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From: Nick Piggin <npiggin@suse.de>
To: Andi Kleen <andi@firstfloor.org>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>,
	Wu Fengguang <fengguang.wu@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC][PATCH] HWPOISON: remove the unsafe __set_page_locked()
Date: Mon, 28 Sep 2009 04:57:41 +0200	[thread overview]
Message-ID: <20090928025741.GI6327@wotan.suse.de> (raw)
In-Reply-To: <20090928011943.GB1656@one.firstfloor.org>

On Mon, Sep 28, 2009 at 03:19:43AM +0200, Andi Kleen wrote:
> > There is no real rush AFAIKS to fix this one single pagecache site
> > while we have problems with slab allocators and all other unaudited
> > places that nonatomically modify page flags with an elevated
> 
> hwpoison ignores slab pages.

"ignores" them *after* it has already written to page flags?
By that time it's too late.

 
> > page reference ... just mark HWPOISON as broken for the moment, or
> > cut it down to do something much simpler I guess?
> 
> Erm no. These cases are *EXTREMLY* unlikely to hit.

Well it's fundamentally badly buggy, rare or not. We could avoid
lots of nasty atomic operations if we just care that it works
most of the time. I guess it's a matter of perspective but I
won't push for one thing or the other in hwpoison code so long
as it stays out of core code for the most part.

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  parent reply	other threads:[~2009-09-28 16:23 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-09-26  3:15 [RFC][PATCH] HWPOISON: remove the unsafe __set_page_locked() Wu Fengguang
2009-09-26  3:49 ` Andi Kleen
2009-09-26 10:52   ` Wu Fengguang
2009-09-26 11:31     ` Wu Fengguang
2009-09-27 10:47       ` Wu Fengguang
2009-09-27 19:20         ` Nick Piggin
2009-09-28  8:44           ` Wu Fengguang
2009-09-29  5:16             ` Wu Fengguang
2009-10-01  2:02             ` Nick Piggin
2009-10-02 10:54               ` Wu Fengguang
2009-09-26 11:09 ` Hugh Dickins
2009-09-26 11:48   ` Wu Fengguang
2009-09-26 11:58     ` Hugh Dickins
2009-09-26 15:05     ` Andi Kleen
2009-09-26 19:12       ` Nick Piggin
2009-09-26 19:14     ` Nick Piggin
2009-09-26 19:06   ` Nick Piggin
2009-09-26 21:32     ` Andi Kleen
2009-09-27 16:26       ` Hugh Dickins
2009-09-27 19:22         ` Nick Piggin
2009-09-27 21:57           ` Hugh Dickins
2009-09-27 23:01             ` Nick Piggin
2009-09-28  1:19               ` Andi Kleen
2009-09-28  1:52                 ` Wu Fengguang
2009-09-28  2:57                 ` Nick Piggin [this message]
2009-09-28  4:11                   ` Andi Kleen
2009-09-28  4:29                     ` Nick Piggin

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