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From: Peter Zijlstra <peterz@infradead.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>,
	"minchan.kim@gmail.com" <minchan.kim@gmail.com>,
	cl@linux-foundation.org
Subject: Re: [RFC PATCH] asynchronous page fault.
Date: Mon, 28 Dec 2009 09:30:47 +0100	[thread overview]
Message-ID: <1261989047.7135.3.camel@laptop> (raw)
In-Reply-To: <20091228093606.9f2e666c.kamezawa.hiroyu@jp.fujitsu.com>

On Mon, 2009-12-28 at 09:36 +0900, KAMEZAWA Hiroyuki wrote:
> 
> > The idea is to let the RCU lock span whatever length you need the vma
> > for, the easy way is to simply use PREEMPT_RCU=y for now, 
> 
> I tried to remove his kind of reference count trick but I can't do that
> without synchronize_rcu() somewhere in unmap code. I don't like that and
> use this refcnt. 

Why, because otherwise we can access page tables for an already unmapped
vma? Yeah that is the interesting bit ;-)




WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.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>,
	"minchan.kim@gmail.com" <minchan.kim@gmail.com>,
	cl@linux-foundation.org
Subject: Re: [RFC PATCH] asynchronous page fault.
Date: Mon, 28 Dec 2009 09:30:47 +0100	[thread overview]
Message-ID: <1261989047.7135.3.camel@laptop> (raw)
In-Reply-To: <20091228093606.9f2e666c.kamezawa.hiroyu@jp.fujitsu.com>

On Mon, 2009-12-28 at 09:36 +0900, KAMEZAWA Hiroyuki wrote:
> 
> > The idea is to let the RCU lock span whatever length you need the vma
> > for, the easy way is to simply use PREEMPT_RCU=y for now, 
> 
> I tried to remove his kind of reference count trick but I can't do that
> without synchronize_rcu() somewhere in unmap code. I don't like that and
> use this refcnt. 

Why, because otherwise we can access page tables for an already unmapped
vma? Yeah that is the interesting bit ;-)



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  parent reply	other threads:[~2009-12-28  8:39 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-12-25  1:51 [RFC PATCH] asynchronous page fault KAMEZAWA Hiroyuki
2009-12-27  9:47 ` Minchan Kim
2009-12-27  9:47   ` Minchan Kim
2009-12-27 23:59   ` KAMEZAWA Hiroyuki
2009-12-27 23:59     ` KAMEZAWA Hiroyuki
2009-12-27 11:19 ` Peter Zijlstra
2009-12-27 11:19   ` Peter Zijlstra
2009-12-28  0:00   ` KAMEZAWA Hiroyuki
2009-12-28  0:00     ` KAMEZAWA Hiroyuki
2009-12-28  0:57   ` Balbir Singh
2009-12-28  0:57     ` Balbir Singh
2009-12-28  1:05     ` KAMEZAWA Hiroyuki
2009-12-28  1:05       ` KAMEZAWA Hiroyuki
2009-12-28  2:58       ` Balbir Singh
2009-12-28  2:58         ` Balbir Singh
2009-12-28  3:13         ` KAMEZAWA Hiroyuki
2009-12-28  3:13           ` KAMEZAWA Hiroyuki
2009-12-28  8:34         ` Peter Zijlstra
2009-12-28  8:34           ` Peter Zijlstra
2009-12-28  8:32     ` Peter Zijlstra
2009-12-28  8:32       ` Peter Zijlstra
2009-12-29  9:54       ` Balbir Singh
2009-12-29  9:54         ` Balbir Singh
2009-12-27 12:03 ` Peter Zijlstra
2009-12-27 12:03   ` Peter Zijlstra
2009-12-28  0:36   ` KAMEZAWA Hiroyuki
2009-12-28  0:36     ` KAMEZAWA Hiroyuki
2009-12-28  1:19     ` KAMEZAWA Hiroyuki
2009-12-28  1:19       ` KAMEZAWA Hiroyuki
2009-12-28  8:30     ` Peter Zijlstra [this message]
2009-12-28  8:30       ` Peter Zijlstra
2009-12-28  9:58       ` KAMEZAWA Hiroyuki
2009-12-28  9:58         ` KAMEZAWA Hiroyuki
2009-12-28 10:30         ` Peter Zijlstra
2009-12-28 10:30           ` Peter Zijlstra
2009-12-28 10:40           ` Peter Zijlstra
2009-12-28 10:40             ` Peter Zijlstra
2010-01-02 16:14             ` Peter Zijlstra
2010-01-02 16:14               ` Peter Zijlstra
2010-01-04  3:02               ` Paul E. McKenney
2010-01-04  3:02                 ` Paul E. McKenney
2010-01-04  7:53                 ` Peter Zijlstra
2010-01-04  7:53                   ` Peter Zijlstra
2010-01-04 15:55                   ` Paul E. McKenney
2010-01-04 15:55                     ` Paul E. McKenney
2010-01-04 16:02                     ` Peter Zijlstra
2010-01-04 16:02                       ` Peter Zijlstra
2010-01-04 16:56                       ` Paul E. McKenney
2010-01-04 16:56                         ` Paul E. McKenney
2010-01-04 13:48               ` [RFC PATCH -v2] speculative " Peter Zijlstra
2010-01-04 13:48                 ` Peter Zijlstra
2009-12-28 10:57           ` [RFC PATCH] asynchronous " KAMEZAWA Hiroyuki
2009-12-28 10:57             ` KAMEZAWA Hiroyuki
2009-12-28 11:06             ` Peter Zijlstra
2009-12-28 11:06               ` Peter Zijlstra
2009-12-28  8:55     ` Peter Zijlstra
2009-12-28  8:55       ` Peter Zijlstra
2009-12-28 10:08       ` KAMEZAWA Hiroyuki
2009-12-28 10:08         ` KAMEZAWA Hiroyuki
2009-12-28 11:43     ` Peter Zijlstra
2009-12-28 11:43       ` Peter Zijlstra
2010-01-02 21:45 ` Benjamin Herrenschmidt
2010-01-02 21:45   ` Benjamin Herrenschmidt

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