* [PATCH] dm-writecache: add unlikely for returned value of rb_next/prev
@ 2019-04-12 15:28 Huaisheng Ye
2019-04-23 15:50 ` Mikulas Patocka
0 siblings, 1 reply; 2+ messages in thread
From: Huaisheng Ye @ 2019-04-12 15:28 UTC (permalink / raw)
To: mpatocka, snitzer, agk
Cc: prarit, chengnt, dm-devel, linux-kernel, Huaisheng Ye
From: Huaisheng Ye <yehs1@lenovo.com>
In functions writecache_discard and writecache_find_entry, there is
high probablity that the pointer of structure rb_node doesn't equal
to NULL. Add unlikly for the pointer node.
Signed-off-by: Huaisheng Ye <yehs1@lenovo.com>
---
drivers/md/dm-writecache.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 5b4d1c1..cfbbfbc 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -571,7 +571,7 @@ static struct wc_entry *writecache_find_entry(struct dm_writecache *wc,
node = rb_prev(&e->rb_node);
else
node = rb_next(&e->rb_node);
- if (!node)
+ if (unlikely(!node))
return e;
e2 = container_of(node, struct wc_entry, rb_node);
if (read_original_sector(wc, e2) != block)
@@ -804,7 +804,7 @@ static void writecache_discard(struct dm_writecache *wc, sector_t start, sector_
writecache_free_entry(wc, e);
}
- if (!node)
+ if (unlikely(!node))
break;
e = container_of(node, struct wc_entry, rb_node);
--
1.8.3.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] dm-writecache: add unlikely for returned value of rb_next/prev
2019-04-12 15:28 [PATCH] dm-writecache: add unlikely for returned value of rb_next/prev Huaisheng Ye
@ 2019-04-23 15:50 ` Mikulas Patocka
0 siblings, 0 replies; 2+ messages in thread
From: Mikulas Patocka @ 2019-04-23 15:50 UTC (permalink / raw)
To: Huaisheng Ye
Cc: snitzer, agk, prarit, chengnt, dm-devel, linux-kernel, Huaisheng Ye
On Fri, 12 Apr 2019, Huaisheng Ye wrote:
> From: Huaisheng Ye <yehs1@lenovo.com>
>
> In functions writecache_discard and writecache_find_entry, there is
> high probablity that the pointer of structure rb_node doesn't equal
> to NULL. Add unlikly for the pointer node.
>
> 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 --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
> index 5b4d1c1..cfbbfbc 100644
> --- a/drivers/md/dm-writecache.c
> +++ b/drivers/md/dm-writecache.c
> @@ -571,7 +571,7 @@ static struct wc_entry *writecache_find_entry(struct dm_writecache *wc,
> node = rb_prev(&e->rb_node);
> else
> node = rb_next(&e->rb_node);
> - if (!node)
> + if (unlikely(!node))
> return e;
> e2 = container_of(node, struct wc_entry, rb_node);
> if (read_original_sector(wc, e2) != block)
> @@ -804,7 +804,7 @@ static void writecache_discard(struct dm_writecache *wc, sector_t start, sector_
> writecache_free_entry(wc, e);
> }
>
> - if (!node)
> + if (unlikely(!node))
> break;
>
> e = container_of(node, struct wc_entry, rb_node);
> --
> 1.8.3.1
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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