From: Balbir Singh <balbir@linux.vnet.ibm.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
nishimura@mxp.nes.nec.co.jp, menage@google.com, xemul@openvz.org,
linux-mm@kvack.org, lizf@cn.fujitsu.com
Subject: Re: [RFC] Reduce the resource counter lock overhead
Date: Thu, 25 Jun 2009 10:31:02 +0530 [thread overview]
Message-ID: <20090625050102.GY8642@balbir.in.ibm.com> (raw)
In-Reply-To: <20090624204426.3dc9e108.akpm@linux-foundation.org>
* Andrew Morton <akpm@linux-foundation.org> [2009-06-24 20:44:26]:
> On Thu, 25 Jun 2009 08:57:17 +0530 Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
>
> > We do a read everytime before we charge.
>
> See, a good way to fix that is to not do it. Instead of
>
> if (under_limit())
> charge_some_more(amount);
> else
> goto fail;
>
> one can do
>
> if (try_to_charge_some_more(amount) < 0)
> goto fail;
>
> which will halve the locking frequency. Which may not be as beneficial
> as avoiding the locking altogether on the read side, dunno.
>
My bad, we do it all under one lock. We do a read within the charge
lock. I should get some Tea or coffee before responding to emails in
the morning.
--
Balbir
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next prev parent reply other threads:[~2009-06-25 5:01 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-24 17:05 Balbir Singh
2009-06-24 19:40 ` Paul Menage
2009-06-24 23:10 ` Andrew Morton
2009-06-24 23:53 ` KAMEZAWA Hiroyuki
2009-06-25 3:27 ` Balbir Singh
2009-06-25 3:44 ` Andrew Morton
2009-06-25 4:39 ` KAMEZAWA Hiroyuki
2009-06-25 5:40 ` Balbir Singh
2009-06-25 6:30 ` KAMEZAWA Hiroyuki
2009-06-25 16:16 ` Balbir Singh
2009-06-25 5:01 ` Balbir Singh [this message]
2009-06-25 4:37 ` KAMEZAWA Hiroyuki
2009-06-25 3:04 ` Balbir Singh
2009-06-25 3:40 ` Andrew Morton
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