On Tue, Apr 02, 2013 at 11:03:36PM +0800, Zheng Liu wrote: > Hi Mel, > > Thanks for reporting it. > > On 04/02/2013 10:27 PM, Mel Gorman wrote: > > I'm testing a page-reclaim-related series on my laptop that is partially > > aimed at fixing long stalls when doing metadata-intensive operations on > > low memory such as a git checkout. I've been running 3.9-rc2 with the > > series applied but found that the interactive performance was awful even > > when there was plenty of free memory. > > > > I activated a monitor from mmtests that logs when a process is stuck for > > a long time in D state and found that there are a lot of stalls in ext4. > > The report first states that processes have been stalled for a total of > > 6498 seconds on IO which seems like a lot. Here is a breakdown of the > > recorded events. > > In this merge window, we add a status tree as a extent cache. Meanwhile > a es_cache shrinker is registered to try to reclaim from this cache when > we are under a high memory pressure. Ok. > So I suspect that the root cause > is this shrinker. Could you please tell me how to reproduce this > problem? If I understand correctly, I can run mmtest to reproduce this > problem, right? > This is normal desktop usage with some development thrown in, nothing spectacular but nothing obviously reproducible either unfortuantely. I just noticed that some git operations were taking abnormally long, mutt was very slow opening mail, applications like mozilla were very slow to launch etc. and dug a little further. I haven't checked if regression tests under mmtests captured something similar yet. -- Mel Gorman SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
