From: Pekka Enberg <penberg@iki.fi>
To: Bob Liu <lliubbo@gmail.com>
Cc: linux-mm@kvack.org, gregkh@linuxfoundation.org,
ngupta@vflare.org, akpm@linux-foundation.org,
konrad.wilk@oracle.com, sjenning@linux.vnet.ibm.com,
riel@redhat.com, mgorman@suse.de, kyungmin.park@samsung.com,
p.sarna@partner.samsung.com, barry.song@csr.com,
penberg@kernel.org, Bob Liu <bob.liu@oracle.com>
Subject: Re: [PATCH v2 4/4] mm: add WasActive page flag
Date: Tue, 13 Aug 2013 09:01:05 +0300 [thread overview]
Message-ID: <5209CBA1.2080009@iki.fi> (raw)
In-Reply-To: <1375788977-12105-5-git-send-email-bob.liu@oracle.com>
On 8/6/13 2:36 PM, Bob Liu wrote:
> Zcache could be ineffective if the compressed memory pool is full with
> compressed inactive file pages and most of them will be never used again.
>
> So we pick up pages from active file list only, those pages would probably be
> accessed again. Compress them in memory can reduce the latency significantly
> compared with rereading from disk.
>
> When a file page is shrinked from active file list to inactive file list,
> PageActive flag is also cleared.
> So adding an extra WasActive page flag for zcache to know whether the file page
> was shrinked from the active list.
>
> Signed-off-by: Bob Liu <bob.liu@oracle.com>
Using a page flag for this seems like an ugly hack to me.
Can we rearrange the code so that vmscan notifies zcache
*before* the active page flag is cleared...?
Pekka
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next prev parent reply other threads:[~2013-08-13 6:01 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-06 11:36 [PATCH v2 0/4] zcache: a compressed file page cache Bob Liu
2013-08-06 11:36 ` [PATCH v2 1/4] mm: zcache: add core files Bob Liu
2013-08-06 11:36 ` [PATCH v2 2/4] zcache: staging: %s/ZCACHE/ZCACHE_OLD Bob Liu
2013-08-06 11:36 ` [PATCH v2 3/4] mm: zcache: add evict zpages supporting Bob Liu
2013-08-06 11:36 ` [PATCH v2 4/4] mm: add WasActive page flag Bob Liu
2013-08-13 6:01 ` Pekka Enberg [this message]
2013-08-13 13:50 ` Bob Liu
2013-08-06 13:58 ` [PATCH v2 0/4] zcache: a compressed file page cache Greg KH
2013-08-06 14:24 ` Bob Liu
2013-08-12 12:19 ` Konrad Rzeszutek Wilk
2013-08-12 12:25 ` Kyungmin Park
2013-08-12 12:30 ` Wanpeng Li
2013-08-12 12:30 ` Wanpeng Li
2013-08-12 13:23 ` Konrad Rzeszutek Wilk
2013-08-12 22:10 ` Greg KH
2013-08-09 8:03 ` Bob Liu
2013-08-09 8:03 ` Bob Liu
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