Re: QUEUE_FLAG_CLUSTER: not working in 2.6.24 ?

[Mark Lord <liml@rtr.ca>]

Mark Lord wrote:
> Andrew Morton wrote:
>> On Thu, 13 Dec 2007 17:15:06 -0500
>> James Bottomley <James.Bottomley@HansenPartnership.com> wrote:
>>
>>> On Thu, 2007-12-13 at 14:02 -0800, Andrew Morton wrote:
>>>> On Thu, 13 Dec 2007 21:09:59 +0100
>>>> Jens Axboe <jens.axboe@oracle.com> wrote:
>>>>
>>>>> OK, it's a vm issue,
>>>> cc linux-mm and probable culprit.
>>>>
>>>>>  I have tens of thousand "backward" pages after a
>>>>> boot - IOW, bvec->bv_page is the page before bvprv->bv_page, not
>>>>> reverse. So it looks like that bug got reintroduced.
>>>> Bill Irwin fixed this a couple of years back: changed the page 
>>>> allocator so
>>>> that it mostly hands out pages in ascending physical-address order.
>>>>
>>>> I guess we broke that, quite possibly in Mel's page allocator rework.
>>>>
>>>> It would help if you could provide us with a simple recipe for
>>>> demonstrating this problem, please.
>>> The simple way seems to be to malloc a large area, touch every page and
>>> then look at the physical pages assigned ... they now mostly seem to be
>>> descending in physical address.
>>>
>>
>> OIC.  -mm's /proc/pid/pagemap can be used to get the pfn's...
> ..
> 
> I'm actually running the treadmill right now (have been for many hours, 
> actually,
> to bisect it to a specific commit.
> 
> Thought I was almost done, and then noticed that git-bisect doesn't keep
> the Makefile VERSION lines the same, so I was actually running the wrong
> kernel after the first few times.. duh.
> 
> Wrote a script to fix it now.
..

Well, that was a waste of three hours.

Somebody else can try it now.

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