From: Johannes Weiner <hannes@cmpxchg.org>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mel@csn.ul.ie>,
linux-mm@kvack.org
Subject: Re: [patch 5/5] vmscan: remove may_swap scan control
Date: Wed, 19 May 2010 23:44:59 +0200 [thread overview]
Message-ID: <20100519214459.GD2868@cmpxchg.org> (raw)
In-Reply-To: <20100513122935.2161.A69D9226@jp.fujitsu.com>
On Thu, May 13, 2010 at 12:36:12PM +0900, KOSAKI Motohiro wrote:
> > The may_swap scan control flag can be naturally merged into the
> > swappiness parameter: swap only if swappiness is non-zero.
>
> Sorry, NAK.
>
> AFAIK, swappiness==0 is very widely used in MySQL users community.
> They expect this parameter mean "very prefer to discard file cache
> rather than swap, but not completely disable swap".
>
> We shouldn't ignore the real world use case. even if it is a bit strange.
Bummer. It's really ugly to have 'zero' mean 'almost nothing'.
But since swappiness is passed around as an int, I think we can
instead use -1 for 'no swap'. Let me look into it and send a
follow-up patch for this as well.
Thanks!
Hannes
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next prev parent reply other threads:[~2010-05-19 21:45 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-30 23:05 [patch 0/5] vmscan: cut down on struct scan_control Johannes Weiner
2010-04-30 23:05 ` [patch 1/5] vmscan: fix unmapping behaviour for RECLAIM_SWAP Johannes Weiner
2010-05-13 3:02 ` KOSAKI Motohiro
2010-05-19 21:32 ` Johannes Weiner
2010-04-30 23:05 ` [patch 2/5] vmscan: remove may_unmap scan control Johannes Weiner
2010-04-30 23:05 ` [patch 3/5] vmscan: remove all_unreclaimable " Johannes Weiner
2010-05-13 3:25 ` KOSAKI Motohiro
2010-05-19 21:34 ` Johannes Weiner
2010-05-31 18:32 ` Greg Thelen
2010-06-01 3:29 ` [PATCH] vmscan: Fix do_try_to_free_pages() return value when priority==0 reclaim failure KOSAKI Motohiro
2010-06-01 6:48 ` KAMEZAWA Hiroyuki
2010-06-01 8:10 ` Balbir Singh
2010-06-02 0:33 ` KAMEZAWA Hiroyuki
2010-06-01 14:50 ` Greg Thelen
2010-06-04 14:32 ` Johannes Weiner
2010-04-30 23:05 ` [patch 4/5] vmscan: remove isolate_pages callback scan control Johannes Weiner
2010-05-13 3:29 ` KOSAKI Motohiro
2010-05-19 21:42 ` Johannes Weiner
2010-05-20 23:23 ` KOSAKI Motohiro
2010-04-30 23:05 ` [patch 5/5] vmscan: remove may_swap " Johannes Weiner
2010-05-13 3:36 ` KOSAKI Motohiro
2010-05-19 21:44 ` Johannes Weiner [this message]
2010-05-21 0:15 ` KOSAKI Motohiro
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