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Commit 62cccb8c authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds
Browse files

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: default avatarJohannes Weiner <hannes@cmpxchg.org>
Suggested-by: default avatarVladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: default avatarVladimir Davydov <vdavydov@virtuozzo.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6a93ca8f

fs/buffer.c

+8 −10
Original line number Diff line number Diff line
@@ -624,14 +624,14 @@ EXPORT_SYMBOL(mark_buffer_dirty_inode); 
 * The caller must hold lock_page_memcg().

 */

static void __set_page_dirty(struct page *page, struct address_space *mapping,

			     struct mem_cgroup *memcg, int warn)

			     int warn)

{

	unsigned long flags;



	spin_lock_irqsave(&mapping->tree_lock, flags);

	if (page->mapping) {	/* Race with truncate? */

		WARN_ON_ONCE(warn && !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);

	}
@@ -666,7 +666,6 @@ static void __set_page_dirty(struct page *page, struct address_space *mapping, 
int __set_page_dirty_buffers(struct page *page)

{

	int newly_dirty;

	struct mem_cgroup *memcg;

	struct address_space *mapping = page_mapping(page);



	if (unlikely(!mapping))
@@ -686,14 +685,14 @@ int __set_page_dirty_buffers(struct page *page) 
	 * Lock out page->mem_cgroup migration to keep PageDirty

	 * synchronized with per-memcg dirty page counters.

	 */

	memcg = lock_page_memcg(page);

	lock_page_memcg(page);

	newly_dirty = !TestSetPageDirty(page);

	spin_unlock(&mapping->private_lock);



	if (newly_dirty)

		__set_page_dirty(page, mapping, memcg, 1);

		__set_page_dirty(page, mapping, 1);



	unlock_page_memcg(memcg);

	unlock_page_memcg(page);



	if (newly_dirty)

		__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
@@ -1167,15 +1166,14 @@ void mark_buffer_dirty(struct buffer_head *bh) 
	if (!test_set_buffer_dirty(bh)) {

		struct page *page = bh->b_page;

		struct address_space *mapping = NULL;

		struct mem_cgroup *memcg;



		memcg = lock_page_memcg(page);

		lock_page_memcg(page);

		if (!TestSetPageDirty(page)) {

			mapping = page_mapping(page);

			if (mapping)

				__set_page_dirty(page, mapping, memcg, 0);

				__set_page_dirty(page, mapping, 0);

		}

		unlock_page_memcg(memcg);

		unlock_page_memcg(page);

		if (mapping)

			__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);

	}

fs/xfs/xfs_aops.c

+3 −4
Original line number Diff line number Diff line
@@ -1957,7 +1957,6 @@ xfs_vm_set_page_dirty( 
	loff_t			end_offset;

	loff_t			offset;

	int			newly_dirty;

	struct mem_cgroup	*memcg;



	if (unlikely(!mapping))

		return !TestSetPageDirty(page);
@@ -1981,7 +1980,7 @@ xfs_vm_set_page_dirty( 
	 * Lock out page->mem_cgroup migration to keep PageDirty

	 * synchronized with per-memcg dirty page counters.

	 */

	memcg = lock_page_memcg(page);

	lock_page_memcg(page);

	newly_dirty = !TestSetPageDirty(page);

	spin_unlock(&mapping->private_lock);
@@ -1992,13 +1991,13 @@ xfs_vm_set_page_dirty( 
		spin_lock_irqsave(&mapping->tree_lock, flags);

		if (page->mapping) {	/* Race with truncate? */

			WARN_ON_ONCE(!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 (newly_dirty)

		__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);

	return newly_dirty;

include/linux/memcontrol.h

+17 −18
Original line number Diff line number Diff line
@@ -455,42 +455,42 @@ bool mem_cgroup_oom_synchronize(bool wait); 
extern int do_swap_account;

#endif



struct mem_cgroup *lock_page_memcg(struct page *page);

void unlock_page_memcg(struct mem_cgroup *memcg);

void lock_page_memcg(struct page *page);

void unlock_page_memcg(struct page *page);



/**

 * mem_cgroup_update_page_stat - update page state statistics

 * @memcg: memcg to account against

 * @page: the page

 * @idx: page state item to account

 * @val: number of pages (positive or negative)

 *

 * Callers must use lock_page_memcg() to prevent double accounting

 * when the page is concurrently being moved to another memcg:

 *

 *   memcg = lock_page_memcg(page);

 *   lock_page_memcg(page);

 *   if (TestClearPageState(page))

 *     mem_cgroup_update_page_stat(memcg, state, -1);

 *   unlock_page_memcg(memcg);

 *     mem_cgroup_update_page_stat(page, state, -1);

 *   unlock_page_memcg(page);

 */

static inline void mem_cgroup_update_page_stat(struct mem_cgroup *memcg,

static inline void mem_cgroup_update_page_stat(struct page *page,

				 enum mem_cgroup_stat_index idx, int val)

{

	VM_BUG_ON(!rcu_read_lock_held());



	if (memcg)

		this_cpu_add(memcg->stat->count[idx], val);

	if (page->mem_cgroup)

		this_cpu_add(page->mem_cgroup->stat->count[idx], val);

}



static inline void mem_cgroup_inc_page_stat(struct mem_cgroup *memcg,

static inline void mem_cgroup_inc_page_stat(struct page *page,

					    enum mem_cgroup_stat_index idx)

{

	mem_cgroup_update_page_stat(memcg, idx, 1);

	mem_cgroup_update_page_stat(page, idx, 1);

}



static inline void mem_cgroup_dec_page_stat(struct mem_cgroup *memcg,

static inline void mem_cgroup_dec_page_stat(struct page *page,

					    enum mem_cgroup_stat_index idx)

{

	mem_cgroup_update_page_stat(memcg, idx, -1);

	mem_cgroup_update_page_stat(page, idx, -1);

}



unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
@@ -661,12 +661,11 @@ mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) 
{

}



static inline struct mem_cgroup *lock_page_memcg(struct page *page)

static inline void lock_page_memcg(struct page *page)

{

	return NULL;

}



static inline void unlock_page_memcg(struct mem_cgroup *memcg)

static inline void unlock_page_memcg(struct page *page)

{

}
@@ -692,12 +691,12 @@ static inline bool mem_cgroup_oom_synchronize(bool wait) 
	return false;

}



static inline void mem_cgroup_inc_page_stat(struct mem_cgroup *memcg,

static inline void mem_cgroup_inc_page_stat(struct page *page,

					    enum mem_cgroup_stat_index idx)

{

}



static inline void mem_cgroup_dec_page_stat(struct mem_cgroup *memcg,

static inline void mem_cgroup_dec_page_stat(struct page *page,

					    enum mem_cgroup_stat_index idx)

{

}

include/linux/mm.h

+2 −3
Original line number Diff line number Diff line
@@ -1291,10 +1291,9 @@ int __set_page_dirty_nobuffers(struct page *page); 
int __set_page_dirty_no_writeback(struct page *page);

int redirty_page_for_writepage(struct writeback_control *wbc,

				struct page *page);

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);

void account_page_cleaned(struct page *page, struct address_space *mapping,

			  struct mem_cgroup *memcg, struct bdi_writeback *wb);

			  struct bdi_writeback *wb);

int set_page_dirty(struct page *page);

int set_page_dirty_lock(struct page *page);

void cancel_dirty_page(struct page *page);

include/linux/pagemap.h

+1 −2
Original line number Diff line number Diff line
@@ -663,8 +663,7 @@ int add_to_page_cache_locked(struct page *page, struct address_space *mapping, 
int add_to_page_cache_lru(struct page *page, struct address_space *mapping,

				pgoff_t index, gfp_t gfp_mask);

extern void delete_from_page_cache(struct page *page);

extern void __delete_from_page_cache(struct page *page, void *shadow,

				     struct mem_cgroup *memcg);

extern void __delete_from_page_cache(struct page *page, void *shadow);

int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask);



/*