memcontrol.c revision 1faf8e40a8ab12ae1f7f474965e6fb031e43f8d6
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/smp.h> 25#include <linux/page-flags.h> 26#include <linux/backing-dev.h> 27#include <linux/bit_spinlock.h> 28#include <linux/rcupdate.h> 29#include <linux/slab.h> 30#include <linux/swap.h> 31#include <linux/spinlock.h> 32#include <linux/fs.h> 33#include <linux/seq_file.h> 34#include <linux/vmalloc.h> 35 36#include <asm/uaccess.h> 37 38struct cgroup_subsys mem_cgroup_subsys; 39static const int MEM_CGROUP_RECLAIM_RETRIES = 5; 40static struct kmem_cache *page_cgroup_cache; 41 42/* 43 * Statistics for memory cgroup. 44 */ 45enum mem_cgroup_stat_index { 46 /* 47 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss. 48 */ 49 MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */ 50 MEM_CGROUP_STAT_RSS, /* # of pages charged as rss */ 51 52 MEM_CGROUP_STAT_NSTATS, 53}; 54 55struct mem_cgroup_stat_cpu { 56 s64 count[MEM_CGROUP_STAT_NSTATS]; 57} ____cacheline_aligned_in_smp; 58 59struct mem_cgroup_stat { 60 struct mem_cgroup_stat_cpu cpustat[NR_CPUS]; 61}; 62 63/* 64 * For accounting under irq disable, no need for increment preempt count. 65 */ 66static void __mem_cgroup_stat_add_safe(struct mem_cgroup_stat *stat, 67 enum mem_cgroup_stat_index idx, int val) 68{ 69 int cpu = smp_processor_id(); 70 stat->cpustat[cpu].count[idx] += val; 71} 72 73static s64 mem_cgroup_read_stat(struct mem_cgroup_stat *stat, 74 enum mem_cgroup_stat_index idx) 75{ 76 int cpu; 77 s64 ret = 0; 78 for_each_possible_cpu(cpu) 79 ret += stat->cpustat[cpu].count[idx]; 80 return ret; 81} 82 83/* 84 * per-zone information in memory controller. 85 */ 86 87enum mem_cgroup_zstat_index { 88 MEM_CGROUP_ZSTAT_ACTIVE, 89 MEM_CGROUP_ZSTAT_INACTIVE, 90 91 NR_MEM_CGROUP_ZSTAT, 92}; 93 94struct mem_cgroup_per_zone { 95 /* 96 * spin_lock to protect the per cgroup LRU 97 */ 98 spinlock_t lru_lock; 99 struct list_head active_list; 100 struct list_head inactive_list; 101 unsigned long count[NR_MEM_CGROUP_ZSTAT]; 102}; 103/* Macro for accessing counter */ 104#define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)]) 105 106struct mem_cgroup_per_node { 107 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES]; 108}; 109 110struct mem_cgroup_lru_info { 111 struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES]; 112}; 113 114/* 115 * The memory controller data structure. The memory controller controls both 116 * page cache and RSS per cgroup. We would eventually like to provide 117 * statistics based on the statistics developed by Rik Van Riel for clock-pro, 118 * to help the administrator determine what knobs to tune. 119 * 120 * TODO: Add a water mark for the memory controller. Reclaim will begin when 121 * we hit the water mark. May be even add a low water mark, such that 122 * no reclaim occurs from a cgroup at it's low water mark, this is 123 * a feature that will be implemented much later in the future. 124 */ 125struct mem_cgroup { 126 struct cgroup_subsys_state css; 127 /* 128 * the counter to account for memory usage 129 */ 130 struct res_counter res; 131 /* 132 * Per cgroup active and inactive list, similar to the 133 * per zone LRU lists. 134 */ 135 struct mem_cgroup_lru_info info; 136 137 int prev_priority; /* for recording reclaim priority */ 138 /* 139 * statistics. 140 */ 141 struct mem_cgroup_stat stat; 142}; 143static struct mem_cgroup init_mem_cgroup; 144 145/* 146 * We use the lower bit of the page->page_cgroup pointer as a bit spin 147 * lock. We need to ensure that page->page_cgroup is at least two 148 * byte aligned (based on comments from Nick Piggin). But since 149 * bit_spin_lock doesn't actually set that lock bit in a non-debug 150 * uniprocessor kernel, we should avoid setting it here too. 151 */ 152#define PAGE_CGROUP_LOCK_BIT 0x0 153#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) 154#define PAGE_CGROUP_LOCK (1 << PAGE_CGROUP_LOCK_BIT) 155#else 156#define PAGE_CGROUP_LOCK 0x0 157#endif 158 159/* 160 * A page_cgroup page is associated with every page descriptor. The 161 * page_cgroup helps us identify information about the cgroup 162 */ 163struct page_cgroup { 164 struct list_head lru; /* per cgroup LRU list */ 165 struct page *page; 166 struct mem_cgroup *mem_cgroup; 167 int ref_cnt; /* cached, mapped, migrating */ 168 int flags; 169}; 170#define PAGE_CGROUP_FLAG_CACHE (0x1) /* charged as cache */ 171#define PAGE_CGROUP_FLAG_ACTIVE (0x2) /* page is active in this cgroup */ 172 173static int page_cgroup_nid(struct page_cgroup *pc) 174{ 175 return page_to_nid(pc->page); 176} 177 178static enum zone_type page_cgroup_zid(struct page_cgroup *pc) 179{ 180 return page_zonenum(pc->page); 181} 182 183enum charge_type { 184 MEM_CGROUP_CHARGE_TYPE_CACHE = 0, 185 MEM_CGROUP_CHARGE_TYPE_MAPPED, 186}; 187 188/* 189 * Always modified under lru lock. Then, not necessary to preempt_disable() 190 */ 191static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, int flags, 192 bool charge) 193{ 194 int val = (charge)? 1 : -1; 195 struct mem_cgroup_stat *stat = &mem->stat; 196 197 VM_BUG_ON(!irqs_disabled()); 198 if (flags & PAGE_CGROUP_FLAG_CACHE) 199 __mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_CACHE, val); 200 else 201 __mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_RSS, val); 202} 203 204static struct mem_cgroup_per_zone * 205mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid) 206{ 207 return &mem->info.nodeinfo[nid]->zoneinfo[zid]; 208} 209 210static struct mem_cgroup_per_zone * 211page_cgroup_zoneinfo(struct page_cgroup *pc) 212{ 213 struct mem_cgroup *mem = pc->mem_cgroup; 214 int nid = page_cgroup_nid(pc); 215 int zid = page_cgroup_zid(pc); 216 217 return mem_cgroup_zoneinfo(mem, nid, zid); 218} 219 220static unsigned long mem_cgroup_get_all_zonestat(struct mem_cgroup *mem, 221 enum mem_cgroup_zstat_index idx) 222{ 223 int nid, zid; 224 struct mem_cgroup_per_zone *mz; 225 u64 total = 0; 226 227 for_each_online_node(nid) 228 for (zid = 0; zid < MAX_NR_ZONES; zid++) { 229 mz = mem_cgroup_zoneinfo(mem, nid, zid); 230 total += MEM_CGROUP_ZSTAT(mz, idx); 231 } 232 return total; 233} 234 235static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) 236{ 237 return container_of(cgroup_subsys_state(cont, 238 mem_cgroup_subsys_id), struct mem_cgroup, 239 css); 240} 241 242struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) 243{ 244 return container_of(task_subsys_state(p, mem_cgroup_subsys_id), 245 struct mem_cgroup, css); 246} 247 248static inline int page_cgroup_locked(struct page *page) 249{ 250 return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); 251} 252 253static void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc) 254{ 255 VM_BUG_ON(!page_cgroup_locked(page)); 256 page->page_cgroup = ((unsigned long)pc | PAGE_CGROUP_LOCK); 257} 258 259struct page_cgroup *page_get_page_cgroup(struct page *page) 260{ 261 return (struct page_cgroup *) (page->page_cgroup & ~PAGE_CGROUP_LOCK); 262} 263 264static void lock_page_cgroup(struct page *page) 265{ 266 bit_spin_lock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); 267} 268 269static int try_lock_page_cgroup(struct page *page) 270{ 271 return bit_spin_trylock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); 272} 273 274static void unlock_page_cgroup(struct page *page) 275{ 276 bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); 277} 278 279static void __mem_cgroup_remove_list(struct mem_cgroup_per_zone *mz, 280 struct page_cgroup *pc) 281{ 282 int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE; 283 284 if (from) 285 MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) -= 1; 286 else 287 MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) -= 1; 288 289 mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, false); 290 list_del_init(&pc->lru); 291} 292 293static void __mem_cgroup_add_list(struct mem_cgroup_per_zone *mz, 294 struct page_cgroup *pc) 295{ 296 int to = pc->flags & PAGE_CGROUP_FLAG_ACTIVE; 297 298 if (!to) { 299 MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) += 1; 300 list_add(&pc->lru, &mz->inactive_list); 301 } else { 302 MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) += 1; 303 list_add(&pc->lru, &mz->active_list); 304 } 305 mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, true); 306} 307 308static void __mem_cgroup_move_lists(struct page_cgroup *pc, bool active) 309{ 310 int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE; 311 struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc); 312 313 if (from) 314 MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) -= 1; 315 else 316 MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) -= 1; 317 318 if (active) { 319 MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) += 1; 320 pc->flags |= PAGE_CGROUP_FLAG_ACTIVE; 321 list_move(&pc->lru, &mz->active_list); 322 } else { 323 MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) += 1; 324 pc->flags &= ~PAGE_CGROUP_FLAG_ACTIVE; 325 list_move(&pc->lru, &mz->inactive_list); 326 } 327} 328 329int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem) 330{ 331 int ret; 332 333 task_lock(task); 334 ret = task->mm && mm_match_cgroup(task->mm, mem); 335 task_unlock(task); 336 return ret; 337} 338 339/* 340 * This routine assumes that the appropriate zone's lru lock is already held 341 */ 342void mem_cgroup_move_lists(struct page *page, bool active) 343{ 344 struct page_cgroup *pc; 345 struct mem_cgroup_per_zone *mz; 346 unsigned long flags; 347 348 /* 349 * We cannot lock_page_cgroup while holding zone's lru_lock, 350 * because other holders of lock_page_cgroup can be interrupted 351 * with an attempt to rotate_reclaimable_page. But we cannot 352 * safely get to page_cgroup without it, so just try_lock it: 353 * mem_cgroup_isolate_pages allows for page left on wrong list. 354 */ 355 if (!try_lock_page_cgroup(page)) 356 return; 357 358 pc = page_get_page_cgroup(page); 359 if (pc) { 360 mz = page_cgroup_zoneinfo(pc); 361 spin_lock_irqsave(&mz->lru_lock, flags); 362 __mem_cgroup_move_lists(pc, active); 363 spin_unlock_irqrestore(&mz->lru_lock, flags); 364 } 365 unlock_page_cgroup(page); 366} 367 368/* 369 * Calculate mapped_ratio under memory controller. This will be used in 370 * vmscan.c for deteremining we have to reclaim mapped pages. 371 */ 372int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem) 373{ 374 long total, rss; 375 376 /* 377 * usage is recorded in bytes. But, here, we assume the number of 378 * physical pages can be represented by "long" on any arch. 379 */ 380 total = (long) (mem->res.usage >> PAGE_SHIFT) + 1L; 381 rss = (long)mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_RSS); 382 return (int)((rss * 100L) / total); 383} 384 385/* 386 * This function is called from vmscan.c. In page reclaiming loop. balance 387 * between active and inactive list is calculated. For memory controller 388 * page reclaiming, we should use using mem_cgroup's imbalance rather than 389 * zone's global lru imbalance. 390 */ 391long mem_cgroup_reclaim_imbalance(struct mem_cgroup *mem) 392{ 393 unsigned long active, inactive; 394 /* active and inactive are the number of pages. 'long' is ok.*/ 395 active = mem_cgroup_get_all_zonestat(mem, MEM_CGROUP_ZSTAT_ACTIVE); 396 inactive = mem_cgroup_get_all_zonestat(mem, MEM_CGROUP_ZSTAT_INACTIVE); 397 return (long) (active / (inactive + 1)); 398} 399 400/* 401 * prev_priority control...this will be used in memory reclaim path. 402 */ 403int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem) 404{ 405 return mem->prev_priority; 406} 407 408void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority) 409{ 410 if (priority < mem->prev_priority) 411 mem->prev_priority = priority; 412} 413 414void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority) 415{ 416 mem->prev_priority = priority; 417} 418 419/* 420 * Calculate # of pages to be scanned in this priority/zone. 421 * See also vmscan.c 422 * 423 * priority starts from "DEF_PRIORITY" and decremented in each loop. 424 * (see include/linux/mmzone.h) 425 */ 426 427long mem_cgroup_calc_reclaim_active(struct mem_cgroup *mem, 428 struct zone *zone, int priority) 429{ 430 long nr_active; 431 int nid = zone->zone_pgdat->node_id; 432 int zid = zone_idx(zone); 433 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(mem, nid, zid); 434 435 nr_active = MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE); 436 return (nr_active >> priority); 437} 438 439long mem_cgroup_calc_reclaim_inactive(struct mem_cgroup *mem, 440 struct zone *zone, int priority) 441{ 442 long nr_inactive; 443 int nid = zone->zone_pgdat->node_id; 444 int zid = zone_idx(zone); 445 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(mem, nid, zid); 446 447 nr_inactive = MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE); 448 return (nr_inactive >> priority); 449} 450 451unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, 452 struct list_head *dst, 453 unsigned long *scanned, int order, 454 int mode, struct zone *z, 455 struct mem_cgroup *mem_cont, 456 int active) 457{ 458 unsigned long nr_taken = 0; 459 struct page *page; 460 unsigned long scan; 461 LIST_HEAD(pc_list); 462 struct list_head *src; 463 struct page_cgroup *pc, *tmp; 464 int nid = z->zone_pgdat->node_id; 465 int zid = zone_idx(z); 466 struct mem_cgroup_per_zone *mz; 467 468 BUG_ON(!mem_cont); 469 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); 470 if (active) 471 src = &mz->active_list; 472 else 473 src = &mz->inactive_list; 474 475 476 spin_lock(&mz->lru_lock); 477 scan = 0; 478 list_for_each_entry_safe_reverse(pc, tmp, src, lru) { 479 if (scan >= nr_to_scan) 480 break; 481 page = pc->page; 482 483 if (unlikely(!PageLRU(page))) 484 continue; 485 486 if (PageActive(page) && !active) { 487 __mem_cgroup_move_lists(pc, true); 488 continue; 489 } 490 if (!PageActive(page) && active) { 491 __mem_cgroup_move_lists(pc, false); 492 continue; 493 } 494 495 scan++; 496 list_move(&pc->lru, &pc_list); 497 498 if (__isolate_lru_page(page, mode) == 0) { 499 list_move(&page->lru, dst); 500 nr_taken++; 501 } 502 } 503 504 list_splice(&pc_list, src); 505 spin_unlock(&mz->lru_lock); 506 507 *scanned = scan; 508 return nr_taken; 509} 510 511/* 512 * Charge the memory controller for page usage. 513 * Return 514 * 0 if the charge was successful 515 * < 0 if the cgroup is over its limit 516 */ 517static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, 518 gfp_t gfp_mask, enum charge_type ctype) 519{ 520 struct mem_cgroup *mem; 521 struct page_cgroup *pc; 522 unsigned long flags; 523 unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES; 524 struct mem_cgroup_per_zone *mz; 525 526 if (mem_cgroup_subsys.disabled) 527 return 0; 528 529 /* 530 * Should page_cgroup's go to their own slab? 531 * One could optimize the performance of the charging routine 532 * by saving a bit in the page_flags and using it as a lock 533 * to see if the cgroup page already has a page_cgroup associated 534 * with it 535 */ 536retry: 537 lock_page_cgroup(page); 538 pc = page_get_page_cgroup(page); 539 /* 540 * The page_cgroup exists and 541 * the page has already been accounted. 542 */ 543 if (pc) { 544 VM_BUG_ON(pc->page != page); 545 VM_BUG_ON(pc->ref_cnt <= 0); 546 547 pc->ref_cnt++; 548 unlock_page_cgroup(page); 549 goto done; 550 } 551 unlock_page_cgroup(page); 552 553 pc = kmem_cache_zalloc(page_cgroup_cache, gfp_mask); 554 if (pc == NULL) 555 goto err; 556 557 /* 558 * We always charge the cgroup the mm_struct belongs to. 559 * The mm_struct's mem_cgroup changes on task migration if the 560 * thread group leader migrates. It's possible that mm is not 561 * set, if so charge the init_mm (happens for pagecache usage). 562 */ 563 if (!mm) 564 mm = &init_mm; 565 566 rcu_read_lock(); 567 mem = mem_cgroup_from_task(rcu_dereference(mm->owner)); 568 /* 569 * For every charge from the cgroup, increment reference count 570 */ 571 css_get(&mem->css); 572 rcu_read_unlock(); 573 574 while (res_counter_charge(&mem->res, PAGE_SIZE)) { 575 if (!(gfp_mask & __GFP_WAIT)) 576 goto out; 577 578 if (try_to_free_mem_cgroup_pages(mem, gfp_mask)) 579 continue; 580 581 /* 582 * try_to_free_mem_cgroup_pages() might not give us a full 583 * picture of reclaim. Some pages are reclaimed and might be 584 * moved to swap cache or just unmapped from the cgroup. 585 * Check the limit again to see if the reclaim reduced the 586 * current usage of the cgroup before giving up 587 */ 588 if (res_counter_check_under_limit(&mem->res)) 589 continue; 590 591 if (!nr_retries--) { 592 mem_cgroup_out_of_memory(mem, gfp_mask); 593 goto out; 594 } 595 } 596 597 pc->ref_cnt = 1; 598 pc->mem_cgroup = mem; 599 pc->page = page; 600 pc->flags = PAGE_CGROUP_FLAG_ACTIVE; 601 if (ctype == MEM_CGROUP_CHARGE_TYPE_CACHE) 602 pc->flags = PAGE_CGROUP_FLAG_CACHE; 603 604 lock_page_cgroup(page); 605 if (page_get_page_cgroup(page)) { 606 unlock_page_cgroup(page); 607 /* 608 * Another charge has been added to this page already. 609 * We take lock_page_cgroup(page) again and read 610 * page->cgroup, increment refcnt.... just retry is OK. 611 */ 612 res_counter_uncharge(&mem->res, PAGE_SIZE); 613 css_put(&mem->css); 614 kmem_cache_free(page_cgroup_cache, pc); 615 goto retry; 616 } 617 page_assign_page_cgroup(page, pc); 618 619 mz = page_cgroup_zoneinfo(pc); 620 spin_lock_irqsave(&mz->lru_lock, flags); 621 __mem_cgroup_add_list(mz, pc); 622 spin_unlock_irqrestore(&mz->lru_lock, flags); 623 624 unlock_page_cgroup(page); 625done: 626 return 0; 627out: 628 css_put(&mem->css); 629 kmem_cache_free(page_cgroup_cache, pc); 630err: 631 return -ENOMEM; 632} 633 634int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) 635{ 636 return mem_cgroup_charge_common(page, mm, gfp_mask, 637 MEM_CGROUP_CHARGE_TYPE_MAPPED); 638} 639 640int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, 641 gfp_t gfp_mask) 642{ 643 if (!mm) 644 mm = &init_mm; 645 return mem_cgroup_charge_common(page, mm, gfp_mask, 646 MEM_CGROUP_CHARGE_TYPE_CACHE); 647} 648 649/* 650 * Uncharging is always a welcome operation, we never complain, simply 651 * uncharge. 652 */ 653void mem_cgroup_uncharge_page(struct page *page) 654{ 655 struct page_cgroup *pc; 656 struct mem_cgroup *mem; 657 struct mem_cgroup_per_zone *mz; 658 unsigned long flags; 659 660 if (mem_cgroup_subsys.disabled) 661 return; 662 663 /* 664 * Check if our page_cgroup is valid 665 */ 666 lock_page_cgroup(page); 667 pc = page_get_page_cgroup(page); 668 if (!pc) 669 goto unlock; 670 671 VM_BUG_ON(pc->page != page); 672 VM_BUG_ON(pc->ref_cnt <= 0); 673 674 if (--(pc->ref_cnt) == 0) { 675 mz = page_cgroup_zoneinfo(pc); 676 spin_lock_irqsave(&mz->lru_lock, flags); 677 __mem_cgroup_remove_list(mz, pc); 678 spin_unlock_irqrestore(&mz->lru_lock, flags); 679 680 page_assign_page_cgroup(page, NULL); 681 unlock_page_cgroup(page); 682 683 mem = pc->mem_cgroup; 684 res_counter_uncharge(&mem->res, PAGE_SIZE); 685 css_put(&mem->css); 686 687 kmem_cache_free(page_cgroup_cache, pc); 688 return; 689 } 690 691unlock: 692 unlock_page_cgroup(page); 693} 694 695/* 696 * Returns non-zero if a page (under migration) has valid page_cgroup member. 697 * Refcnt of page_cgroup is incremented. 698 */ 699int mem_cgroup_prepare_migration(struct page *page) 700{ 701 struct page_cgroup *pc; 702 703 if (mem_cgroup_subsys.disabled) 704 return 0; 705 706 lock_page_cgroup(page); 707 pc = page_get_page_cgroup(page); 708 if (pc) 709 pc->ref_cnt++; 710 unlock_page_cgroup(page); 711 return pc != NULL; 712} 713 714void mem_cgroup_end_migration(struct page *page) 715{ 716 mem_cgroup_uncharge_page(page); 717} 718 719/* 720 * We know both *page* and *newpage* are now not-on-LRU and PG_locked. 721 * And no race with uncharge() routines because page_cgroup for *page* 722 * has extra one reference by mem_cgroup_prepare_migration. 723 */ 724void mem_cgroup_page_migration(struct page *page, struct page *newpage) 725{ 726 struct page_cgroup *pc; 727 struct mem_cgroup_per_zone *mz; 728 unsigned long flags; 729 730 lock_page_cgroup(page); 731 pc = page_get_page_cgroup(page); 732 if (!pc) { 733 unlock_page_cgroup(page); 734 return; 735 } 736 737 mz = page_cgroup_zoneinfo(pc); 738 spin_lock_irqsave(&mz->lru_lock, flags); 739 __mem_cgroup_remove_list(mz, pc); 740 spin_unlock_irqrestore(&mz->lru_lock, flags); 741 742 page_assign_page_cgroup(page, NULL); 743 unlock_page_cgroup(page); 744 745 pc->page = newpage; 746 lock_page_cgroup(newpage); 747 page_assign_page_cgroup(newpage, pc); 748 749 mz = page_cgroup_zoneinfo(pc); 750 spin_lock_irqsave(&mz->lru_lock, flags); 751 __mem_cgroup_add_list(mz, pc); 752 spin_unlock_irqrestore(&mz->lru_lock, flags); 753 754 unlock_page_cgroup(newpage); 755} 756 757/* 758 * This routine traverse page_cgroup in given list and drop them all. 759 * This routine ignores page_cgroup->ref_cnt. 760 * *And* this routine doesn't reclaim page itself, just removes page_cgroup. 761 */ 762#define FORCE_UNCHARGE_BATCH (128) 763static void mem_cgroup_force_empty_list(struct mem_cgroup *mem, 764 struct mem_cgroup_per_zone *mz, 765 int active) 766{ 767 struct page_cgroup *pc; 768 struct page *page; 769 int count = FORCE_UNCHARGE_BATCH; 770 unsigned long flags; 771 struct list_head *list; 772 773 if (active) 774 list = &mz->active_list; 775 else 776 list = &mz->inactive_list; 777 778 spin_lock_irqsave(&mz->lru_lock, flags); 779 while (!list_empty(list)) { 780 pc = list_entry(list->prev, struct page_cgroup, lru); 781 page = pc->page; 782 get_page(page); 783 spin_unlock_irqrestore(&mz->lru_lock, flags); 784 mem_cgroup_uncharge_page(page); 785 put_page(page); 786 if (--count <= 0) { 787 count = FORCE_UNCHARGE_BATCH; 788 cond_resched(); 789 } 790 spin_lock_irqsave(&mz->lru_lock, flags); 791 } 792 spin_unlock_irqrestore(&mz->lru_lock, flags); 793} 794 795/* 796 * make mem_cgroup's charge to be 0 if there is no task. 797 * This enables deleting this mem_cgroup. 798 */ 799static int mem_cgroup_force_empty(struct mem_cgroup *mem) 800{ 801 int ret = -EBUSY; 802 int node, zid; 803 804 if (mem_cgroup_subsys.disabled) 805 return 0; 806 807 css_get(&mem->css); 808 /* 809 * page reclaim code (kswapd etc..) will move pages between 810 * active_list <-> inactive_list while we don't take a lock. 811 * So, we have to do loop here until all lists are empty. 812 */ 813 while (mem->res.usage > 0) { 814 if (atomic_read(&mem->css.cgroup->count) > 0) 815 goto out; 816 for_each_node_state(node, N_POSSIBLE) 817 for (zid = 0; zid < MAX_NR_ZONES; zid++) { 818 struct mem_cgroup_per_zone *mz; 819 mz = mem_cgroup_zoneinfo(mem, node, zid); 820 /* drop all page_cgroup in active_list */ 821 mem_cgroup_force_empty_list(mem, mz, 1); 822 /* drop all page_cgroup in inactive_list */ 823 mem_cgroup_force_empty_list(mem, mz, 0); 824 } 825 } 826 ret = 0; 827out: 828 css_put(&mem->css); 829 return ret; 830} 831 832static int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp) 833{ 834 *tmp = memparse(buf, &buf); 835 if (*buf != '\0') 836 return -EINVAL; 837 838 /* 839 * Round up the value to the closest page size 840 */ 841 *tmp = ((*tmp + PAGE_SIZE - 1) >> PAGE_SHIFT) << PAGE_SHIFT; 842 return 0; 843} 844 845static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft) 846{ 847 return res_counter_read_u64(&mem_cgroup_from_cont(cont)->res, 848 cft->private); 849} 850 851static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft, 852 struct file *file, const char __user *userbuf, 853 size_t nbytes, loff_t *ppos) 854{ 855 return res_counter_write(&mem_cgroup_from_cont(cont)->res, 856 cft->private, userbuf, nbytes, ppos, 857 mem_cgroup_write_strategy); 858} 859 860static int mem_cgroup_reset(struct cgroup *cont, unsigned int event) 861{ 862 struct mem_cgroup *mem; 863 864 mem = mem_cgroup_from_cont(cont); 865 switch (event) { 866 case RES_MAX_USAGE: 867 res_counter_reset_max(&mem->res); 868 break; 869 case RES_FAILCNT: 870 res_counter_reset_failcnt(&mem->res); 871 break; 872 } 873 return 0; 874} 875 876static int mem_force_empty_write(struct cgroup *cont, unsigned int event) 877{ 878 return mem_cgroup_force_empty(mem_cgroup_from_cont(cont)); 879} 880 881static const struct mem_cgroup_stat_desc { 882 const char *msg; 883 u64 unit; 884} mem_cgroup_stat_desc[] = { 885 [MEM_CGROUP_STAT_CACHE] = { "cache", PAGE_SIZE, }, 886 [MEM_CGROUP_STAT_RSS] = { "rss", PAGE_SIZE, }, 887}; 888 889static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft, 890 struct cgroup_map_cb *cb) 891{ 892 struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont); 893 struct mem_cgroup_stat *stat = &mem_cont->stat; 894 int i; 895 896 for (i = 0; i < ARRAY_SIZE(stat->cpustat[0].count); i++) { 897 s64 val; 898 899 val = mem_cgroup_read_stat(stat, i); 900 val *= mem_cgroup_stat_desc[i].unit; 901 cb->fill(cb, mem_cgroup_stat_desc[i].msg, val); 902 } 903 /* showing # of active pages */ 904 { 905 unsigned long active, inactive; 906 907 inactive = mem_cgroup_get_all_zonestat(mem_cont, 908 MEM_CGROUP_ZSTAT_INACTIVE); 909 active = mem_cgroup_get_all_zonestat(mem_cont, 910 MEM_CGROUP_ZSTAT_ACTIVE); 911 cb->fill(cb, "active", (active) * PAGE_SIZE); 912 cb->fill(cb, "inactive", (inactive) * PAGE_SIZE); 913 } 914 return 0; 915} 916 917static struct cftype mem_cgroup_files[] = { 918 { 919 .name = "usage_in_bytes", 920 .private = RES_USAGE, 921 .read_u64 = mem_cgroup_read, 922 }, 923 { 924 .name = "max_usage_in_bytes", 925 .private = RES_MAX_USAGE, 926 .trigger = mem_cgroup_reset, 927 .read_u64 = mem_cgroup_read, 928 }, 929 { 930 .name = "limit_in_bytes", 931 .private = RES_LIMIT, 932 .write = mem_cgroup_write, 933 .read_u64 = mem_cgroup_read, 934 }, 935 { 936 .name = "failcnt", 937 .private = RES_FAILCNT, 938 .trigger = mem_cgroup_reset, 939 .read_u64 = mem_cgroup_read, 940 }, 941 { 942 .name = "force_empty", 943 .trigger = mem_force_empty_write, 944 }, 945 { 946 .name = "stat", 947 .read_map = mem_control_stat_show, 948 }, 949}; 950 951static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) 952{ 953 struct mem_cgroup_per_node *pn; 954 struct mem_cgroup_per_zone *mz; 955 int zone, tmp = node; 956 /* 957 * This routine is called against possible nodes. 958 * But it's BUG to call kmalloc() against offline node. 959 * 960 * TODO: this routine can waste much memory for nodes which will 961 * never be onlined. It's better to use memory hotplug callback 962 * function. 963 */ 964 if (!node_state(node, N_NORMAL_MEMORY)) 965 tmp = -1; 966 pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp); 967 if (!pn) 968 return 1; 969 970 mem->info.nodeinfo[node] = pn; 971 memset(pn, 0, sizeof(*pn)); 972 973 for (zone = 0; zone < MAX_NR_ZONES; zone++) { 974 mz = &pn->zoneinfo[zone]; 975 INIT_LIST_HEAD(&mz->active_list); 976 INIT_LIST_HEAD(&mz->inactive_list); 977 spin_lock_init(&mz->lru_lock); 978 } 979 return 0; 980} 981 982static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) 983{ 984 kfree(mem->info.nodeinfo[node]); 985} 986 987static struct mem_cgroup *mem_cgroup_alloc(void) 988{ 989 struct mem_cgroup *mem; 990 991 if (sizeof(*mem) < PAGE_SIZE) 992 mem = kmalloc(sizeof(*mem), GFP_KERNEL); 993 else 994 mem = vmalloc(sizeof(*mem)); 995 996 if (mem) 997 memset(mem, 0, sizeof(*mem)); 998 return mem; 999} 1000 1001static void mem_cgroup_free(struct mem_cgroup *mem) 1002{ 1003 if (sizeof(*mem) < PAGE_SIZE) 1004 kfree(mem); 1005 else 1006 vfree(mem); 1007} 1008 1009 1010static struct cgroup_subsys_state * 1011mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) 1012{ 1013 struct mem_cgroup *mem; 1014 int node; 1015 1016 if (unlikely((cont->parent) == NULL)) { 1017 mem = &init_mem_cgroup; 1018 page_cgroup_cache = KMEM_CACHE(page_cgroup, SLAB_PANIC); 1019 } else { 1020 mem = mem_cgroup_alloc(); 1021 if (!mem) 1022 return ERR_PTR(-ENOMEM); 1023 } 1024 1025 res_counter_init(&mem->res); 1026 1027 for_each_node_state(node, N_POSSIBLE) 1028 if (alloc_mem_cgroup_per_zone_info(mem, node)) 1029 goto free_out; 1030 1031 return &mem->css; 1032free_out: 1033 for_each_node_state(node, N_POSSIBLE) 1034 free_mem_cgroup_per_zone_info(mem, node); 1035 if (cont->parent != NULL) 1036 mem_cgroup_free(mem); 1037 return ERR_PTR(-ENOMEM); 1038} 1039 1040static void mem_cgroup_pre_destroy(struct cgroup_subsys *ss, 1041 struct cgroup *cont) 1042{ 1043 struct mem_cgroup *mem = mem_cgroup_from_cont(cont); 1044 mem_cgroup_force_empty(mem); 1045} 1046 1047static void mem_cgroup_destroy(struct cgroup_subsys *ss, 1048 struct cgroup *cont) 1049{ 1050 int node; 1051 struct mem_cgroup *mem = mem_cgroup_from_cont(cont); 1052 1053 for_each_node_state(node, N_POSSIBLE) 1054 free_mem_cgroup_per_zone_info(mem, node); 1055 1056 mem_cgroup_free(mem_cgroup_from_cont(cont)); 1057} 1058 1059static int mem_cgroup_populate(struct cgroup_subsys *ss, 1060 struct cgroup *cont) 1061{ 1062 if (mem_cgroup_subsys.disabled) 1063 return 0; 1064 return cgroup_add_files(cont, ss, mem_cgroup_files, 1065 ARRAY_SIZE(mem_cgroup_files)); 1066} 1067 1068static void mem_cgroup_move_task(struct cgroup_subsys *ss, 1069 struct cgroup *cont, 1070 struct cgroup *old_cont, 1071 struct task_struct *p) 1072{ 1073 struct mm_struct *mm; 1074 struct mem_cgroup *mem, *old_mem; 1075 1076 if (mem_cgroup_subsys.disabled) 1077 return; 1078 1079 mm = get_task_mm(p); 1080 if (mm == NULL) 1081 return; 1082 1083 mem = mem_cgroup_from_cont(cont); 1084 old_mem = mem_cgroup_from_cont(old_cont); 1085 1086 if (mem == old_mem) 1087 goto out; 1088 1089 /* 1090 * Only thread group leaders are allowed to migrate, the mm_struct is 1091 * in effect owned by the leader 1092 */ 1093 if (!thread_group_leader(p)) 1094 goto out; 1095 1096out: 1097 mmput(mm); 1098} 1099 1100struct cgroup_subsys mem_cgroup_subsys = { 1101 .name = "memory", 1102 .subsys_id = mem_cgroup_subsys_id, 1103 .create = mem_cgroup_create, 1104 .pre_destroy = mem_cgroup_pre_destroy, 1105 .destroy = mem_cgroup_destroy, 1106 .populate = mem_cgroup_populate, 1107 .attach = mem_cgroup_move_task, 1108 .early_init = 0, 1109}; 1110