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-rw-r--r--Documentation/cgroups/memcg_test.txt128
-rw-r--r--include/linux/memcontrol.h49
-rw-r--r--include/linux/page_cgroup.h43
-rw-r--r--include/linux/swap.h12
-rw-r--r--mm/filemap.c4
-rw-r--r--mm/memcontrol.c828
-rw-r--r--mm/memory.c2
-rw-r--r--mm/migrate.c38
-rw-r--r--mm/rmap.c1
-rw-r--r--mm/shmem.c8
-rw-r--r--mm/swap.c6
-rw-r--r--mm/swap_state.c8
-rw-r--r--mm/swapfile.c7
-rw-r--r--mm/truncate.c9
-rw-r--r--mm/vmscan.c12
-rw-r--r--mm/zswap.c2
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 = &current->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 not actually write the
- * page to disk.
- */
- if (PageSwapCache(page))
- return;
- __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_ANON, false);
-}
-
-void mem_cgroup_uncharge_cache_page(struct page *page)
-{
- VM_BUG_ON_PAGE(page_mapped(page), page);
- VM_BUG_ON_PAGE(page->mapping, page);
- __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE, false);
-}
-
/*
* Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
* In that cases, pages are freed continuously and we can expect pages
@@ -3763,6 +3591,9 @@ void mem_cgroup_uncharge_cache_page(struct page *page)
void mem_cgroup_uncharge_start(void)
{
+ unsigned long flags;
+
+ local_irq_save(flags);
current->memcg_batch.do_batch++;
/* We can do nest. */
if (current->memcg_batch.do_batch == 1) {
@@ -3770,21 +3601,18 @@ void mem_cgroup_uncharge_start(void)
current->memcg_batch.nr_pages = 0;
current->memcg_batch.memsw_nr_pages = 0;
}
+ local_irq_restore(flags);
}
void mem_cgroup_uncharge_end(void)
{
struct memcg_batch_info *batch = &current->memcg_batch;
+ unsigned long flags;
- if (!batch->do_batch)
- return;
-
- batch->do_batch--;
- if (batch->do_batch) /* If stacked, do nothing. */
- return;
-
- if (!batch->memcg)
- return;
+ local_irq_save(flags);
+ VM_BUG_ON(!batch->do_batch);
+ if (--batch->do_batch) /* If stacked, do nothing */
+ goto out;
/*
* This "batch->memcg" is valid without any css_get/put etc...
* bacause we hide charges behind us.
@@ -3796,61 +3624,16 @@ void mem_cgroup_uncharge_end(void)
res_counter_uncharge(&batch->memcg->memsw,
batch->memsw_nr_pages * PAGE_SIZE);
memcg_oom_recover(batch->memcg);
- /* forget this pointer (for sanity check) */
- batch->memcg = NULL;
-}
-
-#ifdef CONFIG_SWAP
-/*
- * called after __delete_from_swap_cache() and drop "page" account.
- * memcg information is recorded to swap_cgroup of "ent"
- */
-void
-mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
-{
- struct mem_cgroup *memcg;
- int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
-
- if (!swapout) /* this was a swap cache but the swap is unused ! */
- ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
-
- memcg = __mem_cgroup_uncharge_common(page, ctype, false);
-
- /*
- * record memcg information, if swapout && memcg != NULL,
- * css_get() was called in uncharge().
- */
- if (do_swap_account && swapout && memcg)
- swap_cgroup_record(ent, mem_cgroup_id(memcg));
+out:
+ local_irq_restore(flags);
}
-#endif
#ifdef CONFIG_MEMCG_SWAP
-/*
- * called from swap_entry_free(). remove record in swap_cgroup and
- * uncharge "memsw" account.
- */
-void mem_cgroup_uncharge_swap(swp_entry_t ent)
+static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
+ bool charge)
{
- struct mem_cgroup *memcg;
- unsigned short id;
-
- if (!do_swap_account)
- return;
-
- id = swap_cgroup_record(ent, 0);
- rcu_read_lock();
- memcg = mem_cgroup_lookup(id);
- if (memcg) {
- /*
- * We uncharge this because swap is freed. This memcg can
- * be obsolete one. We avoid calling css_tryget_online().
- */
- res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
- mem_cgroup_swap_statistics(memcg, false);
- css_put(&memcg->css);
- }
- rcu_read_unlock();
+ int val = (charge) ? 1 : -1;
+ this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val);
}
/**
@@ -3902,169 +3685,6 @@ static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
}
#endif
-/*
- * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
- * page belongs to.
- */
-void mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
- struct mem_cgroup **memcgp)
-{
- struct mem_cgroup *memcg = NULL;
- unsigned int nr_pages = 1;
- struct page_cgroup *pc;
-
- *memcgp = NULL;
-
- if (mem_cgroup_disabled())
- return;
-
- if (PageTransHuge(page))
- nr_pages <<= compound_order(page);
-
- pc = lookup_page_cgroup(page);
- lock_page_cgroup(pc);
- if (PageCgroupUsed(pc)) {
- memcg = pc->mem_cgroup;
- css_get(&memcg->css);
- /*
- * At migrating an anonymous page, its mapcount goes down
- * to 0 and uncharge() will be called. But, even if it's fully
- * unmapped, migration may fail and this page has to be
- * charged again. We set MIGRATION flag here and delay uncharge
- * until end_migration() is called
- *
- * Corner Case Thinking
- * A)
- * When the old page was mapped as Anon and it's unmap-and-freed
- * while migration was ongoing.
- * If unmap finds the old page, uncharge() of it will be delayed
- * until end_migration(). If unmap finds a new page, it's
- * uncharged when it make mapcount to be 1->0. If unmap code
- * finds swap_migration_entry, the new page will not be mapped
- * and end_migration() will find it(mapcount==0).
- *
- * B)
- * When the old page was mapped but migraion fails, the kernel
- * remaps it. A charge for it is kept by MIGRATION flag even
- * if mapcount goes down to 0. We can do remap successfully
- * without charging it again.
- *
- * C)
- * The "old" page is under lock_page() until the end of
- * migration, so, the old page itself will not be swapped-out.
- * If the new page is swapped out before end_migraton, our
- * hook to usual swap-out path will catch the event.
- */
- if (PageAnon(page))
- SetPageCgroupMigration(pc);
- }
- unlock_page_cgroup(pc);
- /*
- * If the page is not charged at this point,
- * we return here.
- */
- if (!memcg)
- return;
-
- *memcgp = memcg;
- /*
- * We charge new page before it's used/mapped. So, even if unlock_page()
- * is called before end_migration, we can catch all events on this new
- * page. In the case new page is migrated but not remapped, new page's
- * mapcount will be finally 0 and we call uncharge in end_migration().
- */
- /*
- * The page is committed to the memcg, but it's not actually
- * charged to the res_counter since we plan on replacing the
- * old one and only one page is going to be left afterwards.
- */
- commit_charge(newpage, memcg, nr_pages, PageAnon(page), false);
-}
-
-/* remove redundant charge if migration failed*/
-void mem_cgroup_end_migration(struct mem_cgroup *memcg,
- struct page *oldpage, struct page *newpage, bool migration_ok)
-{
- struct page *used, *unused;
- struct page_cgroup *pc;
- bool anon;
-
- if (!memcg)
- return;
-
- if (!migration_ok) {
- used = oldpage;
- unused = newpage;
- } else {
- used = newpage;
- unused = oldpage;
- }
- anon = PageAnon(used);
- __mem_cgroup_uncharge_common(unused,
- anon ? MEM_CGROUP_CHARGE_TYPE_ANON
- : MEM_CGROUP_CHARGE_TYPE_CACHE,
- true);
- css_put(&memcg->css);
- /*
- * We disallowed uncharge of pages under migration because mapcount
- * of the page goes down to zero, temporarly.
- * Clear the flag and check the page should be charged.
- */
- pc = lookup_page_cgroup(oldpage);
- lock_page_cgroup(pc);
- ClearPageCgroupMigration(pc);
- unlock_page_cgroup(pc);
-
- /*
- * If a page is a file cache, radix-tree replacement is very atomic
- * and we can skip this check. When it was an Anon page, its mapcount
- * goes down to 0. But because we added MIGRATION flage, it's not
- * uncharged yet. There are several case but page->mapcount check
- * and USED bit check in mem_cgroup_uncharge_page() will do enough
- * check. (see prepare_charge() also)
- */
- if (anon)
- mem_cgroup_uncharge_page(used);
-}
-
-/*
- * At replace page cache, newpage is not under any memcg but it's on
- * LRU. So, this function doesn't touch res_counter but handles LRU
- * in correct way. Both pages are locked so we cannot race with uncharge.
- */
-void mem_cgroup_replace_page_cache(struct page *oldpage,
- struct page *newpage)
-{
- struct mem_cgroup *memcg = NULL;
- struct page_cgroup *pc;
-
- if (mem_cgroup_disabled())
- return;
-
- pc = lookup_page_cgroup(oldpage);
- /* fix accounting on old pages */
- lock_page_cgroup(pc);
- if (PageCgroupUsed(pc)) {
- memcg = pc->mem_cgroup;
- mem_cgroup_charge_statistics(memcg, oldpage, false, -1);
- ClearPageCgroupUsed(pc);
- }
- unlock_page_cgroup(pc);
-
- /*
- * When called from shmem_replace_page(), in some cases the
- * oldpage has already been charged, and in some cases not.
- */
- if (!memcg)
- return;
- /*
- * Even if newpage->mapping was NULL before starting replacement,
- * the newpage may be on LRU(or pagevec for LRU) already. We lock
- * LRU while we overwrite pc->mem_cgroup.
- */
- commit_charge(newpage, memcg, 1, false, true);
-}
-
#ifdef CONFIG_DEBUG_VM
static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
{
@@ -4263,7 +3883,7 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
gfp_mask, &nr_scanned);
nr_reclaimed += reclaimed;
*total_scanned += nr_scanned;
- spin_lock(&mctz->lock);
+ spin_lock_irq(&mctz->lock);
/*
* If we failed to reclaim anything from this memory cgroup
@@ -4303,7 +3923,7 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
*/
/* If excess == 0, no tree ops */
__mem_cgroup_insert_exceeded(mz, mctz, excess);
- spin_unlock(&mctz->lock);
+ spin_unlock_irq(&mctz->lock);
css_put(&mz->memcg->css);
loop++;
/*
@@ -6265,9 +5885,9 @@ static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
if (page) {
pc = lookup_page_cgroup(page);
/*
- * Do only loose check w/o page_cgroup lock.
- * mem_cgroup_move_account() checks the pc is valid or not under
- * the lock.
+ * Do only loose check w/o serialization.
+ * mem_cgroup_move_account() checks the pc is valid or
+ * not under LRU exclusion.
*/
if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
ret = MC_TARGET_PAGE;
@@ -6729,6 +6349,67 @@ static void __init enable_swap_cgroup(void)
}
#endif
+#ifdef CONFIG_MEMCG_SWAP
+/**
+ * mem_cgroup_swapout - transfer a memsw charge to swap
+ * @page: page whose memsw charge to transfer
+ * @entry: swap entry to move the charge to
+ *
+ * Transfer the memsw charge of @page to @entry.
+ */
+void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
+{
+ struct page_cgroup *pc;
+ unsigned short oldid;
+
+ VM_BUG_ON_PAGE(PageLRU(page), page);
+ VM_BUG_ON_PAGE(page_count(page), page);
+
+ if (!do_swap_account)
+ return;
+
+ pc = lookup_page_cgroup(page);
+
+ /* Readahead page, never charged */
+ if (!PageCgroupUsed(pc))
+ return;
+
+ VM_BUG_ON_PAGE(!(pc->flags & PCG_MEMSW), page);
+
+ oldid = swap_cgroup_record(entry, mem_cgroup_id(pc->mem_cgroup));
+ VM_BUG_ON_PAGE(oldid, page);
+
+ pc->flags &= ~PCG_MEMSW;
+ css_get(&pc->mem_cgroup->css);
+ mem_cgroup_swap_statistics(pc->mem_cgroup, true);
+}
+
+/**
+ * mem_cgroup_uncharge_swap - uncharge a swap entry
+ * @entry: swap entry to uncharge
+ *
+ * Drop the memsw charge associated with @entry.
+ */
+void mem_cgroup_uncharge_swap(swp_entry_t entry)
+{
+ struct mem_cgroup *memcg;
+ unsigned short id;
+
+ if (!do_swap_account)
+ return;
+
+ id = swap_cgroup_record(entry, 0);
+ rcu_read_lock();
+ memcg = mem_cgroup_lookup(id);
+ if (memcg) {
+ res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
+ mem_cgroup_swap_statistics(memcg, false);
+ css_put(&memcg->css);
+ }
+ rcu_read_unlock();
+}
+#endif
+
/**
* mem_cgroup_try_charge - try charging a page
* @page: page to charge
@@ -6831,7 +6512,7 @@ void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg,
VM_BUG_ON_PAGE(!PageTransHuge(page), page);
}
- commit_charge(page, memcg, nr_pages, PageAnon(page), lrucare);
+ commit_charge(page, memcg, nr_pages, lrucare);
if (do_swap_account && PageSwapCache(page)) {
swp_entry_t entry = { .val = page_private(page) };
@@ -6873,6 +6554,139 @@ void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg)
cancel_charge(memcg, nr_pages);
}
+/**
+ * mem_cgroup_uncharge - uncharge a page
+ * @page: page to uncharge
+ *
+ * Uncharge a page previously charged with mem_cgroup_try_charge() and
+ * mem_cgroup_commit_charge().
+ */
+void mem_cgroup_uncharge(struct page *page)
+{
+ struct memcg_batch_info *batch;
+ unsigned int nr_pages = 1;
+ struct mem_cgroup *memcg;
+ struct page_cgroup *pc;
+ unsigned long pc_flags;
+ unsigned long flags;
+
+ VM_BUG_ON_PAGE(PageLRU(page), page);
+ VM_BUG_ON_PAGE(page_count(page), page);
+
+ if (mem_cgroup_disabled())
+ return;
+
+ pc = lookup_page_cgroup(page);
+
+ /* Every final put_page() ends up here */
+ if (!PageCgroupUsed(pc))
+ return;
+
+ if (PageTransHuge(page)) {
+ nr_pages <<= compound_order(page);
+ VM_BUG_ON_PAGE(!PageTransHuge(page), page);
+ }
+ /*
+ * Nobody should be changing or seriously looking at
+ * pc->mem_cgroup and pc->flags at this point, we have fully
+ * exclusive access to the page.
+ */
+ memcg = pc->mem_cgroup;
+ pc_flags = pc->flags;
+ pc->flags = 0;
+
+ local_irq_save(flags);
+
+ if (nr_pages > 1)
+ goto direct;
+ if (unlikely(test_thread_flag(TIF_MEMDIE)))
+ goto direct;
+ batch = &current->memcg_batch;
+ if (!batch->do_batch)
+ goto direct;
+ if (batch->memcg && batch->memcg != memcg)
+ goto direct;
+ if (!batch->memcg)
+ batch->memcg = memcg;
+ if (pc_flags & PCG_MEM)
+ batch->nr_pages++;
+ if (pc_flags & PCG_MEMSW)
+ batch->memsw_nr_pages++;
+ goto out;
+direct:
+ if (pc_flags & PCG_MEM)
+ res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE);
+ if (pc_flags & PCG_MEMSW)
+ res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE);
+ memcg_oom_recover(memcg);
+out:
+ mem_cgroup_charge_statistics(memcg, page, -nr_pages);
+ memcg_check_events(memcg, page);
+
+ local_irq_restore(flags);
+}
+
+/**
+ * mem_cgroup_migrate - migrate a charge to another page
+ * @oldpage: currently charged page
+ * @newpage: page to transfer the charge to
+ * @lrucare: both pages might be on the LRU already
+ *
+ * Migrate the charge from @oldpage to @newpage.
+ *
+ * Both pages must be locked, @newpage->mapping must be set up.
+ */
+void mem_cgroup_migrate(struct page *oldpage, struct page *newpage,
+ bool lrucare)
+{
+ unsigned int nr_pages = 1;
+ struct page_cgroup *pc;
+ int isolated;
+
+ VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage);
+ VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
+ VM_BUG_ON_PAGE(!lrucare && PageLRU(oldpage), oldpage);
+ VM_BUG_ON_PAGE(!lrucare && PageLRU(newpage), newpage);
+ VM_BUG_ON_PAGE(PageAnon(oldpage) != PageAnon(newpage), newpage);
+
+ if (mem_cgroup_disabled())
+ return;
+
+ /* Page cache replacement: new page already charged? */
+ pc = lookup_page_cgroup(newpage);
+ if (PageCgroupUsed(pc))
+ return;
+
+ /* Re-entrant migration: old page already uncharged? */
+ pc = lookup_page_cgroup(oldpage);
+ if (!PageCgroupUsed(pc))
+ return;
+
+ VM_BUG_ON_PAGE(!(pc->flags & PCG_MEM), oldpage);
+ VM_BUG_ON_PAGE(do_swap_account && !(pc->flags & PCG_MEMSW), oldpage);
+
+ if (PageTransHuge(oldpage)) {
+ nr_pages <<= compound_order(oldpage);
+ VM_BUG_ON_PAGE(!PageTransHuge(oldpage), oldpage);
+ VM_BUG_ON_PAGE(!PageTransHuge(newpage), newpage);
+ }
+
+ if (lrucare)
+ lock_page_lru(oldpage, &isolated);
+
+ pc->flags = 0;
+
+ if (lrucare)
+ unlock_page_lru(oldpage, isolated);
+
+ local_irq_disable();
+ mem_cgroup_charge_statistics(pc->mem_cgroup, oldpage, -nr_pages);
+ memcg_check_events(pc->mem_cgroup, oldpage);
+ local_irq_enable();
+
+ commit_charge(newpage, pc->mem_cgroup, nr_pages, lrucare);
+}
+
/*
* subsys_initcall() for memory controller.
*
diff --git a/mm/memory.c b/mm/memory.c
index 6d7648773dc4..2a899e4e82ba 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1292,7 +1292,6 @@ static void unmap_page_range(struct mmu_gather *tlb,
details = NULL;
BUG_ON(addr >= end);
- mem_cgroup_uncharge_start();
tlb_start_vma(tlb, vma);
pgd = pgd_offset(vma->vm_mm, addr);
do {
@@ -1302,7 +1301,6 @@ static void unmap_page_range(struct mmu_gather *tlb,
next = zap_pud_range(tlb, vma, pgd, addr, next, details);
} while (pgd++, addr = next, addr != end);
tlb_end_vma(tlb, vma);
- mem_cgroup_uncharge_end();
}
diff --git a/mm/migrate.c b/mm/migrate.c
index be6dbf995c0c..f78ec9bd454d 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -780,6 +780,7 @@ static int move_to_new_page(struct page *newpage, struct page *page,
if (rc != MIGRATEPAGE_SUCCESS) {
newpage->mapping = NULL;
} else {
+ mem_cgroup_migrate(page, newpage, false);
if (remap_swapcache)
remove_migration_ptes(page, newpage);
page->mapping = NULL;
@@ -795,7 +796,6 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
{
int rc = -EAGAIN;
int remap_swapcache = 1;
- struct mem_cgroup *mem;
struct anon_vma *anon_vma = NULL;
if (!trylock_page(page)) {
@@ -821,9 +821,6 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
lock_page(page);
}
- /* charge against new page */
- mem_cgroup_prepare_migration(page, newpage, &mem);
-
if (PageWriteback(page)) {
/*
* Only in the case of a full synchronous migration is it
@@ -833,10 +830,10 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
*/
if (mode != MIGRATE_SYNC) {
rc = -EBUSY;
- goto uncharge;
+ goto out_unlock;
}
if (!force)
- goto uncharge;
+ goto out_unlock;
wait_on_page_writeback(page);
}
/*
@@ -872,7 +869,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
*/
remap_swapcache = 0;
} else {
- goto uncharge;
+ goto out_unlock;
}
}
@@ -885,7 +882,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
* the page migration right away (proteced by page lock).
*/
rc = balloon_page_migrate(newpage, page, mode);
- goto uncharge;
+ goto out_unlock;
}
/*
@@ -904,7 +901,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
VM_BUG_ON_PAGE(PageAnon(page), page);
if (page_has_private(page)) {
try_to_free_buffers(page);
- goto uncharge;
+ goto out_unlock;
}
goto skip_unmap;
}
@@ -923,10 +920,7 @@ skip_unmap:
if (anon_vma)
put_anon_vma(anon_vma);
-uncharge:
- mem_cgroup_end_migration(mem, page, newpage,
- (rc == MIGRATEPAGE_SUCCESS ||
- rc == MIGRATEPAGE_BALLOON_SUCCESS));
+out_unlock:
unlock_page(page);
out:
return rc;
@@ -1786,7 +1780,6 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
pg_data_t *pgdat = NODE_DATA(node);
int isolated = 0;
struct page *new_page = NULL;
- struct mem_cgroup *memcg = NULL;
int page_lru = page_is_file_cache(page);
unsigned long mmun_start = address & HPAGE_PMD_MASK;
unsigned long mmun_end = mmun_start + HPAGE_PMD_SIZE;
@@ -1852,15 +1845,6 @@ fail_putback:
goto out_unlock;
}
- /*
- * Traditional migration needs to prepare the memcg charge
- * transaction early to prevent the old page from being
- * uncharged when installing migration entries. Here we can
- * save the potential rollback and start the charge transfer
- * only when migration is already known to end successfully.
- */
- mem_cgroup_prepare_migration(page, new_page, &memcg);
-
orig_entry = *pmd;
entry = mk_pmd(new_page, vma->vm_page_prot);
entry = pmd_mkhuge(entry);
@@ -1888,14 +1872,10 @@ fail_putback:
goto fail_putback;
}
+ mem_cgroup_migrate(page, new_page, false);
+
page_remove_rmap(page);
- /*
- * Finish the charge transaction under the page table lock to
- * prevent split_huge_page() from dividing up the charge
- * before it's fully transferred to the new page.
- */
- mem_cgroup_end_migration(memcg, page, new_page, true);
spin_unlock(ptl);
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
diff --git a/mm/rmap.c b/mm/rmap.c
index f56b5ed78128..3e8491c504f8 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1089,7 +1089,6 @@ void page_remove_rmap(struct page *page)
if (unlikely(PageHuge(page)))
goto out;
if (anon) {
- mem_cgroup_uncharge_page(page);
if (PageTransHuge(page))
__dec_zone_page_state(page,
NR_ANON_TRANSPARENT_HUGEPAGES);
diff --git a/mm/shmem.c b/mm/shmem.c
index 1f1a8085538b..6dc80d298f9d 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -419,7 +419,6 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
pvec.pages, indices);
if (!pvec.nr)
break;
- mem_cgroup_uncharge_start();
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *page = pvec.pages[i];
@@ -447,7 +446,6 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
}
pagevec_remove_exceptionals(&pvec);
pagevec_release(&pvec);
- mem_cgroup_uncharge_end();
cond_resched();
index++;
}
@@ -495,7 +493,6 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
index = start;
continue;
}
- mem_cgroup_uncharge_start();
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *page = pvec.pages[i];
@@ -531,7 +528,6 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
}
pagevec_remove_exceptionals(&pvec);
pagevec_release(&pvec);
- mem_cgroup_uncharge_end();
index++;
}
@@ -835,7 +831,7 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
}
mutex_unlock(&shmem_swaplist_mutex);
- swapcache_free(swap, NULL);
+ swapcache_free(swap);
redirty:
set_page_dirty(page);
if (wbc->for_reclaim)
@@ -1008,7 +1004,7 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp,
*/
oldpage = newpage;
} else {
- mem_cgroup_replace_page_cache(oldpage, newpage);
+ mem_cgroup_migrate(oldpage, newpage, false);
lru_cache_add_anon(newpage);
*pagep = newpage;
}
diff --git a/mm/swap.c b/mm/swap.c
index 3baca701bb78..00523fffa5ed 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -62,6 +62,7 @@ static void __page_cache_release(struct page *page)
del_page_from_lru_list(page, lruvec, page_off_lru(page));
spin_unlock_irqrestore(&zone->lru_lock, flags);
}
+ mem_cgroup_uncharge(page);
}
static void __put_single_page(struct page *page)
@@ -907,6 +908,8 @@ void release_pages(struct page **pages, int nr, bool cold)
struct lruvec *lruvec;
unsigned long uninitialized_var(flags);
+ mem_cgroup_uncharge_start();
+
for (i = 0; i < nr; i++) {
struct page *page = pages[i];
@@ -938,6 +941,7 @@ void release_pages(struct page **pages, int nr, bool cold)
__ClearPageLRU(page);
del_page_from_lru_list(page, lruvec, page_off_lru(page));
}
+ mem_cgroup_uncharge(page);
/* Clear Active bit in case of parallel mark_page_accessed */
__ClearPageActive(page);
@@ -947,6 +951,8 @@ void release_pages(struct page **pages, int nr, bool cold)
if (zone)
spin_unlock_irqrestore(&zone->lru_lock, flags);
+ mem_cgroup_uncharge_end();
+
free_hot_cold_page_list(&pages_to_free, cold);
}
EXPORT_SYMBOL(release_pages);
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 2972eee184a4..e160151da6b8 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -176,7 +176,7 @@ int add_to_swap(struct page *page, struct list_head *list)
if (unlikely(PageTransHuge(page)))
if (unlikely(split_huge_page_to_list(page, list))) {
- swapcache_free(entry, NULL);
+ swapcache_free(entry);
return 0;
}
@@ -202,7 +202,7 @@ int add_to_swap(struct page *page, struct list_head *list)
* add_to_swap_cache() doesn't return -EEXIST, so we can safely
* clear SWAP_HAS_CACHE flag.
*/
- swapcache_free(entry, NULL);
+ swapcache_free(entry);
return 0;
}
}
@@ -225,7 +225,7 @@ void delete_from_swap_cache(struct page *page)
__delete_from_swap_cache(page);
spin_unlock_irq(&address_space->tree_lock);
- swapcache_free(entry, page);
+ swapcache_free(entry);
page_cache_release(page);
}
@@ -386,7 +386,7 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
* add_to_swap_cache() doesn't return -EEXIST, so we can safely
* clear SWAP_HAS_CACHE flag.
*/
- swapcache_free(entry, NULL);
+ swapcache_free(entry);
} while (err != -ENOMEM);
if (new_page)
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 0883b4912ff7..8798b2e0ac59 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -843,16 +843,13 @@ void swap_free(swp_entry_t entry)
/*
* Called after dropping swapcache to decrease refcnt to swap entries.
*/
-void swapcache_free(swp_entry_t entry, struct page *page)
+void swapcache_free(swp_entry_t entry)
{
struct swap_info_struct *p;
- unsigned char count;
p = swap_info_get(entry);
if (p) {
- count = swap_entry_free(p, entry, SWAP_HAS_CACHE);
- if (page)
- mem_cgroup_uncharge_swapcache(page, entry, count != 0);
+ swap_entry_free(p, entry, SWAP_HAS_CACHE);
spin_unlock(&p->lock);
}
}
diff --git a/mm/truncate.c b/mm/truncate.c
index eda247307164..96d167372d89 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -281,7 +281,6 @@ void truncate_inode_pages_range(struct address_space *mapping,
while (index < end && pagevec_lookup_entries(&pvec, mapping, index,
min(end - index, (pgoff_t)PAGEVEC_SIZE),
indices)) {
- mem_cgroup_uncharge_start();
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *page = pvec.pages[i];
@@ -307,7 +306,6 @@ void truncate_inode_pages_range(struct address_space *mapping,
}
pagevec_remove_exceptionals(&pvec);
pagevec_release(&pvec);
- mem_cgroup_uncharge_end();
cond_resched();
index++;
}
@@ -369,7 +367,6 @@ void truncate_inode_pages_range(struct address_space *mapping,
pagevec_release(&pvec);
break;
}
- mem_cgroup_uncharge_start();
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *page = pvec.pages[i];
@@ -394,7 +391,6 @@ void truncate_inode_pages_range(struct address_space *mapping,
}
pagevec_remove_exceptionals(&pvec);
pagevec_release(&pvec);
- mem_cgroup_uncharge_end();
index++;
}
cleancache_invalidate_inode(mapping);
@@ -493,7 +489,6 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping,
while (index <= end && pagevec_lookup_entries(&pvec, mapping, index,
min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1,
indices)) {
- mem_cgroup_uncharge_start();
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *page = pvec.pages[i];
@@ -522,7 +517,6 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping,
}
pagevec_remove_exceptionals(&pvec);
pagevec_release(&pvec);
- mem_cgroup_uncharge_end();
cond_resched();
index++;
}
@@ -553,7 +547,6 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page)
BUG_ON(page_has_private(page));
__delete_from_page_cache(page, NULL);
spin_unlock_irq(&mapping->tree_lock);
- mem_cgroup_uncharge_cache_page(page);
if (mapping->a_ops->freepage)
mapping->a_ops->freepage(page);
@@ -602,7 +595,6 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
while (index <= end && pagevec_lookup_entries(&pvec, mapping, index,
min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1,
indices)) {
- mem_cgroup_uncharge_start();
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *page = pvec.pages[i];
@@ -655,7 +647,6 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
}
pagevec_remove_exceptionals(&pvec);
pagevec_release(&pvec);
- mem_cgroup_uncharge_end();
cond_resched();
index++;
}
diff --git a/mm/vmscan.c b/mm/vmscan.c
index d2f65c856350..7068e838d22b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -577,9 +577,10 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
if (PageSwapCache(page)) {
swp_entry_t swap = { .val = page_private(page) };
+ mem_cgroup_swapout(page, swap);
__delete_from_swap_cache(page);
spin_unlock_irq(&mapping->tree_lock);
- swapcache_free(swap, page);
+ swapcache_free(swap);
} else {
void (*freepage)(struct page *);
void *shadow = NULL;
@@ -600,7 +601,6 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
shadow = workingset_eviction(mapping, page);
__delete_from_page_cache(page, shadow);
spin_unlock_irq(&mapping->tree_lock);
- mem_cgroup_uncharge_cache_page(page);
if (freepage != NULL)
freepage(page);
@@ -1103,6 +1103,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
*/
__clear_page_locked(page);
free_it:
+ mem_cgroup_uncharge(page);
nr_reclaimed++;
/*
@@ -1132,12 +1133,13 @@ keep:
list_add(&page->lru, &ret_pages);
VM_BUG_ON_PAGE(PageLRU(page) || PageUnevictable(page), page);
}
+ mem_cgroup_uncharge_end();
free_hot_cold_page_list(&free_pages, true);
list_splice(&ret_pages, page_list);
count_vm_events(PGACTIVATE, pgactivate);
- mem_cgroup_uncharge_end();
+
*ret_nr_dirty += nr_dirty;
*ret_nr_congested += nr_congested;
*ret_nr_unqueued_dirty += nr_unqueued_dirty;
@@ -1435,6 +1437,8 @@ putback_inactive_pages(struct lruvec *lruvec, struct list_head *page_list)
__ClearPageActive(page);
del_page_from_lru_list(page, lruvec, lru);
+ mem_cgroup_uncharge(page);
+
if (unlikely(PageCompound(page))) {
spin_unlock_irq(&zone->lru_lock);
(*get_compound_page_dtor(page))(page);
@@ -1656,6 +1660,8 @@ static void move_active_pages_to_lru(struct lruvec *lruvec,
__ClearPageActive(page);
del_page_from_lru_list(page, lruvec, lru);
+ mem_cgroup_uncharge(page);
+
if (unlikely(PageCompound(page))) {
spin_unlock_irq(&zone->lru_lock);
(*get_compound_page_dtor(page))(page);
diff --git a/mm/zswap.c b/mm/zswap.c
index 032c21eeab2b..9da56af24df5 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -507,7 +507,7 @@ static int zswap_get_swap_cache_page(swp_entry_t entry,
* add_to_swap_cache() doesn't return -EEXIST, so we can safely
* clear SWAP_HAS_CACHE flag.
*/
- swapcache_free(entry, NULL);
+ swapcache_free(entry);
} while (err != -ENOMEM);
if (new_page)

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