diff options
| author | Yosry Ahmed <yosryahmed@google.com> | 2024-05-06 19:29:24 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-05-11 15:41:35 -0700 |
| commit | 4f687281012e2da1a34cfe08ab10ea1361c600d2 (patch) | |
| tree | 7fed8d5a44a9c8f5d3879ee6d3bce3ac803ed936 | |
| parent | e6b331ab0a716c1d9273383ae59c5b2eea5ac00d (diff) | |
mm: do not update memcg stats for NR_{FILE/SHMEM}_PMDMAPPED
Previously, all NR_VM_EVENT_ITEMS stats were maintained per-memcg,
although some of those fields are not exposed anywhere. Commit
14e0f6c957e39 ("memcg: reduce memory for the lruvec and memcg stats")
changed this such that we only maintain the stats we actually expose
per-memcg via a translation table.
Additionally, commit 514462bbe927b ("memcg: warn for unexpected events
and stats") added a warning if a per-memcg stat update is attempted for
a stat that is not in the translation table. The warning started firing
for the NR_{FILE/SHMEM}_PMDMAPPED stat updates in the rmap code. These
stats are not maintained per-memcg, and hence are not in the translation
table.
Do not use __lruvec_stat_mod_folio() when updating NR_FILE_PMDMAPPED and
NR_SHMEM_PMDMAPPED. Use __mod_node_page_state() instead, which updates
the global per-node stats only.
Link: https://lkml.kernel.org/r/20240506192924.271999-1-yosryahmed@google.com
Fixes: 514462bbe927 ("memcg: warn for unexpected events and stats")
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Reported-by: syzbot+9319a4268a640e26b72b@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/0000000000001b9d500617c8b23c@google.com
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/rmap.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/mm/rmap.c b/mm/rmap.c index fd021efe02a1..e8fc5ecb59b2 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1435,13 +1435,14 @@ static __always_inline void __folio_add_file_rmap(struct folio *folio, struct page *page, int nr_pages, struct vm_area_struct *vma, enum rmap_level level) { + pg_data_t *pgdat = folio_pgdat(folio); int nr, nr_pmdmapped = 0; VM_WARN_ON_FOLIO(folio_test_anon(folio), folio); nr = __folio_add_rmap(folio, page, nr_pages, level, &nr_pmdmapped); if (nr_pmdmapped) - __lruvec_stat_mod_folio(folio, folio_test_swapbacked(folio) ? + __mod_node_page_state(pgdat, folio_test_swapbacked(folio) ? NR_SHMEM_PMDMAPPED : NR_FILE_PMDMAPPED, nr_pmdmapped); if (nr) __lruvec_stat_mod_folio(folio, NR_FILE_MAPPED, nr); @@ -1493,6 +1494,7 @@ static __always_inline void __folio_remove_rmap(struct folio *folio, enum rmap_level level) { atomic_t *mapped = &folio->_nr_pages_mapped; + pg_data_t *pgdat = folio_pgdat(folio); int last, nr = 0, nr_pmdmapped = 0; bool partially_mapped = false; enum node_stat_item idx; @@ -1540,13 +1542,14 @@ static __always_inline void __folio_remove_rmap(struct folio *folio, } if (nr_pmdmapped) { + /* NR_{FILE/SHMEM}_PMDMAPPED are not maintained per-memcg */ if (folio_test_anon(folio)) - idx = NR_ANON_THPS; - else if (folio_test_swapbacked(folio)) - idx = NR_SHMEM_PMDMAPPED; + __lruvec_stat_mod_folio(folio, NR_ANON_THPS, -nr_pmdmapped); else - idx = NR_FILE_PMDMAPPED; - __lruvec_stat_mod_folio(folio, idx, -nr_pmdmapped); + __mod_node_page_state(pgdat, + folio_test_swapbacked(folio) ? + NR_SHMEM_PMDMAPPED : NR_FILE_PMDMAPPED, + -nr_pmdmapped); } if (nr) { idx = folio_test_anon(folio) ? NR_ANON_MAPPED : NR_FILE_MAPPED; |