I'm running the NUMA tests on 3.13 for some time now and it looks like the change did not introduce any regression...
$ uname -a Linux sf00079894trusty 3.13.11-ckt22-201507231149 #2 SMP Thu Jul 23 13:45:04 BRT 2015 x86_64 x86_64 x86_64 GNU/Linux I'm using a virtualized 16 Domains / 16 CPUs NUMA environment with the stress test tool: $ sudo numactl -H available: 16 nodes (0-15) node 0 cpus: 0 node 0 size: 363 MB node 0 free: 23 MB node 1 cpus: 1 node 1 size: 121 MB node 1 free: 7 MB node 2 cpus: 2 node 2 size: 377 MB node 2 free: 23 MB node 3 cpus: 3 node 3 size: 377 MB node 3 free: 23 MB node 4 cpus: 4 node 4 size: 377 MB node 4 free: 23 MB node 5 cpus: 5 node 5 size: 377 MB node 5 free: 23 MB node 6 cpus: 6 node 6 size: 377 MB node 6 free: 35 MB node 7 cpus: 7 node 7 size: 313 MB node 7 free: 19 MB node 8 cpus: 8 node 8 size: 377 MB node 8 free: 61 MB node 9 cpus: 9 node 9 size: 377 MB node 9 free: 57 MB node 10 cpus: 10 node 10 size: 377 MB node 10 free: 63 MB node 11 cpus: 11 node 11 size: 377 MB node 11 free: 30 MB node 12 cpus: 12 node 12 size: 377 MB node 12 free: 67 MB node 13 cpus: 13 node 13 size: 377 MB node 13 free: 68 MB node 14 cpus: 14 node 14 size: 377 MB node 14 free: 68 MB node 15 cpus: 15 node 15 size: 377 MB node 15 free: 64 MB $ sudo stress --vm 16 --vm-bytes 314572800 --vm-stride 1 --vm-keep & Causing memory allocations of around 300MB on each node and "touching" every byte of the allocation (causing all the pages to be "hot" on the CPU running). And generating concurrency: $ sudo stress --cpu 16 & So kernel scheduler has to migrate tasks, triggering the buggy logic's fix. I can confirm the logic is being triggered by using ftrace: $ sudo trace-cmd record -p function -l numa_migrate_preferred -l task_numa_migrate -l migrate_swap -l stop_two_cpus $ sudo trace-cmd report | grep stop_two_cpus | wc -l162 And can't find any regression. I'll let the tests to run a bit more and will suggest the fix to our kernel team to merge it as a Stable Release Update for Trusty, Utopic and Vivid. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1461620 Title: NUMA task migration race condition due to stop task not being checked when balancing happens To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1461620/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
