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From: Stephen Rothwell <sfr@canb.auug.org.au>
To: mel@skynet.ie (Mel Gorman)
Cc: ppc-dev <linuxppc-dev@ozlabs.org>
Subject: Re: Do not depend on MAX_ORDER when grouping pages by mobility
Date: Tue, 13 Nov 2007 11:44:01 +1100	[thread overview]
Message-ID: <20071113114401.73d81ce2.sfr@canb.auug.org.au> (raw)
In-Reply-To: <20071112155452.GB6653@skynet.ie>

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On Mon, 12 Nov 2007 15:54:53 +0000 mel@skynet.ie (Mel Gorman) wrote:
>
> Ordinarily, the size of a pageblock is determined from the hugepage size.
> On PPC64, the hugepage size is determined at runtime based on the ability
> of the machine. If the machine does not support hugepages, HPAGE_SHIFT is
> 0. This results in pageblock_order being set to -PAGE_SHIFT and a crash
> results shortly afterwards.
> 
> This patch checks that HPAGE_SHIFT is a sensible value before using the
> hugepage size. If it is 0, MAX_ORDER-1 is used instead as this is a sensible
> value of pageblock_order.
> 
> Signed-off-by: Mel Gorman <mel@csn.ul.ie>

Looks good. Legacy iSeries boots fine with this and David Gibson has run
his libhugetlbfs test suite on a Power5+ machine also running the same
kernel (ppc64_defconfig).

I would be good if we could get this in for 2.6.24 (since, as far as
legacy iSeries is concerned, this is a regression from 2.6.23).  I am not
sure what other testing needs to be done.

-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au
http://www.canb.auug.org.au/~sfr/

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  reply	other threads:[~2007-11-13  0:44 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-12  2:21 Do not depend on MAX_ORDER when grouping pages by mobility Stephen Rothwell
2007-11-12 15:54 ` Mel Gorman
2007-11-13  0:44   ` Stephen Rothwell [this message]
2007-11-14 18:10     ` Mel Gorman
2007-11-15  3:17       ` Stephen Rothwell
2007-11-15 10:13         ` Mel Gorman

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