On Tue, Apr 02, 2013 at 04:34:25PM +0200, Stefan Priebe - Profihost AG wrote: > > > > When you see the 100% CPU usage can you cat /proc/PID/stack a couple of > > times and post it here? That might give a hint as to where it's going wrong. > > Sadly i'm not able to reproduce a 100% load process tried now for some > hours. Mostly they segfault. > I see. I checked the v3.8 and v3.9-rc results for my own NUMA machine but I'm seeing no evidence of test failures or segfaults. > >>> Anything in the kernel log? > >> Three examples: > >> pigz[10194]: segfault at 0 ip (null) sp 00007f6197ffed50 error > >> 14 in pigz[400000+e000] > >> > >> rbd[2811]: segfault at b8 ip 00007f73c2d51b9e sp 00007f73bcae3b40 error > >> 4 in librados.so.2.0.0[7f73c2afe000+3b9000] > >> > >> rbd[1805]: segfault at 0 ip 00007f60c28dceb4 sp 00007f60b7ffd1f8 error 4 > >> in ld-2.11.3.so[7f60c28cc000+1e000] > >> > >>> Any particular pattern to the crashes? Any means of reliably > >>> reproducing it? > >> No i just need to run some task and after some time they die or hang > >> forever. I have this on 10 different E5-2640 and also on E56XX. I can > >> "fix" this by: > >> 1.) putting all memory to just ONE CPU > >> 2.) Disable NUMA Balancing > >> > > > > That does point the finger at the automatic balancing. > > > >>> 3.8 vanilla, 3.8-stable or 3.8 with any other patches > >>> applied? > >> 3.8.4 without any patches. > >> > > Did it happen in 3.8? > > I've now tested 3.9-rc5 this gaves me a slightly different kernel log: > [ 197.236518] pigz[2908]: segfault at 0 ip (null) sp > 00007f347bffed00 error 14 > [ 197.237632] traps: pigz[2915] general protection ip:7f3482dbce2d > sp:7f3473ffec10 error:0 in libz.so.1.2.3.4[7f3482db7000+17000] > [ 197.330615] in pigz[400000+10000] > > With 3.8 it is the same as with 3.8.4 or 3.8.5. > Ok. Are there NUMA machines were you do *not* see this problem? If so, can you spot what the common configuration, software or hardware, that affects the broken machines versus the working machines? I'm wondering if there is a bug in a migration handler. Do you know if a NUMA nodes are low on memory when the segfaults occur? I'm also considering the possibility that one of the migration failure paths are failing to clear a NUMA hinting entry properly. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>