On Wed, Sep 08, 2010 at 12:14:29PM +0900, KOSAKI Motohiro wrote: > > There have been numerous reports of stalls that pointed at the problem being > > somewhere in the VM. There are multiple roots to the problems which means > > dealing with any of the root problems in isolation is tricky to justify on > > their own and they would still need integration testing. This patch series > > gathers together three different patch sets which in combination should > > tackle some of the root causes of latency problems being reported. > > > > The first patch improves vmscan latency by tracking when pages get reclaimed > > by shrink_inactive_list. For this series, the most important results is > > being able to calculate the scanning/reclaim ratio as a measure of the > > amount of work being done by page reclaim. > > > > Patches 2 and 3 account for the time spent in congestion_wait() and avoids > > calling going to sleep on congestion when it is unnecessary. This is expected > > to reduce stalls in situations where the system is under memory pressure > > but not due to congestion. > > > > Patches 4-8 were originally developed by Kosaki Motohiro but reworked for > > this series. It has been noted that lumpy reclaim is far too aggressive and > > trashes the system somewhat. As SLUB uses high-order allocations, a large > > cost incurred by lumpy reclaim will be noticeable. It was also reported > > during transparent hugepage support testing that lumpy reclaim was trashing > > the system and these patches should mitigate that problem without disabling > > lumpy reclaim. > > Wow, I'm sorry my lazyness bother you. I'll join to test this patch series > ASAP and take a feedback soon. > It did not bother me at all. I generally agreed with the direction and it seemed sensible to take them into consideration before patches 9 and 10 in particular and make sure they all played nicely together. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>