diff options
| -rw-r--r-- | Documentation/cgroups/memcg_test.txt | 128 | ||||
| -rw-r--r-- | include/linux/memcontrol.h | 49 | ||||
| -rw-r--r-- | include/linux/page_cgroup.h | 43 | ||||
| -rw-r--r-- | include/linux/swap.h | 12 | ||||
| -rw-r--r-- | mm/filemap.c | 4 | ||||
| -rw-r--r-- | mm/memcontrol.c | 828 | ||||
| -rw-r--r-- | mm/memory.c | 2 | ||||
| -rw-r--r-- | mm/migrate.c | 38 | ||||
| -rw-r--r-- | mm/rmap.c | 1 | ||||
| -rw-r--r-- | mm/shmem.c | 8 | ||||
| -rw-r--r-- | mm/swap.c | 6 | ||||
| -rw-r--r-- | mm/swap_state.c | 8 | ||||
| -rw-r--r-- | mm/swapfile.c | 7 | ||||
| -rw-r--r-- | mm/truncate.c | 9 | ||||
| -rw-r--r-- | mm/vmscan.c | 12 | ||||
| -rw-r--r-- | mm/zswap.c | 2 |
16 files changed, 389 insertions, 768 deletions
diff --git a/Documentation/cgroups/memcg_test.txt b/Documentation/cgroups/memcg_test.txt index bcf750d3cecd..8870b0212150 100644 --- a/Documentation/cgroups/memcg_test.txt +++ b/Documentation/cgroups/memcg_test.txt @@ -29,28 +29,13 @@ Please note that implementation details can be changed. 2. Uncharge a page/swp_entry may be uncharged (usage -= PAGE_SIZE) by - mem_cgroup_uncharge_page() - Called when an anonymous page is fully unmapped. I.e., mapcount goes - to 0. If the page is SwapCache, uncharge is delayed until - mem_cgroup_uncharge_swapcache(). - - mem_cgroup_uncharge_cache_page() - Called when a page-cache is deleted from radix-tree. If the page is - SwapCache, uncharge is delayed until mem_cgroup_uncharge_swapcache(). - - mem_cgroup_uncharge_swapcache() - Called when SwapCache is removed from radix-tree. The charge itself - is moved to swap_cgroup. (If mem+swap controller is disabled, no - charge to swap occurs.) + mem_cgroup_uncharge() + Called when a page's refcount goes down to 0. mem_cgroup_uncharge_swap() Called when swp_entry's refcnt goes down to 0. A charge against swap disappears. - mem_cgroup_end_migration(old, new) - At success of migration old is uncharged (if necessary), a charge - to new page is committed. At failure, charge to old page is committed. - 3. charge-commit-cancel Memcg pages are charged in two steps: mem_cgroup_try_charge() @@ -69,18 +54,6 @@ Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y. Anonymous page is newly allocated at - page fault into MAP_ANONYMOUS mapping. - Copy-On-Write. - It is charged right after it's allocated before doing any page table - related operations. Of course, it's uncharged when another page is used - for the fault address. - - At freeing anonymous page (by exit() or munmap()), zap_pte() is called - and pages for ptes are freed one by one.(see mm/memory.c). Uncharges - are done at page_remove_rmap() when page_mapcount() goes down to 0. - - Another page freeing is by page-reclaim (vmscan.c) and anonymous - pages are swapped out. In this case, the page is marked as - PageSwapCache(). uncharge() routine doesn't uncharge the page marked - as SwapCache(). It's delayed until __delete_from_swap_cache(). 4.1 Swap-in. At swap-in, the page is taken from swap-cache. There are 2 cases. @@ -89,41 +62,6 @@ Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y. (b) If the SwapCache has been mapped by processes, it has been charged already. - This swap-in is one of the most complicated work. In do_swap_page(), - following events occur when pte is unchanged. - - (1) the page (SwapCache) is looked up. - (2) lock_page() - (3) try_charge_swapin() - (4) reuse_swap_page() (may call delete_swap_cache()) - (5) commit_charge_swapin() - (6) swap_free(). - - Considering following situation for example. - - (A) The page has not been charged before (2) and reuse_swap_page() - doesn't call delete_from_swap_cache(). - (B) The page has not been charged before (2) and reuse_swap_page() - calls delete_from_swap_cache(). - (C) The page has been charged before (2) and reuse_swap_page() doesn't - call delete_from_swap_cache(). - (D) The page has been charged before (2) and reuse_swap_page() calls - delete_from_swap_cache(). - - memory.usage/memsw.usage changes to this page/swp_entry will be - Case (A) (B) (C) (D) - Event - Before (2) 0/ 1 0/ 1 1/ 1 1/ 1 - =========================================== - (3) +1/+1 +1/+1 +1/+1 +1/+1 - (4) - 0/ 0 - -1/ 0 - (5) 0/-1 0/ 0 -1/-1 0/ 0 - (6) - 0/-1 - 0/-1 - =========================================== - Result 1/ 1 1/ 1 1/ 1 1/ 1 - - In any cases, charges to this page should be 1/ 1. - 4.2 Swap-out. At swap-out, typical state transition is below. @@ -136,28 +74,20 @@ Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y. swp_entry's refcnt -= 1. - At (b), the page is marked as SwapCache and not uncharged. - At (d), the page is removed from SwapCache and a charge in page_cgroup - is moved to swap_cgroup. - Finally, at task exit, (e) zap_pte() is called and swp_entry's refcnt -=1 -> 0. - Here, a charge in swap_cgroup disappears. 5. Page Cache Page Cache is charged at - add_to_page_cache_locked(). - uncharged at - - __remove_from_page_cache(). - The logic is very clear. (About migration, see below) Note: __remove_from_page_cache() is called by remove_from_page_cache() and __remove_mapping(). 6. Shmem(tmpfs) Page Cache - Memcg's charge/uncharge have special handlers of shmem. The best way - to understand shmem's page state transition is to read mm/shmem.c. + The best way to understand shmem's page state transition is to read + mm/shmem.c. But brief explanation of the behavior of memcg around shmem will be helpful to understand the logic. @@ -170,56 +100,10 @@ Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y. It's charged when... - A new page is added to shmem's radix-tree. - A swp page is read. (move a charge from swap_cgroup to page_cgroup) - It's uncharged when - - A page is removed from radix-tree and not SwapCache. - - When SwapCache is removed, a charge is moved to swap_cgroup. - - When swp_entry's refcnt goes down to 0, a charge in swap_cgroup - disappears. 7. Page Migration - One of the most complicated functions is page-migration-handler. - Memcg has 2 routines. Assume that we are migrating a page's contents - from OLDPAGE to NEWPAGE. - - Usual migration logic is.. - (a) remove the page from LRU. - (b) allocate NEWPAGE (migration target) - (c) lock by lock_page(). - (d) unmap all mappings. - (e-1) If necessary, replace entry in radix-tree. - (e-2) move contents of a page. - (f) map all mappings again. - (g) pushback the page to LRU. - (-) OLDPAGE will be freed. - - Before (g), memcg should complete all necessary charge/uncharge to - NEWPAGE/OLDPAGE. - - The point is.... - - If OLDPAGE is anonymous, all charges will be dropped at (d) because - try_to_unmap() drops all mapcount and the page will not be - SwapCache. - - - If OLDPAGE is SwapCache, charges will be kept at (g) because - __delete_from_swap_cache() isn't called at (e-1) - - - If OLDPAGE is page-cache, charges will be kept at (g) because - remove_from_swap_cache() isn't called at (e-1) - - memcg provides following hooks. - - - mem_cgroup_prepare_migration(OLDPAGE) - Called after (b) to account a charge (usage += PAGE_SIZE) against - memcg which OLDPAGE belongs to. - - - mem_cgroup_end_migration(OLDPAGE, NEWPAGE) - Called after (f) before (g). - If OLDPAGE is used, commit OLDPAGE again. If OLDPAGE is already - charged, a charge by prepare_migration() is automatically canceled. - If NEWPAGE is used, commit NEWPAGE and uncharge OLDPAGE. - - But zap_pte() (by exit or munmap) can be called while migration, - we have to check if OLDPAGE/NEWPAGE is a valid page after commit(). + + mem_cgroup_migrate() 8. LRU Each memcg has its own private LRU. Now, its handling is under global diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 1a9a096858e0..806b8fa15c5f 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -60,15 +60,17 @@ void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg, bool lrucare); void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg); -struct lruvec *mem_cgroup_zone_lruvec(struct zone *, struct mem_cgroup *); -struct lruvec *mem_cgroup_page_lruvec(struct page *, struct zone *); +void mem_cgroup_uncharge(struct page *page); + +/* Batched uncharging */ +void mem_cgroup_uncharge_start(void); +void mem_cgroup_uncharge_end(void); -/* For coalescing uncharge for reducing memcg' overhead*/ -extern void mem_cgroup_uncharge_start(void); -extern void mem_cgroup_uncharge_end(void); +void mem_cgroup_migrate(struct page *oldpage, struct page *newpage, + bool lrucare); -extern void mem_cgroup_uncharge_page(struct page *page); -extern void mem_cgroup_uncharge_cache_page(struct page *page); +struct lruvec *mem_cgroup_zone_lruvec(struct zone *, struct mem_cgroup *); +struct lruvec *mem_cgroup_page_lruvec(struct page *, struct zone *); bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, struct mem_cgroup *memcg); @@ -96,12 +98,6 @@ bool mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *memcg) extern struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg); -extern void -mem_cgroup_prepare_migration(struct page *page, struct page *newpage, - struct mem_cgroup **memcgp); -extern void mem_cgroup_end_migration(struct mem_cgroup *memcg, - struct page *oldpage, struct page *newpage, bool migration_ok); - struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *, struct mem_cgroup *, struct mem_cgroup_reclaim_cookie *); @@ -116,8 +112,6 @@ unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list); void mem_cgroup_update_lru_size(struct lruvec *, enum lru_list, int); extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p); -extern void mem_cgroup_replace_page_cache(struct page *oldpage, - struct page *newpage); static inline void mem_cgroup_oom_enable(void) { @@ -235,19 +229,21 @@ static inline void mem_cgroup_cancel_charge(struct page *page, { } -static inline void mem_cgroup_uncharge_start(void) +static inline void mem_cgroup_uncharge(struct page *page) { } -static inline void mem_cgroup_uncharge_end(void) +static inline void mem_cgroup_uncharge_start(void) { } -static inline void mem_cgroup_uncharge_page(struct page *page) +static inline void mem_cgroup_uncharge_end(void) { } -static inline void mem_cgroup_uncharge_cache_page(struct page *page) +static inline void mem_cgroup_migrate(struct page *oldpage, + struct page *newpage, + bool lrucare) { } @@ -286,17 +282,6 @@ static inline struct cgroup_subsys_state return NULL; } -static inline void -mem_cgroup_prepare_migration(struct page *page, struct page *newpage, - struct mem_cgroup **memcgp) -{ -} - -static inline void mem_cgroup_end_migration(struct mem_cgroup *memcg, - struct page *oldpage, struct page *newpage, bool migration_ok) -{ -} - static inline struct mem_cgroup * mem_cgroup_iter(struct mem_cgroup *root, struct mem_cgroup *prev, @@ -392,10 +377,6 @@ static inline void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx) { } -static inline void mem_cgroup_replace_page_cache(struct page *oldpage, - struct page *newpage) -{ -} #endif /* CONFIG_MEMCG */ #if !defined(CONFIG_MEMCG) || !defined(CONFIG_DEBUG_VM) diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h index 777a524716db..9bfb8e68a595 100644 --- a/include/linux/page_cgroup.h +++ b/include/linux/page_cgroup.h @@ -3,9 +3,9 @@ enum { /* flags for mem_cgroup */ - PCG_LOCK, /* Lock for pc->mem_cgroup and following bits. */ - PCG_USED, /* this object is in use. */ - PCG_MIGRATION, /* under page migration */ + PCG_USED = 0x01, /* This page is charged to a memcg */ + PCG_MEM = 0x02, /* This page holds a memory charge */ + PCG_MEMSW = 0x04, /* This page holds a memory+swap charge */ __NR_PCG_FLAGS, }; @@ -44,42 +44,9 @@ static inline void __init page_cgroup_init(void) struct page_cgroup *lookup_page_cgroup(struct page *page); struct page *lookup_cgroup_page(struct page_cgroup *pc); -#define TESTPCGFLAG(uname, lname) \ -static inline int PageCgroup##uname(struct page_cgroup *pc) \ - { return test_bit(PCG_##lname, &pc->flags); } - -#define SETPCGFLAG(uname, lname) \ -static inline void SetPageCgroup##uname(struct page_cgroup *pc)\ - { set_bit(PCG_##lname, &pc->flags); } - -#define CLEARPCGFLAG(uname, lname) \ -static inline void ClearPageCgroup##uname(struct page_cgroup *pc) \ - { clear_bit(PCG_##lname, &pc->flags); } - -#define TESTCLEARPCGFLAG(uname, lname) \ -static inline int TestClearPageCgroup##uname(struct page_cgroup *pc) \ - { return test_and_clear_bit(PCG_##lname, &pc->flags); } - -TESTPCGFLAG(Used, USED) -CLEARPCGFLAG(Used, USED) -SETPCGFLAG(Used, USED) - -SETPCGFLAG(Migration, MIGRATION) -CLEARPCGFLAG(Migration, MIGRATION) -TESTPCGFLAG(Migration, MIGRATION) - -static inline void lock_page_cgroup(struct page_cgroup *pc) -{ - /* - * Don't take this lock in IRQ context. - * This lock is for pc->mem_cgroup, USED, MIGRATION - */ - bit_spin_lock(PCG_LOCK, &pc->flags); -} - -static inline void unlock_page_cgroup(struct page_cgroup *pc) +static inline int PageCgroupUsed(struct page_cgroup *pc) { - bit_spin_unlock(PCG_LOCK, &pc->flags); + return !!(pc->flags & PCG_USED); } #else /* CONFIG_MEMCG */ diff --git a/include/linux/swap.h b/include/linux/swap.h index 46a649e4e8cd..1b72060f093a 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -381,9 +381,13 @@ static inline int mem_cgroup_swappiness(struct mem_cgroup *mem) } #endif #ifdef CONFIG_MEMCG_SWAP -extern void mem_cgroup_uncharge_swap(swp_entry_t ent); +extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry); +extern void mem_cgroup_uncharge_swap(swp_entry_t entry); #else -static inline void mem_cgroup_uncharge_swap(swp_entry_t ent) +static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry) +{ +} +static inline void mem_cgroup_uncharge_swap(swp_entry_t entry) { } #endif @@ -443,7 +447,7 @@ extern void swap_shmem_alloc(swp_entry_t); extern int swap_duplicate(swp_entry_t); extern int swapcache_prepare(swp_entry_t); extern void swap_free(swp_entry_t); -extern void swapcache_free(swp_entry_t, struct page *page); +extern void swapcache_free(swp_entry_t); extern int free_swap_and_cache(swp_entry_t); extern int swap_type_of(dev_t, sector_t, struct block_device **); extern unsigned int count_swap_pages(int, int); @@ -507,7 +511,7 @@ static inline void swap_free(swp_entry_t swp) { } -static inline void swapcache_free(swp_entry_t swp, struct page *page) +static inline void swapcache_free(swp_entry_t swp) { } diff --git a/mm/filemap.c b/mm/filemap.c index 349a40e35545..f501b56ec2c6 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -234,7 +234,6 @@ void delete_from_page_cache(struct page *page) spin_lock_irq(&mapping->tree_lock); __delete_from_page_cache(page, NULL); spin_unlock_irq(&mapping->tree_lock); - mem_cgroup_uncharge_cache_page(page); if (freepage) freepage(page); @@ -490,8 +489,7 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask) if (PageSwapBacked(new)) __inc_zone_page_state(new, NR_SHMEM); spin_unlock_irq(&mapping->tree_lock); - /* mem_cgroup codes must not be called under tree_lock */ - mem_cgroup_replace_page_cache(old, new); + mem_cgroup_migrate(old, new, true); radix_tree_preload_end(); if (freepage) freepage(old); diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 1cbe1e54ff5f..9106f1b12f56 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -754,9 +754,11 @@ static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz, static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz, struct mem_cgroup_tree_per_zone *mctz) { - spin_lock(&mctz->lock); + unsigned long flags; + + spin_lock_irqsave(&mctz->lock, flags); __mem_cgroup_remove_exceeded(mz, mctz); - spin_unlock(&mctz->lock); + spin_unlock_irqrestore(&mctz->lock, flags); } @@ -779,7 +781,9 @@ static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page) * mem is over its softlimit. */ if (excess || mz->on_tree) { - spin_lock(&mctz->lock); + unsigned long flags; + + spin_lock_irqsave(&mctz->lock, flags); /* if on-tree, remove it */ if (mz->on_tree) __mem_cgroup_remove_exceeded(mz, mctz); @@ -788,7 +792,7 @@ static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page) * If excess is 0, no tree ops. */ __mem_cgroup_insert_exceeded(mz, mctz, excess); - spin_unlock(&mctz->lock); + spin_unlock_irqrestore(&mctz->lock, flags); } } } @@ -839,9 +843,9 @@ mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) { struct mem_cgroup_per_zone *mz; - spin_lock(&mctz->lock); + spin_lock_irq(&mctz->lock); mz = __mem_cgroup_largest_soft_limit_node(mctz); - spin_unlock(&mctz->lock); + spin_unlock_irq(&mctz->lock); return mz; } @@ -882,13 +886,6 @@ static long mem_cgroup_read_stat(struct mem_cgroup *memcg, return val; } -static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg, - bool charge) -{ - int val = (charge) ? 1 : -1; - this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val); -} - static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg, enum mem_cgroup_events_index idx) { @@ -909,13 +906,13 @@ static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg, static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, struct page *page, - bool anon, int nr_pages) + int nr_pages) { /* * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is * counted as CACHE even if it's on ANON LRU. */ - if (anon) + if (PageAnon(page)) __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS], nr_pages); else @@ -1013,7 +1010,6 @@ static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, */ static void memcg_check_events(struct mem_cgroup *memcg, struct page *page) { - preempt_disable(); /* threshold event is triggered in finer grain than soft limit */ if (unlikely(mem_cgroup_event_ratelimit(memcg, MEM_CGROUP_TARGET_THRESH))) { @@ -1026,8 +1022,6 @@ static void memcg_check_events(struct mem_cgroup *memcg, struct page *page) do_numainfo = mem_cgroup_event_ratelimit(memcg, MEM_CGROUP_TARGET_NUMAINFO); #endif - preempt_enable(); - mem_cgroup_threshold(memcg); if (unlikely(do_softlimit)) mem_cgroup_update_tree(memcg, page); @@ -1035,8 +1029,7 @@ static void memcg_check_events(struct mem_cgroup *memcg, struct page *page) if (unlikely(do_numainfo)) atomic_inc(&memcg->numainfo_events); #endif - } else - preempt_enable(); + } } struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) @@ -1347,20 +1340,6 @@ out: return lruvec; } -/* - * Following LRU functions are allowed to be used without PCG_LOCK. - * Operations are called by routine of global LRU independently from memcg. - * What we have to take care of here is validness of pc->mem_cgroup. - * - * Changes to pc->mem_cgroup happens when - * 1. charge - * 2. moving account - * In typical case, "charge" is done before add-to-lru. Exception is SwapCache. - * It is added to LRU before charge. - * If PCG_USED bit is not set, page_cgroup is not added to this private LRU. - * When moving account, the page is not on LRU. It's isolated. - */ - /** * mem_cgroup_page_lruvec - return lruvec for adding an lru page * @page: the page @@ -2261,22 +2240,14 @@ cleanup: * * Notes: Race condition * - * We usually use lock_page_cgroup() for accessing page_cgroup member but - * it tends to be costly. But considering some conditions, we doesn't need - * to do so _always_. - * - * Considering "charge", lock_page_cgroup() is not required because all - * file-stat operations happen after a page is attached to radix-tree. There - * are no race with "charge". + * Charging occurs during page instantiation, while the page is + * unmapped and locked in page migration, or while the page table is + * locked in THP migration. No race is possible. * - * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup - * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even - * if there are race with "uncharge". Statistics itself is properly handled - * by flags. + * Uncharge happens to pages with zero references, no race possible. * - * Considering "move", this is an only case we see a race. To make the race - * small, we check memcg->moving_account and detect there are possibility - * of race or not. If there is, we take a lock. + * Charge moving between groups is protected by checking mm->moving + * account and taking the move_lock in the slowpath. */ void __mem_cgroup_begin_update_page_stat(struct page *page, @@ -2689,6 +2660,16 @@ static struct mem_cgroup *mem_cgroup_lookup(unsigned short id) return mem_cgroup_from_id(id); } +/* + * try_get_mem_cgroup_from_page - look up page's memcg association + * @page: the page + * + * Look up, get a css reference, and return the memcg that owns @page. + * + * The page must be locked to prevent racing with swap-in and page + * cache charges. If coming from an unlocked page table, the caller + * must ensure the page is on the LRU or this can race with charging. + */ struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) { struct mem_cgroup *memcg = NULL; @@ -2699,7 +2680,6 @@ struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) VM_BUG_ON_PAGE(!PageLocked(page), page); pc = lookup_page_cgroup(page); - lock_page_cgroup(pc); if (PageCgroupUsed(pc)) { memcg = pc->mem_cgroup; if (memcg && !css_tryget_online(&memcg->css)) @@ -2713,19 +2693,46 @@ struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) memcg = NULL; rcu_read_unlock(); } - unlock_page_cgroup(pc); return memcg; } +static void lock_page_lru(struct page *page, int *isolated) +{ + struct zone *zone = page_zone(page); + + spin_lock_irq(&zone->lru_lock); + if (PageLRU(page)) { + struct lruvec *lruvec; + + lruvec = mem_cgroup_page_lruvec(page, zone); + ClearPageLRU(page); + del_page_from_lru_list(page, lruvec, page_lru(page)); + *isolated = 1; + } else + *isolated = 0; +} + +static void unlock_page_lru(struct page *page, int isolated) +{ + struct zone *zone = page_zone(page); + + if (isolated) { + struct lruvec *lruvec; + + lruvec = mem_cgroup_page_lruvec(page, zone); + VM_BUG_ON_PAGE(PageLRU(page), page); + SetPageLRU(page); + add_page_to_lru_list(page, lruvec, page_lru(page)); + } + spin_unlock_irq(&zone->lru_lock); +} + static void commit_charge(struct page *page, struct mem_cgroup *memcg, - unsigned int nr_pages, bool anon, bool lrucare) + unsigned int nr_pages, bool lrucare) { struct page_cgroup *pc = lookup_page_cgroup(page); - struct zone *uninitialized_var(zone); - struct lruvec *lruvec; - bool was_on_lru = false; + int isolated; - lock_page_cgroup(pc); VM_BUG_ON_PAGE(PageCgroupUsed(pc), page); /* * we don't need page_cgroup_lock about tail pages, becase they are not @@ -2736,39 +2743,38 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg, * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page * may already be on some other mem_cgroup's LRU. Take care of it. */ - if (lrucare) { - zone = page_zone(page); - spin_lock_irq(&zone->lru_lock); - if (PageLRU(page)) { - lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup); - ClearPageLRU(page); - del_page_from_lru_list(page, lruvec, page_lru(page)); - was_on_lru = true; - } - } + if (lrucare) + lock_page_lru(page, &isolated); + /* + * Nobody should be changing or seriously looking at + * pc->mem_cgroup and pc->flags at this point: + * + * - the page is uncharged + * + * - the page is off-LRU + * + * - an anonymous fault has exclusive page access, except for + * a locked page table + * + * - a page cache insertion, a swapin fault, or a migration + * have the page locked + */ pc->mem_cgroup = memcg; - SetPageCgroupUsed(pc); - - if (lrucare) { - if (was_on_lru) { - lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup); - VM_BUG_ON_PAGE(PageLRU(page), page); - SetPageLRU(page); - add_page_to_lru_list(page, lruvec, page_lru(page)); - } - spin_unlock_irq(&zone->lru_lock); - } + pc->flags = PCG_USED | PCG_MEM | (do_swap_account ? PCG_MEMSW : 0); - mem_cgroup_charge_statistics(memcg, page, anon, nr_pages); - unlock_page_cgroup(pc); + if (lrucare) + unlock_page_lru(page, isolated); + local_irq_disable(); + mem_cgroup_charge_statistics(memcg, page, nr_pages); /* * "charge_statistics" updated event counter. Then, check it. * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree. * if they exceeds softlimit. */ memcg_check_events(memcg, page); + local_irq_enable(); } static DEFINE_MUTEX(set_limit_mutex); @@ -3395,7 +3401,6 @@ static inline void memcg_unregister_all_caches(struct mem_cgroup *memcg) #ifdef CONFIG_TRANSPARENT_HUGEPAGE -#define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION) /* * Because tail pages are not marked as "used", set it. We're under * zone->lru_lock, 'splitting on pmd' and compound_lock. @@ -3416,7 +3421,7 @@ void mem_cgroup_split_huge_fixup(struct page *head) for (i = 1; i < HPAGE_PMD_NR; i++) { pc = head_pc + i; pc->mem_cgroup = memcg; - pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT; + pc->flags = head_pc->flags; } __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE], HPAGE_PMD_NR); @@ -3446,7 +3451,6 @@ static int mem_cgroup_move_account(struct page *page, { unsigned long flags; int ret; - bool anon = PageAnon(page); VM_BUG_ON(from == to); VM_BUG_ON_PAGE(PageLRU(page), page); @@ -3460,15 +3464,21 @@ static int mem_cgroup_move_account(struct page *page, if (nr_pages > 1 && !PageTransHuge(page)) goto out; - lock_page_cgroup(pc); + /* + * Prevent mem_cgroup_migrate() from looking at pc->mem_cgroup + * of its source page while we change it: page migration takes + * both pages off the LRU, but page cache replacement doesn't. + */ + if (!trylock_page(page)) + goto out; ret = -EINVAL; if (!PageCgroupUsed(pc) || pc->mem_cgroup != from) - goto unlock; + goto out_unlock; move_lock_mem_cgroup(from, &flags); - if (!anon && page_mapped(page)) { + if (!PageAnon(page) && page_mapped(page)) { __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], nr_pages); __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], @@ -3482,20 +3492,25 @@ static int mem_cgroup_move_account(struct page *page, nr_pages); } - mem_cgroup_charge_statistics(from, page, anon, -nr_pages); + /* + * It is safe to change pc->mem_cgroup here because the page + * is referenced, charged, and isolated - we can't race with + * uncharging, charging, migration, or LRU putback. + */ /* caller should have done css_get */ pc->mem_cgroup = to; - mem_cgroup_charge_statistics(to, page, anon, nr_pages); move_unlock_mem_cgroup(from, &flags); ret = 0; -unlock: - unlock_page_cgroup(pc); - /* - * check events - */ + + local_irq_disable(); + mem_cgroup_charge_statistics(to, page, nr_pages); memcg_check_events(to, page); + mem_cgroup_charge_statistics(from, page, -nr_pages); memcg_check_events(from, page); + local_irq_enable(); +out_unlock: + unlock_page(page); out: return ret; } @@ -3566,193 +3581,6 @@ out: return ret; } -static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg, - unsigned int nr_pages, - const enum charge_type ctype) -{ - struct memcg_batch_info *batch = NULL; - bool uncharge_memsw = true; - - /* If swapout, usage of swap doesn't decrease */ - if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) - uncharge_memsw = false; - - batch = ¤t->memcg_batch; - /* - * In usual, we do css_get() when we remember memcg pointer. - * But in this case, we keep res->usage until end of a series of - * uncharges. Then, it's ok to ignore memcg's refcnt. - */ - if (!batch->memcg) - batch->memcg = memcg; - /* - * do_batch > 0 when unmapping pages or inode invalidate/truncate. - * In those cases, all pages freed continuously can be expected to be in - * the same cgroup and we have chance to coalesce uncharges. - * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE) - * because we want to do uncharge as soon as possible. - */ - - if (!batch->do_batch || test_thread_flag(TIF_MEMDIE)) - goto direct_uncharge; - - if (nr_pages > 1) - goto direct_uncharge; - - /* - * In typical case, batch->memcg == mem. This means we can - * merge a series of uncharges to an uncharge of res_counter. - * If not, we uncharge res_counter ony by one. - */ - if (batch->memcg != memcg) - goto direct_uncharge; - /* remember freed charge and uncharge it later */ - batch->nr_pages++; - if (uncharge_memsw) - batch->memsw_nr_pages++; - return; -direct_uncharge: - res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE); - if (uncharge_memsw) - res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE); - if (unlikely(batch->memcg != memcg)) - memcg_oom_recover(memcg); -} - -/* - * uncharge if !page_mapped(page) - */ -static struct mem_cgroup * -__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype, - bool end_migration) -{ - struct mem_cgroup *memcg = NULL; - unsigned int nr_pages = 1; - struct page_cgroup *pc; - bool anon; - - if (mem_cgroup_disabled()) - return NULL; - - if (PageTransHuge(page)) { - nr_pages <<= compound_order(page); - VM_BUG_ON_PAGE(!PageTransHuge(page), page); - } - /* - * Check if our page_cgroup is valid - */ - pc = lookup_page_cgroup(page); - if (unlikely(!PageCgroupUsed(pc))) - return NULL; - - lock_page_cgroup(pc); - - memcg = pc->mem_cgroup; - - if (!PageCgroupUsed(pc)) - goto unlock_out; - - anon = PageAnon(page); - - switch (ctype) { - case MEM_CGROUP_CHARGE_TYPE_ANON: - /* - * Generally PageAnon tells if it's the anon statistics to be - * updated; but sometimes e.g. mem_cgroup_uncharge_page() is - * used before page reached the stage of being marked PageAnon. - */ - anon = true; - /* fallthrough */ - case MEM_CGROUP_CHARGE_TYPE_DROP: - /* See mem_cgroup_prepare_migration() */ - if (page_mapped(page)) - goto unlock_out; - /* - * Pages under migration may not be uncharged. But - * end_migration() /must/ be the one uncharging the - * unused post-migration page and so it has to call - * here with the migration bit still set. See the - * res_counter handling below. - */ - if (!end_migration && PageCgroupMigration(pc)) - goto unlock_out; - break; - case MEM_CGROUP_CHARGE_TYPE_SWAPOUT: - if (!PageAnon(page)) { /* Shared memory */ - if (page->mapping && !page_is_file_cache(page)) - goto unlock_out; - } else if (page_mapped(page)) /* Anon */ - goto unlock_out; - break; - default: - break; - } - - mem_cgroup_charge_statistics(memcg, page, anon, -nr_pages); - - ClearPageCgroupUsed(pc); - /* - * pc->mem_cgroup is not cleared here. It will be accessed when it's - * freed from LRU. This is safe because uncharged page is expected not - * to be reused (freed soon). Exception is SwapCache, it's handled by - * special functions. - */ - - unlock_page_cgroup(pc); - /* - * even after unlock, we have memcg->res.usage here and this memcg - * will never be freed, so it's safe to call css_get(). - */ - memcg_check_events(memcg, page); - if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) { - mem_cgroup_swap_statistics(memcg, true); - css_get(&memcg->css); - } - /* - * Migration does not charge the res_counter for the - * replacement page, so leave it alone when phasing out the - * page that is unused after the migration. - */ - if (!end_migration) - mem_cgroup_do_uncharge(memcg, nr_pages, ctype); - - return memcg; - -unlock_out: - unlock_page_cgroup(pc); - return NULL; -} - -void mem_cgroup_uncharge_page(struct page *page) -{ - /* early check. */ - if (page_mapped(page)) - return; - VM_BUG_ON_PAGE(page->mapping && !PageAnon(page), page); - /* - * If the page is in swap cache, uncharge should be deferred - * to the swap path, which also properly accounts swap usage - * and handles memcg lifetime. - * - * Note that this check is not stable and reclaim may add the - * page to swap cache at any time after this. However, if the - * page is not in swap cache by the time page->mapcount hits - * 0, there won't be any page table references to the swap - * slot, and reclaim will free it and |