From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: [PATCH AUTOSEL 4.19 157/167] bcache: only clear BTREE_NODE_dirty bit when it is set Date: Tue, 3 Sep 2019 12:25:09 -0400 Message-ID: <20190903162519.7136-157-sashal@kernel.org> References: <20190903162519.7136-1-sashal@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190903162519.7136-1-sashal@kernel.org> Sender: stable-owner@vger.kernel.org To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Coly Li , Jens Axboe , Sasha Levin , linux-bcache@vger.kernel.org List-Id: linux-bcache@vger.kernel.org From: Coly Li [ Upstream commit e5ec5f4765ada9c75fb3eee93a6e72f0e50599d5 ] 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 Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- 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 3f4211b5cd334..8c80833e73a9a 100644 --- a/drivers/md/bcache/btree.c +++ b/drivers/md/bcache/btree.c @@ -772,10 +772,10 @@ 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); } @@ -1063,9 +1063,10 @@ 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); -- 2.20.1