On Wed, May 11, 2016 at 02:26:48PM +0200, Stefan Priebe - Profihost AG wrote: > Hi Brian, > > i'm still unable to grab anything to the trace file? Is there anything > to check if it's working at all? > See my previous mail: http://oss.sgi.com/pipermail/xfs/2016-March/047793.html E.g., something like this should work after writing to and removing a new file: # trace-cmd start -e "xfs:xfs_releasepage" # cat /sys/kernel/debug/tracing/trace_pipe ... rm-8198 [000] .... 9445.774070: xfs_releasepage: dev 253:4 ino 0x69 pgoff 0x9ff000 size 0xa00000 offset 0 length 0 delalloc 0 unwritten 0 Once that is working, add the grep command to filter out "delalloc 0" instances, etc. For example: cat .../trace_pipe | grep -v "delalloc 0" > ~/trace.out Brian > This still happens in the first 48 hours after a fresh reboot. > > Stefan > > Am 24.03.2016 um 13:24 schrieb Brian Foster: > > On Thu, Mar 24, 2016 at 01:17:15PM +0100, Stefan Priebe - Profihost AG wrote: > >> > >> Am 24.03.2016 um 12:17 schrieb Brian Foster: > >>> On Thu, Mar 24, 2016 at 09:15:15AM +0100, Stefan Priebe - Profihost AG wrote: > >>>> > >>>> Am 24.03.2016 um 09:10 schrieb Stefan Priebe - Profihost AG: > >>>>> > >>>>> Am 23.03.2016 um 15:07 schrieb Brian Foster: > >>>>>> On Wed, Mar 23, 2016 at 02:28:03PM +0100, Stefan Priebe - Profihost AG wrote: > >>>>>>> sorry new one the last one got mangled. Comments inside. > >>>>>>> > >>>>>>> Am 05.03.2016 um 23:48 schrieb Dave Chinner: > >>>>>>>> On Fri, Mar 04, 2016 at 04:03:42PM -0500, Brian Foster wrote: > >>>>>>>>> On Fri, Mar 04, 2016 at 09:02:06PM +0100, Stefan Priebe wrote: > >>>>>>>>>> Am 04.03.2016 um 20:13 schrieb Brian Foster: > >>>>>>>>>>> On Fri, Mar 04, 2016 at 07:47:16PM +0100, Stefan Priebe wrote: > >>>>>>>>>>>> Am 20.02.2016 um 19:02 schrieb Stefan Priebe - Profihost AG: > >>>>>>>>>>>>> > >>>>>>>>>>>>>> Am 20.02.2016 um 15:45 schrieb Brian Foster <bfoster@xxxxxxxxxx>: > >>>>>>>>>>>>>> > >>>>>>>>>>>>>>> On Sat, Feb 20, 2016 at 09:02:28AM +0100, Stefan Priebe wrote: > >>>>>> ... > >>>>>>> > >>>>>>> This has happened again on 8 different hosts in the last 24 hours > >>>>>>> running 4.4.6. > >>>>>>> > >>>>>>> All of those are KVM / Qemu hosts and are doing NO I/O except the normal > >>>>>>> OS stuff as the VMs have remote storage. So no database, no rsync on > >>>>>>> those hosts - just the OS doing nearly nothing. > >>>>>>> > >>>>>>> All those show: > >>>>>>> [153360.287040] WARNING: CPU: 0 PID: 109 at fs/xfs/xfs_aops.c:1234 > >>>>>>> xfs_vm_releasepage+0xe2/0xf0() > >>>>>>> > >>>>>> > >>>>>> Ok, well at this point the warning isn't telling us anything beyond > >>>>>> you're reproducing the problem. We can't really make progress without > >>>>>> more information. We don't necessarily know what application or > >>>>>> operations caused this by the time it occurs, but perhaps knowing what > >>>>>> file is affected could give us a hint. > >>>>>> > >>>>>> We have the xfs_releasepage tracepoint, but that's unconditional and so > >>>>>> might generate a lot of noise by default. Could you enable the > >>>>>> xfs_releasepage tracepoint and hunt for instances where delalloc != 0? > >>>>>> E.g., we could leave a long running 'trace-cmd record -e > >>>>>> "xfs:xfs_releasepage" <cmd>' command on several boxes and wait for the > >>>>>> problem to occur. Alternatively (and maybe easier), run 'trace-cmd start > >>>>>> -e "xfs:xfs_releasepage"' and leave something like 'cat > >>>>>> /sys/kernel/debug/tracing/trace_pipe | grep -v "delalloc 0" > > >>>>>> ~/trace.out' running to capture instances. > >>>> > >>>> Isn't the trace a WARN_ONCE? So it does not reoccur or can i check the > >>>> it in the trace.out even the WARN_ONCE was already triggered? > >>>> > >>> > >>> The tracepoint is independent from the warning (see > >>> xfs_vm_releasepage()), so the tracepoint will fire every invocation of > >>> the function regardless of whether delalloc blocks still exist at that > >>> point. That creates the need to filter the entries. > >>> > >>> With regard to performance, I believe the tracepoints are intended to be > >>> pretty lightweight. I don't think it should hurt to try it on a box, > >>> observe for a bit and make sure there isn't a huge impact. Note that the > >>> 'trace-cmd record' approach will save everything to file, so that's > >>> something to consider I suppose. > >> > >> Tests / cat is running. Is there any way to test if it works? Or is it > >> enough that cat prints stuff from time to time but does not match -v > >> delalloc 0 > >> > > > > What is it printing where delalloc != 0? You could always just cat > > trace_pipe and make sure the event is firing, it's just that I suspect > > most entries will have delalloc == unwritten == 0. > > > > Also, while the tracepoint fires independent of the warning, it might > > not be a bad idea to restart a system that has already seen the warning > > since boot, just to provide some correlation or additional notification > > when the problem occurs. > > > > Brian > > > >> Stefan > >> > >> _______________________________________________ > >> xfs mailing list > >> xfs@xxxxxxxxxxx > >> http://oss.sgi.com/mailman/listinfo/xfs > > _______________________________________________ > xfs mailing list > xfs@xxxxxxxxxxx > http://oss.sgi.com/mailman/listinfo/xfs _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
