On Fri, Oct 07, 2011 at 04:17:22PM +0100, Mel Gorman wrote: > From: Rik van Riel <riel@xxxxxxxxxx> > > When suffering from memory fragmentation due to unfreeable pages, > THP page faults will repeatedly try to compact memory. Due to the > unfreeable pages, compaction fails. > > Needless to say, at that point page reclaim also fails to create > free contiguous 2MB areas. However, that doesn't stop the current > code from trying, over and over again, and freeing a minimum of 4MB > (2UL << sc->order pages) at every single invocation. > > This resulted in my 12GB system having 2-3GB free memory, a > corresponding amount of used swap and very sluggish response times. > > This can be avoided by having the direct reclaim code not reclaim from > zones that already have plenty of free memory available for compaction. > > If compaction still fails due to unmovable memory, doing additional > reclaim will only hurt the system, not help. > > Signed-off-by: Rik van Riel <riel@xxxxxxxxxx> > Signed-off-by: Mel Gorman <mgorman@xxxxxxx> Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx> -- Kinds regards, Minchan Kim -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>