From: Bob Liu <bob.liu@oracle.com>
To: Dan Streetman <ddstreet@ieee.org>
Cc: Seth Jennings <sjennings@variantweb.net>,
linux-mm@kvack.org, linux-kernel <linux-kernel@vger.kernel.org>,
Minchan Kim <minchan@kernel.org>,
Weijie Yang <weijie.yang@samsung.com>
Subject: Re: [PATCH v2] mm/zswap: change zswap to writethrough cache
Date: Thu, 21 Nov 2013 08:42:53 +0800 [thread overview]
Message-ID: <528D570D.3020006@oracle.com> (raw)
In-Reply-To: <1384976973-32722-1-git-send-email-ddstreet@ieee.org>
Hi Dan,
On 11/21/2013 03:49 AM, Dan Streetman wrote:
> Currently, zswap is writeback cache; stored pages are not sent
> to swap disk, and when zswap wants to evict old pages it must
> first write them back to swap cache/disk manually. This avoids
> swap out disk I/O up front, but only moves that disk I/O to
> the writeback case (for pages that are evicted), and adds the
> overhead of having to uncompress the evicted pages, and adds the
> need for an additional free page (to store the uncompressed page)
> at a time of likely high memory pressure. Additionally, being
> writeback adds complexity to zswap by having to perform the
> writeback on page eviction.
>
Good work!
> This changes zswap to writethrough cache by enabling
> frontswap_writethrough() before registering, so that any
> successful page store will also be written to swap disk. All the
> writeback code is removed since it is no longer needed, and the
> only operation during a page eviction is now to remove the entry
> from the tree and free it.
>
Could you do some testing using eg. SPECjbb? And compare the result with
original zswap.
Thanks,
-Bob
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next prev parent reply other threads:[~2013-11-21 0:43 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-20 19:49 [PATCH v2] mm/zswap: change zswap to writethrough cache Dan Streetman
2013-11-21 0:42 ` Bob Liu [this message]
2013-11-21 3:50 ` Weijie Yang
2013-11-21 23:00 ` Dan Streetman
2013-11-21 22:38 ` Dan Streetman
2013-11-22 17:29 ` Seth Jennings
2013-11-22 18:07 ` Dan Streetman
2013-11-25 18:00 ` Seth Jennings
2013-11-27 1:28 ` Dan Streetman
2013-12-11 9:02 ` Bob Liu
2013-12-13 2:58 ` Dan Streetman
2013-11-22 22:10 ` [PATCH v3] " Dan Streetman
2013-11-23 2:37 ` Weijie Yang
2013-11-23 20:35 ` Dan Streetman
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