From 7254555c440ff6b136aa97fb3c33fd5e0bb4fb9f Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Sat, 10 Aug 2024 14:40:09 -0400 Subject: [PATCH] bcachefs: Add hysteresis to waiting on btree key cache flush This helps ensure key cache reclaim isn't contending with threads waiting for the key cache to be helped, and fixes a severe performance bug. Signed-off-by: Kent Overstreet --- fs/bcachefs/btree_key_cache.h | 9 +++++++++ fs/bcachefs/btree_trans_commit.c | 2 +- 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/fs/bcachefs/btree_key_cache.h b/fs/bcachefs/btree_key_cache.h index e6b2cd0dd2c1..113309f62918 100644 --- a/fs/bcachefs/btree_key_cache.h +++ b/fs/bcachefs/btree_key_cache.h @@ -20,6 +20,15 @@ static inline bool bch2_btree_key_cache_must_wait(struct bch_fs *c) return nr_dirty > max_dirty; } +static inline bool bch2_btree_key_cache_wait_done(struct bch_fs *c) +{ + size_t nr_dirty = atomic_long_read(&c->btree_key_cache.nr_dirty); + size_t nr_keys = atomic_long_read(&c->btree_key_cache.nr_keys); + size_t max_dirty = 2048 + (nr_keys * 5) / 8; + + return nr_dirty <= max_dirty; +} + int bch2_btree_key_cache_journal_flush(struct journal *, struct journal_entry_pin *, u64); diff --git a/fs/bcachefs/btree_trans_commit.c b/fs/bcachefs/btree_trans_commit.c index cca336fe46e9..f567bfb82850 100644 --- a/fs/bcachefs/btree_trans_commit.c +++ b/fs/bcachefs/btree_trans_commit.c @@ -927,7 +927,7 @@ static inline int do_bch2_trans_commit(struct btree_trans *trans, unsigned flags static int journal_reclaim_wait_done(struct bch_fs *c) { int ret = bch2_journal_error(&c->journal) ?: - !bch2_btree_key_cache_must_wait(c); + bch2_btree_key_cache_wait_done(c); if (!ret) journal_reclaim_kick(&c->journal); -- 2.49.0