: the cpuset that the trial cpuset duplicates
|
| 410 |
|
| 411 | static struct cpuset *alloc_trial_cpuset(struct cpuset *cs)
|
| 412 | {
|
| 413 | struct cpuset *trial;
|
| 414 |
|
| 415 | trial = kmemdup(cs, sizeof(*cs), GFP_KERNEL);
|
| 416 | if (!trial)
|
| 417 | return NULL;
|
| 418 |
|
| 419 | if (!alloc_cpumask_var(&trial->cpus_allowed, GFP_KERNEL))
|
| 420 | goto free_cs;
|
| 421 | if (!alloc_cpumask_var(&trial->effective_cpus, GFP_KERNEL))
|
| 422 | goto free_cpus;
|
| 423 |
|
| 424 | cpumask_copy(trial->cpus_allowed, cs->cpus_allowed);
|
| 425 | cpumask_copy(trial->effective_cpus, cs->effective_cpus);
|
| 426 | return trial;
|
| 427 |
|
| 428 | free_cpus:
|
| 429 | free_cpumask_var(trial->cpus_allowed);
|
| 430 | free_cs:
|
| 431 | kfree(trial);
|
| 432 | return NULL;
|
| 433 | }
|
| 434 |
|
| 435 | |
| 436 | * free_trial_cpuset - free the trial cpuset
|
| 437 | * @trial: the trial cpuset to be freed
|
| 438 |
|
| 439 | static void free_trial_cpuset(struct cpuset *trial)
|
| 440 | {
|
| 441 | free_cpumask_var(trial->effective_cpus);
|
| 442 | free_cpumask_var(trial->cpus_allowed);
|
| 443 | kfree(trial);
|
| 444 | }
|
| 445 |
|
| 446 | |
| 447 | * validate_change() - Used to validate that any proposed cpuset change
|
| 448 | * follows the structural rules for cpusets.
|
| 449 | *
|
| 450 | * If we replaced the flag and mask values of the current cpuset
|
| 451 | * (cur) with those values in the trial cpuset (trial), would
|
| 452 | * our various subset and exclusive rules still be valid? Presumes
|
| 453 | * cpuset_mutex held.
|
| 454 | *
|
| 455 | * 'cur' is the address of an actual, in-use cpuset. Operations
|
| 456 | * such as list traversal that depend on the actual address of the
|
| 457 | * cpuset in the list must use cur below, not trial.
|
| 458 | *
|
| 459 | * 'trial' is the address of bulk structure copy of cur, with
|
| 460 | * perhaps one or more of the fields cpus_allowed, mems_allowed,
|
| 461 | * or flags changed to new, trial values.
|
| 462 | *
|
| 463 | * Return 0 if valid, -errno if not.
|
| 464 |
|
| 465 |
|
| 466 | static int validate_change(struct cpuset *cur, struct cpuset *trial)
|
| 467 | {
|
| 468 | struct cgroup_subsys_state *css;
|
| 469 | struct cpuset *c, *par;
|
| 470 | int ret;
|
| 471 |
|
| 472 | rcu_read_lock();
|
| 473 |
|
| 474 |
|
| 475 | ret = -EBUSY;
|
| 476 | cpuset_for_each_child(c, css, cur)
|
| 477 | if (!is_cpuset_subset(c, trial))
|
| 478 | goto out;
|
| 479 |
|
| 480 |
|
| 481 | ret = 0;
|
| 482 | if (cur == &top_cpuset)
|
| 483 | goto out;
|
| 484 |
|
| 485 | par = parent_cs(cur);
|
| 486 |
|
| 487 |
|
| 488 | ret = -EACCES;
|
| 489 | if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
|
| 490 | !is_cpuset_subset(trial, par))
|
| 491 | goto out;
|
| 492 |
|
| 493 | |
| 494 | * If either I or some sibling (!= me) is exclusive, we can't
|
| 495 | * overlap
|
| 496 |
|
| 497 | ret = -EINVAL;
|
| 498 | cpuset_for_each_child(c, css, par) {
|
| 499 | if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) &&
|
| 500 | c != cur &&
|
| 501 | cpumask_intersects(trial->cpus_allowed, c->cpus_allowed))
|
| 502 | goto out;
|
| 503 | if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) &&
|
| 504 | c != cur &&
|
| 505 | nodes_intersects(trial->mems_allowed, c->mems_allowed))
|
| 506 | goto out;
|
| 507 | }
|
| 508 |
|
| 509 | |
| 510 | * Cpusets with tasks - existing or newly being attached - can't
|
| 511 | * be changed to have empty cpus_allowed or mems_allowed.
|
| 512 |
|
| 513 | ret = -ENOSPC;
|
| 514 | if ((cgroup_is_populated(cur->css.cgroup) || cur->attach_in_progress)) {
|
| 515 | if (!cpumask_empty(cur->cpus_allowed) &&
|
| 516 | cpumask_empty(trial->cpus_allowed))
|
| 517 | goto out;
|
| 518 | if (!nodes_empty(cur->mems_allowed) &&
|
| 519 | nodes_empty(trial->mems_allowed))
|
| 520 | goto out;
|
| 521 | }
|
| 522 |
|
| 523 | |
| 524 | * We can't shrink if we won't have enough room for SCHED_DEADLINE
|
| 525 | * tasks.
|
| 526 |
|
| 527 | ret = -EBUSY;
|
| 528 | if (is_cpu_exclusive(cur) &&
|
| 529 | !cpuset_cpumask_can_shrink(cur->cpus_allowed,
|
| 530 | trial->cpus_allowed))
|
| 531 | goto out;
|
| 532 |
|
| 533 | ret = 0;
|
| 534 | out:
|
| 535 | rcu_read_unlock();
|
| 536 | return ret;
|
| 537 | }
|
| 538 |
|
| 539 | #ifdef CONFIG_SMP
|
| 540 | |
| 541 | * Helper routine for generate_sched_domains().
|
| 542 | * Do cpusets a, b have overlapping effective cpus_allowed masks?
|
| 543 |
|
| 544 | static int cpusets_overlap(struct cpuset *a, struct cpuset *b)
|
| 545 | {
|
| 546 | return cpumask_intersects(a->effective_cpus, b->effective_cpus);
|
| 547 | }
|
| 548 |
|
| 549 | static void
|
| 550 | update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c)
|
| 551 | {
|
| 552 | if (dattr->relax_domain_level < c->relax_domain_level)
|
| 553 | dattr->relax_domain_level = c->relax_domain_level;
|
| 554 | return;
|
| 555 | }
|
| 556 |
|
| 557 | static void update_domain_attr_tree(struct sched_domain_attr *dattr,
|
| 558 | struct cpuset *root_cs)
|
| 559 | {
|
| 560 | struct cpuset *cp;
|
| 561 | struct cgroup_subsys_state *pos_css;
|
| 562 |
|
| 563 | rcu_read_lock();
|
| 564 | cpuset_for_each_descendant_pre(cp, pos_css, root_cs) {
|
| 565 |
|
| 566 | if (cpumask_empty(cp->cpus_allowed)) {
|
| 567 | pos_css = css_rightmost_descendant(pos_css);
|
| 568 | continue;
|
| 569 | }
|
| 570 |
|
| 571 | if (is_sched_load_balance(cp))
|
| 572 | update_domain_attr(dattr, cp);
|
| 573 | }
|
| 574 | rcu_read_unlock();
|
| 575 | }
|
| 576 |
|
| 577 | |
| 578 | * generate_sched_domains()
|
| 579 | *
|
| 580 | * This function builds a partial partition of the systems CPUs
|
| 581 | * A 'partial partition' is a set of non-overlapping subsets whose
|
| 582 | * union is a subset of that set.
|
| 583 | * The output of this function needs to be passed to kernel/sched/core.c
|
| 584 | * partition_sched_domains() routine, which will rebuild the scheduler's
|
| 585 | * load balancing domains (sched domains) as specified by that partial
|
| 586 | * partition.
|
| 587 | *
|
| 588 | * See "What is sched_load_balance" in Documentation/cgroups/cpusets.txt
|
| 589 | * for a background explanation of this.
|
| 590 | *
|
| 591 | * Does not return errors, on the theory that the callers of this
|
| 592 | * routine would rather not worry about failures to rebuild sched
|
| 593 | * domains when operating in the severe memory shortage situations
|
| 594 | * that could cause allocation failures below.
|
| 595 | *
|
| 596 | * Must be called with cpuset_mutex held.
|
| 597 | *
|
| 598 | * The three key local variables below are:
|
| 599 | * q - a linked-list queue of cpuset pointers, used to implement a
|
| 600 | * top-down scan of all cpusets. This scan loads a pointer
|
| 601 | * to each cpuset marked is_sched_load_balance into the
|
| 602 | * array 'csa'. For our purposes, rebuilding the schedulers
|
| 603 | * sched domains, we can ignore !is_sched_load_balance cpusets.
|
| 604 | * csa - (for CpuSet Array) Array of pointers to all the cpusets
|
| 605 | * that need to be load balanced, for convenient iterative
|
| 606 | * access by the subsequent code that finds the best partition,
|
| 607 | * i.e the set of domains (subsets) of CPUs such that the
|
| 608 | * cpus_allowed of every cpuset marked is_sched_load_balance
|
| 609 | * is a subset of one of these domains, while there are as
|
| 610 | * many such domains as possible, each as small as possible.
|
| 611 | * doms - Conversion of 'csa' to an array of cpumasks, for passing to
|
| 612 | * the kernel/sched/core.c routine partition_sched_domains() in a
|
| 613 | * convenient format, that can be easily compared to the prior
|
| 614 | * value to determine what partition elements (sched domains)
|
| 615 | * were changed (added or removed.)
|
| 616 | *
|
| 617 | * Finding the best partition (set of domains):
|
| 618 | * The triple nested loops below over i, j, k scan over the
|
| 619 | * load balanced cpusets (using the array of cpuset pointers in
|
| 620 | * csa[]) looking for pairs of cpusets that have overlapping
|
| 621 | * cpus_allowed, but which don't have the same 'pn' partition
|
| 622 | * number and gives them in the same partition number. It keeps
|
| 623 | * looping on the 'restart' label until it can no longer find
|
| 624 | * any such pairs.
|
| 625 | *
|
| 626 | * The union of the cpus_allowed masks from the set of
|
| 627 | * all cpusets having the same 'pn' value then form the one
|
| 628 | * element of the partition (one sched domain) to be passed to
|
| 629 | * partition_sched_domains().
|
| 630 |
|
| 631 | static int generate_sched_domains(cpumask_var_t **domains,
|
| 632 | struct sched_domain_attr **attributes)
|
| 633 | {
|
| 634 | struct cpuset *cp;
|
| 635 | struct cpuset **csa;
|
| 636 | int csn;
|
| 637 | int i, j, k;
|
| 638 | cpumask_var_t *doms;
|
| 639 | cpumask_var_t non_isolated_cpus;
|
| 640 | struct sched_domain_attr *dattr;
|
| 641 | int ndoms = 0;
|
| 642 | int nslot;
|
| 643 | struct cgroup_subsys_state *pos_css;
|
| 644 |
|
| 645 | doms = NULL;
|
| 646 | dattr = NULL;
|
| 647 | csa = NULL;
|
| 648 |
|
| 649 | if (!alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL))
|
| 650 | goto done;
|
| 651 | cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
|
| 652 |
|
| 653 |
|
| 654 | if (is_sched_load_balance(&top_cpuset)) {
|
| 655 | ndoms = 1;
|
| 656 | doms = alloc_sched_domains(ndoms);
|
| 657 | if (!doms)
|
| 658 | goto done;
|
| 659 |
|
| 660 | dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL);
|
| 661 | if (dattr) {
|
| 662 | *dattr = SD_ATTR_INIT;
|
| 663 | update_domain_attr_tree(dattr, &top_cpuset);
|
| 664 | }
|
| 665 | cpumask_and(doms[0], top_cpuset.effective_cpus,
|
| 666 | non_isolated_cpus);
|
| 667 |
|
| 668 | goto done;
|
| 669 | }
|
| 670 |
|
| 671 | csa = kmalloc(nr_cpusets() * sizeof(cp), GFP_KERNEL);
|
| 672 | if (!csa)
|
| 673 | goto done;
|
| 674 | csn = 0;
|
| 675 |
|
| 676 | rcu_read_lock();
|
| 677 | cpuset_for_each_descendant_pre(cp, pos_css, &top_cpuset) {
|
| 678 | if (cp == &top_cpuset)
|
| 679 | continue;
|
| 680 | |
| 681 | * Continue traversing beyond @cp iff @cp has some CPUs and
|
| 682 | * isn't load balancing. The former is obvious. The
|
| 683 | * latter: All child cpusets contain a subset of the
|
| 684 | * parent's cpus, so just skip them, and then we call
|
| 685 | * update_domain_attr_tree() to calc relax_domain_level of
|
| 686 | * the corresponding sched domain.
|
| 687 |
|
| 688 | if (!cpumask_empty(cp->cpus_allowed) &&
|
| 689 | !(is_sched_load_balance(cp) &&
|
| 690 | cpumask_intersects(cp->cpus_allowed, non_isolated_cpus)))
|
| 691 | continue;
|
| 692 |
|
| 693 | if (is_sched_load_balance(cp))
|
| 694 | csa[csn++] = cp;
|
| 695 |
|
| 696 |
|
| 697 | pos_css = css_rightmost_descendant(pos_css);
|
| 698 | }
|
| 699 | rcu_read_unlock();
|
| 700 |
|
| 701 | for (i = 0; i < csn; i++)
|
| 702 | csa[i]->pn = i;
|
| 703 | ndoms = csn;
|
| 704 |
|
| 705 | restart:
|
| 706 |
|
| 707 | for (i = 0; i < csn; i++) {
|
| 708 | struct cpuset *a = csa[i];
|
| 709 | int apn = a->pn;
|
| 710 |
|
| 711 | for (j = 0; j < csn; j++) {
|
| 712 | struct cpuset *b = csa[j];
|
| 713 | int bpn = b->pn;
|
| 714 |
|
| 715 | if (apn != bpn && cpusets_overlap(a, b)) {
|
| 716 | for (k = 0; k < csn; k++) {
|
| 717 | struct cpuset *c = csa[k];
|
| 718 |
|
| 719 | if (c->pn == bpn)
|
| 720 | c->pn = apn;
|
| 721 | }
|
| 722 | ndoms--;
|
| 723 | goto restart;
|
| 724 | }
|
| 725 | }
|
| 726 | }
|
| 727 |
|
| 728 | |
| 729 | * Now we know how many domains to create.
|
| 730 | * Convert <csn, csa> to <ndoms, doms> and populate cpu masks.
|
| 731 |
|
| 732 | doms = alloc_sched_domains(ndoms);
|
| 733 | if (!doms)
|
| 734 | goto done;
|
| 735 |
|
| 736 | |
| 737 | * The rest of the code, including the scheduler, can deal with
|
| 738 | * dattr==NULL case. No need to abort if alloc fails.
|
| 739 |
|
| 740 | dattr = kmalloc(ndoms * sizeof(struct sched_domain_attr), GFP_KERNEL);
|
| 741 |
|
| 742 | for (nslot = 0, i = 0; i < csn; i++) {
|
| 743 | struct cpuset *a = csa[i];
|
| 744 | struct cpumask *dp;
|
| 745 | int apn = a->pn;
|
| 746 |
|
| 747 | if (apn < 0) {
|
| 748 |
|
| 749 | continue;
|
| 750 | }
|
| 751 |
|
| 752 | dp = doms[nslot];
|
| 753 |
|
| 754 | if (nslot == ndoms) {
|
| 755 | static int warnings = 10;
|
| 756 | if (warnings) {
|
| 757 | pr_warn("rebuild_sched_domains confused: nslot %d, ndoms %d, csn %d, i %d, apn %d\n",
|
| 758 | nslot, ndoms, csn, i, apn);
|
| 759 | warnings--;
|
| 760 | }
|
| 761 | continue;
|
| 762 | }
|
| 763 |
|
| 764 | cpumask_clear(dp);
|
| 765 | if (dattr)
|
| 766 | *(dattr + nslot) = SD_ATTR_INIT;
|
| 767 | for (j = i; j < csn; j++) {
|
| 768 | struct cpuset *b = csa[j];
|
| 769 |
|
| 770 | if (apn == b->pn) {
|
| 771 | cpumask_or(dp, dp, b->effective_cpus);
|
| 772 | cpumask_and(dp, dp, non_isolated_cpus);
|
| 773 | if (dattr)
|
| 774 | update_domain_attr_tree(dattr + nslot, b);
|
| 775 |
|
| 776 |
|
| 777 | b->pn = -1;
|
| 778 | }
|
| 779 | }
|
| 780 | nslot++;
|
| 781 | }
|
| 782 | BUG_ON(nslot != ndoms);
|
| 783 |
|
| 784 | done:
|
| 785 | free_cpumask_var(non_isolated_cpus);
|
| 786 | kfree(csa);
|
| 787 |
|
| 788 | |
| 789 | * Fallback to the default domain if kmalloc() failed.
|
| 790 | * See comments in partition_sched_domains().
|
| 791 |
|
| 792 | if (doms == NULL)
|
| 793 | ndoms = 1;
|
| 794 |
|
| 795 | *domains = doms;
|
| 796 | *attributes = dattr;
|
| 797 | return ndoms;
|
| 798 | }
|
| 799 |
|
| 800 | |
| 801 | * Rebuild scheduler domains.
|
| 802 | *
|
| 803 | * If the flag 'sched_load_balance' of any cpuset with non-empty
|
| 804 | * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset
|
| 805 | * which has that flag enabled, or if any cpuset with a non-empty
|
| 806 | * 'cpus' is removed, then call this routine to rebuild the
|
| 807 | * scheduler's dynamic sched domains.
|
| 808 | *
|
| 809 | * Call with cpuset_mutex held. Takes get_online_cpus().
|
| 810 |
|
| 811 | static void rebuild_sched_domains_locked(void)
|
| 812 | {
|
| 813 | struct sched_domain_attr *attr;
|
| 814 | cpumask_var_t *doms;
|
| 815 | int ndoms;
|
| 816 |
|
| 817 | lockdep_assert_held(&cpuset_mutex);
|
| 818 | get_online_cpus();
|
| 819 |
|
| 820 | |
| 821 | * We have raced with CPU hotplug. Don't do anything to avoid
|
| 822 | * passing doms with offlined cpu to partition_sched_domains().
|
| 823 | * Anyways, hotplug work item will rebuild sched domains.
|
| 824 |
|
| 825 | if (!cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask))
|
| 826 | goto out;
|
| 827 |
|
| 828 |
|
| 829 | ndoms = generate_sched_domains(&doms, &attr);
|
| 830 |
|
| 831 |
|
| 832 | partition_sched_domains(ndoms, doms, attr);
|
| 833 | out:
|
| 834 | put_online_cpus();
|
| 835 | }
|
| 836 | #else
|
| 837 | static void rebuild_sched_domains_locked(void)
|
| 838 | {
|
| 839 | }
|
| 840 | #endif
|
| 841 |
|
| 842 | void rebuild_sched_domains(void)
|
| 843 | {
|
| 844 | mutex_lock(&cpuset_mutex);
|
| 845 | rebuild_sched_domains_locked();
|
| 846 | mutex_unlock(&cpuset_mutex);
|
| 847 | }
|
| 848 |
|
| 849 | |
| 850 | * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset.
|
| 851 | * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed
|
| 852 | *
|
| 853 | * Iterate through each task of @cs updating its cpus_allowed to the
|
| 854 | * effective cpuset's. As this function is called with cpuset_mutex held,
|
| 855 | * cpuset membership stays stable.
|
| 856 |
|
| 857 | static void update_tasks_cpumask(struct cpuset *cs)
|
| 858 | {
|
| 859 | struct css_task_iter it;
|
| 860 | struct task_struct *task;
|
| 861 |
|
| 862 | css_task_iter_start(&cs->css, &it);
|
| 863 | while ((task = css_task_iter_next(&it)))
|
| 864 | set_cpus_allowed_ptr(task, cs->effective_cpus);
|
| 865 | css_task_iter_end(&it);
|
| 866 | }
|
| 867 |
|
| 868 | |
| 869 | * update_cpumasks_hier - Update effective cpumasks and tasks in the subtree
|
| 870 | * @cs: the cpuset to consider
|
| 871 | * @new_cpus: temp variable for calculating new effective_cpus
|
| 872 | *
|
| 873 | * When congifured cpumask is changed, the effective cpumasks of this cpuset
|
| 874 | * and all its descendants need to be updated.
|
| 875 | *
|
| 876 | * On legacy hierachy, effective_cpus will be the same with cpu_allowed.
|
| 877 | *
|
| 878 | * Called with cpuset_mutex held
|
| 879 |
|
| 880 | static void update_cpumasks_hier(struct cpuset *cs, struct cpumask *new_cpus)
|
| 881 | {
|
| 882 | struct cpuset *cp;
|
| 883 | struct cgroup_subsys_state *pos_css;
|
| 884 | bool need_rebuild_sched_domains = false;
|
| 885 |
|
| 886 | rcu_read_lock();
|
| 887 | cpuset_for_each_descendant_pre(cp, pos_css, cs) {
|
| 888 | struct cpuset *parent = parent_cs(cp);
|
| 889 |
|
| 890 | cpumask_and(new_cpus, cp->cpus_allowed, parent->effective_cpus);
|
| 891 |
|
| 892 | |
| 893 | * If it becomes empty, inherit the effective mask of the
|
| 894 | * parent, which is guaranteed to have some CPUs.
|
| 895 |
|
| 896 | if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
|
| 897 | cpumask_empty(new_cpus))
|
| 898 | cpumask_copy(new_cpus, parent->effective_cpus);
|
| 899 |
|
| 900 |
|
| 901 | if (cpumask_equal(new_cpus, cp->effective_cpus)) {
|
| 902 | pos_css = css_rightmost_descendant(pos_css);
|
| 903 | continue;
|
| 904 | }
|
| 905 |
|
| 906 | if (!css_tryget_online(&cp->css))
|
| 907 | continue;
|
| 908 | rcu_read_unlock();
|
| 909 |
|
| 910 | spin_lock_irq(&callback_lock);
|
| 911 | cpumask_copy(cp->effective_cpus, new_cpus);
|
| 912 | spin_unlock_irq(&callback_lock);
|
| 913 |
|
| 914 | WARN_ON(!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
|
| 915 | !cpumask_equal(cp->cpus_allowed, cp->effective_cpus));
|
| 916 |
|
| 917 | update_tasks_cpumask(cp);
|
| 918 |
|
| 919 | |
| 920 | * If the effective cpumask of any non-empty cpuset is changed,
|
| 921 | * we need to rebuild sched domains.
|
| 922 |
|
| 923 | if (!cpumask_empty(cp->cpus_allowed) &&
|
| 924 | is_sched_load_balance(cp))
|
| 925 | need_rebuild_sched_domains = true;
|
| 926 |
|
| 927 | rcu_read_lock();
|
| 928 | css_put(&cp->css);
|
| 929 | }
|
| 930 | rcu_read_unlock();
|
| 931 |
|
| 932 | if (need_rebuild_sched_domains)
|
| 933 | rebuild_sched_domains_locked();
|
| 934 | }
|
| 935 |
|
| 936 | |
| 937 | * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it
|
| 938 | * @cs: the cpuset to consider
|
| 939 | * @trialcs: trial cpuset
|
| 940 | * @buf: buffer of cpu numbers written to this cpuset
|
| 941 |
|
| 942 | static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
|
| 943 | const char *buf)
|
| 944 | {
|
| 945 | int retval;
|
| 946 |
|
| 947 |
|
| 948 | if (cs == &top_cpuset)
|
| 949 | return -EACCES;
|
| 950 |
|
| 951 | |
| 952 | * An empty cpus_allowed is ok only if the cpuset has no tasks.
|
| 953 | * Since cpulist_parse() fails on an empty mask, we special case
|
| 954 | * that parsing. The validate_change() call ensures that cpusets
|
| 955 | * with tasks have cpus.
|
| 956 |
|
| 957 | if (!*buf) {
|
| 958 | cpumask_clear(trialcs->cpus_allowed);
|
| 959 | } else {
|
| 960 | retval = cpulist_parse(buf, trialcs->cpus_allowed);
|
| 961 | if (retval < 0)
|
| 962 | return retval;
|
| 963 |
|
| 964 | if (!cpumask_subset(trialcs->cpus_allowed,
|
| 965 | top_cpuset.cpus_allowed))
|
| 966 | return -EINVAL;
|
| 967 | }
|
| 968 |
|
| 969 |
|
| 970 | if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed))
|
| 971 | return 0;
|
| 972 |
|
| 973 | retval = validate_change(cs, trialcs);
|
| 974 | if (retval < 0)
|
| 975 | return retval;
|
| 976 |
|
| 977 | spin_lock_irq(&callback_lock);
|
| 978 | cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed);
|
| 979 | spin_unlock_irq(&callback_lock);
|
| 980 |
|
| 981 |
|
| 982 | update_cpumasks_hier(cs, trialcs->cpus_allowed);
|
| 983 | return 0;
|
| 984 | }
|
| 985 |
|
| 986 | |
| 987 | * Migrate memory region from one set of nodes to another. This is
|
| 988 | * performed asynchronously as it can be called from process migration path
|
| 989 | * holding locks involved in process management. All mm migrations are
|
| 990 | * performed in the queued order and can be waited for by flushing
|
| 991 | * cpuset_migrate_mm_wq.
|
| 992 |
|
| 993 |
|
| 994 | struct cpuset_migrate_mm_work {
|
| 995 | struct work_struct work;
|
| 996 | struct mm_struct *mm;
|
| 997 | nodemask_t from;
|
| 998 | nodemask_t to;
|
| 999 | };
|
| 1000 |
|
| 1001 | static void cpuset_migrate_mm_workfn(struct work_struct *work)
|
| 1002 | {
|
| 1003 | struct cpuset_migrate_mm_work *mwork =
|
| 1004 | container_of(work, struct cpuset_migrate_mm_work, work);
|
| 1005 |
|
| 1006 |
|
| 1007 | do_migrate_pages(mwork->mm, &mwork->from, &mwork->to, MPOL_MF_MOVE_ALL);
|
| 1008 | mmput(mwork->mm);
|
| 1009 | kfree(mwork);
|
| 1010 | }
|
| 1011 |
|
| 1012 | static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
|
| 1013 | const nodemask_t *to)
|
| 1014 | {
|
| 1015 | struct cpuset_migrate_mm_work *mwork;
|
| 1016 |
|
| 1017 | mwork = kzalloc(sizeof(*mwork), GFP_KERNEL);
|
| 1018 | if (mwork) {
|
| 1019 | mwork->mm = mm;
|
| 1020 | mwork->from = *from;
|
| 1021 | mwork->to = *to;
|
| 1022 | INIT_WORK(&mwork->work, cpuset_migrate_mm_workfn);
|
| 1023 | queue_work(cpuset_migrate_mm_wq, &mwork->work);
|
| 1024 | } else {
|
| 1025 | mmput(mm);
|
| 1026 | }
|
| 1027 | }
|
| 1028 |
|
| 1029 | static void cpuset_post_attach(void)
|
| 1030 | {
|
| 1031 | flush_workqueue(cpuset_migrate_mm_wq);
|
| 1032 | }
|
| 1033 |
|
| 1034 | |
| 1035 | * cpuset_change_task_nodemask - change task's mems_allowed and mempolicy
|
| 1036 | * @tsk: the task to change
|
| 1037 | * @newmems: new nodes that the task will be set
|
| 1038 | *
|
| 1039 | * In order to avoid seeing no nodes if the old and new nodes are disjoint,
|
| 1040 | * we structure updates as setting all new allowed nodes, then clearing newly
|
| 1041 | * disallowed ones.
|
| 1042 |
|
| 1043 | static void cpuset_change_task_nodemask(struct task_struct *tsk,
|
| 1044 | nodemask_t *newmems)
|
| 1045 | {
|
| 1046 | bool need_loop;
|
| 1047 |
|
| 1048 | task_lock(tsk);
|
| 1049 | |
| 1050 | * Determine if a loop is necessary if another thread is doing
|
| 1051 | * read_mems_allowed_begin(). If at least one node remains unchanged and
|
| 1052 | * tsk does not have a mempolicy, then an empty nodemask will not be
|
| 1053 | * possible when mems_allowed is larger than a word.
|
| 1054 |
|
| 1055 | need_loop = task_has_mempolicy(tsk) ||
|
| 1056 | !nodes_intersects(*newmems, tsk->mems_allowed);
|
| 1057 |
|
| 1058 | if (need_loop) {
|
| 1059 | local_irq_disable();
|
| 1060 | write_seqcount_begin(&tsk->mems_allowed_seq);
|
| 1061 | }
|
| 1062 |
|
| 1063 | nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
|
| 1064 | mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP1);
|
| 1065 |
|
| 1066 | mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP2);
|
| 1067 | tsk->mems_allowed = *newmems;
|
| 1068 |
|
| 1069 | if (need_loop) {
|
| 1070 | write_seqcount_end(&tsk->mems_allowed_seq);
|
| 1071 | local_irq_enable();
|
| 1072 | }
|
| 1073 |
|
| 1074 | task_unlock(tsk);
|
| 1075 | }
|
| 1076 |
|
| 1077 | static void *cpuset_being_rebound;
|
| 1078 |
|
| 1079 | |
| 1080 | * update_tasks_nodemask - Update the nodemasks of tasks in the cpuset.
|
| 1081 | * @cs: the cpuset in which each task's mems_allowed mask needs to be changed
|
| 1082 | *
|
| 1083 | * Iterate through each task of @cs updating its mems_allowed to the
|
| 1084 | * effective cpuset's. As this function is called with cpuset_mutex held,
|
| 1085 | * cpuset membership stays stable.
|
| 1086 |
|
| 1087 | static void update_tasks_nodemask(struct cpuset *cs)
|
| 1088 | {
|
| 1089 | static nodemask_t newmems;
|
| 1090 | struct css_task_iter it;
|
| 1091 | struct task_struct *task;
|
| 1092 |
|
| 1093 | cpuset_being_rebound = cs;
|
| 1094 |
|
| 1095 | guarantee_online_mems(cs, &newmems);
|
| 1096 |
|
| 1097 | |
| 1098 | * The mpol_rebind_mm() call takes mmap_sem, which we couldn't
|
| 1099 | * take while holding tasklist_lock. Forks can happen - the
|
| 1100 | * mpol_dup() cpuset_being_rebound check will catch such forks,
|
| 1101 | * and rebind their vma mempolicies too. Because we still hold
|
| 1102 | * the global cpuset_mutex, we know that no other rebind effort
|
| 1103 | * will be contending for the global variable cpuset_being_rebound.
|
| 1104 | * It's ok if we rebind the same mm twice; mpol_rebind_mm()
|
| 1105 | * is idempotent. Also migrate pages in each mm to new nodes.
|
| 1106 |
|
| 1107 | css_task_iter_start(&cs->css, &it);
|
| 1108 | while ((task = css_task_iter_next(&it))) {
|
| 1109 | struct mm_struct *mm;
|
| 1110 | bool migrate;
|
| 1111 |
|
| 1112 | cpuset_change_task_nodemask(task, &newmems);
|
| 1113 |
|
| 1114 | mm = get_task_mm(task);
|
| 1115 | if (!mm)
|
| 1116 | continue;
|
| 1117 |
|
| 1118 | migrate = is_memory_migrate(cs);
|
| 1119 |
|
| 1120 | mpol_rebind_mm(mm, &cs->mems_allowed);
|
| 1121 | if (migrate)
|
| 1122 | cpuset_migrate_mm(mm, &cs->old_mems_allowed, &newmems);
|
| 1123 | else
|
| 1124 | mmput(mm);
|
| 1125 | }
|
| 1126 | css_task_iter_end(&it);
|
| 1127 |
|
| 1128 | |
| 1129 | * All the tasks' nodemasks have been updated, update
|
| 1130 | * cs->old_mems_allowed.
|
| 1131 |
|
| 1132 | cs->old_mems_allowed = newmems;
|
| 1133 |
|
| 1134 |
|
| 1135 | cpuset_being_rebound = NULL;
|
| 1136 | }
|
| 1137 |
|
| 1138 | |
| 1139 | * update_nodemasks_hier - Update effective nodemasks and tasks in the subtree
|
| 1140 | * @cs: the cpuset to consider
|
| 1141 | * @new_mems: a temp variable for calculating new effective_mems
|
| 1142 | *
|
| 1143 | * When configured nodemask is changed, the effective nodemasks of this cpuset
|
| 1144 | * and all its descendants need to be updated.
|
| 1145 | *
|
| 1146 | * On legacy hiearchy, effective_mems will be the same with mems_allowed.
|
| 1147 | *
|
| 1148 | * Called with cpuset_mutex held
|
| 1149 |
|
| 1150 | static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems)
|
| 1151 | {
|
| 1152 | struct cpuset *cp;
|
| 1153 | struct cgroup_subsys_state *pos_css;
|
| 1154 |
|
| 1155 | rcu_read_lock();
|
| 1156 | cpuset_for_each_descendant_pre(cp, pos_css, cs) {
|
| 1157 | struct cpuset *parent = parent_cs(cp);
|
| 1158 |
|
| 1159 | nodes_and(*new_mems, cp->mems_allowed, parent->effective_mems);
|
| 1160 |
|
| 1161 | |
| 1162 | * If it becomes empty, inherit the effective mask of the
|
| 1163 | * parent, which is guaranteed to have some MEMs.
|
| 1164 |
|
| 1165 | if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
|
| 1166 | nodes_empty(*new_mems))
|
| 1167 | *new_mems = parent->effective_mems;
|
| 1168 |
|
| 1169 |
|
| 1170 | if (nodes_equal(*new_mems, cp->effective_mems)) {
|
| 1171 | pos_css = css_rightmost_descendant(pos_css);
|
| 1172 | continue;
|
| 1173 | }
|
| 1174 |
|
| 1175 | if (!css_tryget_online(&cp->css))
|
| 1176 | continue;
|
| 1177 | rcu_read_unlock();
|
| 1178 |
|
| 1179 | spin_lock_irq(&callback_lock);
|
| 1180 | cp->effective_mems = *new_mems;
|
| 1181 | spin_unlock_irq(&callback_lock);
|
| 1182 |
|
| 1183 | WARN_ON(!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
|
| 1184 | !nodes_equal(cp->mems_allowed, cp->effective_mems));
|
| 1185 |
|
| 1186 | update_tasks_nodemask(cp);
|
| 1187 |
|
| 1188 | rcu_read_lock();
|
| 1189 | css_put(&cp->css);
|
| 1190 | }
|
| 1191 | rcu_read_unlock();
|
| 1192 | }
|
| 1193 |
|
| 1194 | |
| 1195 | * Handle user request to change the 'mems' memory placement
|
| 1196 | * of a cpuset. Needs to validate the request, update the
|
| 1197 | * cpusets mems_allowed, and for each task in the cpuset,
|
| 1198 | * update mems_allowed and rebind task's mempolicy and any vma
|
| 1199 | * mempolicies and if the cpuset is marked 'memory_migrate',
|
| 1200 | * migrate the tasks pages to the new memory.
|
| 1201 | *
|
| 1202 | * Call with cpuset_mutex held. May take callback_lock during call.
|
| 1203 | * Will take tasklist_lock, scan tasklist for tasks in cpuset cs,
|
| 1204 | * lock each such tasks mm->mmap_sem, scan its vma's and rebind
|
| 1205 | * their mempolicies to the cpusets new mems_allowed.
|
| 1206 |
|
| 1207 | static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs,
|
| 1208 | const char *buf)
|
| 1209 | {
|
| 1210 | int retval;
|
| 1211 |
|
| 1212 | |
| 1213 | * top_cpuset.mems_allowed tracks node_stats[N_MEMORY];
|
| 1214 | * it's read-only
|
| 1215 |
|
| 1216 | if (cs == &top_cpuset) {
|
| 1217 | retval = -EACCES;
|
| 1218 | goto done;
|
| 1219 | }
|
| 1220 |
|
| 1221 | |
| 1222 | * An empty mems_allowed is ok iff there are no tasks in the cpuset.
|
| 1223 | * Since nodelist_parse() fails on an empty mask, we special case
|
| 1224 | * that parsing. The validate_change() call ensures that cpusets
|
| 1225 | * with tasks have memory.
|
| 1226 |
|
| 1227 | if (!*buf) {
|
| 1228 | nodes_clear(trialcs->mems_allowed);
|
| 1229 | } else {
|
| 1230 | retval = nodelist_parse(buf, trialcs->mems_allowed);
|
| 1231 | if (retval < 0)
|
| 1232 | goto done;
|
| 1233 |
|
| 1234 | if (!nodes_subset(trialcs->mems_allowed,
|
| 1235 | top_cpuset.mems_allowed)) {
|
| 1236 | retval = -EINVAL;
|
| 1237 | goto done;
|
| 1238 | }
|
| 1239 | }
|
| 1240 |
|
| 1241 | if (nodes_equal(cs->mems_allowed, trialcs->mems_allowed)) {
|
| 1242 | retval = 0;
|
| 1243 | goto done;
|
| 1244 | }
|
| 1245 | retval = validate_change(cs, trialcs);
|
| 1246 | if (retval < 0)
|
| 1247 | goto done;
|
| 1248 |
|
| 1249 | spin_lock_irq(&callback_lock);
|
| 1250 | cs->mems_allowed = trialcs->mems_allowed;
|
| 1251 | spin_unlock_irq(&callback_lock);
|
| 1252 |
|
| 1253 |
|
| 1254 | update_nodemasks_hier(cs, &trialcs->mems_allowed);
|
| 1255 | done:
|
| 1256 | return retval;
|
| 1257 | }
|
| 1258 |
|
| 1259 | int current_cpuset_is_being_rebound(void)
|
| 1260 | {
|
| 1261 | int ret;
|
| 1262 |
|
| 1263 | rcu_read_lock();
|
| 1264 | ret = task_cs(current) == cpuset_being_rebound;
|
| 1265 | rcu_read_unlock();
|
| 1266 |
|
| 1267 | return ret;
|
| 1268 | }
|
| 1269 |
|
| 1270 | static int update_relax_domain_level(struct cpuset *cs, s64 val)
|
| 1271 | {
|
| 1272 | #ifdef CONFIG_SMP
|
| 1273 | if (val < -1 || val >= sched_domain_level_max)
|
| 1274 | return -EINVAL;
|
| 1275 | #endif
|
| 1276 |
|
| 1277 | if (val != cs->relax_domain_level) {
|
| 1278 | cs->relax_domain_level = val;
|
| 1279 | if (!cpumask_empty(cs->cpus_allowed) &&
|
| 1280 | is_sched_load_balance(cs))
|
| 1281 | rebuild_sched_domains_locked();
|
| 1282 | }
|
| 1283 |
|
| 1284 | return 0;
|
| 1285 | }
|
| 1286 |
|
| 1287 | |
| 1288 | * update_tasks_flags - update the spread flags of tasks in the cpuset.
|
| 1289 | * @cs: the cpuset in which each task's spread flags needs to be changed
|
| 1290 | *
|
| 1291 | * Iterate through each task of @cs updating its spread flags. As this
|
| 1292 | * function is called with cpuset_mutex held, cpuset membership stays
|
| 1293 | * stable.
|
| 1294 |
|
| 1295 | static void update_tasks_flags(struct cpuset *cs)
|
| 1296 | {
|
| 1297 | struct css_task_iter it;
|
| 1298 | struct task_struct *task;
|
| 1299 |
|
| 1300 | css_task_iter_start(&cs->css, &it);
|
| 1301 | while ((task = css_task_iter_next(&it)))
|
| 1302 | cpuset_update_task_spread_flag(cs, task);
|
| 1303 | css_task_iter_end(&it);
|
| 1304 | }
|
| 1305 |
|
| 1306 | |
| 1307 | * update_flag - read a 0 or a 1 in a file and update associated flag
|
| 1308 | * bit: the bit to update (see cpuset_flagbits_t)
|
| 1309 | * cs: the cpuset to update
|
| 1310 | * turning_on: whether the flag is being set or cleared
|
| 1311 | *
|
| 1312 | * Call with cpuset_mutex held.
|
| 1313 |
|
| 1314 |
|
| 1315 | static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
|
| 1316 | int turning_on)
|
| 1317 | {
|
| 1318 | struct cpuset *trialcs;
|
| 1319 | int balance_flag_changed;
|
| 1320 | int spread_flag_changed;
|
| 1321 | int err;
|
| 1322 |
|
| 1323 | trialcs = alloc_trial_cpuset(cs);
|
| 1324 | if (!trialcs)
|
| 1325 | return -ENOMEM;
|
| 1326 |
|
| 1327 | if (turning_on)
|
| 1328 | set_bit(bit, &trialcs->flags);
|
| 1329 | else
|
| 1330 | clear_bit(bit, &trialcs->flags);
|
| 1331 |
|
| 1332 | err = validate_change(cs, trialcs);
|
| 1333 | if (err < 0)
|
| 1334 | goto out;
|
| 1335 |
|
| 1336 | balance_flag_changed = (is_sched_load_balance(cs) !=
|
| 1337 | is_sched_load_balance(trialcs));
|
| 1338 |
|
| 1339 | spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs))
|
| 1340 | || (is_spread_page(cs) != is_spread_page(trialcs)));
|
| 1341 |
|
| 1342 | spin_lock_irq(&callback_lock);
|
| 1343 | cs->flags = trialcs->flags;
|
| 1344 | spin_unlock_irq(&callback_lock);
|
| 1345 |
|
| 1346 | if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
|
| 1347 | rebuild_sched_domains_locked();
|
| 1348 |
|
| 1349 | if (spread_flag_changed)
|
| 1350 | update_tasks_flags(cs);
|
| 1351 | out:
|
| 1352 | free_trial_cpuset(trialcs);
|
| 1353 | return err;
|
| 1354 | }
|
| 1355 |
|
| 1356 | |
| 1357 | * Frequency meter - How fast is some event occurring?
|
| 1358 | *
|
| 1359 | * These routines manage a digitally filtered, constant time based,
|
| 1360 | * event frequency meter. There are four routines:
|
| 1361 | * fmeter_init() - initialize a frequency meter.
|
| 1362 | * fmeter_markevent() - called each time the event happens.
|
| 1363 | * fmeter_getrate() - returns the recent rate of such events.
|
| 1364 | * fmeter_update() - internal routine used to update fmeter.
|
| 1365 | *
|
| 1366 | * A common data structure is passed to each of these routines,
|
| 1367 | * which is used to keep track of the state required to manage the
|
| 1368 | * frequency meter and its digital filter.
|
| 1369 | *
|
| 1370 | * The filter works on the number of events marked per unit time.
|
| 1371 | * The filter is single-pole low-pass recursive (IIR). The time unit
|
| 1372 | * is 1 second. Arithmetic is done using 32-bit integers scaled to
|
| 1373 | * simulate 3 decimal digits of precision (multiplied by 1000).
|
| 1374 | *
|
| 1375 | * With an FM_COEF of 933, and a time base of 1 second, the filter
|
| 1376 | * has a half-life of 10 seconds, meaning that if the events quit
|
| 1377 | * happening, then the rate returned from the fmeter_getrate()
|
| 1378 | * will be cut in half each 10 seconds, until it converges to zero.
|
| 1379 | *
|
| 1380 | * It is not worth doing a real infinitely recursive filter. If more
|
| 1381 | * than FM_MAXTICKS ticks have elapsed since the last filter event,
|
| 1382 | * just compute FM_MAXTICKS ticks worth, by which point the level
|
| 1383 | * will be stable.
|
| 1384 | *
|
| 1385 | * Limit the count of unprocessed events to FM_MAXCNT, so as to avoid
|
| 1386 | * arithmetic overflow in the fmeter_update() routine.
|
| 1387 | *
|
| 1388 | * Given the simple 32 bit integer arithmetic used, this meter works
|
| 1389 | * best for reporting rates between one per millisecond (msec) and
|
| 1390 | * one per 32 (approx) seconds. At constant rates faster than one
|
| 1391 | * per msec it maxes out at values just under 1,000,000. At constant
|
| 1392 | * rates between one per msec, and one per second it will stabilize
|
| 1393 | * to a value N*1000, where N is the rate of events per second.
|
| 1394 | * At constant rates between one per second and one per 32 seconds,
|
| 1395 | * it will be choppy, moving up on the seconds that have an event,
|
| 1396 | * and then decaying until the next event. At rates slower than
|
| 1397 | * about one in 32 seconds, it decays all the way back to zero between
|
| 1398 | * each event.
|
| 1399 |
|
| 1400 |
|
| 1401 | #define FM_COEF 933
|
| 1402 | #define FM_MAXTICKS ((u32)99)
|
| 1403 | #define FM_MAXCNT 1000000
|
| 1404 | #define FM_SCALE 1000
|
| 1405 |
|
| 1406 |
|
| 1407 | static void fmeter_init(struct fmeter *fmp)
|
| 1408 | {
|
| 1409 | fmp->cnt = 0;
|
| 1410 | fmp->val = 0;
|
| 1411 | fmp->time = 0;
|
| 1412 | spin_lock_init(&fmp->lock);
|
| 1413 | }
|
| 1414 |
|
| 1415 |
|
| 1416 | static void fmeter_update(struct fmeter *fmp)
|
| 1417 | {
|
| 1418 | time64_t now;
|
| 1419 | u32 ticks;
|
| 1420 |
|
| 1421 | now = ktime_get_seconds();
|
| 1422 | ticks = now - fmp->time;
|
| 1423 |
|
| 1424 | if (ticks == 0)
|
| 1425 | return;
|
| 1426 |
|
| 1427 | ticks = min(FM_MAXTICKS, ticks);
|
| 1428 | while (ticks-- > 0)
|
| 1429 | fmp->val = (FM_COEF * fmp->val) / FM_SCALE;
|
| 1430 | fmp->time = now;
|
| 1431 |
|
| 1432 | fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE;
|
| 1433 | fmp->cnt = 0;
|
| 1434 | }
|
| 1435 |
|
| 1436 |
|
| 1437 | static void fmeter_markevent(struct fmeter *fmp)
|
| 1438 | {
|
| 1439 | spin_lock(&fmp->lock);
|
| 1440 | fmeter_update(fmp);
|
| 1441 | fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE);
|
| 1442 | spin_unlock(&fmp->lock);
|
| 1443 | }
|
| 1444 |
|
| 1445 |
|
| 1446 | static int fmeter_getrate(struct fmeter *fmp)
|
| 1447 | {
|
| 1448 | int val;
|
| 1449 |
|
| 1450 | spin_lock(&fmp->lock);
|
| 1451 | fmeter_update(fmp);
|
| 1452 | val = fmp->val;
|
| 1453 | spin_unlock(&fmp->lock);
|
| 1454 | return val;
|
| 1455 | }
|
| 1456 |
|
| 1457 | static struct cpuset *cpuset_attach_old_cs;
|
| 1458 |
|
| 1459 |
|
| 1460 | static int cpuset_can_attach(struct cgroup_taskset *tset)
|
| 1461 | {
|
| 1462 | struct cgroup_subsys_state *css;
|
| 1463 | struct cpuset *cs;
|
| 1464 | struct task_struct *task;
|
| 1465 | int ret;
|
| 1466 |
|
| 1467 |
|
| 1468 | cpuset_attach_old_cs = task_cs(cgroup_taskset_first(tset, &css));
|
| 1469 | cs = css_cs(css);
|
| 1470 |
|
| 1471 | mutex_lock(&cpuset_mutex);
|
| 1472 |
|
| 1473 |
|
| 1474 | ret = -ENOSPC;
|
| 1475 | if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
|
| 1476 | (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)))
|
| 1477 | goto out_unlock;
|
| 1478 |
|
| 1479 | cgroup_taskset_for_each(task, css, tset) {
|
| 1480 | ret = task_can_attach(task, cs->cpus_allowed);
|
| 1481 | if (ret)
|
| 1482 | goto out_unlock;
|
| 1483 | ret = security_task_setscheduler(task);
|
| 1484 | if (ret)
|
| 1485 | goto out_unlock;
|
| 1486 | }
|
| 1487 |
|
| 1488 | |
| 1489 | * Mark attach is in progress. This makes validate_change() fail
|
| 1490 | * changes which zero cpus/mems_allowed.
|
| 1491 |
|
| 1492 | cs->attach_in_progress++;
|
| 1493 | ret = 0;
|
| 1494 | out_unlock:
|
| 1495 | mutex_unlock(&cpuset_mutex);
|
| 1496 | return ret;
|
| 1497 | }
|
| 1498 |
|
| 1499 | static void cpuset_cancel_attach(struct cgroup_taskset *tset)
|
| 1500 | {
|
| 1501 | struct cgroup_subsys_state *css;
|
| 1502 | struct cpuset *cs;
|
| 1503 |
|
| 1504 | cgroup_taskset_first(tset, &css);
|
| 1505 | cs = css_cs(css);
|
| 1506 |
|
| 1507 | mutex_lock(&cpuset_mutex);
|
| 1508 | css_cs(css)->attach_in_progress--;
|
| 1509 | mutex_unlock(&cpuset_mutex);
|
| 1510 | }
|
| 1511 |
|
| 1512 | |
| 1513 | * Protected by cpuset_mutex. cpus_attach is used only by cpuset_attach()
|
| 1514 | * but we can't allocate it dynamically there. Define it global and
|
| 1515 | * allocate from cpuset_init().
|
| 1516 |
|
| 1517 | static cpumask_var_t cpus_attach;
|
| 1518 |
|
| 1519 | static void cpuset_attach(struct cgroup_taskset *tset)
|
| 1520 | {
|
| 1521 |
|
| 1522 | static nodemask_t cpuset_attach_nodemask_to;
|
| 1523 | struct task_struct *task;
|
| 1524 | struct task_struct *leader;
|
| 1525 | struct cgroup_subsys_state *css;
|
| 1526 | struct cpuset *cs;
|
| 1527 | struct cpuset *oldcs = cpuset_attach_old_cs;
|
| 1528 |
|
| 1529 | cgroup_taskset_first(tset, &css);
|
| 1530 | cs = css_cs(css);
|
| 1531 |
|
| 1532 | mutex_lock(&cpuset_mutex);
|
| 1533 |
|
| 1534 |
|
| 1535 | if (cs == &top_cpuset)
|
| 1536 | cpumask_copy(cpus_attach, cpu_possible_mask);
|
| 1537 | else
|
| 1538 | guarantee_online_cpus(cs, cpus_attach);
|
| 1539 |
|
| 1540 | guarantee_online_mems(cs, &cpuset_attach_nodemask_to);
|
| 1541 |
|
| 1542 | cgroup_taskset_for_each(task, css, tset) {
|
| 1543 | |
| 1544 | * can_attach beforehand should guarantee that this doesn't
|
| 1545 | * fail. TODO: have a better way to handle failure here
|
| 1546 |
|
| 1547 | WARN_ON_ONCE(set_cpus_allowed_ptr(task, cpus_attach));
|
| 1548 |
|
| 1549 | cpuset_change_task_nodemask(task, &cpuset_attach_nodemask_to);
|
| 1550 | cpuset_update_task_spread_flag(cs, task);
|
| 1551 | }
|
| 1552 |
|
| 1553 | |
| 1554 | * Change mm for all threadgroup leaders. This is expensive and may
|
| 1555 | * sleep and should be moved outside migration path proper.
|
| 1556 |
|
| 1557 | cpuset_attach_nodemask_to = cs->effective_mems;
|
| 1558 | cgroup_taskset_for_each_leader(leader, css, tset) {
|
| 1559 | struct mm_struct *mm = get_task_mm(leader);
|
| 1560 |
|
| 1561 | if (mm) {
|
| 1562 | mpol_rebind_mm(mm, &cpuset_attach_nodemask_to);
|
| 1563 |
|
| 1564 | |
| 1565 | * old_mems_allowed is the same with mems_allowed
|
| 1566 | * here, except if this task is being moved
|
| 1567 | * automatically due to hotplug. In that case
|
| 1568 | * @mems_allowed has been updated and is empty, so
|
| 1569 | * @old_mems_allowed is the right nodesets that we
|
| 1570 | * migrate mm from.
|
| 1571 |
|
| 1572 | if (is_memory_migrate(cs))
|
| 1573 | cpuset_migrate_mm(mm, &oldcs->old_mems_allowed,
|
| 1574 | &cpuset_attach_nodemask_to);
|
| 1575 | else
|
| 1576 | mmput(mm);
|
| 1577 | }
|
| 1578 | }
|
| 1579 |
|
| 1580 | cs->old_mems_allowed = cpuset_attach_nodemask_to;
|
| 1581 |
|
| 1582 | cs->attach_in_progress--;
|
| 1583 | if (!cs->attach_in_progress)
|
| 1584 | wake_up(&cpuset_attach_wq);
|
| 1585 |
|
| 1586 | mutex_unlock(&cpuset_mutex);
|
| 1587 | }
|
| 1588 |
|
| 1589 |
|
| 1590 |
|
| 1591 | typedef enum {
|
| 1592 | FILE_MEMORY_MIGRATE,
|
| 1593 | FILE_CPULIST,
|
| 1594 | FILE_MEMLIST,
|
| 1595 | FILE_EFFECTIVE_CPULIST,
|
| 1596 | FILE_EFFECTIVE_MEMLIST,
|
| 1597 | FILE_CPU_EXCLUSIVE,
|
| 1598 | FILE_MEM_EXCLUSIVE,
|
| 1599 | FILE_MEM_HARDWALL,
|
| 1600 | FILE_SCHED_LOAD_BALANCE,
|
| 1601 | FILE_SCHED_RELAX_DOMAIN_LEVEL,
|
| 1602 | FILE_MEMORY_PRESSURE_ENABLED,
|
| 1603 | FILE_MEMORY_PRESSURE,
|
| 1604 | FILE_SPREAD_PAGE,
|
| 1605 | FILE_SPREAD_SLAB,
|
| 1606 | } cpuset_filetype_t;
|
| 1607 |
|
| 1608 | static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft,
|
| 1609 | u64 val)
|
| 1610 | {
|
| 1611 | struct cpuset *cs = css_cs(css);
|
| 1612 | cpuset_filetype_t type = cft->private;
|
| 1613 | int retval = 0;
|
| 1614 |
|
| 1615 | mutex_lock(&cpuset_mutex);
|
| 1616 | if (!is_cpuset_online(cs)) {
|
| 1617 | retval = -ENODEV;
|
| 1618 | goto out_unlock;
|
| 1619 | }
|
| 1620 |
|
| 1621 | switch (type) {
|
| 1622 | case FILE_CPU_EXCLUSIVE:
|
| 1623 | retval = update_flag(CS_CPU_EXCLUSIVE, cs, val);
|
| 1624 | break;
|
| 1625 | case FILE_MEM_EXCLUSIVE:
|
| 1626 | retval = update_flag(CS_MEM_EXCLUSIVE, cs, val);
|
| 1627 | break;
|
| 1628 | case FILE_MEM_HARDWALL:
|
| 1629 | retval = update_flag(CS_MEM_HARDWALL, cs, val);
|
| 1630 | break;
|
| 1631 | case FILE_SCHED_LOAD_BALANCE:
|
| 1632 | retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, val);
|
| 1633 | break;
|
| 1634 | case FILE_MEMORY_MIGRATE:
|
| 1635 | retval = update_flag(CS_MEMORY_MIGRATE, cs, val);
|
| 1636 | break;
|
| 1637 | case FILE_MEMORY_PRESSURE_ENABLED:
|
| 1638 | cpuset_memory_pressure_enabled = !!val;
|
| 1639 | break;
|
| 1640 | case FILE_SPREAD_PAGE:
|
| 1641 | retval = update_flag(CS_SPREAD_PAGE, cs, val);
|
| 1642 | break;
|
| 1643 | case FILE_SPREAD_SLAB:
|
| 1644 | retval = update_flag(CS_SPREAD_SLAB, cs, val);
|
| 1645 | break;
|
| 1646 | default:
|
| 1647 | retval = -EINVAL;
|
| 1648 | break;
|
| 1649 | }
|
| 1650 | out_unlock:
|
| 1651 | mutex_unlock(&cpuset_mutex);
|
| 1652 | return retval;
|
| 1653 | }
|
| 1654 |
|
| 1655 | static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft,
|
| 1656 | s64 val)
|
| 1657 | {
|
| 1658 | struct cpuset *cs = css_cs(css);
|
| 1659 | cpuset_filetype_t type = cft->private;
|
| 1660 | int retval = -ENODEV;
|
| 1661 |
|
| 1662 | mutex_lock(&cpuset_mutex);
|
| 1663 | if (!is_cpuset_online(cs))
|
| 1664 | goto out_unlock;
|
| 1665 |
|
| 1666 | switch (type) {
|
| 1667 | case FILE_SCHED_RELAX_DOMAIN_LEVEL:
|
| 1668 | retval = update_relax_domain_level(cs, val);
|
| 1669 | break;
|
| 1670 | default:
|
| 1671 | retval = -EINVAL;
|
| 1672 | break;
|
| 1673 | }
|
| 1674 | out_unlock:
|
| 1675 | mutex_unlock(&cpuset_mutex);
|
| 1676 | return retval;
|
| 1677 | }
|
| 1678 |
|
| 1679 | |
| 1680 | * Common handling for a write to a "cpus" or "mems" file.
|
| 1681 |
|
| 1682 | static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
|
| 1683 | char *buf, size_t nbytes, loff_t off)
|
| 1684 | {
|
| 1685 | struct cpuset *cs = css_cs(of_css(of));
|
| 1686 | struct cpuset *trialcs;
|
| 1687 | int retval = -ENODEV;
|
| 1688 |
|
| 1689 | buf = strstrip(buf);
|
| 1690 |
|
| 1691 | |
| 1692 | * CPU or memory hotunplug may leave @cs w/o any execution
|
| 1693 | * resources, in which case the hotplug code asynchronously updates
|
| 1694 | * configuration and transfers all tasks to the nearest ancestor
|
| 1695 | * which can execute.
|
| 1696 | *
|
| 1697 | * As writes to "cpus" or "mems" may restore @cs's execution
|
| 1698 | * resources, wait for the previously scheduled operations before
|
| 1699 | * proceeding, so that we don't end up keep removing tasks added
|
| 1700 | * after execution capability is restored.
|
| 1701 | *
|
| 1702 | * cpuset_hotplug_work calls back into cgroup core via
|
| 1703 | * cgroup_transfer_tasks() and waiting for it from a cgroupfs
|
| 1704 | * operation like this one can lead to a deadlock through kernfs
|
| 1705 | * active_ref protection. Let's break the protection. Losing the
|
| 1706 | * protection is okay as we check whether @cs is online after
|
| 1707 | * grabbing cpuset_mutex anyway. This only happens on the legacy
|
| 1708 | * hierarchies.
|
| 1709 |
|
| 1710 | css_get(&cs->css);
|
| 1711 | kernfs_break_active_protection(of->kn);
|
| 1712 | flush_work(&cpuset_hotplug_work);
|
| 1713 |
|
| 1714 | mutex_lock(&cpuset_mutex);
|
| 1715 | if (!is_cpuset_online(cs))
|
| 1716 | goto out_unlock;
|
| 1717 |
|
| 1718 | trialcs = alloc_trial_cpuset(cs);
|
| 1719 | if (!trialcs) {
|
| 1720 | retval = -ENOMEM;
|
| 1721 | goto out_unlock;
|
| 1722 | }
|
| 1723 |
|
| 1724 | switch (of_cft(of)->private) {
|
| 1725 | case FILE_CPULIST:
|
| 1726 | retval = update_cpumask(cs, trialcs, buf);
|
| 1727 | break;
|
| 1728 | case FILE_MEMLIST:
|
| 1729 | retval = update_nodemask(cs, trialcs, buf);
|
| 1730 | break;
|
| 1731 | default:
|
| 1732 | retval = -EINVAL;
|
| 1733 | break;
|
| 1734 | }
|
| 1735 |
|
| 1736 | free_trial_cpuset(trialcs);
|
| 1737 | out_unlock:
|
| 1738 | mutex_unlock(&cpuset_mutex);
|
| 1739 | kernfs_unbreak_active_protection(of->kn);
|
| 1740 | css_put(&cs->css);
|
| 1741 | flush_workqueue(cpuset_migrate_mm_wq);
|
| 1742 | return retval ?: nbytes;
|
| 1743 | }
|
| 1744 |
|
| 1745 | |
| 1746 | * These ascii lists should be read in a single call, by using a user
|
| 1747 | * buffer large enough to hold the entire map. If read in smaller
|
| 1748 | * chunks, there is no guarantee of atomicity. Since the display format
|
| 1749 | * used, list of ranges of sequential numbers, is variable length,
|
| 1750 | * and since these maps can change value dynamically, one could read
|
| 1751 | * gibberish by doing partial reads while a list was changing.
|
| 1752 |
|
| 1753 | static int cpuset_common_seq_show(struct seq_file *sf, void *v)
|
| 1754 | {
|
| 1755 | struct cpuset *cs = css_cs(seq_css(sf));
|
| 1756 | cpuset_filetype_t type = seq_cft(sf)->private;
|
| 1757 | int ret = 0;
|
| 1758 |
|
| 1759 | spin_lock_irq(&callback_lock);
|
| 1760 |
|
| 1761 | switch (type) {
|
| 1762 | case FILE_CPULIST:
|
| 1763 | seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->cpus_allowed));
|
| 1764 | break;
|
| 1765 | case FILE_MEMLIST:
|
| 1766 | seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->mems_allowed));
|
| 1767 | break;
|
| 1768 | case FILE_EFFECTIVE_CPULIST:
|
| 1769 | seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->effective_cpus));
|
| 1770 | break;
|
| 1771 | case FILE_EFFECTIVE_MEMLIST:
|
| 1772 | seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->effective_mems));
|
| 1773 | break;
|
| 1774 | default:
|
| 1775 | ret = -EINVAL;
|
| 1776 | }
|
| 1777 |
|
| 1778 | spin_unlock_irq(&callback_lock);
|
| 1779 | return ret;
|
| 1780 | }
|
| 1781 |
|
| 1782 | static u64 cpuset_read_u64(struct cgroup_subsys_state *css, struct cftype *cft)
|
| 1783 | {
|
| 1784 | struct cpuset *cs = css_cs(css);
|
| 1785 | cpuset_filetype_t type = cft->private;
|
| 1786 | switch (type) {
|
| 1787 | case FILE_CPU_EXCLUSIVE:
|
| 1788 | return is_cpu_exclusive(cs);
|
| 1789 | case FILE_MEM_EXCLUSIVE:
|
| 1790 | return is_mem_exclusive(cs);
|
| 1791 | case FILE_MEM_HARDWALL:
|
| 1792 | return is_mem_hardwall(cs);
|
| 1793 | case FILE_SCHED_LOAD_BALANCE:
|
| 1794 | return is_sched_load_balance(cs);
|
| 1795 | case FILE_MEMORY_MIGRATE:
|
| 1796 | return is_memory_migrate(cs);
|
| 1797 | case FILE_MEMORY_PRESSURE_ENABLED:
|
| 1798 | return cpuset_memory_pressure_enabled;
|
| 1799 | case FILE_MEMORY_PRESSURE:
|
| 1800 | return fmeter_getrate(&cs->fmeter);
|
| 1801 | case FILE_SPREAD_PAGE:
|
| 1802 | return is_spread_page(cs);
|
| 1803 | case FILE_SPREAD_SLAB:
|
| 1804 | return is_spread_slab(cs);
|
| 1805 | default:
|
| 1806 | BUG();
|
| 1807 | }
|
| 1808 |
|
| 1809 |
|
| 1810 | return 0;
|
| 1811 | }
|
| 1812 |
|
| 1813 | static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft)
|
| 1814 | {
|
| 1815 | struct cpuset *cs = css_cs(css);
|
| 1816 | cpuset_filetype_t type = cft->private;
|
| 1817 | switch (type) {
|
| 1818 | case FILE_SCHED_RELAX_DOMAIN_LEVEL:
|
| 1819 | return cs->relax_domain_level;
|
| 1820 | default:
|
| 1821 | BUG();
|
| 1822 | }
|
| 1823 |
|
| 1824 |
|
| 1825 | return 0;
|
| 1826 | }
|
| 1827 |
|
| 1828 |
|
| 1829 | |
| 1830 | * for the common functions, 'private' gives the type of file
|
| 1831 |
|
| 1832 |
|
| 1833 | static struct cftype files[] = {
|
| 1834 | {
|
| 1835 | .name = "cpus",
|
| 1836 | .seq_show = cpuset_common_seq_show,
|
| 1837 | .write = cpuset_write_resmask,
|
| 1838 | .max_write_len = (100U + 6 * NR_CPUS),
|
| 1839 | .private = FILE_CPULIST,
|
| 1840 | },
|
| 1841 |
|
| 1842 | {
|
| 1843 | .name = "mems",
|
| 1844 | .seq_show = cpuset_common_seq_show,
|
| 1845 | .write = cpuset_write_resmask,
|
| 1846 | .max_write_len = (100U + 6 * MAX_NUMNODES),
|
| 1847 | .private = FILE_MEMLIST,
|
| 1848 | },
|
| 1849 |
|
| 1850 | {
|
| 1851 | .name = "effective_cpus",
|
| 1852 | .seq_show = cpuset_common_seq_show,
|
| 1853 | .private = FILE_EFFECTIVE_CPULIST,
|
| 1854 | },
|
| 1855 |
|
| 1856 | {
|
| 1857 | .name = "effective_mems",
|
| 1858 | .seq_show = cpuset_common_seq_show,
|
| 1859 | .private = FILE_EFFECTIVE_MEMLIST,
|
| 1860 | },
|
| 1861 |
|
| 1862 | {
|
| 1863 | .name = "cpu_exclusive",
|
| 1864 | .read_u64 = cpuset_read_u64,
|
| 1865 | .write_u64 = cpuset_write_u64,
|
| 1866 | .private = FILE_CPU_EXCLUSIVE,
|
| 1867 | },
|
| 1868 |
|
| 1869 | {
|
| 1870 | .name = "mem_exclusive",
|
| 1871 | .read_u64 = cpuset_read_u64,
|
| 1872 | .write_u64 = cpuset_write_u64,
|
| 1873 | .private = FILE_MEM_EXCLUSIVE,
|
| 1874 | },
|
| 1875 |
|
| 1876 | {
|
| 1877 | .name = "mem_hardwall",
|
| 1878 | .read_u64 = cpuset_read_u64,
|
| 1879 | .write_u64 = cpuset_write_u64,
|
| 1880 | .private = FILE_MEM_HARDWALL,
|
| 1881 | },
|
| 1882 |
|
| 1883 | {
|
| 1884 | .name = "sched_load_balance",
|
| 1885 | .read_u64 = cpuset_read_u64,
|
| 1886 | .write_u64 = cpuset_write_u64,
|
| 1887 | .private = FILE_SCHED_LOAD_BALANCE,
|
| 1888 | },
|
| 1889 |
|
| 1890 | {
|
| 1891 | .name = "sched_relax_domain_level",
|
| 1892 | .read_s64 = cpuset_read_s64,
|
| 1893 | .write_s64 = cpuset_write_s64,
|
| 1894 | .private = FILE_SCHED_RELAX_DOMAIN_LEVEL,
|
| 1895 | },
|
| 1896 |
|
| 1897 | {
|
| 1898 | .name = "memory_migrate",
|
| 1899 | .read_u64 = cpuset_read_u64,
|
| 1900 | .write_u64 = cpuset_write_u64,
|
| 1901 | .private = FILE_MEMORY_MIGRATE,
|
| 1902 | },
|
| 1903 |
|
| 1904 | {
|
| 1905 | .name = "memory_pressure",
|
| 1906 | .read_u64 = cpuset_read_u64,
|
| 1907 | },
|
| 1908 |
|
| 1909 | {
|
| 1910 | .name = "memory_spread_page",
|
| 1911 | .read_u64 = cpuset_read_u64,
|
| 1912 | .write_u64 = cpuset_write_u64,
|
| 1913 | .private = FILE_SPREAD_PAGE,
|
| 1914 | },
|
| 1915 |
|
| 1916 | {
|
| 1917 | .name = "memory_spread_slab",
|
| 1918 | .read_u64 = cpuset_read_u64,
|
| 1919 | .write_u64 = cpuset_write_u64,
|
| 1920 | .private = FILE_SPREAD_SLAB,
|
| 1921 | },
|
| 1922 |
|
| 1923 | {
|
| 1924 | .name = "memory_pressure_enabled",
|
| 1925 | .flags = CFTYPE_ONLY_ON_ROOT,
|
| 1926 | .read_u64 = cpuset_read_u64,
|
| 1927 | .write_u64 = cpuset_write_u64,
|
| 1928 | .private = FILE_MEMORY_PRESSURE_ENABLED,
|
| 1929 | },
|
| 1930 |
|
| 1931 | { }
|
| 1932 | };
|
| 1933 |
|
| 1934 | |
| 1935 | * cpuset_css_alloc - allocate a cpuset css
|
| 1936 | * cgrp: control group that the new cpuset will be part of
|
| 1937 |
|
| 1938 |
|
| 1939 | static struct cgroup_subsys_state *
|
| 1940 | cpuset_css_alloc(struct cgroup_subsys_state *parent_css)
|
| 1941 | {
|
| 1942 | struct cpuset *cs;
|
| 1943 |
|
| 1944 | if (!parent_css)
|
| 1945 | return &top_cpuset.css;
|
| 1946 |
|
| 1947 | cs = kzalloc(sizeof(*cs), GFP_KERNEL);
|
| 1948 | if (!cs)
|
| 1949 | return ERR_PTR(-ENOMEM);
|
| 1950 | if (!alloc_cpumask_var(&cs->cpus_allowed, GFP_KERNEL))
|
| 1951 | goto free_cs;
|
| 1952 | if (!alloc_cpumask_var(&cs->effective_cpus, GFP_KERNEL))
|
| 1953 | goto free_cpus;
|
| 1954 |
|
| 1955 | set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
|
| 1956 | cpumask_clear(cs->cpus_allowed);
|
| 1957 | nodes_clear(cs->mems_allowed);
|
| 1958 | cpumask_clear(cs->effective_cpus);
|
| 1959 | nodes_clear(cs->effective_mems);
|
| 1960 | fmeter_init(&cs->fmeter);
|
| 1961 | cs->relax_domain_level = -1;
|
| 1962 |
|
| 1963 | return &cs->css;
|
| 1964 |
|
| 1965 | free_cpus:
|
| 1966 | free_cpumask_var(cs->cpus_allowed);
|
| 1967 | free_cs:
|
| 1968 | kfree(cs);
|
| 1969 | return ERR_PTR(-ENOMEM);
|
| 1970 | }
|
| 1971 |
|
| 1972 | static int cpuset_css_online(struct cgroup_subsys_state *css)
|
| 1973 | {
|
| 1974 | struct cpuset *cs = css_cs(css);
|
| 1975 | struct cpuset *parent = parent_cs(cs);
|
| 1976 | struct cpuset *tmp_cs;
|
| 1977 | struct cgroup_subsys_state *pos_css;
|
| 1978 |
|
| 1979 | if (!parent)
|
| 1980 | return 0;
|
| 1981 |
|
| 1982 | mutex_lock(&cpuset_mutex);
|
| 1983 |
|
| 1984 | set_bit(CS_ONLINE, &cs->flags);
|
| 1985 | if (is_spread_page(parent))
|
| 1986 | set_bit(CS_SPREAD_PAGE, &cs->flags);
|
| 1987 | if (is_spread_slab(parent))
|
| 1988 | set_bit(CS_SPREAD_SLAB, &cs->flags);
|
| 1989 |
|
| 1990 | cpuset_inc();
|
| 1991 |
|
| 1992 | spin_lock_irq(&callback_lock);
|
| 1993 | if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) {
|
| 1994 | cpumask_copy(cs->effective_cpus, parent->effective_cpus);
|
| 1995 | cs->effective_mems = parent->effective_mems;
|
| 1996 | }
|
| 1997 | spin_unlock_irq(&callback_lock);
|
| 1998 |
|
| 1999 | if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags))
|
| 2000 | goto out_unlock;
|
| 2001 |
|
| 2002 | |
| 2003 | * Clone @parent's configuration if CGRP_CPUSET_CLONE_CHILDREN is
|
| 2004 | * set. This flag handling is implemented in cgroup core for
|
| 2005 | * histrical reasons - the flag may be specified during mount.
|
| 2006 | *
|
| 2007 | * Currently, if any sibling cpusets have exclusive cpus or mem, we
|
| 2008 | * refuse to clone the configuration - thereby refusing the task to
|
| 2009 | * be entered, and as a result refusing the sys_unshare() or
|
| 2010 | * clone() which initiated it. If this becomes a problem for some
|
| 2011 | * users who wish to allow that scenario, then this could be
|
| 2012 | * changed to grant parent->cpus_allowed-sibling_cpus_exclusive
|
| 2013 | * (and likewise for mems) to the new cgroup.
|
| 2014 |
|
| 2015 | rcu_read_lock();
|
| 2016 | cpuset_for_each_child(tmp_cs, pos_css, parent) {
|
| 2017 | if (is_mem_exclusive(tmp_cs) || is_cpu_exclusive(tmp_cs)) {
|
| 2018 | rcu_read_unlock();
|
| 2019 | goto out_unlock;
|
| 2020 | }
|
| 2021 | }
|
| 2022 | rcu_read_unlock();
|
| 2023 |
|
| 2024 | spin_lock_irq(&callback_lock);
|
| 2025 | cs->mems_allowed = parent->mems_allowed;
|
| 2026 | cs->effective_mems = parent->mems_allowed;
|
| 2027 | cpumask_copy(cs->cpus_allowed, parent->cpus_allowed);
|
| 2028 | cpumask_copy(cs->effective_cpus, parent->cpus_allowed);
|
| 2029 | spin_unlock_irq(&callback_lock);
|
| 2030 | out_unlock:
|
| 2031 | mutex_unlock(&cpuset_mutex);
|
| 2032 | return 0;
|
| 2033 | }
|
| 2034 |
|
| 2035 | |
| 2036 | * If the cpuset being removed has its flag 'sched_load_balance'
|
| 2037 | * enabled, then simulate turning sched_load_balance off, which
|
| 2038 | * will call rebuild_sched_domains_locked().
|
| 2039 |
|
| 2040 |
|
| 2041 | static void cpuset_css_offline(struct cgroup_subsys_state *css)
|
| 2042 | {
|
| 2043 | struct cpuset *cs = css_cs(css);
|
| 2044 |
|
| 2045 | mutex_lock(&cpuset_mutex);
|
| 2046 |
|
| 2047 | if (is_sched_load_balance(cs))
|
| 2048 | update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
|
| 2049 |
|
| 2050 | cpuset_dec();
|
| 2051 | clear_bit(CS_ONLINE, &cs->flags);
|
| 2052 |
|
| 2053 | mutex_unlock(&cpuset_mutex);
|
| 2054 | }
|
| 2055 |
|
| 2056 | static void cpuset_css_free(struct cgroup_subsys_state *css)
|
| 2057 | {
|
| 2058 | struct cpuset *cs = css_cs(css);
|
| 2059 |
|
| 2060 | free_cpumask_var(cs->effective_cpus);
|
| 2061 | free_cpumask_var(cs->cpus_allowed);
|
| 2062 | kfree(cs);
|
| 2063 | }
|
| 2064 |
|
| 2065 | static void cpuset_bind(struct cgroup_subsys_state *root_css)
|
| 2066 | {
|
| 2067 | mutex_lock(&cpuset_mutex);
|
| 2068 | spin_lock_irq(&callback_lock);
|
| 2069 |
|
| 2070 | if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) {
|
| 2071 | cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask);
|
| 2072 | top_cpuset.mems_allowed = node_possible_map;
|
| 2073 | } else {
|
| 2074 | cpumask_copy(top_cpuset.cpus_allowed,
|
| 2075 | top_cpuset.effective_cpus);
|
| 2076 | top_cpuset.mems_allowed = top_cpuset.effective_mems;
|
| 2077 | }
|
| 2078 |
|
| 2079 | spin_unlock_irq(&callback_lock);
|
| 2080 | mutex_unlock(&cpuset_mutex);
|
| 2081 | }
|
| 2082 |
|
| 2083 | |
| 2084 | * Make sure the new task conform to the current state of its parent,
|
| 2085 | * which could have been changed by cpuset just after it inherits the
|
| 2086 | * state from the parent and before it sits on the cgroup's task list.
|
| 2087 |
|
| 2088 | static void cpuset_fork(struct task_struct *task)
|
| 2089 | {
|
| 2090 | if (task_css_is_root(task, cpuset_cgrp_id))
|
| 2091 | return;
|
| 2092 |
|
| 2093 | set_cpus_allowed_ptr(task, ¤t->cpus_allowed);
|
| 2094 | task->mems_allowed = current->mems_allowed;
|
| 2095 | }
|
| 2096 |
|
| 2097 | struct cgroup_subsys cpuset_cgrp_subsys = {
|
| 2098 | .css_alloc = cpuset_css_alloc,
|
| 2099 | .css_online = cpuset_css_online,
|
| 2100 | .css_offline = cpuset_css_offline,
|
| 2101 | .css_free = cpuset_css_free,
|
| 2102 | .can_attach = cpuset_can_attach,
|
| 2103 | .cancel_attach = cpuset_cancel_attach,
|
| 2104 | .attach = cpuset_attach,
|
| 2105 | .post_attach = cpuset_post_attach,
|
| 2106 | .bind = cpuset_bind,
|
| 2107 | .fork = cpuset_fork,
|
| 2108 | .legacy_cftypes = files,
|
| 2109 | .early_init = true,
|
| 2110 | };
|
| 2111 |
|
| 2112 | |
| 2113 | * cpuset_init - initialize cpusets at system boot
|
| 2114 | *
|
| 2115 | * Description: Initialize top_cpuset and the cpuset internal file system,
|
| 2116 | *
|
| 2117 |
|
| 2118 | int __init cpuset_init(void)
|
| 2119 | {
|
| 2120 | int err = 0;
|
| 2121 |
|
| 2122 | if (!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL))
|
| 2123 | BUG();
|
| 2124 | if (!alloc_cpumask_var(&top_cpuset.effective_cpus, GFP_KERNEL))
|
| 2125 | BUG();
|
| 2126 |
|
| 2127 | cpumask_setall(top_cpuset.cpus_allowed);
|
| 2128 | nodes_setall(top_cpuset.mems_allowed);
|
| 2129 | cpumask_setall(top_cpuset.effective_cpus);
|
| 2130 | nodes_setall(top_cpuset.effective_mems);
|
| 2131 |
|
| 2132 | fmeter_init(&top_cpuset.fmeter);
|
| 2133 | set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags);
|
| 2134 | top_cpuset.relax_domain_level = -1;
|
| 2135 |
|
| 2136 | err = register_filesystem(&cpuset_fs_type);
|
| 2137 | if (err < 0)
|
| 2138 | return err;
|
| 2139 |
|
| 2140 | if (!alloc_cpumask_var(&cpus_attach, GFP_KERNEL))
|
| 2141 | BUG();
|
| 2142 |
|
| 2143 | return 0;
|
| 2144 | }
|
| 2145 |
|
| 2146 | |
| 2147 | * If CPU and/or memory hotplug handlers, below, unplug any CPUs
|
| 2148 | * or memory nodes, we need to walk over the cpuset hierarchy,
|
| 2149 | * removing that CPU or node from all cpusets. If this removes the
|
| 2150 | * last CPU or node from a cpuset, then move the tasks in the empty
|
| 2151 | * cpuset to its next-highest non-empty parent.
|
| 2152 |
|
| 2153 | static void remove_tasks_in_empty_cpuset(struct cpuset *cs)
|
| 2154 | {
|
| 2155 | struct cpuset *parent;
|
| 2156 |
|
| 2157 | |
| 2158 | * Find its next-highest non-empty parent, (top cpuset
|
| 2159 | * has online cpus, so can't be empty).
|
| 2160 |
|
| 2161 | parent = parent_cs(cs);
|
| 2162 | while (cpumask_empty(parent->cpus_allowed) ||
|
| 2163 | nodes_empty(parent->mems_allowed))
|
| 2164 | parent = parent_cs(parent);
|
| 2165 |
|
| 2166 | if (cgroup_transfer_tasks(parent->css.cgroup, cs->css.cgroup)) {
|
| 2167 | pr_err("cpuset: failed to transfer tasks out of empty cpuset ");
|
| 2168 | pr_cont_cgroup_name(cs->css.cgroup);
|
| 2169 | pr_cont("\n");
|
| 2170 | }
|
| 2171 | }
|
| 2172 |
|
| 2173 | static void
|
| 2174 | hotplug_update_tasks_legacy(struct cpuset *cs,
|
| 2175 | struct cpumask *new_cpus, nodemask_t *new_mems,
|
| 2176 | bool cpus_updated, bool mems_updated)
|
| 2177 | {
|
| 2178 | bool is_empty;
|
| 2179 |
|
| 2180 | spin_lock_irq(&callback_lock);
|
| 2181 | cpumask_copy(cs->cpus_allowed, new_cpus);
|
| 2182 | cpumask_copy(cs->effective_cpus, new_cpus);
|
| 2183 | cs->mems_allowed = *new_mems;
|
| 2184 | cs->effective_mems = *new_mems;
|
| 2185 | spin_unlock_irq(&callback_lock);
|
| 2186 |
|
| 2187 | |
| 2188 | * Don't call update_tasks_cpumask() if the cpuset becomes empty,
|
| 2189 | * as the tasks will be migratecd to an ancestor.
|
| 2190 |
|
| 2191 | if (cpus_updated && !cpumask_empty(cs->cpus_allowed))
|
| 2192 | update_tasks_cpumask(cs);
|
| 2193 | if (mems_updated && !nodes_empty(cs->mems_allowed))
|
| 2194 | update_tasks_nodemask(cs);
|
| 2195 |
|
| 2196 | is_empty = cpumask_empty(cs->cpus_allowed) ||
|
| 2197 | nodes_empty(cs->mems_allowed);
|
| 2198 |
|
| 2199 | mutex_unlock(&cpuset_mutex);
|
| 2200 |
|
| 2201 | |
| 2202 | * Move tasks to the nearest ancestor with execution resources,
|
| 2203 | * This is full cgroup operation which will also call back into
|
| 2204 | * cpuset. Should be done outside any lock.
|
| 2205 |
|
| 2206 | if (is_empty)
|
| 2207 | remove_tasks_in_empty_cpuset(cs);
|
| 2208 |
|
| 2209 | mutex_lock(&cpuset_mutex);
|
| 2210 | }
|
| 2211 |
|
| 2212 | static void
|
| 2213 | hotplug_update_tasks(struct cpuset *cs,
|
| 2214 | struct cpumask *new_cpus, nodemask_t *new_mems,
|
| 2215 | bool cpus_updated, bool mems_updated)
|
| 2216 | {
|
| 2217 | if (cpumask_empty(new_cpus))
|
| 2218 | cpumask_copy(new_cpus, parent_cs(cs)->effective_cpus);
|
| 2219 | if (nodes_empty(*new_mems))
|
| 2220 | *new_mems = parent_cs(cs)->effective_mems;
|
| 2221 |
|
| 2222 | spin_lock_irq(&callback_lock);
|
| 2223 | cpumask_copy(cs->effective_cpus, new_cpus);
|
| 2224 | cs->effective_mems = *new_mems;
|
| 2225 | spin_unlock_irq(&callback_lock);
|
| 2226 |
|
| 2227 | if (cpus_updated)
|
| 2228 | update_tasks_cpumask(cs);
|
| 2229 | if (mems_updated)
|
| 2230 | update_tasks_nodemask(cs);
|
| 2231 | }
|
| 2232 |
|
| 2233 | |
| 2234 | * cpuset_hotplug_update_tasks - update tasks in a cpuset for hotunplug
|
| 2235 | * @cs: cpuset in interest
|
| 2236 | *
|
| 2237 | * Compare @cs's cpu and mem masks against top_cpuset and if some have gone
|
| 2238 | * offline, update @cs accordingly. If @cs ends up with no CPU or memory,
|
| 2239 | * all its tasks are moved to the nearest ancestor with both resources.
|
| 2240 |
|
| 2241 | static void cpuset_hotplug_update_tasks(struct cpuset *cs)
|
| 2242 | {
|
| 2243 | static cpumask_t new_cpus;
|
| 2244 | static nodemask_t new_mems;
|
| 2245 | bool cpus_updated;
|
| 2246 | bool mems_updated;
|
| 2247 | retry:
|
| 2248 | wait_event(cpuset_attach_wq, cs->attach_in_progress == 0);
|
| 2249 |
|
| 2250 | mutex_lock(&cpuset_mutex);
|
| 2251 |
|
| 2252 | |
| 2253 | * We have raced with task attaching. We wait until attaching
|
| 2254 | * is finished, so we won't attach a task to an empty cpuset.
|
| 2255 |
|
| 2256 | if (cs->attach_in_progress) {
|
| 2257 | mutex_unlock(&cpuset_mutex);
|
| 2258 | goto retry;
|
| 2259 | }
|
| 2260 |
|
| 2261 | cpumask_and(&new_cpus, cs->cpus_allowed, parent_cs(cs)->effective_cpus);
|
| 2262 | nodes_and(new_mems, cs->mems_allowed, parent_cs(cs)->effective_mems);
|
| 2263 |
|
| 2264 | cpus_updated = !cpumask_equal(&new_cpus, cs->effective_cpus);
|
| 2265 | mems_updated = !nodes_equal(new_mems, cs->effective_mems);
|
| 2266 |
|
| 2267 | if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys))
|
| 2268 | hotplug_update_tasks(cs, &new_cpus, &new_mems,
|
| 2269 | cpus_updated, mems_updated);
|
| 2270 | else
|
| 2271 | hotplug_update_tasks_legacy(cs, &new_cpus, &new_mems,
|
| 2272 | cpus_updated, mems_updated);
|
| 2273 |
|
| 2274 | mutex_unlock(&cpuset_mutex);
|
| 2275 | }
|
| 2276 |
|
| 2277 | |
| 2278 | * cpuset_hotplug_workfn - handle CPU/memory hotunplug for a cpuset
|
| 2279 | *
|
| 2280 | * This function is called after either CPU or memory configuration has
|
| 2281 | * changed and updates cpuset accordingly. The top_cpuset is always
|
| 2282 | * synchronized to cpu_active_mask and N_MEMORY, which is necessary in
|
| 2283 | * order to make cpusets transparent (of no affect) on systems that are
|
| 2284 | * actively using CPU hotplug but making no active use of cpusets.
|
| 2285 | *
|
| 2286 | * Non-root cpusets are only affected by offlining. If any CPUs or memory
|
| 2287 | * nodes have been taken down, cpuset_hotplug_update_tasks() is invoked on
|
| 2288 | * all descendants.
|
| 2289 | *
|
| 2290 | * Note that CPU offlining during suspend is ignored. We don't modify
|
| 2291 | * cpusets across suspend/resume cycles at all.
|
| 2292 |
|
| 2293 | static void cpuset_hotplug_workfn(struct work_struct *work)
|
| 2294 | {
|
| 2295 | static cpumask_t new_cpus;
|
| 2296 | static nodemask_t new_mems;
|
| 2297 | bool cpus_updated, mems_updated;
|
| 2298 | bool on_dfl = cgroup_subsys_on_dfl(cpuset_cgrp_subsys);
|
| 2299 |
|
| 2300 | mutex_lock(&cpuset_mutex);
|
| 2301 |
|
| 2302 |
|
| 2303 | cpumask_copy(&new_cpus, cpu_active_mask);
|
| 2304 | new_mems = node_states[N_MEMORY];
|
| 2305 |
|
| 2306 | cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus);
|
| 2307 | mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems);
|
| 2308 |
|
| 2309 |
|
| 2310 | if (cpus_updated) {
|
| 2311 | spin_lock_irq(&callback_lock);
|
| 2312 | if (!on_dfl)
|
| 2313 | cpumask_copy(top_cpuset.cpus_allowed, &new_cpus);
|
| 2314 | cpumask_copy(top_cpuset.effective_cpus, &new_cpus);
|
| 2315 | spin_unlock_irq(&callback_lock);
|
| 2316 |
|
| 2317 | }
|
| 2318 |
|
| 2319 |
|
| 2320 | if (mems_updated) {
|
| 2321 | spin_lock_irq(&callback_lock);
|
| 2322 | if (!on_dfl)
|
| 2323 | top_cpuset.mems_allowed = new_mems;
|
| 2324 | top_cpuset.effective_mems = new_mems;
|
| 2325 | spin_unlock_irq(&callback_lock);
|
| 2326 | update_tasks_nodemask(&top_cpuset);
|
| 2327 | }
|
| 2328 |
|
| 2329 | mutex_unlock(&cpuset_mutex);
|
| 2330 |
|
| 2331 |
|
| 2332 | if (cpus_updated || mems_updated) {
|
| 2333 | struct cpuset *cs;
|
| 2334 | struct cgroup_subsys_state *pos_css;
|
| 2335 |
|
| 2336 | rcu_read_lock();
|
| 2337 | cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) {
|
| 2338 | if (cs == &top_cpuset || !css_tryget_online(&cs->css))
|
| 2339 | continue;
|
| 2340 | rcu_read_unlock();
|
| 2341 |
|
| 2342 | cpuset_hotplug_update_tasks(cs);
|
| 2343 |
|
| 2344 | rcu_read_lock();
|
| 2345 | css_put(&cs->css);
|
| 2346 | }
|
| 2347 | rcu_read_unlock();
|
| 2348 | }
|
| 2349 |
|
| 2350 |
|
| 2351 | if (cpus_updated)
|
| 2352 | rebuild_sched_domains();
|
| 2353 | }
|
| 2354 |
|
| 2355 | void cpuset_update_active_cpus(bool cpu_online)
|
| 2356 | {
|
| 2357 | |
| 2358 | * We're inside cpu hotplug critical region which usually nests
|
| 2359 | * inside cgroup synchronization. Bounce actual hotplug processing
|
| 2360 | * to a work item to avoid reverse locking order.
|
| 2361 | *
|
| 2362 | * We still need to do partition_sched_domains() synchronously;
|
| 2363 | * otherwise, the scheduler will get confused and put tasks to the
|
| 2364 | * dead CPU. Fall back to the default single domain.
|
| 2365 | * cpuset_hotplug_workfn() will rebuild it as necessary.
|
| 2366 |
|
| 2367 | partition_sched_domains(1, NULL, NULL);
|
| 2368 | schedule_work(&cpuset_hotplug_work);
|
| 2369 | }
|
| 2370 |
|
| 2371 | |
| 2372 | * Keep top_cpuset.mems_allowed tracking node_states[N_MEMORY].
|
| 2373 | * Call this routine anytime after node_states[N_MEMORY] changes.
|
| 2374 | * See cpuset_update_active_cpus() for CPU hotplug handling.
|
| 2375 |
|
| 2376 | static int cpuset_track_online_nodes(struct notifier_block *self,
|
| 2377 | unsigned long action, void *arg)
|
| 2378 | {
|
| 2379 | schedule_work(&cpuset_hotplug_work);
|
| 2380 | return NOTIFY_OK;
|
| 2381 | }
|
| 2382 |
|
| 2383 | static struct notifier_block cpuset_track_online_nodes_nb = {
|
| 2384 | .notifier_call = cpuset_track_online_nodes,
|
| 2385 | .priority = 10,
|
| 2386 | };
|
| 2387 |
|
| 2388 | |
| 2389 | * cpuset_init_smp - initialize cpus_allowed
|
| 2390 | *
|
| 2391 | * Description: Finish top cpuset after cpu, node maps are initialized
|
| 2392 |
|
| 2393 | void __init cpuset_init_smp(void)
|
| 2394 | {
|
| 2395 | cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask);
|
| 2396 | top_cpuset.mems_allowed = node_states[N_MEMORY];
|
| 2397 | top_cpuset.old_mems_allowed = top_cpuset.mems_allowed;
|
| 2398 |
|
| 2399 | cpumask_copy(top_cpuset.effective_cpus, cpu_active_mask);
|
| 2400 | top_cpuset.effective_mems = node_states[N_MEMORY];
|
| 2401 |
|
| 2402 | register_hotmemory_notifier(&cpuset_track_online_nodes_nb);
|
| 2403 |
|
| 2404 | cpuset_migrate_mm_wq = alloc_ordered_workqueue("cpuset_migrate_mm", 0);
|
| 2405 | BUG_ON(!cpuset_migrate_mm_wq);
|
| 2406 | }
|
| 2407 |
|
| 2408 | |
| 2409 | * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
|
| 2410 | * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
|
| 2411 | * @pmask: pointer to struct cpumask variable to receive cpus_allowed set.
|
| 2412 | *
|
| 2413 | * Description: Returns the cpumask_var_t cpus_allowed of the cpuset
|
| 2414 | * attached to the specified @tsk. Guaranteed to return some non-empty
|
| 2415 | * subset of cpu_online_mask, even if this means going outside the
|
| 2416 | * tasks cpuset.
|
| 2417 | *
|
| 2418 |
|
| 2419 | void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask)
|
| 2420 | {
|
| 2421 | unsigned long flags;
|
| 2422 |
|
| 2423 | spin_lock_irqsave(&callback_lock, flags);
|
| 2424 | rcu_read_lock();
|
| 2425 | guarantee_online_cpus(task_cs(tsk), pmask);
|
| 2426 | rcu_read_unlock();
|
| 2427 | spin_unlock_irqrestore(&callback_lock, flags);
|
| 2428 | }
|
| 2429 |
|
| 2430 | void cpuset_cpus_allowed_fallback(struct task_struct *tsk)
|
| 2431 | {
|
| 2432 | rcu_read_lock();
|
| 2433 | do_set_cpus_allowed(tsk, task_cs(tsk)->effective_cpus);
|
| 2434 | rcu_read_unlock();
|
| 2435 |
|
| 2436 | |
| 2437 | * We own tsk->cpus_allowed, nobody can change it under us.
|
| 2438 | *
|
| 2439 | * But we used cs && cs->cpus_allowed lockless and thus can
|
| 2440 | * race with cgroup_attach_task() or update_cpumask() and get
|
| 2441 | * the wrong tsk->cpus_allowed. However, both cases imply the
|
| 2442 | * subsequent cpuset_change_cpumask()->set_cpus_allowed_ptr()
|
| 2443 | * which takes task_rq_lock().
|
| 2444 | *
|
| 2445 | * If we are called after it dropped the lock we must see all
|
| 2446 | * changes in tsk_cs()->cpus_allowed. Otherwise we can temporary
|
| 2447 | * set any mask even if it is not right from task_cs() pov,
|
| 2448 | * the pending set_cpus_allowed_ptr() will fix things.
|
| 2449 | *
|
| 2450 | * select_fallback_rq() will fix things ups and set cpu_possible_mask
|
| 2451 | * if required.
|
| 2452 |
|
| 2453 | }
|
| 2454 |
|
| 2455 | void __init cpuset_init_current_mems_allowed(void)
|
| 2456 | {
|
| 2457 | nodes_setall(current->mems_allowed);
|
| 2458 | }
|
| 2459 |
|
| 2460 | |
| 2461 | * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset.
|
| 2462 | * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed.
|
| 2463 | *
|
| 2464 | * Description: Returns the nodemask_t mems_allowed of the cpuset
|
| 2465 | * attached to the specified @tsk. Guaranteed to return some non-empty
|
| 2466 | * subset of node_states[N_MEMORY], even if this means going outside the
|
| 2467 | * tasks cpuset.
|
| 2468 | *
|
| 2469 |
|
| 2470 | nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
|
| 2471 | {
|
| 2472 | nodemask_t mask;
|
| 2473 | unsigned long flags;
|
| 2474 |
|
| 2475 | spin_lock_irqsave(&callback_lock, flags);
|
| 2476 | rcu_read_lock();
|
| 2477 | guarantee_online_mems(task_cs(tsk), &mask);
|
| 2478 | rcu_read_unlock();
|
| 2479 | spin_unlock_irqrestore(&callback_lock, flags);
|
| 2480 |
|
| 2481 | return mask;
|
| 2482 | }
|
| 2483 |
|
| 2484 | |
| 2485 | * cpuset_nodemask_valid_mems_allowed - check nodemask vs. curremt mems_allowed
|
| 2486 | * @nodemask: the nodemask to be checked
|
| 2487 | *
|
| 2488 | * Are any of the nodes in the nodemask allowed in current->mems_allowed?
|
| 2489 |
|
| 2490 | int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
|
| 2491 | {
|
| 2492 | return nodes_intersects(*nodemask, current->mems_allowed);
|
| 2493 | }
|
| 2494 |
|
| 2495 | |
| 2496 | * nearest_hardwall_ancestor() - Returns the nearest mem_exclusive or
|
| 2497 | * mem_hardwall ancestor to the specified cpuset. Call holding
|
| 2498 | * callback_lock. If no ancestor is mem_exclusive or mem_hardwall
|
| 2499 | * (an unusual configuration), then returns the root cpuset.
|
| 2500 |
|
| 2501 | static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs)
|
| 2502 | {
|
| 2503 | while (!(is_mem_exclusive(cs) || is_mem_hardwall(cs)) && parent_cs(cs))
|
| 2504 | cs = parent_cs(cs);
|
| 2505 | return cs;
|
| 2506 | }
|
| 2507 |
|
| 2508 | |
| 2509 | * cpuset_node_allowed - Can we allocate on a memory node?
|
| 2510 | * @node: is this an allowed node?
|
| 2511 | * @gfp_mask: memory allocation flags
|
| 2512 | *
|
| 2513 | * If we're in interrupt, yes, we can always allocate. If @node is set in
|
| 2514 | * current's mems_allowed, yes. If it's not a __GFP_HARDWALL request and this
|
| 2515 | * node is set in the nearest hardwalled cpuset ancestor to current's cpuset,
|
| 2516 | * yes. If current has access to memory reserves due to TIF_MEMDIE, yes.
|
| 2517 | * Otherwise, no.
|
| 2518 | *
|
| 2519 | * GFP_USER allocations are marked with the __GFP_HARDWALL bit,
|
| 2520 | * and do not allow allocations outside the current tasks cpuset
|
| 2521 | * unless the task has been OOM killed as is marked TIF_MEMDIE.
|
| 2522 | * GFP_KERNEL allocations are not so marked, so can escape to the
|
| 2523 | * nearest enclosing hardwalled ancestor cpuset.
|
| 2524 | *
|
| 2525 | * Scanning up parent cpusets requires callback_lock. The
|
| 2526 | * __alloc_pages() routine only calls here with __GFP_HARDWALL bit
|
| 2527 | * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the
|
| 2528 | * current tasks mems_allowed came up empty on the first pass over
|
| 2529 | * the zonelist. So only GFP_KERNEL allocations, if all nodes in the
|
| 2530 | * cpuset are short of memory, might require taking the callback_lock.
|
| 2531 | *
|
| 2532 | * The first call here from mm/page_alloc:get_page_from_freelist()
|
| 2533 | * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets,
|
| 2534 | * so no allocation on a node outside the cpuset is allowed (unless
|
| 2535 | * in interrupt, of course).
|
| 2536 | *
|
| 2537 | * The second pass through get_page_from_freelist() doesn't even call
|
| 2538 | * here for GFP_ATOMIC calls. For those calls, the __alloc_pages()
|
| 2539 | * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set
|
| 2540 | * in alloc_flags. That logic and the checks below have the combined
|
| 2541 | * affect that:
|
| 2542 | * in_interrupt - any node ok (current task context irrelevant)
|
| 2543 | * GFP_ATOMIC - any node ok
|
| 2544 | * TIF_MEMDIE - any node ok
|
| 2545 | * GFP_KERNEL - any node in enclosing hardwalled cpuset ok
|
| 2546 | * GFP_USER - only nodes in current tasks mems allowed ok.
|
| 2547 |
|
| 2548 | bool __cpuset_node_allowed(int node, gfp_t gfp_mask)
|
| 2549 | {
|
| 2550 | struct cpuset *cs;
|
| 2551 | int allowed;
|
| 2552 | unsigned long flags;
|
| 2553 |
|
| 2554 | if (in_interrupt())
|
| 2555 | return true;
|
| 2556 | if (node_isset(node, current->mems_allowed))
|
| 2557 | return true;
|
| 2558 | |
| 2559 | * Allow tasks that have access to memory reserves because they have
|
| 2560 | * been OOM killed to get memory anywhere.
|
| 2561 |
|
| 2562 | if (unlikely(test_thread_flag(TIF_MEMDIE)))
|
| 2563 | return true;
|
| 2564 | if (gfp_mask & __GFP_HARDWALL)
|
| 2565 | return false;
|
| 2566 |
|
| 2567 | if (current->flags & PF_EXITING)
|
| 2568 | return true;
|
| 2569 |
|
| 2570 |
|
| 2571 | spin_lock_irqsave(&callback_lock, flags);
|
| 2572 |
|
| 2573 | rcu_read_lock();
|
| 2574 | cs = nearest_hardwall_ancestor(task_cs(current));
|
| 2575 | allowed = node_isset(node, cs->mems_allowed);
|
| 2576 | rcu_read_unlock();
|
| 2577 |
|
| 2578 | spin_unlock_irqrestore(&callback_lock, flags);
|
| 2579 | return allowed;
|
| 2580 | }
|
| 2581 |
|
| 2582 | |
| 2583 | * cpuset_mem_spread_node() - On which node to begin search for a file page
|
| 2584 | * cpuset_slab_spread_node() - On which node to begin search for a slab page
|
| 2585 | *
|
| 2586 | * If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for
|
| 2587 | * tasks in a cpuset with is_spread_page or is_spread_slab set),
|
| 2588 | * and if the memory allocation used cpuset_mem_spread_node()
|
| 2589 | * to determine on which node to start looking, as it will for
|
| 2590 | * certain page cache or slab cache pages such as used for file
|
| 2591 | * system buffers and inode caches, then instead of starting on the
|
| 2592 | * local node to look for a free page, rather spread the starting
|
| 2593 | * node around the tasks mems_allowed nodes.
|
| 2594 | *
|
| 2595 | * We don't have to worry about the returned node being offline
|
| 2596 | * because "it can't happen", and even if it did, it would be ok.
|
| 2597 | *
|
| 2598 | * The routines calling guarantee_online_mems() are careful to
|
| 2599 | * only set nodes in task->mems_allowed that are online. So it
|
| 2600 | * should not be possible for the following code to return an
|
| 2601 | * offline node. But if it did, that would be ok, as this routine
|
| 2602 | * is not returning the node where the allocation must be, only
|
| 2603 | * the node where the search should start. The zonelist passed to
|
| 2604 | * __alloc_pages() will include all nodes. If the slab allocator
|
| 2605 | * is passed an offline node, it will fall back to the local node.
|
| 2606 | * See kmem_cache_alloc_node().
|
| 2607 |
|
| 2608 |
|
| 2609 | static int cpuset_spread_node(int *rotor)
|
| 2610 | {
|
| 2611 | return *rotor = next_node_in(*rotor, current->mems_allowed);
|
| 2612 | }
|
| 2613 |
|
| 2614 | int cpuset_mem_spread_node(void)
|
| 2615 | {
|
| 2616 | if (current->cpuset_mem_spread_rotor == NUMA_NO_NODE)
|
| 2617 | current->cpuset_mem_spread_rotor =
|
| 2618 | node_random(¤t->mems_allowed);
|
| 2619 |
|
| 2620 | return cpuset_spread_node(¤t->cpuset_mem_spread_rotor);
|
| 2621 | }
|
| 2622 |
|
| 2623 | int cpuset_slab_spread_node(void)
|
| 2624 | {
|
| 2625 | if (current->cpuset_slab_spread_rotor == NUMA_NO_NODE)
|
| 2626 | current->cpuset_slab_spread_rotor =
|
| 2627 | node_random(¤t->mems_allowed);
|
| 2628 |
|
| 2629 | return cpuset_spread_node(¤t->cpuset_slab_spread_rotor);
|
| 2630 | }
|
| 2631 |
|
| 2632 | EXPORT_SYMBOL_GPL(cpuset_mem_spread_node);
|
| 2633 |
|
| 2634 | |
| 2635 | * cpuset_mems_allowed_intersects - Does @tsk1's mems_allowed intersect @tsk2's?
|
| 2636 | * @tsk1: pointer to task_struct of some task.
|
| 2637 | * @tsk2: pointer to task_struct of some other task.
|
| 2638 | *
|
| 2639 | * Description: Return true if @tsk1's mems_allowed intersects the
|
| 2640 | * mems_allowed of @tsk2. Used by the OOM killer to determine if
|
| 2641 | * one of the task's memory usage might impact the memory available
|
| 2642 | * to the other.
|
| 2643 | *
|
| 2644 |
|
| 2645 | int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
|
| 2646 | const struct task_struct *tsk2)
|
| 2647 | {
|
| 2648 | return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed);
|
| 2649 | }
|
| 2650 |
|
| 2651 | |
| 2652 | * cpuset_print_current_mems_allowed - prints current's cpuset and mems_allowed
|
| 2653 | *
|
| 2654 | * Description: Prints current's name, cpuset name, and cached copy of its
|
| 2655 | * mems_allowed to the kernel log.
|
| 2656 |
|
| 2657 | void cpuset_print_current_mems_allowed(void)
|
| 2658 | {
|
| 2659 | struct cgroup *cgrp;
|
| 2660 |
|
| 2661 | rcu_read_lock();
|
| 2662 |
|
| 2663 | cgrp = task_cs(current)->css.cgroup;
|
| 2664 | pr_info("%s cpuset=", current->comm);
|
| 2665 | pr_cont_cgroup_name(cgrp);
|
| 2666 | pr_cont(" mems_allowed=%*pbl\n",
|
| 2667 | nodemask_pr_args(¤t->mems_allowed));
|
| 2668 |
|
| 2669 | rcu_read_unlock();
|
| 2670 | }
|
| 2671 |
|
| 2672 | |
| 2673 | * Collection of memory_pressure is suppressed unless
|
| 2674 | * this flag is enabled by writing "1" to the special
|
| 2675 | * cpuset file 'memory_pressure_enabled' in the root cpuset.
|
| 2676 |
|
| 2677 |
|
| 2678 | int cpuset_memory_pressure_enabled __read_mostly;
|
| 2679 |
|
| 2680 | |
| 2681 | * cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims.
|
| 2682 | *
|
| 2683 | * Keep a running average of the rate of synchronous (direct)
|
| 2684 | * page reclaim efforts initiated by tasks in each cpuset.
|
| 2685 | *
|
| 2686 | * This represents the rate at which some task in the cpuset
|
| 2687 | * ran low on memory on all nodes it was allowed to use, and
|
| 2688 | * had to enter the kernels page reclaim code in an effort to
|
| 2689 | * create more free memory by tossing clean pages or swapping
|
| 2690 | * or writing dirty pages.
|
| 2691 | *
|
| 2692 | * Display to user space in the per-cpuset read-only file
|
| 2693 | * "memory_pressure". Value displayed is an integer
|
| 2694 | * representing the recent rate of entry into the synchronous
|
| 2695 | * (direct) page reclaim by any task attached to the cpuset.
|
| 2696 | *
|
| 2697 |
|
| 2698 | void __cpuset_memory_pressure_bump(void)
|
| 2699 | {
|
| 2700 | rcu_read_lock();
|
| 2701 | fmeter_markevent(&task_cs(current)->fmeter);
|
| 2702 | rcu_read_unlock();
|
| 2703 | }
|
| 2704 |
|
| 2705 | #ifdef CONFIG_PROC_PID_CPUSET
|
| 2706 | |
| 2707 | * proc_cpuset_show()
|
| 2708 | * - Print tasks cpuset path into seq_file.
|
| 2709 | * - Used for /proc/<pid>/cpuset.
|
| 2710 | * - No need to task_lock(tsk) on this tsk->cpuset reference, as it
|
| 2711 | * doesn't really matter if tsk->cpuset changes after we read it,
|
| 2712 | * and we take cpuset_mutex, keeping cpuset_attach() from changing it
|
| 2713 | * anyway.
|
| 2714 |
|
| 2715 | int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
|
| 2716 | struct pid *pid, struct task_struct *tsk)
|
| 2717 | {
|
| 2718 | char *buf;
|
| 2719 | struct cgroup_subsys_state *css;
|
| 2720 | int retval;
|
| 2721 |
|
| 2722 | retval = -ENOMEM;
|
| 2723 | buf = kmalloc(PATH_MAX, GFP_KERNEL);
|
| 2724 | if (!buf)
|
| 2725 | goto out;
|
| 2726 |
|
| 2727 | css = task_get_css(tsk, cpuset_cgrp_id);
|
| 2728 | retval = cgroup_path_ns(css->cgroup, buf, PATH_MAX,
|
| 2729 | current->nsproxy->cgroup_ns);
|
| 2730 | css_put(css);
|
| 2731 | if (retval >= PATH_MAX)
|
| 2732 | retval = -ENAMETOOLONG;
|
| 2733 | if (retval < 0)
|
| 2734 | goto out_free;
|
| 2735 | seq_puts(m, buf);
|
| 2736 | seq_putc(m, '\n');
|
| 2737 | retval = 0;
|
| 2738 | out_free:
|
| 2739 | kfree(buf);
|
| 2740 | out:
|
| 2741 | return retval;
|
| 2742 | }
|
| 2743 | #endif
|
| 2744 |
|
| 2745 |
|
| 2746 | void cpuset_task_status_allowed(struct seq_file *m, struct task_struct *task)
|
| 2747 | {
|
| 2748 | seq_printf(m, "Mems_allowed:\t%*pb\n",
|
| 2749 | nodemask_pr_args(&task->mems_allowed));
|
| 2750 | seq_printf(m, "Mems_allowed_list:\t%*pbl\n",
|
| 2751 | nodemask_pr_args(&task->mems_allowed));
|
| 2752 | }
|