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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

WARNING: multiple messages have this Message-ID (diff)
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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  parent reply	other threads:[~2009-07-29 11:21 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-07-20 15:25 [PATCH] hibernate / memory hotplug: always use for_each_populated_zone() Gerald Schaefer
2009-07-20 16:04 ` Rafael J. Wysocki
2009-07-20 16:04 ` Rafael J. Wysocki
2009-07-20 16:15 ` KOSAKI Motohiro
2009-07-20 21:29 ` Nigel Cunningham
2009-07-21  7:15   ` Heiko Carstens
2009-07-21  7:15     ` Heiko Carstens
2009-07-21  7:21     ` Nick Piggin
2009-07-21  7:21       ` Nick Piggin
2009-07-21  7:38     ` KAMEZAWA Hiroyuki
2009-07-21  7:38       ` KAMEZAWA Hiroyuki
2009-07-21 14:11       ` Rafael J. Wysocki
2009-07-21 14:11         ` Rafael J. Wysocki
2009-07-22  0:25         ` KAMEZAWA Hiroyuki
2009-07-22  0:25           ` KAMEZAWA Hiroyuki
2009-07-22  0:38           ` KAMEZAWA Hiroyuki
2009-07-22  0:38             ` KAMEZAWA Hiroyuki
2009-07-22 17:49           ` Rafael J. Wysocki
2009-07-22 17:49             ` Rafael J. Wysocki
2009-07-22 23:46             ` KAMEZAWA Hiroyuki
2009-07-22 23:46               ` KAMEZAWA Hiroyuki
2009-07-29 11:20         ` Gerald Schaefer [this message]
2009-07-29 11:20           ` Gerald Schaefer

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