From: Andrew Morton <akpm@osdl.org>
To: Christoph Lameter <clameter@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC] Track mlock()ed pages
Date: Fri, 26 Jan 2007 10:10:27 -0800 [thread overview]
Message-ID: <20070126101027.90bf3e63.akpm@osdl.org> (raw)
In-Reply-To: <Pine.LNX.4.64.0701260742340.6141@schroedinger.engr.sgi.com>
On Fri, 26 Jan 2007 07:44:42 -0800 (PST)
Christoph Lameter <clameter@sgi.com> wrote:
> On Fri, 26 Jan 2007, Andrew Morton wrote:
>
> > > > > Track mlocked pages via a ZVC
> >
> > Why?
>
> Large amounts of mlocked pages may be a problem for
>
> 1. Reclaim behavior.
>
> 2. Defragmentation
>
We know that. What has that to do with this patch?
>
> > You could perhaps go for a walk across all the other vmas which presently
> > map this page. If any of them have VM_LOCKED, don't increment the counter.
> > Similar on removal: only decrement the counter when the final mlocked VMA
> > is dropping the pte.
>
> For that we would need an additional refcount for vmlocked maps in the
> page struct.
No you don't. The refcount is already there. It is "the sum of the VM_LOCKED
VMAs which map this page".
It might be impractical or expensive to calculate it, but it's there.
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@osdl.org>
To: Christoph Lameter <clameter@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC] Track mlock()ed pages
Date: Fri, 26 Jan 2007 10:10:27 -0800 [thread overview]
Message-ID: <20070126101027.90bf3e63.akpm@osdl.org> (raw)
In-Reply-To: <Pine.LNX.4.64.0701260742340.6141@schroedinger.engr.sgi.com>
On Fri, 26 Jan 2007 07:44:42 -0800 (PST)
Christoph Lameter <clameter@sgi.com> wrote:
> On Fri, 26 Jan 2007, Andrew Morton wrote:
>
> > > > > Track mlocked pages via a ZVC
> >
> > Why?
>
> Large amounts of mlocked pages may be a problem for
>
> 1. Reclaim behavior.
>
> 2. Defragmentation
>
We know that. What has that to do with this patch?
>
> > You could perhaps go for a walk across all the other vmas which presently
> > map this page. If any of them have VM_LOCKED, don't increment the counter.
> > Similar on removal: only decrement the counter when the final mlocked VMA
> > is dropping the pte.
>
> For that we would need an additional refcount for vmlocked maps in the
> page struct.
No you don't. The refcount is already there. It is "the sum of the VM_LOCKED
VMAs which map this page".
It might be impractical or expensive to calculate it, but it's there.
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next prev parent reply other threads:[~2007-01-26 18:10 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-26 5:43 [RFC] Track mlock()ed pages Christoph Lameter
2007-01-26 5:43 ` Christoph Lameter
2007-01-26 6:30 ` Nick Piggin
2007-01-26 6:30 ` Nick Piggin
2007-01-26 6:36 ` Christoph Lameter
2007-01-26 6:36 ` Christoph Lameter
2007-01-26 11:13 ` Andrew Morton
2007-01-26 11:13 ` Andrew Morton
2007-01-26 12:00 ` Nick Piggin
2007-01-26 12:00 ` Nick Piggin
2007-01-26 15:44 ` Christoph Lameter
2007-01-26 15:44 ` Christoph Lameter
2007-01-26 18:10 ` Andrew Morton [this message]
2007-01-26 18:10 ` Andrew Morton
2007-01-26 18:21 ` KAMEZAWA Hiroyuki
2007-01-26 18:21 ` KAMEZAWA Hiroyuki
2007-01-26 18:23 ` Christoph Lameter
2007-01-26 18:23 ` Christoph Lameter
2007-01-26 18:42 ` Andrew Morton
2007-01-26 18:42 ` Andrew Morton
2007-01-27 22:19 ` Rik van Riel
2007-01-27 22:19 ` Rik van Riel
2007-01-27 22:30 ` Andrew Morton
2007-01-27 22:30 ` Andrew Morton
2007-01-27 22:36 ` Rik van Riel
2007-01-27 22:36 ` Rik van Riel
2007-01-26 11:46 ` Nick Piggin
2007-01-26 11:46 ` Nick Piggin
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