1 /* memcontrol.c - Memory Controller 2 * 3 * Copyright IBM Corporation, 2007 4 * Author Balbir Singh <balbir@linux.vnet.ibm.com> 5 * 6 * Copyright 2007 OpenVZ SWsoft Inc 7 * Author: Pavel Emelianov <xemul@openvz.org> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License as published by 11 * the Free Software Foundation; either version 2 of the License, or 12 * (at your option) any later version. 13 * 14 * This program is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 * GNU General Public License for more details. 18 */ 19 20 #include <linux/res_counter.h> 21 #include <linux/memcontrol.h> 22 #include <linux/cgroup.h> 23 #include <linux/mm.h> 24 #include <linux/pagemap.h> 25 #include <linux/smp.h> 26 #include <linux/page-flags.h> 27 #include <linux/backing-dev.h> 28 #include <linux/bit_spinlock.h> 29 #include <linux/rcupdate.h> 30 #include <linux/limits.h> 31 #include <linux/mutex.h> 32 #include <linux/slab.h> 33 #include <linux/swap.h> 34 #include <linux/spinlock.h> 35 #include <linux/fs.h> 36 #include <linux/seq_file.h> 37 #include <linux/vmalloc.h> 38 #include <linux/mm_inline.h> 39 #include <linux/page_cgroup.h> 40 #include "internal.h" 41 42 #include <asm/uaccess.h> 43 44 struct cgroup_subsys mem_cgroup_subsys __read_mostly; 45 #define MEM_CGROUP_RECLAIM_RETRIES 5 46 47 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 48 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 0 */ 49 int do_swap_account __read_mostly; 50 static int really_do_swap_account __initdata = 1; /* for remember boot option*/ 51 #else 52 #define do_swap_account (0) 53 #endif 54 55 static DEFINE_MUTEX(memcg_tasklist); /* can be hold under cgroup_mutex */ 56 57 /* 58 * Statistics for memory cgroup. 59 */ 60 enum mem_cgroup_stat_index { 61 /* 62 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss. 63 */ 64 MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */ 65 MEM_CGROUP_STAT_RSS, /* # of pages charged as rss */ 66 MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */ 67 MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */ 68 69 MEM_CGROUP_STAT_NSTATS, 70 }; 71 72 struct mem_cgroup_stat_cpu { 73 s64 count[MEM_CGROUP_STAT_NSTATS]; 74 } ____cacheline_aligned_in_smp; 75 76 struct mem_cgroup_stat { 77 struct mem_cgroup_stat_cpu cpustat[0]; 78 }; 79 80 /* 81 * For accounting under irq disable, no need for increment preempt count. 82 */ 83 static inline void __mem_cgroup_stat_add_safe(struct mem_cgroup_stat_cpu *stat, 84 enum mem_cgroup_stat_index idx, int val) 85 { 86 stat->count[idx] += val; 87 } 88 89 static s64 mem_cgroup_read_stat(struct mem_cgroup_stat *stat, 90 enum mem_cgroup_stat_index idx) 91 { 92 int cpu; 93 s64 ret = 0; 94 for_each_possible_cpu(cpu) 95 ret += stat->cpustat[cpu].count[idx]; 96 return ret; 97 } 98 99 static s64 mem_cgroup_local_usage(struct mem_cgroup_stat *stat) 100 { 101 s64 ret; 102 103 ret = mem_cgroup_read_stat(stat, MEM_CGROUP_STAT_CACHE); 104 ret += mem_cgroup_read_stat(stat, MEM_CGROUP_STAT_RSS); 105 return ret; 106 } 107 108 /* 109 * per-zone information in memory controller. 110 */ 111 struct mem_cgroup_per_zone { 112 /* 113 * spin_lock to protect the per cgroup LRU 114 */ 115 struct list_head lists[NR_LRU_LISTS]; 116 unsigned long count[NR_LRU_LISTS]; 117 118 struct zone_reclaim_stat reclaim_stat; 119 }; 120 /* Macro for accessing counter */ 121 #define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)]) 122 123 struct mem_cgroup_per_node { 124 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES]; 125 }; 126 127 struct mem_cgroup_lru_info { 128 struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES]; 129 }; 130 131 /* 132 * The memory controller data structure. The memory controller controls both 133 * page cache and RSS per cgroup. We would eventually like to provide 134 * statistics based on the statistics developed by Rik Van Riel for clock-pro, 135 * to help the administrator determine what knobs to tune. 136 * 137 * TODO: Add a water mark for the memory controller. Reclaim will begin when 138 * we hit the water mark. May be even add a low water mark, such that 139 * no reclaim occurs from a cgroup at it's low water mark, this is 140 * a feature that will be implemented much later in the future. 141 */ 142 struct mem_cgroup { 143 struct cgroup_subsys_state css; 144 /* 145 * the counter to account for memory usage 146 */ 147 struct res_counter res; 148 /* 149 * the counter to account for mem+swap usage. 150 */ 151 struct res_counter memsw; 152 /* 153 * Per cgroup active and inactive list, similar to the 154 * per zone LRU lists. 155 */ 156 struct mem_cgroup_lru_info info; 157 158 /* 159 protect against reclaim related member. 160 */ 161 spinlock_t reclaim_param_lock; 162 163 int prev_priority; /* for recording reclaim priority */ 164 165 /* 166 * While reclaiming in a hiearchy, we cache the last child we 167 * reclaimed from. 168 */ 169 int last_scanned_child; 170 /* 171 * Should the accounting and control be hierarchical, per subtree? 172 */ 173 bool use_hierarchy; 174 unsigned long last_oom_jiffies; 175 atomic_t refcnt; 176 177 unsigned int swappiness; 178 179 /* 180 * statistics. This must be placed at the end of memcg. 181 */ 182 struct mem_cgroup_stat stat; 183 }; 184 185 enum charge_type { 186 MEM_CGROUP_CHARGE_TYPE_CACHE = 0, 187 MEM_CGROUP_CHARGE_TYPE_MAPPED, 188 MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */ 189 MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */ 190 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */ 191 NR_CHARGE_TYPE, 192 }; 193 194 /* only for here (for easy reading.) */ 195 #define PCGF_CACHE (1UL << PCG_CACHE) 196 #define PCGF_USED (1UL << PCG_USED) 197 #define PCGF_LOCK (1UL << PCG_LOCK) 198 static const unsigned long 199 pcg_default_flags[NR_CHARGE_TYPE] = { 200 PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* File Cache */ 201 PCGF_USED | PCGF_LOCK, /* Anon */ 202 PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* Shmem */ 203 0, /* FORCE */ 204 }; 205 206 /* for encoding cft->private value on file */ 207 #define _MEM (0) 208 #define _MEMSWAP (1) 209 #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val)) 210 #define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff) 211 #define MEMFILE_ATTR(val) ((val) & 0xffff) 212 213 static void mem_cgroup_get(struct mem_cgroup *mem); 214 static void mem_cgroup_put(struct mem_cgroup *mem); 215 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem); 216 217 static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, 218 struct page_cgroup *pc, 219 bool charge) 220 { 221 int val = (charge)? 1 : -1; 222 struct mem_cgroup_stat *stat = &mem->stat; 223 struct mem_cgroup_stat_cpu *cpustat; 224 int cpu = get_cpu(); 225 226 cpustat = &stat->cpustat[cpu]; 227 if (PageCgroupCache(pc)) 228 __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_CACHE, val); 229 else 230 __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_RSS, val); 231 232 if (charge) 233 __mem_cgroup_stat_add_safe(cpustat, 234 MEM_CGROUP_STAT_PGPGIN_COUNT, 1); 235 else 236 __mem_cgroup_stat_add_safe(cpustat, 237 MEM_CGROUP_STAT_PGPGOUT_COUNT, 1); 238 put_cpu(); 239 } 240 241 static struct mem_cgroup_per_zone * 242 mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid) 243 { 244 return &mem->info.nodeinfo[nid]->zoneinfo[zid]; 245 } 246 247 static struct mem_cgroup_per_zone * 248 page_cgroup_zoneinfo(struct page_cgroup *pc) 249 { 250 struct mem_cgroup *mem = pc->mem_cgroup; 251 int nid = page_cgroup_nid(pc); 252 int zid = page_cgroup_zid(pc); 253 254 if (!mem) 255 return NULL; 256 257 return mem_cgroup_zoneinfo(mem, nid, zid); 258 } 259 260 static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem, 261 enum lru_list idx) 262 { 263 int nid, zid; 264 struct mem_cgroup_per_zone *mz; 265 u64 total = 0; 266 267 for_each_online_node(nid) 268 for (zid = 0; zid < MAX_NR_ZONES; zid++) { 269 mz = mem_cgroup_zoneinfo(mem, nid, zid); 270 total += MEM_CGROUP_ZSTAT(mz, idx); 271 } 272 return total; 273 } 274 275 static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) 276 { 277 return container_of(cgroup_subsys_state(cont, 278 mem_cgroup_subsys_id), struct mem_cgroup, 279 css); 280 } 281 282 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) 283 { 284 /* 285 * mm_update_next_owner() may clear mm->owner to NULL 286 * if it races with swapoff, page migration, etc. 287 * So this can be called with p == NULL. 288 */ 289 if (unlikely(!p)) 290 return NULL; 291 292 return container_of(task_subsys_state(p, mem_cgroup_subsys_id), 293 struct mem_cgroup, css); 294 } 295 296 static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) 297 { 298 struct mem_cgroup *mem = NULL; 299 300 if (!mm) 301 return NULL; 302 /* 303 * Because we have no locks, mm->owner's may be being moved to other 304 * cgroup. We use css_tryget() here even if this looks 305 * pessimistic (rather than adding locks here). 306 */ 307 rcu_read_lock(); 308 do { 309 mem = mem_cgroup_from_task(rcu_dereference(mm->owner)); 310 if (unlikely(!mem)) 311 break; 312 } while (!css_tryget(&mem->css)); 313 rcu_read_unlock(); 314 return mem; 315 } 316 317 static bool mem_cgroup_is_obsolete(struct mem_cgroup *mem) 318 { 319 if (!mem) 320 return true; 321 return css_is_removed(&mem->css); 322 } 323 324 325 /* 326 * Call callback function against all cgroup under hierarchy tree. 327 */ 328 static int mem_cgroup_walk_tree(struct mem_cgroup *root, void *data, 329 int (*func)(struct mem_cgroup *, void *)) 330 { 331 int found, ret, nextid; 332 struct cgroup_subsys_state *css; 333 struct mem_cgroup *mem; 334 335 if (!root->use_hierarchy) 336 return (*func)(root, data); 337 338 nextid = 1; 339 do { 340 ret = 0; 341 mem = NULL; 342 343 rcu_read_lock(); 344 css = css_get_next(&mem_cgroup_subsys, nextid, &root->css, 345 &found); 346 if (css && css_tryget(css)) 347 mem = container_of(css, struct mem_cgroup, css); 348 rcu_read_unlock(); 349 350 if (mem) { 351 ret = (*func)(mem, data); 352 css_put(&mem->css); 353 } 354 nextid = found + 1; 355 } while (!ret && css); 356 357 return ret; 358 } 359 360 /* 361 * Following LRU functions are allowed to be used without PCG_LOCK. 362 * Operations are called by routine of global LRU independently from memcg. 363 * What we have to take care of here is validness of pc->mem_cgroup. 364 * 365 * Changes to pc->mem_cgroup happens when 366 * 1. charge 367 * 2. moving account 368 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache. 369 * It is added to LRU before charge. 370 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU. 371 * When moving account, the page is not on LRU. It's isolated. 372 */ 373 374 void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru) 375 { 376 struct page_cgroup *pc; 377 struct mem_cgroup *mem; 378 struct mem_cgroup_per_zone *mz; 379 380 if (mem_cgroup_disabled()) 381 return; 382 pc = lookup_page_cgroup(page); 383 /* can happen while we handle swapcache. */ 384 if (list_empty(&pc->lru) || !pc->mem_cgroup) 385 return; 386 /* 387 * We don't check PCG_USED bit. It's cleared when the "page" is finally 388 * removed from global LRU. 389 */ 390 mz = page_cgroup_zoneinfo(pc); 391 mem = pc->mem_cgroup; 392 MEM_CGROUP_ZSTAT(mz, lru) -= 1; 393 list_del_init(&pc->lru); 394 return; 395 } 396 397 void mem_cgroup_del_lru(struct page *page) 398 { 399 mem_cgroup_del_lru_list(page, page_lru(page)); 400 } 401 402 void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru) 403 { 404 struct mem_cgroup_per_zone *mz; 405 struct page_cgroup *pc; 406 407 if (mem_cgroup_disabled()) 408 return; 409 410 pc = lookup_page_cgroup(page); 411 /* 412 * Used bit is set without atomic ops but after smp_wmb(). 413 * For making pc->mem_cgroup visible, insert smp_rmb() here. 414 */ 415 smp_rmb(); 416 /* unused page is not rotated. */ 417 if (!PageCgroupUsed(pc)) 418 return; 419 mz = page_cgroup_zoneinfo(pc); 420 list_move(&pc->lru, &mz->lists[lru]); 421 } 422 423 void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru) 424 { 425 struct page_cgroup *pc; 426 struct mem_cgroup_per_zone *mz; 427 428 if (mem_cgroup_disabled()) 429 return; 430 pc = lookup_page_cgroup(page); 431 /* 432 * Used bit is set without atomic ops but after smp_wmb(). 433 * For making pc->mem_cgroup visible, insert smp_rmb() here. 434 */ 435 smp_rmb(); 436 if (!PageCgroupUsed(pc)) 437 return; 438 439 mz = page_cgroup_zoneinfo(pc); 440 MEM_CGROUP_ZSTAT(mz, lru) += 1; 441 list_add(&pc->lru, &mz->lists[lru]); 442 } 443 444 /* 445 * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to 446 * lru because the page may.be reused after it's fully uncharged (because of 447 * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge 448 * it again. This function is only used to charge SwapCache. It's done under 449 * lock_page and expected that zone->lru_lock is never held. 450 */ 451 static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page) 452 { 453 unsigned long flags; 454 struct zone *zone = page_zone(page); 455 struct page_cgroup *pc = lookup_page_cgroup(page); 456 457 spin_lock_irqsave(&zone->lru_lock, flags); 458 /* 459 * Forget old LRU when this page_cgroup is *not* used. This Used bit 460 * is guarded by lock_page() because the page is SwapCache. 461 */ 462 if (!PageCgroupUsed(pc)) 463 mem_cgroup_del_lru_list(page, page_lru(page)); 464 spin_unlock_irqrestore(&zone->lru_lock, flags); 465 } 466 467 static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page) 468 { 469 unsigned long flags; 470 struct zone *zone = page_zone(page); 471 struct page_cgroup *pc = lookup_page_cgroup(page); 472 473 spin_lock_irqsave(&zone->lru_lock, flags); 474 /* link when the page is linked to LRU but page_cgroup isn't */ 475 if (PageLRU(page) && list_empty(&pc->lru)) 476 mem_cgroup_add_lru_list(page, page_lru(page)); 477 spin_unlock_irqrestore(&zone->lru_lock, flags); 478 } 479 480 481 void mem_cgroup_move_lists(struct page *page, 482 enum lru_list from, enum lru_list to) 483 { 484 if (mem_cgroup_disabled()) 485 return; 486 mem_cgroup_del_lru_list(page, from); 487 mem_cgroup_add_lru_list(page, to); 488 } 489 490 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem) 491 { 492 int ret; 493 struct mem_cgroup *curr = NULL; 494 495 task_lock(task); 496 rcu_read_lock(); 497 curr = try_get_mem_cgroup_from_mm(task->mm); 498 rcu_read_unlock(); 499 task_unlock(task); 500 if (!curr) 501 return 0; 502 if (curr->use_hierarchy) 503 ret = css_is_ancestor(&curr->css, &mem->css); 504 else 505 ret = (curr == mem); 506 css_put(&curr->css); 507 return ret; 508 } 509 510 /* 511 * prev_priority control...this will be used in memory reclaim path. 512 */ 513 int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem) 514 { 515 int prev_priority; 516 517 spin_lock(&mem->reclaim_param_lock); 518 prev_priority = mem->prev_priority; 519 spin_unlock(&mem->reclaim_param_lock); 520 521 return prev_priority; 522 } 523 524 void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority) 525 { 526 spin_lock(&mem->reclaim_param_lock); 527 if (priority < mem->prev_priority) 528 mem->prev_priority = priority; 529 spin_unlock(&mem->reclaim_param_lock); 530 } 531 532 void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority) 533 { 534 spin_lock(&mem->reclaim_param_lock); 535 mem->prev_priority = priority; 536 spin_unlock(&mem->reclaim_param_lock); 537 } 538 539 static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages) 540 { 541 unsigned long active; 542 unsigned long inactive; 543 unsigned long gb; 544 unsigned long inactive_ratio; 545 546 inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON); 547 active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON); 548 549 gb = (inactive + active) >> (30 - PAGE_SHIFT); 550 if (gb) 551 inactive_ratio = int_sqrt(10 * gb); 552 else 553 inactive_ratio = 1; 554 555 if (present_pages) { 556 present_pages[0] = inactive; 557 present_pages[1] = active; 558 } 559 560 return inactive_ratio; 561 } 562 563 int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg) 564 { 565 unsigned long active; 566 unsigned long inactive; 567 unsigned long present_pages[2]; 568 unsigned long inactive_ratio; 569 570 inactive_ratio = calc_inactive_ratio(memcg, present_pages); 571 572 inactive = present_pages[0]; 573 active = present_pages[1]; 574 575 if (inactive * inactive_ratio < active) 576 return 1; 577 578 return 0; 579 } 580 581 unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg, 582 struct zone *zone, 583 enum lru_list lru) 584 { 585 int nid = zone->zone_pgdat->node_id; 586 int zid = zone_idx(zone); 587 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid); 588 589 return MEM_CGROUP_ZSTAT(mz, lru); 590 } 591 592 struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg, 593 struct zone *zone) 594 { 595 int nid = zone->zone_pgdat->node_id; 596 int zid = zone_idx(zone); 597 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid); 598 599 return &mz->reclaim_stat; 600 } 601 602 struct zone_reclaim_stat * 603 mem_cgroup_get_reclaim_stat_from_page(struct page *page) 604 { 605 struct page_cgroup *pc; 606 struct mem_cgroup_per_zone *mz; 607 608 if (mem_cgroup_disabled()) 609 return NULL; 610 611 pc = lookup_page_cgroup(page); 612 /* 613 * Used bit is set without atomic ops but after smp_wmb(). 614 * For making pc->mem_cgroup visible, insert smp_rmb() here. 615 */ 616 smp_rmb(); 617 if (!PageCgroupUsed(pc)) 618 return NULL; 619 620 mz = page_cgroup_zoneinfo(pc); 621 if (!mz) 622 return NULL; 623 624 return &mz->reclaim_stat; 625 } 626 627 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, 628 struct list_head *dst, 629 unsigned long *scanned, int order, 630 int mode, struct zone *z, 631 struct mem_cgroup *mem_cont, 632 int active, int file) 633 { 634 unsigned long nr_taken = 0; 635 struct page *page; 636 unsigned long scan; 637 LIST_HEAD(pc_list); 638 struct list_head *src; 639 struct page_cgroup *pc, *tmp; 640 int nid = z->zone_pgdat->node_id; 641 int zid = zone_idx(z); 642 struct mem_cgroup_per_zone *mz; 643 int lru = LRU_FILE * !!file + !!active; 644 645 BUG_ON(!mem_cont); 646 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); 647 src = &mz->lists[lru]; 648 649 scan = 0; 650 list_for_each_entry_safe_reverse(pc, tmp, src, lru) { 651 if (scan >= nr_to_scan) 652 break; 653 654 page = pc->page; 655 if (unlikely(!PageCgroupUsed(pc))) 656 continue; 657 if (unlikely(!PageLRU(page))) 658 continue; 659 660 scan++; 661 if (__isolate_lru_page(page, mode, file) == 0) { 662 list_move(&page->lru, dst); 663 nr_taken++; 664 } 665 } 666 667 *scanned = scan; 668 return nr_taken; 669 } 670 671 #define mem_cgroup_from_res_counter(counter, member) \ 672 container_of(counter, struct mem_cgroup, member) 673 674 static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem) 675 { 676 if (do_swap_account) { 677 if (res_counter_check_under_limit(&mem->res) && 678 res_counter_check_under_limit(&mem->memsw)) 679 return true; 680 } else 681 if (res_counter_check_under_limit(&mem->res)) 682 return true; 683 return false; 684 } 685 686 static unsigned int get_swappiness(struct mem_cgroup *memcg) 687 { 688 struct cgroup *cgrp = memcg->css.cgroup; 689 unsigned int swappiness; 690 691 /* root ? */ 692 if (cgrp->parent == NULL) 693 return vm_swappiness; 694 695 spin_lock(&memcg->reclaim_param_lock); 696 swappiness = memcg->swappiness; 697 spin_unlock(&memcg->reclaim_param_lock); 698 699 return swappiness; 700 } 701 702 static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data) 703 { 704 int *val = data; 705 (*val)++; 706 return 0; 707 } 708 709 /** 710 * mem_cgroup_print_mem_info: Called from OOM with tasklist_lock held in read mode. 711 * @memcg: The memory cgroup that went over limit 712 * @p: Task that is going to be killed 713 * 714 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is 715 * enabled 716 */ 717 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) 718 { 719 struct cgroup *task_cgrp; 720 struct cgroup *mem_cgrp; 721 /* 722 * Need a buffer in BSS, can't rely on allocations. The code relies 723 * on the assumption that OOM is serialized for memory controller. 724 * If this assumption is broken, revisit this code. 725 */ 726 static char memcg_name[PATH_MAX]; 727 int ret; 728 729 if (!memcg) 730 return; 731 732 733 rcu_read_lock(); 734 735 mem_cgrp = memcg->css.cgroup; 736 task_cgrp = task_cgroup(p, mem_cgroup_subsys_id); 737 738 ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX); 739 if (ret < 0) { 740 /* 741 * Unfortunately, we are unable to convert to a useful name 742 * But we'll still print out the usage information 743 */ 744 rcu_read_unlock(); 745 goto done; 746 } 747 rcu_read_unlock(); 748 749 printk(KERN_INFO "Task in %s killed", memcg_name); 750 751 rcu_read_lock(); 752 ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX); 753 if (ret < 0) { 754 rcu_read_unlock(); 755 goto done; 756 } 757 rcu_read_unlock(); 758 759 /* 760 * Continues from above, so we don't need an KERN_ level 761 */ 762 printk(KERN_CONT " as a result of limit of %s\n", memcg_name); 763 done: 764 765 printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n", 766 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10, 767 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10, 768 res_counter_read_u64(&memcg->res, RES_FAILCNT)); 769 printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, " 770 "failcnt %llu\n", 771 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10, 772 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10, 773 res_counter_read_u64(&memcg->memsw, RES_FAILCNT)); 774 } 775 776 /* 777 * This function returns the number of memcg under hierarchy tree. Returns 778 * 1(self count) if no children. 779 */ 780 static int mem_cgroup_count_children(struct mem_cgroup *mem) 781 { 782 int num = 0; 783 mem_cgroup_walk_tree(mem, &num, mem_cgroup_count_children_cb); 784 return num; 785 } 786 787 /* 788 * Visit the first child (need not be the first child as per the ordering 789 * of the cgroup list, since we track last_scanned_child) of @mem and use 790 * that to reclaim free pages from. 791 */ 792 static struct mem_cgroup * 793 mem_cgroup_select_victim(struct mem_cgroup *root_mem) 794 { 795 struct mem_cgroup *ret = NULL; 796 struct cgroup_subsys_state *css; 797 int nextid, found; 798 799 if (!root_mem->use_hierarchy) { 800 css_get(&root_mem->css); 801 ret = root_mem; 802 } 803 804 while (!ret) { 805 rcu_read_lock(); 806 nextid = root_mem->last_scanned_child + 1; 807 css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css, 808 &found); 809 if (css && css_tryget(css)) 810 ret = container_of(css, struct mem_cgroup, css); 811 812 rcu_read_unlock(); 813 /* Updates scanning parameter */ 814 spin_lock(&root_mem->reclaim_param_lock); 815 if (!css) { 816 /* this means start scan from ID:1 */ 817 root_mem->last_scanned_child = 0; 818 } else 819 root_mem->last_scanned_child = found; 820 spin_unlock(&root_mem->reclaim_param_lock); 821 } 822 823 return ret; 824 } 825 826 /* 827 * Scan the hierarchy if needed to reclaim memory. We remember the last child 828 * we reclaimed from, so that we don't end up penalizing one child extensively 829 * based on its position in the children list. 830 * 831 * root_mem is the original ancestor that we've been reclaim from. 832 * 833 * We give up and return to the caller when we visit root_mem twice. 834 * (other groups can be removed while we're walking....) 835 * 836 * If shrink==true, for avoiding to free too much, this returns immedieately. 837 */ 838 static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem, 839 gfp_t gfp_mask, bool noswap, bool shrink) 840 { 841 struct mem_cgroup *victim; 842 int ret, total = 0; 843 int loop = 0; 844 845 while (loop < 2) { 846 victim = mem_cgroup_select_victim(root_mem); 847 if (victim == root_mem) 848 loop++; 849 if (!mem_cgroup_local_usage(&victim->stat)) { 850 /* this cgroup's local usage == 0 */ 851 css_put(&victim->css); 852 continue; 853 } 854 /* we use swappiness of local cgroup */ 855 ret = try_to_free_mem_cgroup_pages(victim, gfp_mask, noswap, 856 get_swappiness(victim)); 857 css_put(&victim->css); 858 /* 859 * At shrinking usage, we can't check we should stop here or 860 * reclaim more. It's depends on callers. last_scanned_child 861 * will work enough for keeping fairness under tree. 862 */ 863 if (shrink) 864 return ret; 865 total += ret; 866 if (mem_cgroup_check_under_limit(root_mem)) 867 return 1 + total; 868 } 869 return total; 870 } 871 872 bool mem_cgroup_oom_called(struct task_struct *task) 873 { 874 bool ret = false; 875 struct mem_cgroup *mem; 876 struct mm_struct *mm; 877 878 rcu_read_lock(); 879 mm = task->mm; 880 if (!mm) 881 mm = &init_mm; 882 mem = mem_cgroup_from_task(rcu_dereference(mm->owner)); 883 if (mem && time_before(jiffies, mem->last_oom_jiffies + HZ/10)) 884 ret = true; 885 rcu_read_unlock(); 886 return ret; 887 } 888 889 static int record_last_oom_cb(struct mem_cgroup *mem, void *data) 890 { 891 mem->last_oom_jiffies = jiffies; 892 return 0; 893 } 894 895 static void record_last_oom(struct mem_cgroup *mem) 896 { 897 mem_cgroup_walk_tree(mem, NULL, record_last_oom_cb); 898 } 899 900 901 /* 902 * Unlike exported interface, "oom" parameter is added. if oom==true, 903 * oom-killer can be invoked. 904 */ 905 static int __mem_cgroup_try_charge(struct mm_struct *mm, 906 gfp_t gfp_mask, struct mem_cgroup **memcg, 907 bool oom) 908 { 909 struct mem_cgroup *mem, *mem_over_limit; 910 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; 911 struct res_counter *fail_res; 912 913 if (unlikely(test_thread_flag(TIF_MEMDIE))) { 914 /* Don't account this! */ 915 *memcg = NULL; 916 return 0; 917 } 918 919 /* 920 * We always charge the cgroup the mm_struct belongs to. 921 * The mm_struct's mem_cgroup changes on task migration if the 922 * thread group leader migrates. It's possible that mm is not 923 * set, if so charge the init_mm (happens for pagecache usage). 924 */ 925 mem = *memcg; 926 if (likely(!mem)) { 927 mem = try_get_mem_cgroup_from_mm(mm); 928 *memcg = mem; 929 } else { 930 css_get(&mem->css); 931 } 932 if (unlikely(!mem)) 933 return 0; 934 935 VM_BUG_ON(!mem || mem_cgroup_is_obsolete(mem)); 936 937 while (1) { 938 int ret; 939 bool noswap = false; 940 941 ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res); 942 if (likely(!ret)) { 943 if (!do_swap_account) 944 break; 945 ret = res_counter_charge(&mem->memsw, PAGE_SIZE, 946 &fail_res); 947 if (likely(!ret)) 948 break; 949 /* mem+swap counter fails */ 950 res_counter_uncharge(&mem->res, PAGE_SIZE); 951 noswap = true; 952 mem_over_limit = mem_cgroup_from_res_counter(fail_res, 953 memsw); 954 } else 955 /* mem counter fails */ 956 mem_over_limit = mem_cgroup_from_res_counter(fail_res, 957 res); 958 959 if (!(gfp_mask & __GFP_WAIT)) 960 goto nomem; 961 962 ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, gfp_mask, 963 noswap, false); 964 if (ret) 965 continue; 966 967 /* 968 * try_to_free_mem_cgroup_pages() might not give us a full 969 * picture of reclaim. Some pages are reclaimed and might be 970 * moved to swap cache or just unmapped from the cgroup. 971 * Check the limit again to see if the reclaim reduced the 972 * current usage of the cgroup before giving up 973 * 974 */ 975 if (mem_cgroup_check_under_limit(mem_over_limit)) 976 continue; 977 978 if (!nr_retries--) { 979 if (oom) { 980 mutex_lock(&memcg_tasklist); 981 mem_cgroup_out_of_memory(mem_over_limit, gfp_mask); 982 mutex_unlock(&memcg_tasklist); 983 record_last_oom(mem_over_limit); 984 } 985 goto nomem; 986 } 987 } 988 return 0; 989 nomem: 990 css_put(&mem->css); 991 return -ENOMEM; 992 } 993 994 995 /* 996 * A helper function to get mem_cgroup from ID. must be called under 997 * rcu_read_lock(). The caller must check css_is_removed() or some if 998 * it's concern. (dropping refcnt from swap can be called against removed 999 * memcg.) 1000 */ 1001 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id) 1002 { 1003 struct cgroup_subsys_state *css; 1004 1005 /* ID 0 is unused ID */ 1006 if (!id) 1007 return NULL; 1008 css = css_lookup(&mem_cgroup_subsys, id); 1009 if (!css) 1010 return NULL; 1011 return container_of(css, struct mem_cgroup, css); 1012 } 1013 1014 static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page) 1015 { 1016 struct mem_cgroup *mem; 1017 struct page_cgroup *pc; 1018 unsigned short id; 1019 swp_entry_t ent; 1020 1021 VM_BUG_ON(!PageLocked(page)); 1022 1023 if (!PageSwapCache(page)) 1024 return NULL; 1025 1026 pc = lookup_page_cgroup(page); 1027 /* 1028 * Used bit of swapcache is solid under page lock. 1029 */ 1030 if (PageCgroupUsed(pc)) { 1031 mem = pc->mem_cgroup; 1032 if (mem && !css_tryget(&mem->css)) 1033 mem = NULL; 1034 } else { 1035 ent.val = page_private(page); 1036 id = lookup_swap_cgroup(ent); 1037 rcu_read_lock(); 1038 mem = mem_cgroup_lookup(id); 1039 if (mem && !css_tryget(&mem->css)) 1040 mem = NULL; 1041 rcu_read_unlock(); 1042 } 1043 return mem; 1044 } 1045 1046 /* 1047 * commit a charge got by __mem_cgroup_try_charge() and makes page_cgroup to be 1048 * USED state. If already USED, uncharge and return. 1049 */ 1050 1051 static void __mem_cgroup_commit_charge(struct mem_cgroup *mem, 1052 struct page_cgroup *pc, 1053 enum charge_type ctype) 1054 { 1055 /* try_charge() can return NULL to *memcg, taking care of it. */ 1056 if (!mem) 1057 return; 1058 1059 lock_page_cgroup(pc); 1060 if (unlikely(PageCgroupUsed(pc))) { 1061 unlock_page_cgroup(pc); 1062 res_counter_uncharge(&mem->res, PAGE_SIZE); 1063 if (do_swap_account) 1064 res_counter_uncharge(&mem->memsw, PAGE_SIZE); 1065 css_put(&mem->css); 1066 return; 1067 } 1068 pc->mem_cgroup = mem; 1069 smp_wmb(); 1070 pc->flags = pcg_default_flags[ctype]; 1071 1072 mem_cgroup_charge_statistics(mem, pc, true); 1073 1074 unlock_page_cgroup(pc); 1075 } 1076 1077 /** 1078 * mem_cgroup_move_account - move account of the page 1079 * @pc: page_cgroup of the page. 1080 * @from: mem_cgroup which the page is moved from. 1081 * @to: mem_cgroup which the page is moved to. @from != @to. 1082 * 1083 * The caller must confirm following. 1084 * - page is not on LRU (isolate_page() is useful.) 1085 * 1086 * returns 0 at success, 1087 * returns -EBUSY when lock is busy or "pc" is unstable. 1088 * 1089 * This function does "uncharge" from old cgroup but doesn't do "charge" to 1090 * new cgroup. It should be done by a caller. 1091 */ 1092 1093 static int mem_cgroup_move_account(struct page_cgroup *pc, 1094 struct mem_cgroup *from, struct mem_cgroup *to) 1095 { 1096 struct mem_cgroup_per_zone *from_mz, *to_mz; 1097 int nid, zid; 1098 int ret = -EBUSY; 1099 1100 VM_BUG_ON(from == to); 1101 VM_BUG_ON(PageLRU(pc->page)); 1102 1103 nid = page_cgroup_nid(pc); 1104 zid = page_cgroup_zid(pc); 1105 from_mz = mem_cgroup_zoneinfo(from, nid, zid); 1106 to_mz = mem_cgroup_zoneinfo(to, nid, zid); 1107 1108 if (!trylock_page_cgroup(pc)) 1109 return ret; 1110 1111 if (!PageCgroupUsed(pc)) 1112 goto out; 1113 1114 if (pc->mem_cgroup != from) 1115 goto out; 1116 1117 res_counter_uncharge(&from->res, PAGE_SIZE); 1118 mem_cgroup_charge_statistics(from, pc, false); 1119 if (do_swap_account) 1120 res_counter_uncharge(&from->memsw, PAGE_SIZE); 1121 css_put(&from->css); 1122 1123 css_get(&to->css); 1124 pc->mem_cgroup = to; 1125 mem_cgroup_charge_statistics(to, pc, true); 1126 ret = 0; 1127 out: 1128 unlock_page_cgroup(pc); 1129 return ret; 1130 } 1131 1132 /* 1133 * move charges to its parent. 1134 */ 1135 1136 static int mem_cgroup_move_parent(struct page_cgroup *pc, 1137 struct mem_cgroup *child, 1138 gfp_t gfp_mask) 1139 { 1140 struct page *page = pc->page; 1141 struct cgroup *cg = child->css.cgroup; 1142 struct cgroup *pcg = cg->parent; 1143 struct mem_cgroup *parent; 1144 int ret; 1145 1146 /* Is ROOT ? */ 1147 if (!pcg) 1148 return -EINVAL; 1149 1150 1151 parent = mem_cgroup_from_cont(pcg); 1152 1153 1154 ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false); 1155 if (ret || !parent) 1156 return ret; 1157 1158 if (!get_page_unless_zero(page)) { 1159 ret = -EBUSY; 1160 goto uncharge; 1161 } 1162 1163 ret = isolate_lru_page(page); 1164 1165 if (ret) 1166 goto cancel; 1167 1168 ret = mem_cgroup_move_account(pc, child, parent); 1169 1170 putback_lru_page(page); 1171 if (!ret) { 1172 put_page(page); 1173 /* drop extra refcnt by try_charge() */ 1174 css_put(&parent->css); 1175 return 0; 1176 } 1177 1178 cancel: 1179 put_page(page); 1180 uncharge: 1181 /* drop extra refcnt by try_charge() */ 1182 css_put(&parent->css); 1183 /* uncharge if move fails */ 1184 res_counter_uncharge(&parent->res, PAGE_SIZE); 1185 if (do_swap_account) 1186 res_counter_uncharge(&parent->memsw, PAGE_SIZE); 1187 return ret; 1188 } 1189 1190 /* 1191 * Charge the memory controller for page usage. 1192 * Return 1193 * 0 if the charge was successful 1194 * < 0 if the cgroup is over its limit 1195 */ 1196 static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, 1197 gfp_t gfp_mask, enum charge_type ctype, 1198 struct mem_cgroup *memcg) 1199 { 1200 struct mem_cgroup *mem; 1201 struct page_cgroup *pc; 1202 int ret; 1203 1204 pc = lookup_page_cgroup(page); 1205 /* can happen at boot */ 1206 if (unlikely(!pc)) 1207 return 0; 1208 prefetchw(pc); 1209 1210 mem = memcg; 1211 ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true); 1212 if (ret || !mem) 1213 return ret; 1214 1215 __mem_cgroup_commit_charge(mem, pc, ctype); 1216 return 0; 1217 } 1218 1219 int mem_cgroup_newpage_charge(struct page *page, 1220 struct mm_struct *mm, gfp_t gfp_mask) 1221 { 1222 if (mem_cgroup_disabled()) 1223 return 0; 1224 if (PageCompound(page)) 1225 return 0; 1226 /* 1227 * If already mapped, we don't have to account. 1228 * If page cache, page->mapping has address_space. 1229 * But page->mapping may have out-of-use anon_vma pointer, 1230 * detecit it by PageAnon() check. newly-mapped-anon's page->mapping 1231 * is NULL. 1232 */ 1233 if (page_mapped(page) || (page->mapping && !PageAnon(page))) 1234 return 0; 1235 if (unlikely(!mm)) 1236 mm = &init_mm; 1237 return mem_cgroup_charge_common(page, mm, gfp_mask, 1238 MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL); 1239 } 1240 1241 static void 1242 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr, 1243 enum charge_type ctype); 1244 1245 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, 1246 gfp_t gfp_mask) 1247 { 1248 struct mem_cgroup *mem = NULL; 1249 int ret; 1250 1251 if (mem_cgroup_disabled()) 1252 return 0; 1253 if (PageCompound(page)) 1254 return 0; 1255 /* 1256 * Corner case handling. This is called from add_to_page_cache() 1257 * in usual. But some FS (shmem) precharges this page before calling it 1258 * and call add_to_page_cache() with GFP_NOWAIT. 1259 * 1260 * For GFP_NOWAIT case, the page may be pre-charged before calling 1261 * add_to_page_cache(). (See shmem.c) check it here and avoid to call 1262 * charge twice. (It works but has to pay a bit larger cost.) 1263 * And when the page is SwapCache, it should take swap information 1264 * into account. This is under lock_page() now. 1265 */ 1266 if (!(gfp_mask & __GFP_WAIT)) { 1267 struct page_cgroup *pc; 1268 1269 1270 pc = lookup_page_cgroup(page); 1271 if (!pc) 1272 return 0; 1273 lock_page_cgroup(pc); 1274 if (PageCgroupUsed(pc)) { 1275 unlock_page_cgroup(pc); 1276 return 0; 1277 } 1278 unlock_page_cgroup(pc); 1279 } 1280 1281 if (unlikely(!mm && !mem)) 1282 mm = &init_mm; 1283 1284 if (page_is_file_cache(page)) 1285 return mem_cgroup_charge_common(page, mm, gfp_mask, 1286 MEM_CGROUP_CHARGE_TYPE_CACHE, NULL); 1287 1288 /* shmem */ 1289 if (PageSwapCache(page)) { 1290 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem); 1291 if (!ret) 1292 __mem_cgroup_commit_charge_swapin(page, mem, 1293 MEM_CGROUP_CHARGE_TYPE_SHMEM); 1294 } else 1295 ret = mem_cgroup_charge_common(page, mm, gfp_mask, 1296 MEM_CGROUP_CHARGE_TYPE_SHMEM, mem); 1297 1298 return ret; 1299 } 1300 1301 /* 1302 * While swap-in, try_charge -> commit or cancel, the page is locked. 1303 * And when try_charge() successfully returns, one refcnt to memcg without 1304 * struct page_cgroup is aquired. This refcnt will be cumsumed by 1305 * "commit()" or removed by "cancel()" 1306 */ 1307 int mem_cgroup_try_charge_swapin(struct mm_struct *mm, 1308 struct page *page, 1309 gfp_t mask, struct mem_cgroup **ptr) 1310 { 1311 struct mem_cgroup *mem; 1312 int ret; 1313 1314 if (mem_cgroup_disabled()) 1315 return 0; 1316 1317 if (!do_swap_account) 1318 goto charge_cur_mm; 1319 /* 1320 * A racing thread's fault, or swapoff, may have already updated 1321 * the pte, and even removed page from swap cache: return success 1322 * to go on to do_swap_page()'s pte_same() test, which should fail. 1323 */ 1324 if (!PageSwapCache(page)) 1325 return 0; 1326 mem = try_get_mem_cgroup_from_swapcache(page); 1327 if (!mem) 1328 goto charge_cur_mm; 1329 *ptr = mem; 1330 ret = __mem_cgroup_try_charge(NULL, mask, ptr, true); 1331 /* drop extra refcnt from tryget */ 1332 css_put(&mem->css); 1333 return ret; 1334 charge_cur_mm: 1335 if (unlikely(!mm)) 1336 mm = &init_mm; 1337 return __mem_cgroup_try_charge(mm, mask, ptr, true); 1338 } 1339 1340 static void 1341 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr, 1342 enum charge_type ctype) 1343 { 1344 struct page_cgroup *pc; 1345 1346 if (mem_cgroup_disabled()) 1347 return; 1348 if (!ptr) 1349 return; 1350 pc = lookup_page_cgroup(page); 1351 mem_cgroup_lru_del_before_commit_swapcache(page); 1352 __mem_cgroup_commit_charge(ptr, pc, ctype); 1353 mem_cgroup_lru_add_after_commit_swapcache(page); 1354 /* 1355 * Now swap is on-memory. This means this page may be 1356 * counted both as mem and swap....double count. 1357 * Fix it by uncharging from memsw. Basically, this SwapCache is stable 1358 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page() 1359 * may call delete_from_swap_cache() before reach here. 1360 */ 1361 if (do_swap_account && PageSwapCache(page)) { 1362 swp_entry_t ent = {.val = page_private(page)}; 1363 unsigned short id; 1364 struct mem_cgroup *memcg; 1365 1366 id = swap_cgroup_record(ent, 0); 1367 rcu_read_lock(); 1368 memcg = mem_cgroup_lookup(id); 1369 if (memcg) { 1370 /* 1371 * This recorded memcg can be obsolete one. So, avoid 1372 * calling css_tryget 1373 */ 1374 res_counter_uncharge(&memcg->memsw, PAGE_SIZE); 1375 mem_cgroup_put(memcg); 1376 } 1377 rcu_read_unlock(); 1378 } 1379 /* add this page(page_cgroup) to the LRU we want. */ 1380 1381 } 1382 1383 void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr) 1384 { 1385 __mem_cgroup_commit_charge_swapin(page, ptr, 1386 MEM_CGROUP_CHARGE_TYPE_MAPPED); 1387 } 1388 1389 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem) 1390 { 1391 if (mem_cgroup_disabled()) 1392 return; 1393 if (!mem) 1394 return; 1395 res_counter_uncharge(&mem->res, PAGE_SIZE); 1396 if (do_swap_account) 1397 res_counter_uncharge(&mem->memsw, PAGE_SIZE); 1398 css_put(&mem->css); 1399 } 1400 1401 1402 /* 1403 * uncharge if !page_mapped(page) 1404 */ 1405 static struct mem_cgroup * 1406 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype) 1407 { 1408 struct page_cgroup *pc; 1409 struct mem_cgroup *mem = NULL; 1410 struct mem_cgroup_per_zone *mz; 1411 1412 if (mem_cgroup_disabled()) 1413 return NULL; 1414 1415 if (PageSwapCache(page)) 1416 return NULL; 1417 1418 /* 1419 * Check if our page_cgroup is valid 1420 */ 1421 pc = lookup_page_cgroup(page); 1422 if (unlikely(!pc || !PageCgroupUsed(pc))) 1423 return NULL; 1424 1425 lock_page_cgroup(pc); 1426 1427 mem = pc->mem_cgroup; 1428 1429 if (!PageCgroupUsed(pc)) 1430 goto unlock_out; 1431 1432 switch (ctype) { 1433 case MEM_CGROUP_CHARGE_TYPE_MAPPED: 1434 if (page_mapped(page)) 1435 goto unlock_out; 1436 break; 1437 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT: 1438 if (!PageAnon(page)) { /* Shared memory */ 1439 if (page->mapping && !page_is_file_cache(page)) 1440 goto unlock_out; 1441 } else if (page_mapped(page)) /* Anon */ 1442 goto unlock_out; 1443 break; 1444 default: 1445 break; 1446 } 1447 1448 res_counter_uncharge(&mem->res, PAGE_SIZE); 1449 if (do_swap_account && (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)) 1450 res_counter_uncharge(&mem->memsw, PAGE_SIZE); 1451 mem_cgroup_charge_statistics(mem, pc, false); 1452 1453 ClearPageCgroupUsed(pc); 1454 /* 1455 * pc->mem_cgroup is not cleared here. It will be accessed when it's 1456 * freed from LRU. This is safe because uncharged page is expected not 1457 * to be reused (freed soon). Exception is SwapCache, it's handled by 1458 * special functions. 1459 */ 1460 1461 mz = page_cgroup_zoneinfo(pc); 1462 unlock_page_cgroup(pc); 1463 1464 /* at swapout, this memcg will be accessed to record to swap */ 1465 if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT) 1466 css_put(&mem->css); 1467 1468 return mem; 1469 1470 unlock_out: 1471 unlock_page_cgroup(pc); 1472 return NULL; 1473 } 1474 1475 void mem_cgroup_uncharge_page(struct page *page) 1476 { 1477 /* early check. */ 1478 if (page_mapped(page)) 1479 return; 1480 if (page->mapping && !PageAnon(page)) 1481 return; 1482 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED); 1483 } 1484 1485 void mem_cgroup_uncharge_cache_page(struct page *page) 1486 { 1487 VM_BUG_ON(page_mapped(page)); 1488 VM_BUG_ON(page->mapping); 1489 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE); 1490 } 1491 1492 /* 1493 * called from __delete_from_swap_cache() and drop "page" account. 1494 * memcg information is recorded to swap_cgroup of "ent" 1495 */ 1496 void mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent) 1497 { 1498 struct mem_cgroup *memcg; 1499 1500 memcg = __mem_cgroup_uncharge_common(page, 1501 MEM_CGROUP_CHARGE_TYPE_SWAPOUT); 1502 /* record memcg information */ 1503 if (do_swap_account && memcg) { 1504 swap_cgroup_record(ent, css_id(&memcg->css)); 1505 mem_cgroup_get(memcg); 1506 } 1507 if (memcg) 1508 css_put(&memcg->css); 1509 } 1510 1511 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 1512 /* 1513 * called from swap_entry_free(). remove record in swap_cgroup and 1514 * uncharge "memsw" account. 1515 */ 1516 void mem_cgroup_uncharge_swap(swp_entry_t ent) 1517 { 1518 struct mem_cgroup *memcg; 1519 unsigned short id; 1520 1521 if (!do_swap_account) 1522 return; 1523 1524 id = swap_cgroup_record(ent, 0); 1525 rcu_read_lock(); 1526 memcg = mem_cgroup_lookup(id); 1527 if (memcg) { 1528 /* 1529 * We uncharge this because swap is freed. 1530 * This memcg can be obsolete one. We avoid calling css_tryget 1531 */ 1532 res_counter_uncharge(&memcg->memsw, PAGE_SIZE); 1533 mem_cgroup_put(memcg); 1534 } 1535 rcu_read_unlock(); 1536 } 1537 #endif 1538 1539 /* 1540 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old 1541 * page belongs to. 1542 */ 1543 int mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr) 1544 { 1545 struct page_cgroup *pc; 1546 struct mem_cgroup *mem = NULL; 1547 int ret = 0; 1548 1549 if (mem_cgroup_disabled()) 1550 return 0; 1551 1552 pc = lookup_page_cgroup(page); 1553 lock_page_cgroup(pc); 1554 if (PageCgroupUsed(pc)) { 1555 mem = pc->mem_cgroup; 1556 css_get(&mem->css); 1557 } 1558 unlock_page_cgroup(pc); 1559 1560 if (mem) { 1561 ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false); 1562 css_put(&mem->css); 1563 } 1564 *ptr = mem; 1565 return ret; 1566 } 1567 1568 /* remove redundant charge if migration failed*/ 1569 void mem_cgroup_end_migration(struct mem_cgroup *mem, 1570 struct page *oldpage, struct page *newpage) 1571 { 1572 struct page *target, *unused; 1573 struct page_cgroup *pc; 1574 enum charge_type ctype; 1575 1576 if (!mem) 1577 return; 1578 1579 /* at migration success, oldpage->mapping is NULL. */ 1580 if (oldpage->mapping) { 1581 target = oldpage; 1582 unused = NULL; 1583 } else { 1584 target = newpage; 1585 unused = oldpage; 1586 } 1587 1588 if (PageAnon(target)) 1589 ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED; 1590 else if (page_is_file_cache(target)) 1591 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; 1592 else 1593 ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM; 1594 1595 /* unused page is not on radix-tree now. */ 1596 if (unused) 1597 __mem_cgroup_uncharge_common(unused, ctype); 1598 1599 pc = lookup_page_cgroup(target); 1600 /* 1601 * __mem_cgroup_commit_charge() check PCG_USED bit of page_cgroup. 1602 * So, double-counting is effectively avoided. 1603 */ 1604 __mem_cgroup_commit_charge(mem, pc, ctype); 1605 1606 /* 1607 * Both of oldpage and newpage are still under lock_page(). 1608 * Then, we don't have to care about race in radix-tree. 1609 * But we have to be careful that this page is unmapped or not. 1610 * 1611 * There is a case for !page_mapped(). At the start of 1612 * migration, oldpage was mapped. But now, it's zapped. 1613 * But we know *target* page is not freed/reused under us. 1614 * mem_cgroup_uncharge_page() does all necessary checks. 1615 */ 1616 if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED) 1617 mem_cgroup_uncharge_page(target); 1618 } 1619 1620 /* 1621 * A call to try to shrink memory usage under specified resource controller. 1622 * This is typically used for page reclaiming for shmem for reducing side 1623 * effect of page allocation from shmem, which is used by some mem_cgroup. 1624 */ 1625 int mem_cgroup_shrink_usage(struct page *page, 1626 struct mm_struct *mm, 1627 gfp_t gfp_mask) 1628 { 1629 struct mem_cgroup *mem = NULL; 1630 int progress = 0; 1631 int retry = MEM_CGROUP_RECLAIM_RETRIES; 1632 1633 if (mem_cgroup_disabled()) 1634 return 0; 1635 if (page) 1636 mem = try_get_mem_cgroup_from_swapcache(page); 1637 if (!mem && mm) 1638 mem = try_get_mem_cgroup_from_mm(mm); 1639 if (unlikely(!mem)) 1640 return 0; 1641 1642 do { 1643 progress = mem_cgroup_hierarchical_reclaim(mem, 1644 gfp_mask, true, false); 1645 progress += mem_cgroup_check_under_limit(mem); 1646 } while (!progress && --retry); 1647 1648 css_put(&mem->css); 1649 if (!retry) 1650 return -ENOMEM; 1651 return 0; 1652 } 1653 1654 static DEFINE_MUTEX(set_limit_mutex); 1655 1656 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, 1657 unsigned long long val) 1658 { 1659 int retry_count; 1660 int progress; 1661 u64 memswlimit; 1662 int ret = 0; 1663 int children = mem_cgroup_count_children(memcg); 1664 u64 curusage, oldusage; 1665 1666 /* 1667 * For keeping hierarchical_reclaim simple, how long we should retry 1668 * is depends on callers. We set our retry-count to be function 1669 * of # of children which we should visit in this loop. 1670 */ 1671 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children; 1672 1673 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE); 1674 1675 while (retry_count) { 1676 if (signal_pending(current)) { 1677 ret = -EINTR; 1678 break; 1679 } 1680 /* 1681 * Rather than hide all in some function, I do this in 1682 * open coded manner. You see what this really does. 1683 * We have to guarantee mem->res.limit < mem->memsw.limit. 1684 */ 1685 mutex_lock(&set_limit_mutex); 1686 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); 1687 if (memswlimit < val) { 1688 ret = -EINVAL; 1689 mutex_unlock(&set_limit_mutex); 1690 break; 1691 } 1692 ret = res_counter_set_limit(&memcg->res, val); 1693 mutex_unlock(&set_limit_mutex); 1694 1695 if (!ret) 1696 break; 1697 1698 progress = mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL, 1699 false, true); 1700 curusage = res_counter_read_u64(&memcg->res, RES_USAGE); 1701 /* Usage is reduced ? */ 1702 if (curusage >= oldusage) 1703 retry_count--; 1704 else 1705 oldusage = curusage; 1706 } 1707 1708 return ret; 1709 } 1710 1711 int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, 1712 unsigned long long val) 1713 { 1714 int retry_count; 1715 u64 memlimit, oldusage, curusage; 1716 int children = mem_cgroup_count_children(memcg); 1717 int ret = -EBUSY; 1718 1719 if (!do_swap_account) 1720 return -EINVAL; 1721 /* see mem_cgroup_resize_res_limit */ 1722 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES; 1723 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); 1724 while (retry_count) { 1725 if (signal_pending(current)) { 1726 ret = -EINTR; 1727 break; 1728 } 1729 /* 1730 * Rather than hide all in some function, I do this in 1731 * open coded manner. You see what this really does. 1732 * We have to guarantee mem->res.limit < mem->memsw.limit. 1733 */ 1734 mutex_lock(&set_limit_mutex); 1735 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); 1736 if (memlimit > val) { 1737 ret = -EINVAL; 1738 mutex_unlock(&set_limit_mutex); 1739 break; 1740 } 1741 ret = res_counter_set_limit(&memcg->memsw, val); 1742 mutex_unlock(&set_limit_mutex); 1743 1744 if (!ret) 1745 break; 1746 1747 mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL, true, true); 1748 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); 1749 /* Usage is reduced ? */ 1750 if (curusage >= oldusage) 1751 retry_count--; 1752 else 1753 oldusage = curusage; 1754 } 1755 return ret; 1756 } 1757 1758 /* 1759 * This routine traverse page_cgroup in given list and drop them all. 1760 * *And* this routine doesn't reclaim page itself, just removes page_cgroup. 1761 */ 1762 static int mem_cgroup_force_empty_list(struct mem_cgroup *mem, 1763 int node, int zid, enum lru_list lru) 1764 { 1765 struct zone *zone; 1766 struct mem_cgroup_per_zone *mz; 1767 struct page_cgroup *pc, *busy; 1768 unsigned long flags, loop; 1769 struct list_head *list; 1770 int ret = 0; 1771 1772 zone = &NODE_DATA(node)->node_zones[zid]; 1773 mz = mem_cgroup_zoneinfo(mem, node, zid); 1774 list = &mz->lists[lru]; 1775 1776 loop = MEM_CGROUP_ZSTAT(mz, lru); 1777 /* give some margin against EBUSY etc...*/ 1778 loop += 256; 1779 busy = NULL; 1780 while (loop--) { 1781 ret = 0; 1782 spin_lock_irqsave(&zone->lru_lock, flags); 1783 if (list_empty(list)) { 1784 spin_unlock_irqrestore(&zone->lru_lock, flags); 1785 break; 1786 } 1787 pc = list_entry(list->prev, struct page_cgroup, lru); 1788 if (busy == pc) { 1789 list_move(&pc->lru, list); 1790 busy = 0; 1791 spin_unlock_irqrestore(&zone->lru_lock, flags); 1792 continue; 1793 } 1794 spin_unlock_irqrestore(&zone->lru_lock, flags); 1795 1796 ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL); 1797 if (ret == -ENOMEM) 1798 break; 1799 1800 if (ret == -EBUSY || ret == -EINVAL) { 1801 /* found lock contention or "pc" is obsolete. */ 1802 busy = pc; 1803 cond_resched(); 1804 } else 1805 busy = NULL; 1806 } 1807 1808 if (!ret && !list_empty(list)) 1809 return -EBUSY; 1810 return ret; 1811 } 1812 1813 /* 1814 * make mem_cgroup's charge to be 0 if there is no task. 1815 * This enables deleting this mem_cgroup. 1816 */ 1817 static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all) 1818 { 1819 int ret; 1820 int node, zid, shrink; 1821 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; 1822 struct cgroup *cgrp = mem->css.cgroup; 1823 1824 css_get(&mem->css); 1825 1826 shrink = 0; 1827 /* should free all ? */ 1828 if (free_all) 1829 goto try_to_free; 1830 move_account: 1831 while (mem->res.usage > 0) { 1832 ret = -EBUSY; 1833 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children)) 1834 goto out; 1835 ret = -EINTR; 1836 if (signal_pending(current)) 1837 goto out; 1838 /* This is for making all *used* pages to be on LRU. */ 1839 lru_add_drain_all(); 1840 ret = 0; 1841 for_each_node_state(node, N_HIGH_MEMORY) { 1842 for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) { 1843 enum lru_list l; 1844 for_each_lru(l) { 1845 ret = mem_cgroup_force_empty_list(mem, 1846 node, zid, l); 1847 if (ret) 1848 break; 1849 } 1850 } 1851 if (ret) 1852 break; 1853 } 1854 /* it seems parent cgroup doesn't have enough mem */ 1855 if (ret == -ENOMEM) 1856 goto try_to_free; 1857 cond_resched(); 1858 } 1859 ret = 0; 1860 out: 1861 css_put(&mem->css); 1862 return ret; 1863 1864 try_to_free: 1865 /* returns EBUSY if there is a task or if we come here twice. */ 1866 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) { 1867 ret = -EBUSY; 1868 goto out; 1869 } 1870 /* we call try-to-free pages for make this cgroup empty */ 1871 lru_add_drain_all(); 1872 /* try to free all pages in this cgroup */ 1873 shrink = 1; 1874 while (nr_retries && mem->res.usage > 0) { 1875 int progress; 1876 1877 if (signal_pending(current)) { 1878 ret = -EINTR; 1879 goto out; 1880 } 1881 progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL, 1882 false, get_swappiness(mem)); 1883 if (!progress) { 1884 nr_retries--; 1885 /* maybe some writeback is necessary */ 1886 congestion_wait(WRITE, HZ/10); 1887 } 1888 1889 } 1890 lru_add_drain(); 1891 /* try move_account...there may be some *locked* pages. */ 1892 if (mem->res.usage) 1893 goto move_account; 1894 ret = 0; 1895 goto out; 1896 } 1897 1898 int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event) 1899 { 1900 return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true); 1901 } 1902 1903 1904 static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft) 1905 { 1906 return mem_cgroup_from_cont(cont)->use_hierarchy; 1907 } 1908 1909 static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft, 1910 u64 val) 1911 { 1912 int retval = 0; 1913 struct mem_cgroup *mem = mem_cgroup_from_cont(cont); 1914 struct cgroup *parent = cont->parent; 1915 struct mem_cgroup *parent_mem = NULL; 1916 1917 if (parent) 1918 parent_mem = mem_cgroup_from_cont(parent); 1919 1920 cgroup_lock(); 1921 /* 1922 * If parent's use_hiearchy is set, we can't make any modifications 1923 * in the child subtrees. If it is unset, then the change can 1924 * occur, provided the current cgroup has no children. 1925 * 1926 * For the root cgroup, parent_mem is NULL, we allow value to be 1927 * set if there are no children. 1928 */ 1929 if ((!parent_mem || !parent_mem->use_hierarchy) && 1930 (val == 1 || val == 0)) { 1931 if (list_empty(&cont->children)) 1932 mem->use_hierarchy = val; 1933 else 1934 retval = -EBUSY; 1935 } else 1936 retval = -EINVAL; 1937 cgroup_unlock(); 1938 1939 return retval; 1940 } 1941 1942 static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft) 1943 { 1944 struct mem_cgroup *mem = mem_cgroup_from_cont(cont); 1945 u64 val = 0; 1946 int type, name; 1947 1948 type = MEMFILE_TYPE(cft->private); 1949 name = MEMFILE_ATTR(cft->private); 1950 switch (type) { 1951 case _MEM: 1952 val = res_counter_read_u64(&mem->res, name); 1953 break; 1954 case _MEMSWAP: 1955 if (do_swap_account) 1956 val = res_counter_read_u64(&mem->memsw, name); 1957 break; 1958 default: 1959 BUG(); 1960 break; 1961 } 1962 return val; 1963 } 1964 /* 1965 * The user of this function is... 1966 * RES_LIMIT. 1967 */ 1968 static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft, 1969 const char *buffer) 1970 { 1971 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); 1972 int type, name; 1973 unsigned long long val; 1974 int ret; 1975 1976 type = MEMFILE_TYPE(cft->private); 1977 name = MEMFILE_ATTR(cft->private); 1978 switch (name) { 1979 case RES_LIMIT: 1980 /* This function does all necessary parse...reuse it */ 1981 ret = res_counter_memparse_write_strategy(buffer, &val); 1982 if (ret) 1983 break; 1984 if (type == _MEM) 1985 ret = mem_cgroup_resize_limit(memcg, val); 1986 else 1987 ret = mem_cgroup_resize_memsw_limit(memcg, val); 1988 break; 1989 default: 1990 ret = -EINVAL; /* should be BUG() ? */ 1991 break; 1992 } 1993 return ret; 1994 } 1995 1996 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg, 1997 unsigned long long *mem_limit, unsigned long long *memsw_limit) 1998 { 1999 struct cgroup *cgroup; 2000 unsigned long long min_limit, min_memsw_limit, tmp; 2001 2002 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT); 2003 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); 2004 cgroup = memcg->css.cgroup; 2005 if (!memcg->use_hierarchy) 2006 goto out; 2007 2008 while (cgroup->parent) { 2009 cgroup = cgroup->parent; 2010 memcg = mem_cgroup_from_cont(cgroup); 2011 if (!memcg->use_hierarchy) 2012 break; 2013 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT); 2014 min_limit = min(min_limit, tmp); 2015 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT); 2016 min_memsw_limit = min(min_memsw_limit, tmp); 2017 } 2018 out: 2019 *mem_limit = min_limit; 2020 *memsw_limit = min_memsw_limit; 2021 return; 2022 } 2023 2024 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event) 2025 { 2026 struct mem_cgroup *mem; 2027 int type, name; 2028 2029 mem = mem_cgroup_from_cont(cont); 2030 type = MEMFILE_TYPE(event); 2031 name = MEMFILE_ATTR(event); 2032 switch (name) { 2033 case RES_MAX_USAGE: 2034 if (type == _MEM) 2035 res_counter_reset_max(&mem->res); 2036 else 2037 res_counter_reset_max(&mem->memsw); 2038 break; 2039 case RES_FAILCNT: 2040 if (type == _MEM) 2041 res_counter_reset_failcnt(&mem->res); 2042 else 2043 res_counter_reset_failcnt(&mem->memsw); 2044 break; 2045 } 2046 return 0; 2047 } 2048 2049 2050 /* For read statistics */ 2051 enum { 2052 MCS_CACHE, 2053 MCS_RSS, 2054 MCS_PGPGIN, 2055 MCS_PGPGOUT, 2056 MCS_INACTIVE_ANON, 2057 MCS_ACTIVE_ANON, 2058 MCS_INACTIVE_FILE, 2059 MCS_ACTIVE_FILE, 2060 MCS_UNEVICTABLE, 2061 NR_MCS_STAT, 2062 }; 2063 2064 struct mcs_total_stat { 2065 s64 stat[NR_MCS_STAT]; 2066 }; 2067 2068 struct { 2069 char *local_name; 2070 char *total_name; 2071 } memcg_stat_strings[NR_MCS_STAT] = { 2072 {"cache", "total_cache"}, 2073 {"rss", "total_rss"}, 2074 {"pgpgin", "total_pgpgin"}, 2075 {"pgpgout", "total_pgpgout"}, 2076 {"inactive_anon", "total_inactive_anon"}, 2077 {"active_anon", "total_active_anon"}, 2078 {"inactive_file", "total_inactive_file"}, 2079 {"active_file", "total_active_file"}, 2080 {"unevictable", "total_unevictable"} 2081 }; 2082 2083 2084 static int mem_cgroup_get_local_stat(struct mem_cgroup *mem, void *data) 2085 { 2086 struct mcs_total_stat *s = data; 2087 s64 val; 2088 2089 /* per cpu stat */ 2090 val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_CACHE); 2091 s->stat[MCS_CACHE] += val * PAGE_SIZE; 2092 val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_RSS); 2093 s->stat[MCS_RSS] += val * PAGE_SIZE; 2094 val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_PGPGIN_COUNT); 2095 s->stat[MCS_PGPGIN] += val; 2096 val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_PGPGOUT_COUNT); 2097 s->stat[MCS_PGPGOUT] += val; 2098 2099 /* per zone stat */ 2100 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON); 2101 s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE; 2102 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON); 2103 s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE; 2104 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE); 2105 s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE; 2106 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE); 2107 s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE; 2108 val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE); 2109 s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE; 2110 return 0; 2111 } 2112 2113 static void 2114 mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s) 2115 { 2116 mem_cgroup_walk_tree(mem, s, mem_cgroup_get_local_stat); 2117 } 2118 2119 static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft, 2120 struct cgroup_map_cb *cb) 2121 { 2122 struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont); 2123 struct mcs_total_stat mystat; 2124 int i; 2125 2126 memset(&mystat, 0, sizeof(mystat)); 2127 mem_cgroup_get_local_stat(mem_cont, &mystat); 2128 2129 for (i = 0; i < NR_MCS_STAT; i++) 2130 cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]); 2131 2132 /* Hierarchical information */ 2133 { 2134 unsigned long long limit, memsw_limit; 2135 memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit); 2136 cb->fill(cb, "hierarchical_memory_limit", limit); 2137 if (do_swap_account) 2138 cb->fill(cb, "hierarchical_memsw_limit", memsw_limit); 2139 } 2140 2141 memset(&mystat, 0, sizeof(mystat)); 2142 mem_cgroup_get_total_stat(mem_cont, &mystat); 2143 for (i = 0; i < NR_MCS_STAT; i++) 2144 cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]); 2145 2146 2147 #ifdef CONFIG_DEBUG_VM 2148 cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL)); 2149 2150 { 2151 int nid, zid; 2152 struct mem_cgroup_per_zone *mz; 2153 unsigned long recent_rotated[2] = {0, 0}; 2154 unsigned long recent_scanned[2] = {0, 0}; 2155 2156 for_each_online_node(nid) 2157 for (zid = 0; zid < MAX_NR_ZONES; zid++) { 2158 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); 2159 2160 recent_rotated[0] += 2161 mz->reclaim_stat.recent_rotated[0]; 2162 recent_rotated[1] += 2163 mz->reclaim_stat.recent_rotated[1]; 2164 recent_scanned[0] += 2165 mz->reclaim_stat.recent_scanned[0]; 2166 recent_scanned[1] += 2167 mz->reclaim_stat.recent_scanned[1]; 2168 } 2169 cb->fill(cb, "recent_rotated_anon", recent_rotated[0]); 2170 cb->fill(cb, "recent_rotated_file", recent_rotated[1]); 2171 cb->fill(cb, "recent_scanned_anon", recent_scanned[0]); 2172 cb->fill(cb, "recent_scanned_file", recent_scanned[1]); 2173 } 2174 #endif 2175 2176 return 0; 2177 } 2178 2179 static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft) 2180 { 2181 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 2182 2183 return get_swappiness(memcg); 2184 } 2185 2186 static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft, 2187 u64 val) 2188 { 2189 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 2190 struct mem_cgroup *parent; 2191 2192 if (val > 100) 2193 return -EINVAL; 2194 2195 if (cgrp->parent == NULL) 2196 return -EINVAL; 2197 2198 parent = mem_cgroup_from_cont(cgrp->parent); 2199 2200 cgroup_lock(); 2201 2202 /* If under hierarchy, only empty-root can set this value */ 2203 if ((parent->use_hierarchy) || 2204 (memcg->use_hierarchy && !list_empty(&cgrp->children))) { 2205 cgroup_unlock(); 2206 return -EINVAL; 2207 } 2208 2209 spin_lock(&memcg->reclaim_param_lock); 2210 memcg->swappiness = val; 2211 spin_unlock(&memcg->reclaim_param_lock); 2212 2213 cgroup_unlock(); 2214 2215 return 0; 2216 } 2217 2218 2219 static struct cftype mem_cgroup_files[] = { 2220 { 2221 .name = "usage_in_bytes", 2222 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE), 2223 .read_u64 = mem_cgroup_read, 2224 }, 2225 { 2226 .name = "max_usage_in_bytes", 2227 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE), 2228 .trigger = mem_cgroup_reset, 2229 .read_u64 = mem_cgroup_read, 2230 }, 2231 { 2232 .name = "limit_in_bytes", 2233 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT), 2234 .write_string = mem_cgroup_write, 2235 .read_u64 = mem_cgroup_read, 2236 }, 2237 { 2238 .name = "failcnt", 2239 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT), 2240 .trigger = mem_cgroup_reset, 2241 .read_u64 = mem_cgroup_read, 2242 }, 2243 { 2244 .name = "stat", 2245 .read_map = mem_control_stat_show, 2246 }, 2247 { 2248 .name = "force_empty", 2249 .trigger = mem_cgroup_force_empty_write, 2250 }, 2251 { 2252 .name = "use_hierarchy", 2253 .write_u64 = mem_cgroup_hierarchy_write, 2254 .read_u64 = mem_cgroup_hierarchy_read, 2255 }, 2256 { 2257 .name = "swappiness", 2258 .read_u64 = mem_cgroup_swappiness_read, 2259 .write_u64 = mem_cgroup_swappiness_write, 2260 }, 2261 }; 2262 2263 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 2264 static struct cftype memsw_cgroup_files[] = { 2265 { 2266 .name = "memsw.usage_in_bytes", 2267 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE), 2268 .read_u64 = mem_cgroup_read, 2269 }, 2270 { 2271 .name = "memsw.max_usage_in_bytes", 2272 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE), 2273 .trigger = mem_cgroup_reset, 2274 .read_u64 = mem_cgroup_read, 2275 }, 2276 { 2277 .name = "memsw.limit_in_bytes", 2278 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT), 2279 .write_string = mem_cgroup_write, 2280 .read_u64 = mem_cgroup_read, 2281 }, 2282 { 2283 .name = "memsw.failcnt", 2284 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT), 2285 .trigger = mem_cgroup_reset, 2286 .read_u64 = mem_cgroup_read, 2287 }, 2288 }; 2289 2290 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss) 2291 { 2292 if (!do_swap_account) 2293 return 0; 2294 return cgroup_add_files(cont, ss, memsw_cgroup_files, 2295 ARRAY_SIZE(memsw_cgroup_files)); 2296 }; 2297 #else 2298 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss) 2299 { 2300 return 0; 2301 } 2302 #endif 2303 2304 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) 2305 { 2306 struct mem_cgroup_per_node *pn; 2307 struct mem_cgroup_per_zone *mz; 2308 enum lru_list l; 2309 int zone, tmp = node; 2310 /* 2311 * This routine is called against possible nodes. 2312 * But it's BUG to call kmalloc() against offline node. 2313 * 2314 * TODO: this routine can waste much memory for nodes which will 2315 * never be onlined. It's better to use memory hotplug callback 2316 * function. 2317 */ 2318 if (!node_state(node, N_NORMAL_MEMORY)) 2319 tmp = -1; 2320 pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp); 2321 if (!pn) 2322 return 1; 2323 2324 mem->info.nodeinfo[node] = pn; 2325 memset(pn, 0, sizeof(*pn)); 2326 2327 for (zone = 0; zone < MAX_NR_ZONES; zone++) { 2328 mz = &pn->zoneinfo[zone]; 2329 for_each_lru(l) 2330 INIT_LIST_HEAD(&mz->lists[l]); 2331 } 2332 return 0; 2333 } 2334 2335 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) 2336 { 2337 kfree(mem->info.nodeinfo[node]); 2338 } 2339 2340 static int mem_cgroup_size(void) 2341 { 2342 int cpustat_size = nr_cpu_ids * sizeof(struct mem_cgroup_stat_cpu); 2343 return sizeof(struct mem_cgroup) + cpustat_size; 2344 } 2345 2346 static struct mem_cgroup *mem_cgroup_alloc(void) 2347 { 2348 struct mem_cgroup *mem; 2349 int size = mem_cgroup_size(); 2350 2351 if (size < PAGE_SIZE) 2352 mem = kmalloc(size, GFP_KERNEL); 2353 else 2354 mem = vmalloc(size); 2355 2356 if (mem) 2357 memset(mem, 0, size); 2358 return mem; 2359 } 2360 2361 /* 2362 * At destroying mem_cgroup, references from swap_cgroup can remain. 2363 * (scanning all at force_empty is too costly...) 2364 * 2365 * Instead of clearing all references at force_empty, we remember 2366 * the number of reference from swap_cgroup and free mem_cgroup when 2367 * it goes down to 0. 2368 * 2369 * Removal of cgroup itself succeeds regardless of refs from swap. 2370 */ 2371 2372 static void __mem_cgroup_free(struct mem_cgroup *mem) 2373 { 2374 int node; 2375 2376 free_css_id(&mem_cgroup_subsys, &mem->css); 2377 2378 for_each_node_state(node, N_POSSIBLE) 2379 free_mem_cgroup_per_zone_info(mem, node); 2380 2381 if (mem_cgroup_size() < PAGE_SIZE) 2382 kfree(mem); 2383 else 2384 vfree(mem); 2385 } 2386 2387 static void mem_cgroup_get(struct mem_cgroup *mem) 2388 { 2389 atomic_inc(&mem->refcnt); 2390 } 2391 2392 static void mem_cgroup_put(struct mem_cgroup *mem) 2393 { 2394 if (atomic_dec_and_test(&mem->refcnt)) { 2395 struct mem_cgroup *parent = parent_mem_cgroup(mem); 2396 __mem_cgroup_free(mem); 2397 if (parent) 2398 mem_cgroup_put(parent); 2399 } 2400 } 2401 2402 /* 2403 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled. 2404 */ 2405 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem) 2406 { 2407 if (!mem->res.parent) 2408 return NULL; 2409 return mem_cgroup_from_res_counter(mem->res.parent, res); 2410 } 2411 2412 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 2413 static void __init enable_swap_cgroup(void) 2414 { 2415 if (!mem_cgroup_disabled() && really_do_swap_account) 2416 do_swap_account = 1; 2417 } 2418 #else 2419 static void __init enable_swap_cgroup(void) 2420 { 2421 } 2422 #endif 2423 2424 static struct cgroup_subsys_state * __ref 2425 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) 2426 { 2427 struct mem_cgroup *mem, *parent; 2428 long error = -ENOMEM; 2429 int node; 2430 2431 mem = mem_cgroup_alloc(); 2432 if (!mem) 2433 return ERR_PTR(error); 2434 2435 for_each_node_state(node, N_POSSIBLE) 2436 if (alloc_mem_cgroup_per_zone_info(mem, node)) 2437 goto free_out; 2438 /* root ? */ 2439 if (cont->parent == NULL) { 2440 enable_swap_cgroup(); 2441 parent = NULL; 2442 } else { 2443 parent = mem_cgroup_from_cont(cont->parent); 2444 mem->use_hierarchy = parent->use_hierarchy; 2445 } 2446 2447 if (parent && parent->use_hierarchy) { 2448 res_counter_init(&mem->res, &parent->res); 2449 res_counter_init(&mem->memsw, &parent->memsw); 2450 /* 2451 * We increment refcnt of the parent to ensure that we can 2452 * safely access it on res_counter_charge/uncharge. 2453 * This refcnt will be decremented when freeing this 2454 * mem_cgroup(see mem_cgroup_put). 2455 */ 2456 mem_cgroup_get(parent); 2457 } else { 2458 res_counter_init(&mem->res, NULL); 2459 res_counter_init(&mem->memsw, NULL); 2460 } 2461 mem->last_scanned_child = 0; 2462 spin_lock_init(&mem->reclaim_param_lock); 2463 2464 if (parent) 2465 mem->swappiness = get_swappiness(parent); 2466 atomic_set(&mem->refcnt, 1); 2467 return &mem->css; 2468 free_out: 2469 __mem_cgroup_free(mem); 2470 return ERR_PTR(error); 2471 } 2472 2473 static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss, 2474 struct cgroup *cont) 2475 { 2476 struct mem_cgroup *mem = mem_cgroup_from_cont(cont); 2477 2478 return mem_cgroup_force_empty(mem, false); 2479 } 2480 2481 static void mem_cgroup_destroy(struct cgroup_subsys *ss, 2482 struct cgroup *cont) 2483 { 2484 struct mem_cgroup *mem = mem_cgroup_from_cont(cont); 2485 2486 mem_cgroup_put(mem); 2487 } 2488 2489 static int mem_cgroup_populate(struct cgroup_subsys *ss, 2490 struct cgroup *cont) 2491 { 2492 int ret; 2493 2494 ret = cgroup_add_files(cont, ss, mem_cgroup_files, 2495 ARRAY_SIZE(mem_cgroup_files)); 2496 2497 if (!ret) 2498 ret = register_memsw_files(cont, ss); 2499 return ret; 2500 } 2501 2502 static void mem_cgroup_move_task(struct cgroup_subsys *ss, 2503 struct cgroup *cont, 2504 struct cgroup *old_cont, 2505 struct task_struct *p) 2506 { 2507 mutex_lock(&memcg_tasklist); 2508 /* 2509 * FIXME: It's better to move charges of this process from old 2510 * memcg to new memcg. But it's just on TODO-List now. 2511 */ 2512 mutex_unlock(&memcg_tasklist); 2513 } 2514 2515 struct cgroup_subsys mem_cgroup_subsys = { 2516 .name = "memory", 2517 .subsys_id = mem_cgroup_subsys_id, 2518 .create = mem_cgroup_create, 2519 .pre_destroy = mem_cgroup_pre_destroy, 2520 .destroy = mem_cgroup_destroy, 2521 .populate = mem_cgroup_populate, 2522 .attach = mem_cgroup_move_task, 2523 .early_init = 0, 2524 .use_id = 1, 2525 }; 2526 2527 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 2528 2529 static int __init disable_swap_account(char *s) 2530 { 2531 really_do_swap_account = 0; 2532 return 1; 2533 } 2534 __setup("noswapaccount", disable_swap_account); 2535 #endif 2536