linux-kernel - Re: [PATCH/RFCv4 0/6] The Contiguous Memory Allocator framework

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Date:	Thu, 26 Aug 2010 04:12:10 +0200
From:	Michał Nazarewicz <m.nazarewicz@...sung.com>
To:	Andrew Morton <akpm@...ux-foundation.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
Cc:	Hans Verkuil <hverkuil@...all.nl>,
	Daniel Walker <dwalker@...eaurora.org>,
	Russell King <linux@....linux.org.uk>,
	Jonathan Corbet <corbet@....net>,
	Peter Zijlstra <peterz@...radead.org>,
	Pawel Osciak <p.osciak@...sung.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	linux-kernel@...r.kernel.org,
	FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>,
	linux-mm@...ck.org, Kyungmin Park <kyungmin.park@...sung.com>,
	Zach Pfeffer <zpfeffer@...eaurora.org>,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	Mel Gorman <mel@....ul.ie>, linux-media@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	Marek Szyprowski <m.szyprowski@...sung.com>
Subject: Re: [PATCH/RFCv4 0/6] The Contiguous Memory Allocator framework

On Thu, 26 Aug 2010 02:58:57 +0200, KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com> wrote:
> Hmm, you may not like this..but how about following kind of interface ?
>
> Now, memoyr hotplug supports following operation to free and _isolate_
> memory region.
> 	# echo offline > /sys/devices/system/memory/memoryX/state
>
> Then, a region of memory will be isolated. (This succeeds if there are free
> memory.)
>
> Add a new interface.
>
> 	% echo offline > /sys/devices/system/memory/memoryX/state
> 	# extract memory from System RAM and make them invisible from buddy allocator.
>
> 	% echo cma > /sys/devices/system/memory/memoryX/state
> 	# move invisible memory to cma.

At this point I need to say that I have no experience with hotplug memory but
I think that for this to make sense the regions of memory would have to be
smaller.  Unless I'm misunderstanding something, the above would convert
a region of sizes in order of GiBs to use for CMA.

-- 
Best regards,                                        _     _
| Humble Liege of Serenely Enlightened Majesty of  o' \,=./ `o
| Computer Science,  Michał "mina86" Nazarewicz       (o o)
+----[mina86*mina86.com]---[mina86*jabber.org]----ooO--(_)--Ooo--

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