linux-kernel - Re: Populating multiple ptes at fault time

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Date:	Fri, 19 Sep 2008 08:16:43 +0900
From:	"MinChan Kim" <minchan.kim@...il.com>
To:	"Chris Snook" <csnook@...hat.com>
Cc:	"Christoph Lameter" <cl@...ux-foundation.org>,
	"Martin Bligh" <mbligh@...gle.com>,
	"Jeremy Fitzhardinge" <jeremy@...p.org>,
	"Nick Piggin" <nickpiggin@...oo.com.au>,
	"Hugh Dickens" <hugh@...itas.com>,
	"Linux Memory Management List" <linux-mm@...ck.org>,
	"Linux Kernel Mailing List" <linux-kernel@...r.kernel.org>,
	"Avi Kivity" <avi@...ranet.com>,
	"Andrew Morton" <akpm@...ux-foundation.org>,
	"Rik van Riel" <riel@...hat.com>
Subject: Re: Populating multiple ptes at fault time

On Fri, Sep 19, 2008 at 7:23 AM, Chris Snook <csnook@...hat.com> wrote:
> Christoph Lameter wrote:
>>
>> Martin Bligh wrote:
>>>>
>>>> My patches were only for anonymous pages not for file backed because
>>>> readahead
>>>> is available for file backed mappings.
>>>
>>> Do we populate the PTEs though? I didn't think that was batched, but I
>>> might well be wrong.
>>
>> We do not populate the PTEs and AFAICT PTE population was assumed not to
>> be
>> performance critical since the backing media is comparatively slow.
>>
>
> Perhaps we should.  In a virtual guest, the backing media is often an
> emulated IDE device, or something similarly inefficient, such that the
> bottleneck is the CPU.

In embedded environment, many people use nand-like device as storage.
Read cost of nand-like device is less than IDE's one.
Also, Nowaday Embedded stuff would like to use multi-core step by step.
So, pte population become important more and more.


> -- Chris
>



-- 
Kinds regards,
MinChan Kim
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