Commit 9da7b521 authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds
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mm: memcontrol: prepare cgroup vmstat infrastructure for native anon counters 



Anonymous compound pages can be mapped by ptes, which means that if we
want to track NR_MAPPED_ANON, NR_ANON_THPS on a per-cgroup basis, we have
to be prepared to see tail pages in our accounting functions.

Make mod_lruvec_page_state() and lock_page_memcg() deal with tail pages
correctly, namely by redirecting to the head page which has the
page->mem_cgroup set up.

Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-9-hannes@cmpxchg.org


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 49e50d27

include/linux/memcontrol.h

+3 −2
Original line number Diff line number Diff line
@@ -709,16 +709,17 @@ static inline void mod_lruvec_state(struct lruvec *lruvec, 
static inline void __mod_lruvec_page_state(struct page *page,

					   enum node_stat_item idx, int val)

{

	struct page *head = compound_head(page); /* rmap on tail pages */

	pg_data_t *pgdat = page_pgdat(page);

	struct lruvec *lruvec;



	/* Untracked pages have no memcg, no lruvec. Update only the node */

	if (!page->mem_cgroup) {

	if (!head->mem_cgroup) {

		__mod_node_page_state(pgdat, idx, val);

		return;

	}



	lruvec = mem_cgroup_lruvec(page->mem_cgroup, pgdat);

	lruvec = mem_cgroup_lruvec(head->mem_cgroup, pgdat);

	__mod_lruvec_state(lruvec, idx, val);

}

mm/memcontrol.c

+6 −3
Original line number Diff line number Diff line
@@ -1981,6 +1981,7 @@ void mem_cgroup_print_oom_group(struct mem_cgroup *memcg) 
 */

struct mem_cgroup *lock_page_memcg(struct page *page)

{

	struct page *head = compound_head(page); /* rmap on tail pages */

	struct mem_cgroup *memcg;

	unsigned long flags;
@@ -2000,7 +2001,7 @@ struct mem_cgroup *lock_page_memcg(struct page *page) 
	if (mem_cgroup_disabled())

		return NULL;

again:

	memcg = page->mem_cgroup;

	memcg = head->mem_cgroup;

	if (unlikely(!memcg))

		return NULL;
@@ -2008,7 +2009,7 @@ again: 
		return memcg;



	spin_lock_irqsave(&memcg->move_lock, flags);

	if (memcg != page->mem_cgroup) {

	if (memcg != head->mem_cgroup) {

		spin_unlock_irqrestore(&memcg->move_lock, flags);

		goto again;

	}
@@ -2051,7 +2052,9 @@ void __unlock_page_memcg(struct mem_cgroup *memcg) 
 */

void unlock_page_memcg(struct page *page)

{

	__unlock_page_memcg(page->mem_cgroup);

	struct page *head = compound_head(page);



	__unlock_page_memcg(head->mem_cgroup);

}

EXPORT_SYMBOL(unlock_page_memcg);

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