On Thu, Nov 01, 2007 at 07:20:51PM +0100, Torsten Kaiser wrote: > On 11/1/07, Fengguang Wu <wfg@xxxxxxxxxxxxxxxx> wrote: > > On Wed, Oct 31, 2007 at 04:22:10PM +0100, Torsten Kaiser wrote: > > > Since 2.6.23-mm1 I also experience strange hangs during heavy writeouts. > > > Each time I noticed this I was using emerge (package util from the > > > gentoo distribution) to install/upgrade a package. The last step, > > > where this hang occurred, is moving the prepared files from a tmpfs > > > partion to the main xfs filesystem. > > > The hangs where not fatal, after a few second everything resumed > > > normal, so I was not able to capture a good image of what was > > > happening. > > > > Thank you for the detailed report. > > > > How severe was the hangs? Only writeouts stalled, all apps stalled, or > > cannot type and run new commands? > > Only writeout stalled. The emerge that was moving the files hung, but > everything else worked normaly. > I was able to run new commands, like coping the /proc/meminfo. But you mentioned in the next mail that `watch cat /proc/meminfo` could also be blocked for some time - I guess in the same time emerge was stalled? > [snip] > > > After this SysRq+W writeback resumed again. Possible that writing > > > above into the syslog triggered that. > > > > Maybe. Are the log files on another disk/partition? > > No, everything was going to / > > What might be interesting is, that doing cat /proc/meminfo > >~/stall/meminfo did not resume the writeback. So there might some > threshold that only was broken with the additional write from > syslog-ng. Or syslog-ng does some flushing, I dont now. (I'm using the Have you tried explicit `sync`? ;-) > syslog-ng package from gentoo: > http://www.balabit.com/products/syslog_ng/ , version 2.0.5) > > > > The source tmpfs is mounted with any special parameters, but the > > > target xfs filesystem resides on a dm-crypt device that is on top a 3 > > > disk RAID5 md. > > > During the hang all CPUs where idle. > > > > No iowaits? ;-) > > No, I have a KSysGuard in my taskbar that showed no activity at all. > > OK, the subject does not match for my case, but there was also a tmpfs > involved. And I found no thread with stalls on xfs. :-) Do you mean it is actually related with tmpfs? > > > The system is x86_64 with CONFIG_NO_HZ=y, but was still receiving ~330 > > > interrupts per second because of the bttv driver. (But I was not using > > > that device at this time.) > > > > > > I'm willing to test patches or more provide more information, but lack > > > a good testcase to trigger this on demand. > > > > Thank you. Maybe we can start by the applied debug patch :-) > > Will applied it and try to recreate this. > > Thanks for looking into it. Thank you for the rich information, too :-) Fengguang - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
