Messages in this thread | | | Date | Mon, 07 Oct 2013 13:24:26 -0400 | From | Rik van Riel <> | Subject | Re: [PATCH 13/63] sched: numa: Mitigate chance that same task always updates PTEs |
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On 10/07/2013 06:28 AM, Mel Gorman wrote: > From: Peter Zijlstra <peterz@infradead.org> > > With a trace_printk("working\n"); right after the cmpxchg in > task_numa_work() we can see that of a 4 thread process, its always the > same task winning the race and doing the protection change. > > This is a problem since the task doing the protection change has a > penalty for taking faults -- it is busy when marking the PTEs. If its > always the same task the ->numa_faults[] get severely skewed. > > Avoid this by delaying the task doing the protection change such that > it is unlikely to win the privilege again.
> Signed-off-by: Peter Zijlstra <peterz@infradead.org> > Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
-- All rights reversed
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