2013-09-23 08:23:03

by Weijie Yang

[permalink] [raw]
Subject: [PATCH v3 3/3] mm/zswap: avoid unnecessary page scanning

add SetPageReclaim before __swap_writepage so that page can be moved to the
tail of the inactive list, which can avoid unnecessary page scanning as this
page was reclaimed by swap subsystem before.

Signed-off-by: Weijie Yang <[email protected]>
Reviewed-by: Bob Liu <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: [email protected]
Acked-by: Seth Jennings <[email protected]>
---
mm/zswap.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/mm/zswap.c b/mm/zswap.c
index 1be7b90..cc40e6a 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -556,6 +556,9 @@ static int zswap_writeback_entry(struct zbud_pool *pool, unsigned long handle)
SetPageUptodate(page);
}

+ /* move it to the tail of the inactive list after end_writeback */
+ SetPageReclaim(page);
+
/* start writeback */
__swap_writepage(page, &wbc, end_swap_bio_write);
page_cache_release(page);
--
1.7.10.4


2013-09-24 01:03:31

by Minchan Kim

[permalink] [raw]
Subject: Re: [PATCH v3 3/3] mm/zswap: avoid unnecessary page scanning

On Mon, Sep 23, 2013 at 04:21:49PM +0800, Weijie Yang wrote:
> add SetPageReclaim before __swap_writepage so that page can be moved to the
> tail of the inactive list, which can avoid unnecessary page scanning as this
> page was reclaimed by swap subsystem before.
>
> Signed-off-by: Weijie Yang <[email protected]>
> Reviewed-by: Bob Liu <[email protected]>
> Cc: Minchan Kim <[email protected]>
> Cc: [email protected]
> Acked-by: Seth Jennings <[email protected]>
Reviewed-by: Minchan Kim <[email protected]>

--
Kind regards,
Minchan Kim

2013-10-10 19:55:09

by Andrew Morton

[permalink] [raw]
Subject: Re: [PATCH v3 3/3] mm/zswap: avoid unnecessary page scanning

On Mon, 23 Sep 2013 16:21:49 +0800 Weijie Yang <[email protected]> wrote:

> add SetPageReclaim before __swap_writepage so that page can be moved to the
> tail of the inactive list, which can avoid unnecessary page scanning as this
> page was reclaimed by swap subsystem before.
>
> Signed-off-by: Weijie Yang <[email protected]>
> Reviewed-by: Bob Liu <[email protected]>
> Cc: Minchan Kim <[email protected]>
> Cc: [email protected]
> Acked-by: Seth Jennings <[email protected]>

As a minor(?) performance tweak, I don't believe this is suitable for
-stable backporting, so I took that out. If you believe this was a
mistake, please explain why.

2013-10-11 07:14:30

by Minchan Kim

[permalink] [raw]
Subject: Re: [PATCH v3 3/3] mm/zswap: avoid unnecessary page scanning

On Thu, Oct 10, 2013 at 12:55:06PM -0700, Andrew Morton wrote:
> On Mon, 23 Sep 2013 16:21:49 +0800 Weijie Yang <[email protected]> wrote:
>
> > add SetPageReclaim before __swap_writepage so that page can be moved to the
> > tail of the inactive list, which can avoid unnecessary page scanning as this
> > page was reclaimed by swap subsystem before.
> >
> > Signed-off-by: Weijie Yang <[email protected]>
> > Reviewed-by: Bob Liu <[email protected]>
> > Cc: Minchan Kim <[email protected]>
> > Cc: [email protected]
> > Acked-by: Seth Jennings <[email protected]>
>
> As a minor(?) performance tweak, I don't believe this is suitable for
> -stable backporting, so I took that out. If you believe this was a
> mistake, please explain why.
>

Yes. It's never stable stuff.

--
Kind regards,
Minchan Kim