On 10/07/2013 06:28 AM, Mel Gorman wrote: > From: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > > 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@xxxxxxxxxxxxx> > Signed-off-by: Mel Gorman <mgorman@xxxxxxx> Reviewed-by: Rik van Riel <riel@xxxxxxxxxx> -- All rights reversed -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>