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authorJohannes Weiner <hannes@cmpxchg.org>2020-06-04 02:01:57 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-04 06:09:47 +0300
commitbe5d0a74c62d8da43f9526a5b08cdd18e2bbc37a (patch)
tree6eeb26db5ce3b90cc2e79462e60e2d8e6119d5b6 /mm/userfaultfd.c
parent0d1c20722ab333ac0ac03ae2188922c1021d3abc (diff)
downloadlinux-be5d0a74c62d8da43f9526a5b08cdd18e2bbc37a.tar.xz
mm: memcontrol: switch to native NR_ANON_MAPPED counter
Memcg maintains a private MEMCG_RSS counter. This divergence from the generic VM accounting means unnecessary code overhead, and creates a dependency for memcg that page->mapping is set up at the time of charging, so that page types can be told apart. Convert the generic accounting sites to mod_lruvec_page_state and friends to maintain the per-cgroup vmstat counter of NR_ANON_MAPPED. We use lock_page_memcg() to stabilize page->mem_cgroup during rmap changes, the same way we do for NR_FILE_MAPPED. With the previous patch removing MEMCG_CACHE and the private NR_SHMEM counter, this patch finally eliminates the need to have page->mapping set up at charge time. However, we need to have page->mem_cgroup set up by the time rmap runs and does the accounting, so switch the commit and the rmap callbacks around. v2: fix temporary accounting bug by switching rmap<->commit (Joonsoo) Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Alex Shi <alex.shi@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.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/20200508183105.225460-11-hannes@cmpxchg.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/userfaultfd.c')
-rw-r--r--mm/userfaultfd.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index bb57d0a3fca7..3dea268d2850 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -123,8 +123,8 @@ static int mcopy_atomic_pte(struct mm_struct *dst_mm,
goto out_release_uncharge_unlock;
inc_mm_counter(dst_mm, MM_ANONPAGES);
- page_add_new_anon_rmap(page, dst_vma, dst_addr, false);
mem_cgroup_commit_charge(page, memcg, false);
+ page_add_new_anon_rmap(page, dst_vma, dst_addr, false);
lru_cache_add_active_or_unevictable(page, dst_vma);
set_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);