diff options
| author | Wei Xu <weixugc@google.com> | 2024-10-17 18:15:28 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-11-06 20:11:15 -0800 |
| commit | f1001f3d3b6868998cab73d10fda1a5c99ddf963 (patch) | |
| tree | 3f7f32f84fcc5f8da92a540aa375f1a4c807be3c /include | |
| parent | d3ea85c6c5f70acff970f3339afb2da8f9a805a6 (diff) | |
mm/mglru: reset page lru tier bits when activating
When a folio is activated, lru_gen_add_folio() moves the folio to the
youngest generation. But unlike folio_update_gen()/folio_inc_gen(),
lru_gen_add_folio() doesn't reset the folio lru tier bits (LRU_REFS_MASK |
LRU_REFS_FLAGS). This inconsistency can affect how pages are aged via
folio_mark_accessed() (e.g. fd accesses), though no user visible impact
related to this has been detected yet.
Note that lru_gen_add_folio() cannot clear PG_workingset if the activation
is due to workingset refault, otherwise PSI accounting will be skipped.
So fix lru_gen_add_folio() to clear the lru tier bits other than
PG_workingset when activating a folio, and also clear all the lru tier
bits when a folio is activated via folio_activate() in
lru_gen_look_around().
Link: https://lkml.kernel.org/r/20241017181528.3358821-1-weixugc@google.com
Fixes: 018ee47f1489 ("mm: multi-gen LRU: exploit locality in rmap")
Signed-off-by: Wei Xu <weixugc@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Jan Alexander Steffens <heftig@archlinux.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/mm_inline.h | 15 | ||||
| -rw-r--r-- | include/linux/mmzone.h | 2 |
2 files changed, 16 insertions, 1 deletions
diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h index 6f801c7b36e2..355cf46a01a6 100644 --- a/include/linux/mm_inline.h +++ b/include/linux/mm_inline.h @@ -155,6 +155,11 @@ static inline int folio_lru_refs(struct folio *folio) return ((flags & LRU_REFS_MASK) >> LRU_REFS_PGOFF) + workingset; } +static inline void folio_clear_lru_refs(struct folio *folio) +{ + set_mask_bits(&folio->flags, LRU_REFS_MASK | LRU_REFS_FLAGS, 0); +} + static inline int folio_lru_gen(struct folio *folio) { unsigned long flags = READ_ONCE(folio->flags); @@ -222,6 +227,7 @@ static inline bool lru_gen_add_folio(struct lruvec *lruvec, struct folio *folio, { unsigned long seq; unsigned long flags; + unsigned long mask; int gen = folio_lru_gen(folio); int type = folio_is_file_lru(folio); int zone = folio_zonenum(folio); @@ -257,7 +263,14 @@ static inline bool lru_gen_add_folio(struct lruvec *lruvec, struct folio *folio, gen = lru_gen_from_seq(seq); flags = (gen + 1UL) << LRU_GEN_PGOFF; /* see the comment on MIN_NR_GENS about PG_active */ - set_mask_bits(&folio->flags, LRU_GEN_MASK | BIT(PG_active), flags); + mask = LRU_GEN_MASK; + /* + * Don't clear PG_workingset here because it can affect PSI accounting + * if the activation is due to workingset refault. + */ + if (folio_test_active(folio)) + mask |= LRU_REFS_MASK | BIT(PG_referenced) | BIT(PG_active); + set_mask_bits(&folio->flags, mask, flags); lru_gen_update_size(lruvec, folio, -1, gen); /* for folio_rotate_reclaimable() */ diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 5b1c984daf45..2e8c4307c728 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -403,6 +403,8 @@ enum { NR_LRU_GEN_CAPS }; +#define LRU_REFS_FLAGS (BIT(PG_referenced) | BIT(PG_workingset)) + #define MIN_LRU_BATCH BITS_PER_LONG #define MAX_LRU_BATCH (MIN_LRU_BATCH * 64) |