Date: Wed, 16 Dec 2009 11:49:51 +0100
From: Andi Kleen <andi@firstfloor.org>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>,
       "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
       "linux-mm@kvack.org" <linux-mm@kvack.org>, cl@linux-foundation.org,
       "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
       "mingo@elte.hu" <mingo@elte.hu>, minchan.kim@gmail.com
Subject: Re: [mm][RFC][PATCH 0/11] mm accessor updates.
Message-ID: <20091216104951.GD15031@basil.fritz.box>
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On Wed, Dec 16, 2009 at 07:31:09PM +0900, KAMEZAWA Hiroyuki wrote:
> On Wed, 16 Dec 2009 11:28:06 +0100
> Andi Kleen <andi@firstfloor.org> wrote:
> 
> > > > Also the patches didn't fare too well in testing unfortunately.
> > > > 
> > > > I suspect we'll rather need multiple locks split per address
> > > > space range.
> > > 
> > > This set doesn't include any changes of the logic. Just replace all mmap_sem.
> > > I think this is good start point (for introducing another logic etc..)
> > 
> > The problem is that for range locking simple wrapping the locks
> > in macros is not enough. You need more changes.
> > 
> maybe. but removing scatterred mmap_sem from codes is the first thing to do.
> I think this removing itself will take 3 month or a half year.
> (So, I didn't remove mmap_sem and leave it as it is.)

I suspect you would just need to change them again then.

> The problem of range locking is more than mmap_sem, anyway. I don't think
> it's possible easily.

Yes, it has some tricky aspects. But my feeling is that there's no good
alternative to it for real scalability.

-Andi
-- 
ak@linux.intel.com -- Speaking for myself only.
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