Am 11.05.2016 um 15:34 schrieb Brian Foster: > 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 arg sorry yes that's working but delalloc is always 0. May be i have to hook that into my initramfs to be fast enough? Stefan > 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 -- 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
