From: Christoph Lameter <cl@linux-foundation.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: npiggin@suse.de, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, Tejun Heo <tj@kernel.org>,
Ingo Molnar <mingo@elte.hu>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
"hugh.dickins@tiscali.co.uk" <hugh.dickins@tiscali.co.uk>
Subject: Re: [RFC MM] mmap_sem scaling: only scan cpus used by an mm
Date: Fri, 6 Nov 2009 14:45:58 -0500 (EST) [thread overview]
Message-ID: <alpine.DEB.1.10.0911061443120.21579@V090114053VZO-1> (raw)
In-Reply-To: <20091106191448.GD819@basil.fritz.box>
On Fri, 6 Nov 2009, Andi Kleen wrote:
> On Fri, Nov 06, 2009 at 01:53:35PM -0500, Christoph Lameter wrote:
> > One way to reduce the cost of the writer lock is to track the cpus used
> > and loop over the processors in that bitmap.
>
> Can't you use the same mask as is used for TLB flushing?
They are clearing the cpus that are no longer in use. We could use the
same mask if we would transfer the counters but for that we would need to
make sure that no concurrent user of the counters is out there. Probably
too expensive to do.
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next prev parent reply other threads:[~2009-11-06 19:47 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-05 19:19 [RFC MM] Accessors for mm locking Christoph Lameter
2009-11-05 19:20 ` Subject: [RFC MM] mmap_sem scaling: Use mutex and percpu counter instead Christoph Lameter
2009-11-05 20:56 ` Andi Kleen
2009-11-05 21:03 ` Christoph Lameter
2009-11-06 7:39 ` Andi Kleen
2009-11-06 17:08 ` Christoph Lameter
2009-11-06 17:44 ` Andi Kleen
2009-11-06 17:54 ` Christoph Lameter
2009-11-10 6:21 ` KOSAKI Motohiro
2009-11-10 9:19 ` Andi Kleen
2009-11-06 18:53 ` [RFC MM] mmap_sem scaling: only scan cpus used by an mm Christoph Lameter
2009-11-06 19:14 ` Andi Kleen
2009-11-06 19:45 ` Christoph Lameter [this message]
2009-11-05 22:05 ` [RFC MM] swap counters Christoph Lameter
2009-11-06 2:54 ` KAMEZAWA Hiroyuki
2009-11-06 15:41 ` Subject: [RFC MM] mmap_sem scaling: Use mutex and percpu counter instead Minchan Kim
2009-11-06 17:10 ` Christoph Lameter
2009-11-07 4:19 ` Minchan Kim
2009-11-10 20:20 ` Christoph Lameter
2009-11-05 20:52 ` [RFC MM] Accessors for mm locking Andi Kleen
2009-11-05 20:57 ` Christoph Lameter
2009-11-17 6:42 ` Zhang, Yanmin
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