The patch titled
Subject: mm/mglru: reset page lru tier bits when activating
has been added to the -mm mm-unstable branch. Its filename is
mm-mglru-reset-page-lru-tier-bits-when-activating.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mglru-reset-page-lru-tier-bits-when-activating.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Wei Xu <weixugc@xxxxxxxxxx>
Subject: mm/mglru: reset page lru tier bits when activating
Date: Mon, 14 Oct 2024 22:12:31 +0000
folio_activate() calls lru_gen_add_folio() to move 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). Fix this inconsistency in lru_gen_add_folio() when
activating a folio.
Link: https://lkml.kernel.org/r/20241014221231.832959-1-weixugc@xxxxxxxxxx
Fixes: 018ee47f1489 ("mm: multi-gen LRU: exploit locality in rmap")
Signed-off-by: Wei Xu <weixugc@xxxxxxxxxx>
Cc: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Cc: Brian Geffon <bgeffon@xxxxxxxxxx>
Cc: Jan Alexander Steffens <heftig@xxxxxxxxxxxxx>
Cc: Suleiman Souhlal <suleiman@xxxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm_inline.h | 5 ++++-
include/linux/mmzone.h | 2 ++
mm/vmscan.c | 2 --
3 files changed, 6 insertions(+), 3 deletions(-)
--- a/include/linux/mm_inline.h~mm-mglru-reset-page-lru-tier-bits-when-activating
+++ a/include/linux/mm_inline.h
@@ -222,6 +222,7 @@ static inline bool lru_gen_add_folio(str
{
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 +258,9 @@ static inline bool lru_gen_add_folio(str
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 | BIT(PG_active);
+ mask |= folio_test_active(folio) ? (LRU_REFS_MASK | LRU_REFS_FLAGS) : 0;
+ set_mask_bits(&folio->flags, mask, flags);
lru_gen_update_size(lruvec, folio, -1, gen);
/* for folio_rotate_reclaimable() */
--- a/include/linux/mmzone.h~mm-mglru-reset-page-lru-tier-bits-when-activating
+++ a/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)
--- a/mm/vmscan.c~mm-mglru-reset-page-lru-tier-bits-when-activating
+++ a/mm/vmscan.c
@@ -2607,8 +2607,6 @@ static bool should_clear_pmd_young(void)
* shorthand helpers
******************************************************************************/
-#define LRU_REFS_FLAGS (BIT(PG_referenced) | BIT(PG_workingset))
-
#define DEFINE_MAX_SEQ(lruvec) \
unsigned long max_seq = READ_ONCE((lruvec)->lrugen.max_seq)
_
Patches currently in -mm which might be from weixugc@xxxxxxxxxx are
mm-mglru-only-clear-kswapd_failures-if-reclaimable.patch
mm-mglru-reset-page-lru-tier-bits-when-activating.patch
