On Mon, Aug 23, 2010 at 02:23:27AM -0700, David Rientjes wrote: > On Mon, 23 Aug 2010, Wu Fengguang wrote: > > > > I've been testing parallel create workloads over the weekend, and > > > I've seen this a couple of times now under 8 thread parallel creates > > > with XFS. I'm running on an 8p VM with 4GB RAM and a fast disk > > > subsystem. Basically I am seeing the create rate drop to zero > > > with all 8 CPUs stuck spinning for up to 2 minutes. 'echo t > > > > /proc/sysrq-trigger' while this is occurring gives the following > > > trace for all the fs-mark processes: ..... > > You may be interested in Mel's patchset that he just proposed for -mm > which identifies watermark variations on machines with high cpu counts > (perhaps even eight, as in this report). The last patch actually reworks > this hunk of the code as well. > > http://marc.info/?l=linux-mm&m=128255044912938 > http://marc.info/?l=linux-mm&m=128255045312950 > http://marc.info/?l=linux-mm&m=128255045012942 > http://marc.info/?l=linux-mm&m=128255045612954 > > Dave, it would be interesting to see if this fixes your problem. That looks promising - I'll give it a shot, though my test case is not really what you'd call reproducable(*) so it might take a couple of days before I can say whether the issue has gone away or not. Cheers, Dave. (*) create 100 million inodes in parallel using fsmark, collect and watch behavioural metrics via PCP/pmchart for stuff out of the ordinary, and dump stack traces, etc when somthing strange occurs. -- Dave Chinner david@xxxxxxxxxxxxx -- 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>