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Date: Fri, 2 Mar 2007 19:15:38 -0800 (PST)
From: Christoph Lameter <clameter@engr.sgi.com>
To: William Lee Irwin III <wli@holomorphy.com>
cc: Andrew Morton <akpm@linux-foundation.org>, Rik van Riel <riel@redhat.com>,
       Bill Irwin <bill.irwin@oracle.com>, Mel Gorman <mel@skynet.ie>,
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       arjan@infradead.org, torvalds@linux-foundation.org, mbligh@mbligh.org,
       linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: The performance and behaviour of the anti-fragmentation related
 patches
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On Fri, 2 Mar 2007, William Lee Irwin III wrote:

> On Fri, Mar 02, 2007 at 02:22:56PM -0800, Andrew Morton wrote:
> > Opterons seem to be particularly prone to lock starvation where a cacheline
> > gets captured in a single package for ever.
> 
> AIUI that phenomenon is universal to NUMA. Maybe it's time we
> reexamined our locking algorithms in the light of fairness
> considerations.

This is a phenomenon that is usually addressed at the cache logic level. 
Its a hardware maturation issue. A certain package should not be allowed
to hold onto a cacheline forever and other packages must have a mininum 
time when they can operate on that cacheline.