On Mon, Jul 23, 2012 at 02:38:43PM +0100, Mel Gorman wrote: > commit ad2b8e601099a23dffffb53f91c18d874fe98854 upstream - WARNING: this is a substitute patch. > > Stable note: Not tracked in Bugzilla. This is a substitute for an > upstream commit addressing a completely different issue that > accidentally contained an important fix. The workload this patch > helps was memcached when IO is started in the background. memcached > should stay resident but without this patch it gets swapped more > than it should. Sometimes this manifests as a drop in throughput > but mostly it was observed through /proc/vmstat. > > Commit [246e87a9: memcg: fix get_scan_count() for small targets] was > meant to fix a problem whereby small scan targets on memcg were ignored > causing priority to raise too sharply. It forced scanning to take place > if the target was small, memcg or kswapd. > > >From the time it was introduced it cause excessive reclaim by kswapd > with workloads being pushed to swap that previously would have stayed > resident. This was accidentally fixed by commit [ad2b8e60: mm: memcg: > remove optimization of keeping the root_mem_cgroup LRU lists empty] but > that patchset is not suitable for backporting. > > The original patch came with no information on what workloads it benefits > but the cost of it is obvious in that it forces scanning to take place > on lists that would otherwise have been ignored such as small anonymous > inactive lists. This patch partially reverts 246e87a9 so that small lists > are not force scanned which means that IO-intensive workloads with small > amounts of anonymous memory will not be swapped. > > Signed-off-by: Mel Gorman <mgorman@xxxxxxx> > --- > mm/vmscan.c | 3 --- > 1 file changed, 3 deletions(-) I don't understand this patch. The original ad2b8e601099a23dffffb53f91c18d874fe98854 commit touched the file mm/memcontrol.c and seemed to do something quite different from what you have done below. I'm all for fixing things in a different way than what was done in Linus's tree, IF there is a reason to, but the comparison between these two patches (yours and upstream) are not making any sense at all. confused, greg k-h -- 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>