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Date: Wed, 13 Oct 2010 16:12:06 +0900
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: "linux-mm\@kvack.org" <linux-mm@kvack.org>,
        "linux-kernel\@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "minchan.kim\@gmail.com" <minchan.kim@gmail.com>,
        fujita.tomonori@lab.ntt.co.jp
Subject: Re: [RFC][PATCH 1/3] contigous big page allocator
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On Wed, 13 Oct 2010 09:01:43 +0200
Andi Kleen <andi@firstfloor.org> wrote:

> KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> writes:
> >
> > What this wants to do: 
> >   allocates a contiguous chunk of pages larger than MAX_ORDER.
> >   for device drivers (camera? etc..)
> 
> I think to really move forward you need a concrete use case
> actually implemented in tree.
> 

yes. I heard there were users at LinuxCon Japan, so restarted.
I heared video-for-linux + ARM wants this.

I found this thread, now.
http://kerneltrap.org/mailarchive/linux-kernel/2010/10/10/4630166

Hmm. 

> >   My intention is not for allocating HUGEPAGE(> MAX_ORDER).
> 
> I still believe using this for 1GB pages would be one of the more
> interesting use cases.
> 

I'm successfully allocating 1GB of continous pages at test. But I'm not sure
requirements and users. How quick this allocation should be ?
For example, if prep_new_page() for 1GB page is slow, what kind of chunk-of-page
construction is the best. 

THanks,
-Kame