From: Andi Kleen <andi@firstfloor.org>
To: Ulrich Drepper <drepper@redhat.com>
Cc: Eric Dumazet <dada1@cosmosbay.com>,
Rik van Riel <riel@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andi Kleen <andi@firstfloor.org>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Jakub Jelinek <jakub@redhat.com>,
linux-mm@kvack.org, Hugh Dickins <hugh@veritas.com>
Subject: Re: missing madvise functionality
Date: Wed, 4 Apr 2007 00:51:55 +0200 [thread overview]
Message-ID: <20070403225155.GA26567@one.firstfloor.org> (raw)
In-Reply-To: <4612CB21.9020005@redhat.com>
On Tue, Apr 03, 2007 at 02:46:09PM -0700, Ulrich Drepper wrote:
> Eric Dumazet wrote:
> > A page fault is not that expensive. But clearing N*PAGE_SIZE bytes is,
> > because it potentially evicts a large part of CPU cache.
>
> *A* page fault is not that expensive. The problem is that you get a
> page fault for every single page. For 200k allocated you get 50 page
> faults. It quickly adds up.
If you know in advance you need them it might be possible to
batch that. e.g. MADV_WILLNEED could be extended to
work on anonymous memory and establish the mappings in the syscall.
Would that be useful?
-Andi
WARNING: multiple messages have this Message-ID (diff)
From: Andi Kleen <andi@firstfloor.org>
To: Ulrich Drepper <drepper@redhat.com>
Cc: Eric Dumazet <dada1@cosmosbay.com>,
Rik van Riel <riel@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andi Kleen <andi@firstfloor.org>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Jakub Jelinek <jakub@redhat.com>,
linux-mm@kvack.org, Hugh Dickins <hugh@veritas.com>
Subject: Re: missing madvise functionality
Date: Wed, 4 Apr 2007 00:51:55 +0200 [thread overview]
Message-ID: <20070403225155.GA26567@one.firstfloor.org> (raw)
In-Reply-To: <4612CB21.9020005@redhat.com>
On Tue, Apr 03, 2007 at 02:46:09PM -0700, Ulrich Drepper wrote:
> Eric Dumazet wrote:
> > A page fault is not that expensive. But clearing N*PAGE_SIZE bytes is,
> > because it potentially evicts a large part of CPU cache.
>
> *A* page fault is not that expensive. The problem is that you get a
> page fault for every single page. For 200k allocated you get 50 page
> faults. It quickly adds up.
If you know in advance you need them it might be possible to
batch that. e.g. MADV_WILLNEED could be extended to
work on anonymous memory and establish the mappings in the syscall.
Would that be useful?
-Andi
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next prev parent reply other threads:[~2007-04-03 22:52 UTC|newest]
Thread overview: 171+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-03 16:26 missing madvise functionality Ulrich Drepper
2007-04-03 16:55 ` Rik van Riel
2007-04-03 17:10 ` Ulrich Drepper
2007-04-03 17:37 ` Rik van Riel
2007-04-03 18:14 ` Andi Kleen
2007-04-03 17:20 ` Ulrich Drepper
2007-04-03 17:28 ` Andi Kleen
2007-04-03 19:59 ` Andrew Morton
2007-04-03 19:59 ` Andrew Morton
2007-04-03 20:09 ` Andi Kleen
2007-04-03 20:09 ` Andi Kleen
2007-04-03 20:17 ` Ulrich Drepper
2007-04-03 20:29 ` Jakub Jelinek
2007-04-03 20:29 ` Jakub Jelinek
2007-04-03 20:38 ` Rik van Riel
2007-04-03 20:38 ` Rik van Riel
2007-04-03 21:49 ` Andrew Morton
2007-04-03 21:49 ` Andrew Morton
2007-04-03 23:01 ` Eric Dumazet
2007-04-03 23:01 ` Eric Dumazet
2007-04-04 2:22 ` Nick Piggin
2007-04-04 2:22 ` Nick Piggin
2007-04-04 5:41 ` Eric Dumazet
2007-04-04 5:41 ` Eric Dumazet
2007-04-04 6:09 ` [patches] threaded vma patches (was Re: missing madvise functionality) Nick Piggin
2007-04-04 6:09 ` Nick Piggin
2007-04-04 6:26 ` Andrew Morton
2007-04-04 6:26 ` Andrew Morton
2007-04-04 6:38 ` Nick Piggin
2007-04-04 6:38 ` Nick Piggin
2007-04-04 6:42 ` Ulrich Drepper
2007-04-04 6:44 ` Nick Piggin
2007-04-04 6:44 ` Nick Piggin
2007-04-04 6:50 ` Eric Dumazet
2007-04-04 6:50 ` Eric Dumazet
2007-04-04 6:54 ` Ulrich Drepper
2007-04-04 7:33 ` Eric Dumazet
2007-04-04 7:33 ` Eric Dumazet
2007-04-04 8:25 ` missing madvise functionality Peter Zijlstra
2007-04-04 8:25 ` Peter Zijlstra
2007-04-04 8:55 ` Nick Piggin
2007-04-04 9:12 ` William Lee Irwin III
2007-04-04 9:12 ` William Lee Irwin III
2007-04-04 9:23 ` Nick Piggin
2007-04-04 9:23 ` Nick Piggin
2007-04-04 9:34 ` Eric Dumazet
2007-04-04 9:34 ` Eric Dumazet
2007-04-04 9:45 ` Nick Piggin
2007-04-04 9:45 ` Nick Piggin
2007-04-04 10:05 ` Nick Piggin
2007-04-04 10:05 ` Nick Piggin
2007-04-04 11:54 ` Eric Dumazet
2007-04-04 11:54 ` Eric Dumazet
2007-04-05 2:01 ` Nick Piggin
2007-04-05 2:01 ` Nick Piggin
2007-04-05 6:09 ` Eric Dumazet
2007-04-05 6:09 ` Eric Dumazet
2007-04-05 6:19 ` Ulrich Drepper
2007-04-05 6:54 ` Eric Dumazet
2007-04-05 6:54 ` Eric Dumazet
2007-04-03 23:02 ` Andrew Morton
2007-04-03 23:02 ` Andrew Morton
2007-04-04 9:15 ` Hugh Dickins
2007-04-04 9:15 ` Hugh Dickins
2007-04-04 14:55 ` Rik van Riel
2007-04-04 14:55 ` Rik van Riel
2007-04-04 15:25 ` Hugh Dickins
2007-04-04 15:25 ` Hugh Dickins
2007-04-05 1:44 ` Nick Piggin
2007-04-05 1:44 ` Nick Piggin
2007-04-04 18:04 ` Andrew Morton
2007-04-04 18:04 ` Andrew Morton
2007-04-04 18:08 ` Rik van Riel
2007-04-04 18:08 ` Rik van Riel
2007-04-04 20:56 ` Andrew Morton
2007-04-04 20:56 ` Andrew Morton
2007-04-04 18:39 ` Hugh Dickins
2007-04-04 18:39 ` Hugh Dickins
2007-04-03 23:44 ` Andrew Morton
2007-04-03 23:44 ` Andrew Morton
2007-04-04 13:09 ` William Lee Irwin III
2007-04-04 13:38 ` William Lee Irwin III
2007-04-04 13:38 ` William Lee Irwin III
2007-04-04 18:51 ` Andrew Morton
2007-04-04 18:51 ` Andrew Morton
2007-04-05 4:14 ` William Lee Irwin III
2007-04-05 4:14 ` William Lee Irwin III
2007-04-04 23:00 ` preemption and rwsems (was: Re: missing madvise functionality) Andrew Morton
2007-04-04 23:00 ` Andrew Morton
2007-04-05 12:48 ` David Howells
2007-04-05 12:48 ` David Howells
2007-04-05 19:11 ` Ingo Molnar
2007-04-05 19:11 ` Ingo Molnar
2007-04-05 20:37 ` Andrew Morton
2007-04-05 20:37 ` Andrew Morton
2007-04-06 9:08 ` Ingo Molnar
2007-04-06 19:30 ` Andrew Morton
2007-04-06 19:30 ` Andrew Morton
2007-04-06 19:40 ` Ingo Molnar
2007-04-06 19:40 ` Ingo Molnar
2007-04-05 19:27 ` Andrew Morton
2007-04-05 19:27 ` Andrew Morton
2007-04-05 7:31 ` missing madvise functionality Rik van Riel
2007-04-05 7:39 ` Rik van Riel
2007-04-05 7:39 ` Rik van Riel
2007-04-05 8:32 ` Andrew Morton
2007-04-05 8:32 ` Andrew Morton
2007-04-05 15:47 ` Rik van Riel
2007-04-05 15:47 ` Rik van Riel
2007-04-05 8:08 ` Eric Dumazet
2007-04-05 8:08 ` Eric Dumazet
2007-04-05 8:31 ` Rik van Riel
2007-04-05 8:31 ` Rik van Riel
2007-04-05 9:06 ` Eric Dumazet
2007-04-05 9:06 ` Eric Dumazet
2007-04-05 9:45 ` Jakub Jelinek
2007-04-05 9:45 ` Jakub Jelinek
2007-04-05 16:15 ` Rik van Riel
2007-04-05 16:15 ` Rik van Riel
2007-04-05 16:10 ` Ulrich Drepper
2007-04-06 2:28 ` Nick Piggin
2007-04-06 2:28 ` Nick Piggin
2007-04-06 2:52 ` Ulrich Drepper
2007-04-06 2:59 ` Nick Piggin
2007-04-06 2:59 ` Nick Piggin
2007-04-03 20:51 ` Andrew Morton
2007-04-03 20:51 ` Andrew Morton
2007-04-03 20:57 ` Ulrich Drepper
2007-04-03 21:00 ` Rik van Riel
2007-04-03 21:00 ` Rik van Riel
2007-04-03 21:10 ` Eric Dumazet
2007-04-03 21:10 ` Eric Dumazet
2007-04-03 21:12 ` Jörn Engel
2007-04-03 21:12 ` Jörn Engel
2007-04-03 21:15 ` Rik van Riel
2007-04-03 21:15 ` Rik van Riel
2007-04-03 21:30 ` Eric Dumazet
2007-04-03 21:30 ` Eric Dumazet
2007-04-03 21:22 ` Jeremy Fitzhardinge
2007-04-03 21:22 ` Jeremy Fitzhardinge
2007-04-03 21:29 ` Rik van Riel
2007-04-03 21:29 ` Rik van Riel
2007-04-03 21:46 ` Ulrich Drepper
2007-04-03 22:51 ` Andi Kleen [this message]
2007-04-03 22:51 ` Andi Kleen
2007-04-03 23:07 ` Ulrich Drepper
2007-04-03 21:16 ` Andrew Morton
2007-04-03 21:16 ` Andrew Morton
2007-04-04 18:49 ` Anton Blanchard
2007-04-04 18:49 ` Anton Blanchard
2007-04-03 22:07 ` Arnd Bergmann
2007-04-03 22:23 ` Ulrich Drepper
2007-04-04 2:53 ` Marko Macek
2007-04-04 2:56 ` Rik van Riel
2007-04-04 14:37 ` Hugh Dickins
2007-04-04 7:46 ` Nick Piggin
2007-04-04 8:04 ` Nick Piggin
2007-04-04 8:04 ` Nick Piggin
2007-04-04 8:20 ` Jakub Jelinek
2007-04-04 8:20 ` Jakub Jelinek
2007-04-04 8:47 ` Nick Piggin
2007-04-04 8:47 ` Nick Piggin
2007-04-05 4:23 ` Nick Piggin
2007-04-05 18:38 ` Rik van Riel
2007-04-05 18:38 ` Rik van Riel
2007-04-05 21:07 ` Andrew Morton
2007-04-05 21:07 ` Andrew Morton
2007-04-05 21:39 ` Rik van Riel
2007-04-05 21:39 ` Rik van Riel
2007-04-06 1:28 ` Nick Piggin
2007-04-06 1:28 ` Nick Piggin
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