dm writecache: add unlikely for getting two block with same LBA

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>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Huaisheng Ye 2019-08-25 15:24:32 +08:00 committed by Mike Snitzer
parent 58912dbce6
commit 62421b3880

View File

@ -1628,8 +1628,8 @@ restart:
if (unlikely(!next_node)) if (unlikely(!next_node))
break; break;
g = container_of(next_node, struct wc_entry, rb_node); g = container_of(next_node, struct wc_entry, rb_node);
if (read_original_sector(wc, g) == if (unlikely(read_original_sector(wc, g) ==
read_original_sector(wc, f)) { read_original_sector(wc, f))) {
f = g; f = g;
continue; continue;
} }