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authorJohannes Weiner <hannes@cmpxchg.org>2016-03-16 00:57:22 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-16 02:55:16 +0300
commit62cccb8c8e7a3ca233f49d5e7dcb1557d25465cd (patch)
tree43a902faf461c65393a4efebf9ff9622017b92b1 /mm
parent6a93ca8fde3cfce0f00f02281139a377c83e8d8c (diff)
downloadlinux-62cccb8c8e7a3ca233f49d5e7dcb1557d25465cd.tar.xz
mm: simplify lock_page_memcg()
Now that migration doesn't clear page->mem_cgroup of live pages anymore, it's safe to make lock_page_memcg() and the memcg stat functions take pages, and spare the callers from memcg objects. [akpm@linux-foundation.org: fix warnings] Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Suggested-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/filemap.c20
-rw-r--r--mm/memcontrol.c23
-rw-r--r--mm/page-writeback.c49
-rw-r--r--mm/rmap.c16
-rw-r--r--mm/truncate.c9
-rw-r--r--mm/vmscan.c11
-rw-r--r--mm/workingset.c9
7 files changed, 57 insertions, 80 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index d8317caffe85..8e629c4ef0c8 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -179,8 +179,7 @@ static void page_cache_tree_delete(struct address_space *mapping,
* is safe. The caller must hold the mapping's tree_lock and
* lock_page_memcg().
*/
-void __delete_from_page_cache(struct page *page, void *shadow,
- struct mem_cgroup *memcg)
+void __delete_from_page_cache(struct page *page, void *shadow)
{
struct address_space *mapping = page->mapping;
@@ -239,8 +238,7 @@ void __delete_from_page_cache(struct page *page, void *shadow,
* anyway will be cleared before returning page into buddy allocator.
*/
if (WARN_ON_ONCE(PageDirty(page)))
- account_page_cleaned(page, mapping, memcg,
- inode_to_wb(mapping->host));
+ account_page_cleaned(page, mapping, inode_to_wb(mapping->host));
}
/**
@@ -254,7 +252,6 @@ void __delete_from_page_cache(struct page *page, void *shadow,
void delete_from_page_cache(struct page *page)
{
struct address_space *mapping = page->mapping;
- struct mem_cgroup *memcg;
unsigned long flags;
void (*freepage)(struct page *);
@@ -263,11 +260,11 @@ void delete_from_page_cache(struct page *page)
freepage = mapping->a_ops->freepage;
- memcg = lock_page_memcg(page);
+ lock_page_memcg(page);
spin_lock_irqsave(&mapping->tree_lock, flags);
- __delete_from_page_cache(page, NULL, memcg);
+ __delete_from_page_cache(page, NULL);
spin_unlock_irqrestore(&mapping->tree_lock, flags);
- unlock_page_memcg(memcg);
+ unlock_page_memcg(page);
if (freepage)
freepage(page);
@@ -551,7 +548,6 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
if (!error) {
struct address_space *mapping = old->mapping;
void (*freepage)(struct page *);
- struct mem_cgroup *memcg;
unsigned long flags;
pgoff_t offset = old->index;
@@ -561,9 +557,9 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
new->mapping = mapping;
new->index = offset;
- memcg = lock_page_memcg(old);
+ lock_page_memcg(old);
spin_lock_irqsave(&mapping->tree_lock, flags);
- __delete_from_page_cache(old, NULL, memcg);
+ __delete_from_page_cache(old, NULL);
error = radix_tree_insert(&mapping->page_tree, offset, new);
BUG_ON(error);
mapping->nrpages++;
@@ -576,7 +572,7 @@ 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_irqrestore(&mapping->tree_lock, flags);
- unlock_page_memcg(memcg);
+ unlock_page_memcg(old);
mem_cgroup_migrate(old, new);
radix_tree_preload_end();
if (freepage)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 64506b2eef34..3e4199830456 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1690,7 +1690,7 @@ cleanup:
* This function protects unlocked LRU pages from being moved to
* another cgroup and stabilizes their page->mem_cgroup binding.
*/
-struct mem_cgroup *lock_page_memcg(struct page *page)
+void lock_page_memcg(struct page *page)
{
struct mem_cgroup *memcg;
unsigned long flags;
@@ -1699,25 +1699,18 @@ struct mem_cgroup *lock_page_memcg(struct page *page)
* The RCU lock is held throughout the transaction. The fast
* path can get away without acquiring the memcg->move_lock
* because page moving starts with an RCU grace period.
- *
- * The RCU lock also protects the memcg from being freed when
- * the page state that is going to change is the only thing
- * preventing the page from being uncharged.
- * E.g. end-writeback clearing PageWriteback(), which allows
- * migration to go ahead and uncharge the page before the
- * account transaction might be complete.
*/
rcu_read_lock();
if (mem_cgroup_disabled())
- return NULL;
+ return;
again:
memcg = page->mem_cgroup;
if (unlikely(!memcg))
- return NULL;
+ return;
if (atomic_read(&memcg->moving_account) <= 0)
- return memcg;
+ return;
spin_lock_irqsave(&memcg->move_lock, flags);
if (memcg != page->mem_cgroup) {
@@ -1733,16 +1726,18 @@ again:
memcg->move_lock_task = current;
memcg->move_lock_flags = flags;
- return memcg;
+ return;
}
EXPORT_SYMBOL(lock_page_memcg);
/**
* unlock_page_memcg - unlock a page->mem_cgroup binding
- * @memcg: the memcg returned by lock_page_memcg()
+ * @page: the page
*/
-void unlock_page_memcg(struct mem_cgroup *memcg)
+void unlock_page_memcg(struct page *page)
{
+ struct mem_cgroup *memcg = page->mem_cgroup;
+
if (memcg && memcg->move_lock_task == current) {
unsigned long flags = memcg->move_lock_flags;
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 2b5ea1271e32..d7cf2c53d125 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2414,8 +2414,7 @@ int __set_page_dirty_no_writeback(struct page *page)
*
* NOTE: This relies on being atomic wrt interrupts.
*/
-void account_page_dirtied(struct page *page, struct address_space *mapping,
- struct mem_cgroup *memcg)
+void account_page_dirtied(struct page *page, struct address_space *mapping)
{
struct inode *inode = mapping->host;
@@ -2427,7 +2426,7 @@ void account_page_dirtied(struct page *page, struct address_space *mapping,
inode_attach_wb(inode, page);
wb = inode_to_wb(inode);
- mem_cgroup_inc_page_stat(memcg, MEM_CGROUP_STAT_DIRTY);
+ mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_DIRTY);
__inc_zone_page_state(page, NR_FILE_DIRTY);
__inc_zone_page_state(page, NR_DIRTIED);
__inc_wb_stat(wb, WB_RECLAIMABLE);
@@ -2445,10 +2444,10 @@ EXPORT_SYMBOL(account_page_dirtied);
* Caller must hold lock_page_memcg().
*/
void account_page_cleaned(struct page *page, struct address_space *mapping,
- struct mem_cgroup *memcg, struct bdi_writeback *wb)
+ struct bdi_writeback *wb)
{
if (mapping_cap_account_dirty(mapping)) {
- mem_cgroup_dec_page_stat(memcg, MEM_CGROUP_STAT_DIRTY);
+ mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_DIRTY);
dec_zone_page_state(page, NR_FILE_DIRTY);
dec_wb_stat(wb, WB_RECLAIMABLE);
task_io_account_cancelled_write(PAGE_CACHE_SIZE);
@@ -2469,26 +2468,24 @@ void account_page_cleaned(struct page *page, struct address_space *mapping,
*/
int __set_page_dirty_nobuffers(struct page *page)
{
- struct mem_cgroup *memcg;
-
- memcg = lock_page_memcg(page);
+ lock_page_memcg(page);
if (!TestSetPageDirty(page)) {
struct address_space *mapping = page_mapping(page);
unsigned long flags;
if (!mapping) {
- unlock_page_memcg(memcg);
+ unlock_page_memcg(page);
return 1;
}
spin_lock_irqsave(&mapping->tree_lock, flags);
BUG_ON(page_mapping(page) != mapping);
WARN_ON_ONCE(!PagePrivate(page) && !PageUptodate(page));
- account_page_dirtied(page, mapping, memcg);
+ account_page_dirtied(page, mapping);
radix_tree_tag_set(&mapping->page_tree, page_index(page),
PAGECACHE_TAG_DIRTY);
spin_unlock_irqrestore(&mapping->tree_lock, flags);
- unlock_page_memcg(memcg);
+ unlock_page_memcg(page);
if (mapping->host) {
/* !PageAnon && !swapper_space */
@@ -2496,7 +2493,7 @@ int __set_page_dirty_nobuffers(struct page *page)
}
return 1;
}
- unlock_page_memcg(memcg);
+ unlock_page_memcg(page);
return 0;
}
EXPORT_SYMBOL(__set_page_dirty_nobuffers);
@@ -2626,17 +2623,16 @@ void cancel_dirty_page(struct page *page)
if (mapping_cap_account_dirty(mapping)) {
struct inode *inode = mapping->host;
struct bdi_writeback *wb;
- struct mem_cgroup *memcg;
bool locked;
- memcg = lock_page_memcg(page);
+ lock_page_memcg(page);
wb = unlocked_inode_to_wb_begin(inode, &locked);
if (TestClearPageDirty(page))
- account_page_cleaned(page, mapping, memcg, wb);
+ account_page_cleaned(page, mapping, wb);
unlocked_inode_to_wb_end(inode, locked);
- unlock_page_memcg(memcg);
+ unlock_page_memcg(page);
} else {
ClearPageDirty(page);
}
@@ -2667,7 +2663,6 @@ int clear_page_dirty_for_io(struct page *page)
if (mapping && mapping_cap_account_dirty(mapping)) {
struct inode *inode = mapping->host;
struct bdi_writeback *wb;
- struct mem_cgroup *memcg;
bool locked;
/*
@@ -2705,16 +2700,16 @@ int clear_page_dirty_for_io(struct page *page)
* always locked coming in here, so we get the desired
* exclusion.
*/
- memcg = lock_page_memcg(page);
+ lock_page_memcg(page);
wb = unlocked_inode_to_wb_begin(inode, &locked);
if (TestClearPageDirty(page)) {
- mem_cgroup_dec_page_stat(memcg, MEM_CGROUP_STAT_DIRTY);
+ mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_DIRTY);
dec_zone_page_state(page, NR_FILE_DIRTY);
dec_wb_stat(wb, WB_RECLAIMABLE);
ret = 1;
}
unlocked_inode_to_wb_end(inode, locked);
- unlock_page_memcg(memcg);
+ unlock_page_memcg(page);
return ret;
}
return TestClearPageDirty(page);
@@ -2724,10 +2719,9 @@ EXPORT_SYMBOL(clear_page_dirty_for_io);
int test_clear_page_writeback(struct page *page)
{
struct address_space *mapping = page_mapping(page);
- struct mem_cgroup *memcg;
int ret;
- memcg = lock_page_memcg(page);
+ lock_page_memcg(page);
if (mapping) {
struct inode *inode = mapping->host;
struct backing_dev_info *bdi = inode_to_bdi(inode);
@@ -2751,21 +2745,20 @@ int test_clear_page_writeback(struct page *page)
ret = TestClearPageWriteback(page);
}
if (ret) {
- mem_cgroup_dec_page_stat(memcg, MEM_CGROUP_STAT_WRITEBACK);
+ mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_WRITEBACK);
dec_zone_page_state(page, NR_WRITEBACK);
inc_zone_page_state(page, NR_WRITTEN);
}
- unlock_page_memcg(memcg);
+ unlock_page_memcg(page);
return ret;
}
int __test_set_page_writeback(struct page *page, bool keep_write)
{
struct address_space *mapping = page_mapping(page);
- struct mem_cgroup *memcg;
int ret;
- memcg = lock_page_memcg(page);
+ lock_page_memcg(page);
if (mapping) {
struct inode *inode = mapping->host;
struct backing_dev_info *bdi = inode_to_bdi(inode);
@@ -2793,10 +2786,10 @@ int __test_set_page_writeback(struct page *page, bool keep_write)
ret = TestSetPageWriteback(page);
}
if (!ret) {
- mem_cgroup_inc_page_stat(memcg, MEM_CGROUP_STAT_WRITEBACK);
+ mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_WRITEBACK);
inc_zone_page_state(page, NR_WRITEBACK);
}
- unlock_page_memcg(memcg);
+ unlock_page_memcg(page);
return ret;
}
diff --git a/mm/rmap.c b/mm/rmap.c
index 2871e7d3cced..02f0bfc3c80a 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1287,21 +1287,17 @@ void page_add_new_anon_rmap(struct page *page,
*/
void page_add_file_rmap(struct page *page)
{
- struct mem_cgroup *memcg;
-
- memcg = lock_page_memcg(page);
+ lock_page_memcg(page);
if (atomic_inc_and_test(&page->_mapcount)) {
__inc_zone_page_state(page, NR_FILE_MAPPED);
- mem_cgroup_inc_page_stat(memcg, MEM_CGROUP_STAT_FILE_MAPPED);
+ mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED);
}
- unlock_page_memcg(memcg);
+ unlock_page_memcg(page);
}
static void page_remove_file_rmap(struct page *page)
{
- struct mem_cgroup *memcg;
-
- memcg = lock_page_memcg(page);
+ lock_page_memcg(page);
/* Hugepages are not counted in NR_FILE_MAPPED for now. */
if (unlikely(PageHuge(page))) {
@@ -1320,12 +1316,12 @@ static void page_remove_file_rmap(struct page *page)
* pte lock(a spinlock) is held, which implies preemption disabled.
*/
__dec_zone_page_state(page, NR_FILE_MAPPED);
- mem_cgroup_dec_page_stat(memcg, MEM_CGROUP_STAT_FILE_MAPPED);
+ mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED);
if (unlikely(PageMlocked(page)))
clear_page_mlock(page);
out:
- unlock_page_memcg(memcg);
+ unlock_page_memcg(page);
}
static void page_remove_anon_compound_rmap(struct page *page)
diff --git a/mm/truncate.c b/mm/truncate.c
index 51a24f6a555d..87311af936f2 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -519,7 +519,6 @@ EXPORT_SYMBOL(invalidate_mapping_pages);
static int
invalidate_complete_page2(struct address_space *mapping, struct page *page)
{
- struct mem_cgroup *memcg;
unsigned long flags;
if (page->mapping != mapping)
@@ -528,15 +527,15 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page)
if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL))
return 0;
- memcg = lock_page_memcg(page);
+ lock_page_memcg(page);
spin_lock_irqsave(&mapping->tree_lock, flags);
if (PageDirty(page))
goto failed;
BUG_ON(page_has_private(page));
- __delete_from_page_cache(page, NULL, memcg);
+ __delete_from_page_cache(page, NULL);
spin_unlock_irqrestore(&mapping->tree_lock, flags);
- unlock_page_memcg(memcg);
+ unlock_page_memcg(page);
if (mapping->a_ops->freepage)
mapping->a_ops->freepage(page);
@@ -545,7 +544,7 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page)
return 1;
failed:
spin_unlock_irqrestore(&mapping->tree_lock, flags);
- unlock_page_memcg(memcg);
+ unlock_page_memcg(page);
return 0;
}
diff --git a/mm/vmscan.c b/mm/vmscan.c
index fd434cc89bea..34f7e2dae0a0 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -603,12 +603,11 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
bool reclaimed)
{
unsigned long flags;
- struct mem_cgroup *memcg;
BUG_ON(!PageLocked(page));
BUG_ON(mapping != page_mapping(page));
- memcg = lock_page_memcg(page);
+ lock_page_memcg(page);
spin_lock_irqsave(&mapping->tree_lock, flags);
/*
* The non racy check for a busy page.
@@ -648,7 +647,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
mem_cgroup_swapout(page, swap);
__delete_from_swap_cache(page);
spin_unlock_irqrestore(&mapping->tree_lock, flags);
- unlock_page_memcg(memcg);
+ unlock_page_memcg(page);
swapcache_free(swap);
} else {
void (*freepage)(struct page *);
@@ -674,9 +673,9 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
if (reclaimed && page_is_file_cache(page) &&
!mapping_exiting(mapping) && !dax_mapping(mapping))
shadow = workingset_eviction(mapping, page);
- __delete_from_page_cache(page, shadow, memcg);
+ __delete_from_page_cache(page, shadow);
spin_unlock_irqrestore(&mapping->tree_lock, flags);
- unlock_page_memcg(memcg);
+ unlock_page_memcg(page);
if (freepage != NULL)
freepage(page);
@@ -686,7 +685,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
cannot_free:
spin_unlock_irqrestore(&mapping->tree_lock, flags);
- unlock_page_memcg(memcg);
+ unlock_page_memcg(page);
return 0;
}
diff --git a/mm/workingset.c b/mm/workingset.c
index 14bc23a7779b..6130ba0b2641 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -305,10 +305,9 @@ bool workingset_refault(void *shadow)
*/
void workingset_activation(struct page *page)
{
- struct mem_cgroup *memcg;
struct lruvec *lruvec;
- memcg = lock_page_memcg(page);
+ lock_page_memcg(page);
/*
* Filter non-memcg pages here, e.g. unmap can call
* mark_page_accessed() on VDSO pages.
@@ -316,12 +315,12 @@ void workingset_activation(struct page *page)
* XXX: See workingset_refault() - this should return
* root_mem_cgroup even for !CONFIG_MEMCG.
*/
- if (!mem_cgroup_disabled() && !memcg)
+ if (!mem_cgroup_disabled() && !page_memcg(page))
goto out;
- lruvec = mem_cgroup_zone_lruvec(page_zone(page), memcg);
+ lruvec = mem_cgroup_zone_lruvec(page_zone(page), page_memcg(page));
atomic_long_inc(&lruvec->inactive_age);
out:
- unlock_page_memcg(memcg);
+ unlock_page_memcg(page);
}
/*