| Date | Wed, 31 Jul 2013 10:13:30 +0100 | From | Mel Gorman <> | Subject | Re: [PATCH 13/18] mm: numa: Scan pages with elevated page_mapcount |
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On Wed, Jul 17, 2013 at 01:22:22PM +0800, Sam Ben wrote: > On 07/15/2013 11:20 PM, Mel Gorman wrote: > >Currently automatic NUMA balancing is unable to distinguish between false > >shared versus private pages except by ignoring pages with an elevated > > What's the meaning of false shared? >
Two tasks may be operating on a shared buffer that is not aligned. It is expected that will at least cache align to avoid CPU cache line bouncing but the buffers are not necessarily page aligned. A page is the minimum granularity we can track NUMA hinting faults so two tasks sharing such a page will appear to be sharing data when in fact they are not.
-- Mel Gorman SUSE Labs
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