UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

bcache: only clear BTREE_NODE_dirty bit when it is set 

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 <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Coly Li 2019-06-28 19:59:55 +08:00 committed by Jens Axboe
parent 249a5f6da5
commit e5ec5f4765
1 changed files with 6 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
drivers/md/bcache/btree.c
View File

@ -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);