From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
"Rafael J. Wysocki" <rjw@sisk.pl>,
Ondrej Zary <linux@rainbow-software.org>,
Andrea Gelmini <andrea.gelmini@gmail.com>,
Balbir Singh <balbir@in.ibm.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Nigel Cunningham <nigel@tuxonice.net>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/4] swap: revert special hibernation allocation
Date: Mon, 6 Sep 2010 17:13:07 +0900 [thread overview]
Message-ID: <20100906171307.9e8d9637.kamezawa.hiroyu@jp.fujitsu.com> (raw)
In-Reply-To: <alpine.LSU.2.00.1009060104410.13600@sister.anvils>
On Mon, 6 Sep 2010 01:10:55 -0700 (PDT)
Hugh Dickins <hughd@google.com> wrote:
> Please revert 2.6.36-rc commit d2997b1042ec150616c1963b5e5e919ffd0b0ebf
> "hibernation: freeze swap at hibernation". It complicated matters by
> adding a second swap allocation path, just for hibernation; without in
> any way fixing the issue that it was intended to address - page reclaim
> after fixing the hibernation image might free swap from a page already
> imaged as swapcache, letting its swap be reallocated to store a different
> page of the image: resulting in data corruption if the imaged page were
> freed as clean then swapped back in. Pages freed to si->swap_map were
> still in danger of being reallocated by the alternative allocation path.
>
> I guess it inadvertently fixed slow SSD swap allocation for hibernation,
> as reported by Nigel Cunningham: by missing out the discards that occur
> on the usual swap allocation path; but that was unintentional, and needs
> a separate fix.
>
> Signed-off-by: Hugh Dickins <hughd@google.com>
> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
> Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
> Cc: Ondrej Zary <linux@rainbow-software.org>
> Cc: Andrea Gelmini <andrea.gelmini@gmail.com>
> Cc: Balbir Singh <balbir@in.ibm.com>
> Cc: Andrea Arcangeli <aarcange@redhat.com>
> Cc: Nigel Cunningham <nigel@tuxonice.net>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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next prev parent reply other threads:[~2010-09-06 8:18 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-06 8:10 Hugh Dickins
2010-09-06 8:12 ` [PATCH 2/4] swap: prevent reuse during hibernation Hugh Dickins
2010-09-06 8:15 ` KAMEZAWA Hiroyuki
2010-09-06 18:34 ` Rafael J. Wysocki
2010-09-07 1:03 ` KOSAKI Motohiro
2010-09-07 20:20 ` Andrew Morton
2010-09-07 21:38 ` Hugh Dickins
2010-09-09 5:44 ` Nigel Cunningham
2010-09-06 8:13 ` KAMEZAWA Hiroyuki [this message]
2010-09-06 8:17 ` [PATCH 3/4] swap: do not send discards as barriers Hugh Dickins
2010-09-06 8:21 ` [PATCH 4/4] swap: discard while swapping only if SWAP_FLAG_DISCARD Hugh Dickins
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