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: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joonsoo 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: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f82ae37..a875a97 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -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 @@ struct mem_cgroup *lock_page_memcg(struct page *page)
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);