On Mon, Oct 4, 2010 at 11:21 AM, Dave Chinner <david@xxxxxxxxxxxxx> wrote: > On Mon, Oct 04, 2010 at 11:01:19AM +0200, Tejun Heo wrote: >> Hello, >> >> On 09/25/2010 03:08 PM, Torsten Kaiser wrote: >> > [adding Tejun Heo, because I'm partly blaming his workqueues] >> >> :-) Sorry about the delay. I was away the last week. >> >> > After that I enabled lockdep and retried the same update: This time no >> > hang, only the same lockdep report that Yang Ruirui had. >> > >> > So I'm currently at a loss how I should continue from here. The XFS >> > false positive drowns any other lockdep problems, but XFS had some >> > hang problems with the new workqueues. (Personally I had no other hang >> > with earlier 2.6.36-rcs) > > What XFS hang problem? I've seen temporary livelocks from the new > workqueue code, but thay have been fixed. I haven't come across any > deadlocks or hangs. Do you have a pointer to a bug report in case my > memory is failing me? I was referring to the hang that prompted to increase of the priority of the xfslogd thread. Its commit 51749e47e191db8e588ad5cebea731caf7b705d7 in Linus' tree. But it seems I have misremembered that one as a hang. The hang I have seen is describe here: http://marc.info/?l=linux-kernel&m=128542018414916&w=2 As 2.6.36-rc5 already includes this priority fix, I believe this hang is something different and wrote that mail. >> If workqueue lockdep annotations are triggering spuriously, just nuke >> all lockdep annotations in workqueue.c. Currently the annotations are >> the same as before and trigger even when an actual deadlock won't >> happen anymore around flushes (but then again all the current users >> should be operating under the same constraints as before). I'm >> looking into how to improve the lockdep annotations but in the end it >> might be best to leave it as it is. I'll try to analyze the warnings. > > It looks like there's been some discussion that has been private so > I'm clueless as to the context being discussed here. Can someone > fill me in on whatever is going on? I only send the above message both to the lkml and the XFS mailing list. But it could have been wrong to make it a reply in this thread, because now there are three different things mixed up. 1) the old livelock, that I was referring too -> That is already fixed in mainline, I just wanted to note, that this is unrelated to the hang I have seen. 2) the hang with 2.6.35-rc5 I have seen twice (triggered probably by high load while building KOffice on an tmpfs) 3) the lockdep issue that started this thread and that I am seeing in mainline 2.6.36-rc5 and -rc6 and that seems to be rather easy to trigger for me. Because 3) is regarded as a false positive, it should not be the cause of 2). But because 3) triggers on my system I can't see if lockdep might give better pointers to what might be the real cause of 2). So, I would like to test the patch Christoph was testing in http://marc.info/?l=linux-kernel&m=128501006509743&w=2 to see, if that helps to debug my hang. (And because I did not see that patch on the lkml, I replied to Christophs mail.) I CC'ed Tejun, because I believe the primary suspect for my hang was the stuck kworker/u:8:845 and I was hoping he might see something obvious wrong in that stacktrace. Torsten _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
