From: Andi Kleen <andi@firstfloor.org>
To: Wu Fengguang <fengguang.wu@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hugh.dickins@tiscali.co.uk>,
Nick Piggin <npiggin@suse.de>, Andi Kleen <andi@firstfloor.org>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC][PATCH] HWPOISON: remove the unsafe __set_page_locked()
Date: Sat, 26 Sep 2009 05:49:36 +0200 [thread overview]
Message-ID: <20090926034936.GK30185@one.firstfloor.org> (raw)
In-Reply-To: <20090926031537.GA10176@localhost>
On Sat, Sep 26, 2009 at 11:15:37AM +0800, Wu Fengguang wrote:
> The swap cache and page cache code assume that they 'own' the newly
> allocated page and therefore can disregard the locking rules. However
> now hwpoison can hit any time on any page.
>
> So use the safer lock_page()/trylock_page(). The main intention is not
> to close such a small time window of memory corruption. But to avoid
> kernel oops that may result from such races, and also avoid raising
> false alerts in hwpoison stress tests.
>
> This in theory will slightly increase page cache/swap cache overheads,
> however it seems to be too small to be measurable in benchmark.
Thanks. Can you please describe what benchmarks you used?
Acked-by: Andi Kleen <ak@linux.intel.com>
-andi
WARNING: multiple messages have this Message-ID (diff)
From: Andi Kleen <andi@firstfloor.org>
To: Wu Fengguang <fengguang.wu@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hugh.dickins@tiscali.co.uk>,
Nick Piggin <npiggin@suse.de>, Andi Kleen <andi@firstfloor.org>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC][PATCH] HWPOISON: remove the unsafe __set_page_locked()
Date: Sat, 26 Sep 2009 05:49:36 +0200 [thread overview]
Message-ID: <20090926034936.GK30185@one.firstfloor.org> (raw)
In-Reply-To: <20090926031537.GA10176@localhost>
On Sat, Sep 26, 2009 at 11:15:37AM +0800, Wu Fengguang wrote:
> The swap cache and page cache code assume that they 'own' the newly
> allocated page and therefore can disregard the locking rules. However
> now hwpoison can hit any time on any page.
>
> So use the safer lock_page()/trylock_page(). The main intention is not
> to close such a small time window of memory corruption. But to avoid
> kernel oops that may result from such races, and also avoid raising
> false alerts in hwpoison stress tests.
>
> This in theory will slightly increase page cache/swap cache overheads,
> however it seems to be too small to be measurable in benchmark.
Thanks. Can you please describe what benchmarks you used?
Acked-by: Andi Kleen <ak@linux.intel.com>
-andi
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next prev parent reply other threads:[~2009-09-26 3:49 UTC|newest]
Thread overview: 54+ 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 3:15 ` Wu Fengguang
2009-09-26 3:49 ` Andi Kleen [this message]
2009-09-26 3:49 ` Andi Kleen
2009-09-26 10:52 ` Wu Fengguang
2009-09-26 10:52 ` Wu Fengguang
2009-09-26 11:31 ` Wu Fengguang
2009-09-26 11:31 ` Wu Fengguang
2009-09-27 10:47 ` Wu Fengguang
2009-09-27 10:47 ` Wu Fengguang
2009-09-27 19:20 ` Nick Piggin
2009-09-27 19:20 ` Nick Piggin
2009-09-28 8:44 ` Wu Fengguang
2009-09-28 8:44 ` Wu Fengguang
2009-09-29 5:16 ` Wu Fengguang
2009-09-29 5:16 ` Wu Fengguang
2009-10-01 2:02 ` Nick Piggin
2009-10-01 2:02 ` Nick Piggin
2009-10-02 10:54 ` Wu Fengguang
2009-10-02 10:54 ` Wu Fengguang
2009-09-26 11:09 ` Hugh Dickins
2009-09-26 11:09 ` Hugh Dickins
2009-09-26 11:48 ` Wu Fengguang
2009-09-26 11:48 ` Wu Fengguang
2009-09-26 11:58 ` Hugh Dickins
2009-09-26 11:58 ` Hugh Dickins
2009-09-26 15:05 ` Andi Kleen
2009-09-26 15:05 ` Andi Kleen
2009-09-26 19:12 ` Nick Piggin
2009-09-26 19:12 ` Nick Piggin
2009-09-26 19:14 ` Nick Piggin
2009-09-26 19:14 ` Nick Piggin
2009-09-26 19:06 ` Nick Piggin
2009-09-26 19:06 ` Nick Piggin
2009-09-26 21:32 ` Andi Kleen
2009-09-26 21:32 ` Andi Kleen
2009-09-27 16:26 ` Hugh Dickins
2009-09-27 16:26 ` Hugh Dickins
2009-09-27 19:22 ` Nick Piggin
2009-09-27 19:22 ` Nick Piggin
2009-09-27 21:57 ` Hugh Dickins
2009-09-27 21:57 ` Hugh Dickins
2009-09-27 23:01 ` Nick Piggin
2009-09-27 23:01 ` Nick Piggin
2009-09-28 1:19 ` Andi Kleen
2009-09-28 1:19 ` Andi Kleen
2009-09-28 1:52 ` Wu Fengguang
2009-09-28 1:52 ` Wu Fengguang
2009-09-28 2:57 ` Nick Piggin
2009-09-28 2:57 ` Nick Piggin
2009-09-28 4:11 ` Andi Kleen
2009-09-28 4:11 ` Andi Kleen
2009-09-28 4:29 ` Nick Piggin
2009-09-28 4:29 ` Nick Piggin
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