[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-ID: <alpine.LRH.2.02.1904231150360.17390@file01.intranet.prod.int.rdu2.redhat.com>
Date: Tue, 23 Apr 2019 11:50:51 -0400 (EDT)
From: Mikulas Patocka <mpatocka@...hat.com>
To: Huaisheng Ye <huye@...hat.com>
cc: snitzer@...hat.com, agk@...hat.com, prarit@...hat.com,
chengnt@...ovo.com, dm-devel@...hat.com,
linux-kernel@...r.kernel.org, Huaisheng Ye <yehs1@...ovo.com>
Subject: Re: [PATCH] dm-writecache: add unlikely for returned value of
rb_next/prev
On Fri, 12 Apr 2019, Huaisheng Ye wrote:
> From: Huaisheng Ye <yehs1@...ovo.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@...ovo.com>
Acked-by: Mikulas Patocka <mpatocka@...hat.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
>
Powered by blists - more mailing lists