Date: Sat, 14 Nov 2009 03:00:59 +0900 (JST)
From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [PATCH 2/6] mm: mlocking in try_to_unmap_one
Cc: kosaki.motohiro@jp.fujitsu.com, Hugh Dickins <hugh.dickins@tiscali.co.uk>,
       Andrew Morton <akpm@linux-foundation.org>,
       Izik Eidus <ieidus@redhat.com>, Nick Piggin <npiggin@suse.de>,
       Rik van Riel <riel@redhat.com>,
       Lee Schermerhorn <Lee.Schermerhorn@hp.com>,
       linux-kernel@vger.kernel.org, linux-mm@kvack.org
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> On Fri, Nov 13, 2009 at 05:26:14PM +0900, KOSAKI Motohiro wrote:
> > Probably we can remove VM_NONLINEAR perfectly. I've never seen real user of it.
> 
> Do you mean as a whole or in the mlock logic? databases are using
> remap_file_pages on 32bit archs to avoid generating zillon of vmas on
> tmpfs scattered mappings. On 64bits it could only be useful to some
> emulators but with real shadow paging and nonlinear rmap already
> created on shadow pagetables, it looks pretty useless on 64bit archs
> to me.

Hehe, you point out kosaki is stupid and knoledgeless.
thanks correct me.

Probaby we have to maintain VM_NONLINEAR for one or two year. two years
later, nobody use database on 32bit machine.
(low-end DB might be use on 32bit, but that's ok. it doesn't use VM_NONLINEAR)


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