Message-ID: <4FE35DB9.10704@redhat.com>
Date: Thu, 21 Jun 2012 13:45:29 -0400
From: Rik van Riel <riel@redhat.com>
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To: Andrew Morton <akpm@linux-foundation.org>
CC: Peter Zijlstra <peterz@infradead.org>, linux-mm@kvack.org,
        aarcange@redhat.com, minchan@gmail.com, kosaki.motohiro@gmail.com,
        andi@firstfloor.org, hannes@cmpxchg.org, mel@csn.ul.ie,
        linux-kernel@vger.kernel.org, Rik van Riel <riel@surriel.com>
Subject: Re: [PATCH -mm 4/7] mm: make page colouring code generic
References: <1340057126-31143-1-git-send-email-riel@redhat.com> <1340057126-31143-5-git-send-email-riel@redhat.com> <1340277624.21745.173.camel@twins> <4FE33002.6040703@redhat.com> <20120621104005.604fa9cc.akpm@linux-foundation.org>
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On 06/21/2012 01:40 PM, Andrew Morton wrote:
> On Thu, 21 Jun 2012 10:30:26 -0400 Rik van Riel<riel@redhat.com>  wrote:
>
>> On 06/21/2012 07:20 AM, Peter Zijlstra wrote:
>>> On Mon, 2012-06-18 at 18:05 -0400, Rik van Riel wrote:
>>>> Fix the x86-64 page colouring code to take pgoff into account.
>>>
>>> Shouldn't that be a separate patch?
>>
>> My idea was that it would be easier to review
>> these two nearly identical functions together.
>>
>> Andrew, do you have any strong opinions?
>
> It depends on the significance of the change.  I suspect it's one of
> things which speeds up many workloads by 1.5% and slows down a few
> weird/important ones by 11%.  Which makes it a thing to be put under
> the microscope and poked at.  Some people might end up reverting it,
> making it tunable/configurable etc etc.
>
> If any of that is true then yes, I guess it should be a standalone thing.

Behaviour is not changed by this patch, except
for taking pgoff into account - which should not
matter a whole lot in practice, because mmap of
files is generally done starting at offset 0.
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