[PATCH RFC 03/32] mm/mglru: wrap all access to folio flags with accessor
From: Kairui Song via B4 Relay
Date: Fri May 01 2026 - 17:05:15 EST
From: Kairui Song <kasong@xxxxxxxxxxx>
Instead of reading folio->flags.f, use the folio_flags helper which is
design exactly for this which more checks.
Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
---
include/linux/mm_inline.h | 12 ++++++------
mm/swap.c | 8 ++++----
mm/vmscan.c | 16 ++++++++--------
3 files changed, 18 insertions(+), 18 deletions(-)
diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index 045f9ee3880a..9c8ad8af37de 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -143,7 +143,7 @@ static inline int lru_tier_from_refs(int refs, bool workingset)
static inline int folio_lru_refs(const struct folio *folio)
{
- unsigned long flags = READ_ONCE(folio->flags.f);
+ unsigned long flags = READ_ONCE(*const_folio_flags(folio, 0));
if (!(flags & BIT(PG_referenced)))
return 0;
@@ -156,7 +156,7 @@ static inline int folio_lru_refs(const struct folio *folio)
static inline int folio_lru_gen(const struct folio *folio)
{
- unsigned long flags = READ_ONCE(folio->flags.f);
+ unsigned long flags = READ_ONCE(*const_folio_flags(folio, 0));
return ((flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1;
}
@@ -269,7 +269,7 @@ 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.f, LRU_GEN_MASK | BIT(PG_active), flags);
+ set_mask_bits(folio_flags(folio, 0), LRU_GEN_MASK | BIT(PG_active), flags);
lru_gen_update_size(lruvec, folio, -1, gen);
/* for folio_rotate_reclaimable() */
@@ -294,7 +294,7 @@ static inline bool lru_gen_del_folio(struct lruvec *lruvec, struct folio *folio,
/* for folio_migrate_flags() */
flags = !reclaiming && lru_gen_is_active(lruvec, gen) ? BIT(PG_active) : 0;
- flags = set_mask_bits(&folio->flags.f, LRU_GEN_MASK, flags);
+ flags = set_mask_bits(folio_flags(folio, 0), LRU_GEN_MASK, flags);
gen = ((flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1;
lru_gen_update_size(lruvec, folio, gen, -1);
@@ -305,9 +305,9 @@ static inline bool lru_gen_del_folio(struct lruvec *lruvec, struct folio *folio,
static inline void folio_migrate_refs(struct folio *new, const struct folio *old)
{
- unsigned long refs = READ_ONCE(old->flags.f) & LRU_REFS_MASK;
+ unsigned long refs = READ_ONCE(*const_folio_flags(old, 0)) & LRU_REFS_MASK;
- set_mask_bits(&new->flags.f, LRU_REFS_MASK, refs);
+ set_mask_bits(folio_flags(new, 0), LRU_REFS_MASK, refs);
}
#else /* !CONFIG_LRU_GEN */
diff --git a/mm/swap.c b/mm/swap.c
index e3cf703ccb89..e7037ea2c10f 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -392,14 +392,14 @@ static void __lru_cache_activate_folio(struct folio *folio)
static void lru_gen_inc_refs(struct folio *folio)
{
- unsigned long new_flags, old_flags = READ_ONCE(folio->flags.f);
+ unsigned long new_flags, old_flags = READ_ONCE(*folio_flags(folio, 0));
if (folio_test_unevictable(folio))
return;
/* see the comment on LRU_REFS_FLAGS */
if (!folio_test_referenced(folio)) {
- set_mask_bits(&folio->flags.f, LRU_REFS_MASK, BIT(PG_referenced));
+ set_mask_bits(folio_flags(folio, 0), LRU_REFS_MASK, BIT(PG_referenced));
return;
}
@@ -411,7 +411,7 @@ static void lru_gen_inc_refs(struct folio *folio)
}
new_flags = old_flags + BIT(LRU_REFS_PGOFF);
- } while (!try_cmpxchg(&folio->flags.f, &old_flags, new_flags));
+ } while (!try_cmpxchg(folio_flags(folio, 0), &old_flags, new_flags));
}
static bool lru_gen_clear_refs(struct folio *folio)
@@ -423,7 +423,7 @@ static bool lru_gen_clear_refs(struct folio *folio)
if (gen < 0)
return true;
- set_mask_bits(&folio->flags.f, LRU_REFS_FLAGS | BIT(PG_workingset), 0);
+ set_mask_bits(folio_flags(folio, 0), LRU_REFS_FLAGS | BIT(PG_workingset), 0);
rcu_read_lock();
seq = READ_ONCE(folio_lruvec(folio)->lrugen.min_seq[type]);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 53b43e3f5795..7a1f08147dee 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -844,11 +844,11 @@ static bool lru_gen_set_refs(struct folio *folio)
{
/* see the comment on LRU_REFS_FLAGS */
if (!folio_test_referenced(folio) && !folio_test_workingset(folio)) {
- set_mask_bits(&folio->flags.f, LRU_REFS_MASK, BIT(PG_referenced));
+ set_mask_bits(folio_flags(folio, 0), LRU_REFS_MASK, BIT(PG_referenced));
return false;
}
- set_mask_bits(&folio->flags.f, LRU_REFS_FLAGS, BIT(PG_workingset));
+ set_mask_bits(folio_flags(folio, 0), LRU_REFS_FLAGS, BIT(PG_workingset));
return true;
}
#else
@@ -3193,13 +3193,13 @@ static bool positive_ctrl_err(struct ctrl_pos *sp, struct ctrl_pos *pv)
/* promote pages accessed through page tables */
static int folio_update_gen(struct folio *folio, int gen)
{
- unsigned long new_flags, old_flags = READ_ONCE(folio->flags.f);
+ unsigned long new_flags, old_flags = READ_ONCE(*folio_flags(folio, 0));
VM_WARN_ON_ONCE(gen >= MAX_NR_GENS);
/* see the comment on LRU_REFS_FLAGS */
if (!folio_test_referenced(folio) && !folio_test_workingset(folio)) {
- set_mask_bits(&folio->flags.f, LRU_REFS_MASK, BIT(PG_referenced));
+ set_mask_bits(folio_flags(folio, 0), LRU_REFS_MASK, BIT(PG_referenced));
return -1;
}
@@ -3210,7 +3210,7 @@ static int folio_update_gen(struct folio *folio, int gen)
new_flags = old_flags & ~(LRU_GEN_MASK | LRU_REFS_FLAGS);
new_flags |= ((gen + 1UL) << LRU_GEN_PGOFF) | BIT(PG_workingset);
- } while (!try_cmpxchg(&folio->flags.f, &old_flags, new_flags));
+ } while (!try_cmpxchg(folio_flags(folio, 0), &old_flags, new_flags));
return ((old_flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1;
}
@@ -3221,7 +3221,7 @@ static int folio_inc_gen(struct lruvec *lruvec, struct folio *folio)
int type = folio_is_file_lru(folio);
struct lru_gen_folio *lrugen = &lruvec->lrugen;
int new_gen, old_gen = lru_gen_from_seq(lrugen->min_seq[type]);
- unsigned long new_flags, old_flags = READ_ONCE(folio->flags.f);
+ unsigned long new_flags, old_flags = READ_ONCE(*folio_flags(folio, 0));
VM_WARN_ON_ONCE_FOLIO(!(old_flags & LRU_GEN_MASK), folio);
@@ -4639,7 +4639,7 @@ static bool isolate_folio(struct lruvec *lruvec, struct folio *folio, struct sca
/* see the comment on LRU_REFS_FLAGS */
if (!folio_test_referenced(folio))
- set_mask_bits(&folio->flags.f, LRU_REFS_MASK, 0);
+ set_mask_bits(folio_flags(folio, 0), LRU_REFS_MASK, 0);
success = lru_gen_del_folio(lruvec, folio, true);
VM_WARN_ON_ONCE_FOLIO(!success, folio);
@@ -4855,7 +4855,7 @@ static int evict_folios(unsigned long nr_to_scan, struct lruvec *lruvec,
/* don't add rejected folios to the oldest generation */
if (lru_gen_folio_seq(lruvec, folio, false) == min_seq[type])
- set_mask_bits(&folio->flags.f, LRU_REFS_FLAGS, BIT(PG_active));
+ set_mask_bits(folio_flags(folio, 0), LRU_REFS_FLAGS, BIT(PG_active));
}
move_folios_to_lru(&list);
--
2.54.0