From: Gerald Schaefer <gerald.schaefer@de.ibm.com>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Nigel Cunningham <ncunningham@crca.org.au>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Yasunori Goto <y-goto@jp.fujitsu.com>,
Nick Piggin <npiggin@suse.de>,
linux-mm@kvack.org
Subject: Re: [PATCH] hibernate / memory hotplug: always use for_each_populated_zone()
Date: Wed, 29 Jul 2009 13:20:58 +0200 [thread overview]
Message-ID: <4A70309A.3030304@de.ibm.com> (raw)
In-Reply-To: <200907211611.09525.rjw@sisk.pl>
Rafael J. Wysocki wrote:
>>> So it looks like checking for pfn_valid() and afterwards checking
>>> for PG_Reserved (?) might give what one would expect.
>> I think so, too. If memory is offline, PG_reserved is always set.
>>
>> In general, it's expected that "page is contiguous in MAX_ORDER range"
>> and no memory holes in MAX_ORDER. In most case, PG_reserved is checked
>> for skipping not-existing memory.
>
> PG_reserved is also set for kernel text, at least on some architectures, and
> for some other areas that we want to save.
How about checking for PG_reserved && ZONE_MOVABLE? I think we don't
have any special cases for PG_reserved inside ZONE_MOVABLE, but I'm not
sure if this is true for all architectures and NUMA systems.
If this would work, it could be a simple way to determine which hotplug
memory should be saved.
--
Regards,
Gerald
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prev parent reply other threads:[~2009-07-29 11:21 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1248103551.23961.0.camel@localhost.localdomain>
[not found] ` <4A64E1D6.8090102@crca.org.au>
2009-07-21 7:15 ` [PATCH] hibernate / memory hotplug: always use for_each_populated_zone() Heiko Carstens
2009-07-21 7:21 ` Nick Piggin
2009-07-21 7:38 ` KAMEZAWA Hiroyuki
2009-07-21 14:11 ` Rafael J. Wysocki
2009-07-22 0:25 ` KAMEZAWA Hiroyuki
2009-07-22 0:38 ` KAMEZAWA Hiroyuki
2009-07-22 17:49 ` Rafael J. Wysocki
2009-07-22 23:46 ` KAMEZAWA Hiroyuki
2009-07-29 11:20 ` Gerald Schaefer [this message]
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