[PATCH 32/37] bcache: only clear BTREE_NODE_dirty bit when it is set
From: Coly Li <hidden>
Date: 2019-06-28 12:02:20
Subsystem:
bcache (block layer cache), the rest · Maintainers:
Coly Li, Kent Overstreet, Linus Torvalds
In bch_btree_cache_free() and btree_node_free(), BTREE_NODE_dirty is always set no matter btree node is dirty or not. The code looks like this, if (btree_node_dirty(b)) btree_complete_write(b, btree_current_write(b)); clear_bit(BTREE_NODE_dirty, &b->flags); Indeed if btree_node_dirty(b) returns false, it means BTREE_NODE_dirty bit is cleared, then it is unnecessary to clear the bit again. This patch only clears BTREE_NODE_dirty when btree_node_dirty(b) is true (the bit is set), to save a few CPU cycles. Signed-off-by: Coly Li <redacted> --- drivers/md/bcache/btree.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index cf38a1b031fa..88e5aa3fbb07 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c@@ -782,10 +782,10 @@ void bch_btree_cache_free(struct cache_set *c) while (!list_empty(&c->btree_cache)) { b = list_first_entry(&c->btree_cache, struct btree, list); - if (btree_node_dirty(b)) + if (btree_node_dirty(b)) { btree_complete_write(b, btree_current_write(b)); - clear_bit(BTREE_NODE_dirty, &b->flags); - + clear_bit(BTREE_NODE_dirty, &b->flags); + } mca_data_free(b); }
@@ -1073,9 +1073,10 @@ static void btree_node_free(struct btree *b) mutex_lock(&b->write_lock); - if (btree_node_dirty(b)) + if (btree_node_dirty(b)) { btree_complete_write(b, btree_current_write(b)); - clear_bit(BTREE_NODE_dirty, &b->flags); + clear_bit(BTREE_NODE_dirty, &b->flags); + } mutex_unlock(&b->write_lock);
--
2.16.4