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From: Andi Kleen <andi@firstfloor.org>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	cl@linux-foundation.org,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"mingo@elte.hu" <mingo@elte.hu>,
	andi@firstfloor.org, minchan.kim@gmail.com
Subject: Re: [mm][RFC][PATCH 0/11] mm accessor updates.
Date: Wed, 16 Dec 2009 11:11:07 +0100	[thread overview]
Message-ID: <20091216101107.GA15031@basil.fritz.box> (raw)
In-Reply-To: <20091216120011.3eecfe79.kamezawa.hiroyu@jp.fujitsu.com>

On Wed, Dec 16, 2009 at 12:00:11PM +0900, KAMEZAWA Hiroyuki wrote:
> This is from Christoph Lameter's mm_accessor patch posted 5/Nov.
> 
> Replacing all access to mm->mmap_sem with mm-accessor functions as
>  mm_read_lock,
>  mm_write_lock,
>  etc...
> 
> This kind of function allows us to improve page fault performance etc..
> For example, skil down_read(mmap_sem) in some situation.
> (as: http://marc.info/?l=linux-mm&m=125809791306459&w=2)

The problem is that it also slows down the writers, and we have
some workloads where writing is the bottleneck.

I don't think this is the right trade off at this time.

Also the patches didn't fare too well in testing unfortunately.

I suspect we'll rather need multiple locks split per address
space range.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.

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  parent reply	other threads:[~2009-12-16 10:11 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-12-16  3:00 [mm][RFC][PATCH 0/11] mm accessor updates KAMEZAWA Hiroyuki
2009-12-16  3:01 ` [mm][RFC][PATCH 1/11] mm accessor for replacing mmap_sem KAMEZAWA Hiroyuki
2009-12-16  3:02 ` [mm][RFC][PATCH 2/11] mm accessor for kernel core KAMEZAWA Hiroyuki
2009-12-16  3:03 ` [mm][RFC][PATCH 3/11] mm accessor for fs KAMEZAWA Hiroyuki
2009-12-16  3:04 ` [mm][RFC][PATCH 4/11] mm accessor for kvm KAMEZAWA Hiroyuki
2009-12-16  3:05 ` [mm][RFC][PATCH 5/11] mm accessor for tomoyo KAMEZAWA Hiroyuki
2009-12-16  3:06 ` [mm][RFC][PATCH 6/11] mm accessor for driver/gpu KAMEZAWA Hiroyuki
2009-12-16  3:07 ` [mm][RFC][PATCH 7/11] mm accessor for inifiniband KAMEZAWA Hiroyuki
2009-12-16  3:08 ` [mm][RFC][PATCH 8/11] mm accessor for video KAMEZAWA Hiroyuki
2009-12-16  3:09 ` [mm][RFC][PATCH 9/11] mm accessor for sgi gru KAMEZAWA Hiroyuki
2009-12-16  3:10 ` [mm][RFC][PATCH 10/11] mm accessor for misc drivers KAMEZAWA Hiroyuki
2009-12-16  3:11 ` [mm][RFC][PATCH 11/11] mm accessor for x86 KAMEZAWA Hiroyuki
2009-12-16 10:11 ` Andi Kleen [this message]
2009-12-16 10:13   ` [mm][RFC][PATCH 0/11] mm accessor updates KAMEZAWA Hiroyuki
2009-12-16 10:28     ` Andi Kleen
2009-12-16 10:31       ` KAMEZAWA Hiroyuki
2009-12-16 10:49         ` Andi Kleen
2009-12-16 11:12           ` KAMEZAWA Hiroyuki
2009-12-16 11:31             ` Andi Kleen
2009-12-16 16:27               ` Christoph Lameter
2009-12-16 23:01                 ` Peter Zijlstra
2009-12-17  4:11                   ` KOSAKI Motohiro
2009-12-17  8:41                   ` Andi Kleen
2009-12-16 22:57         ` Peter Zijlstra
2009-12-17  8:40           ` Andi Kleen
2009-12-17  8:45             ` Peter Zijlstra
2009-12-17  8:54               ` Andi Kleen
2009-12-17 14:45                 ` Paul E. McKenney
2009-12-17 15:02                   ` Peter Zijlstra
2009-12-17 17:53                   ` Andi Kleen
2009-12-17 19:08                     ` Paul E. McKenney
2009-12-17 19:55                       ` Andi Kleen
2009-12-17 19:56                         ` Christoph Lameter
2009-12-17 20:14                           ` Peter Zijlstra
2009-12-17 20:42                             ` Christoph Lameter
2009-12-18  5:17                               ` Ingo Molnar
2009-12-18 17:00                                 ` Avi Kivity
2009-12-18 17:12                                   ` Ingo Molnar
2009-12-18 18:12                                     ` Christoph Lameter
2009-12-18 18:43                                       ` Andi Kleen
2009-12-18 18:45                                       ` Ingo Molnar
2009-12-18 23:18                                         ` KAMEZAWA Hiroyuki
2009-12-17 19:33             ` Christoph Lameter
2009-12-17 20:07               ` Peter Zijlstra
2009-12-17 20:13                 ` Christoph Lameter
2009-12-17 20:19                   ` Peter Zijlstra
2009-12-16 10:31       ` Minchan Kim
2009-12-16 10:33         ` KAMEZAWA Hiroyuki
2009-12-18  0:38           ` [RFC 0/4] speculative page fault (Was " KAMEZAWA Hiroyuki
2009-12-18  0:41             ` [RFC 1/4] uninline mm accessor KAMEZAWA Hiroyuki
2009-12-18  0:43             ` [RFC 2/4] add mm event counter KAMEZAWA Hiroyuki
2009-12-19  3:23               ` Minchan Kim
2009-12-19  6:37                 ` KAMEZAWA Hiroyuki
2009-12-18  0:45             ` [RFC 3/4] lockless vma caching KAMEZAWA Hiroyuki
2009-12-19  3:43               ` Minchan Kim
2009-12-19  6:44                 ` KAMEZAWA Hiroyuki
2009-12-18  0:46             ` [RFC 4/4] speculative pag fault KAMEZAWA Hiroyuki
2009-12-18  5:54               ` Minchan Kim
2009-12-18  6:06                 ` KAMEZAWA Hiroyuki
2009-12-18  6:33                   ` Minchan Kim
2009-12-19  3:55               ` Minchan Kim
2009-12-19  6:49                 ` KAMEZAWA Hiroyuki
2009-12-16 16:24   ` [mm][RFC][PATCH 0/11] mm accessor updates Christoph Lameter

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