diff mbox series

[2/3] dm writecache: add unlikely for getting two block with same LBA

Message ID 20190825072433.2628-3-yehs2007@zoho.com (mailing list archive)
State Accepted, archived
Delegated to: Mike Snitzer
Headers show
Series optimize writecache_writeback for performance | expand

Commit Message

Huaisheng Ye Aug. 25, 2019, 7:24 a.m. UTC 
From: Huaisheng Ye <yehs1@lenovo.com>

In function writecache_writeback, entries g and f has same original
sector only happens at entry f has been committed, but entry g has
NOT yet.

The probability of this happening is very low in the following
256 blocks at most of entry e.

Signed-off-by: Huaisheng Ye <yehs1@lenovo.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
---
 drivers/md/dm-writecache.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 5c7009d..3643084 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -1628,8 +1628,8 @@  static void writecache_writeback(struct work_struct *work)
 			if (unlikely(!next_node))
 				break;
 			g = container_of(next_node, struct wc_entry, rb_node);
-			if (read_original_sector(wc, g) ==
-			    read_original_sector(wc, f)) {
+			if (unlikely(read_original_sector(wc, g) ==
+			    read_original_sector(wc, f))) {
 				f = g;
 				continue;
 			}