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| author | Hugh Dickins <hughd@google.com> | 2025-07-13 12:57:18 -0700 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-07-24 19:12:28 -0700 |
| commit | 3865301dc58aec2ab77651bdbf1e55352f50a608 (patch) | |
| tree | 51e3c77ac8885924fc885bcc3c102d8ef3a7c872 /mm/swap.c | |
| parent | 526660b950a425b9d32798703b839e3c08cdf81b (diff) | |
| download | linux-3865301dc58aec2ab77651bdbf1e55352f50a608.tar.gz linux-3865301dc58aec2ab77651bdbf1e55352f50a608.tar.bz2 linux-3865301dc58aec2ab77651bdbf1e55352f50a608.zip | |
mm: optimize lru_note_cost() by adding lru_note_cost_unlock_irq()
Dropping a lock, just to demand it again for an afterthought, cannot be
good if contended: convert lru_note_cost() to lru_note_cost_unlock_irq().
[hughd@google.com: delete unneeded comment]
Link: https://lkml.kernel.org/r/dbf9352a-1ed9-a021-c0c7-9309ac73e174@google.com
Link: https://lkml.kernel.org/r/21100102-51b6-79d5-03db-1bb7f97fa94c@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Tested-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: David Hildenbrand <david@redhat.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/swap.c')
| -rw-r--r-- | mm/swap.c | 33 |
1 files changed, 19 insertions, 14 deletions
diff --git a/mm/swap.c b/mm/swap.c index 4fc322f7111a..3632dd061beb 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -237,8 +237,9 @@ void folio_rotate_reclaimable(struct folio *folio) folio_batch_add_and_move(folio, lru_move_tail, true); } -void lru_note_cost(struct lruvec *lruvec, bool file, - unsigned int nr_io, unsigned int nr_rotated) +void lru_note_cost_unlock_irq(struct lruvec *lruvec, bool file, + unsigned int nr_io, unsigned int nr_rotated) + __releases(lruvec->lru_lock) { unsigned long cost; @@ -250,18 +251,14 @@ void lru_note_cost(struct lruvec *lruvec, bool file, * different between them, adjust scan balance for CPU work. */ cost = nr_io * SWAP_CLUSTER_MAX + nr_rotated; + if (!cost) { + spin_unlock_irq(&lruvec->lru_lock); + return; + } - do { + for (;;) { unsigned long lrusize; - /* - * Hold lruvec->lru_lock is safe here, since - * 1) The pinned lruvec in reclaim, or - * 2) From a pre-LRU page during refault (which also holds the - * rcu lock, so would be safe even if the page was on the LRU - * and could move simultaneously to a new lruvec). - */ - spin_lock_irq(&lruvec->lru_lock); /* Record cost event */ if (file) lruvec->file_cost += cost; @@ -285,14 +282,22 @@ void lru_note_cost(struct lruvec *lruvec, bool file, lruvec->file_cost /= 2; lruvec->anon_cost /= 2; } + spin_unlock_irq(&lruvec->lru_lock); - } while ((lruvec = parent_lruvec(lruvec))); + lruvec = parent_lruvec(lruvec); + if (!lruvec) + break; + spin_lock_irq(&lruvec->lru_lock); + } } void lru_note_cost_refault(struct folio *folio) { - lru_note_cost(folio_lruvec(folio), folio_is_file_lru(folio), - folio_nr_pages(folio), 0); + struct lruvec *lruvec; + + lruvec = folio_lruvec_lock_irq(folio); + lru_note_cost_unlock_irq(lruvec, folio_is_file_lru(folio), + folio_nr_pages(folio), 0); } static void lru_activate(struct lruvec *lruvec, struct folio *folio) |