Messages in this thread | | | Date | Fri, 25 Jul 2014 15:50:06 +0800 | From | Daniel J Blueman <> | Subject | [3.14] core onlining/hotplug regression |
| |
Hi Thomas et al,
On a larger x86 system with 1728 cores, 3.15(.6) asserts on smpboot_thread_fn's td->cpu != smp_processor_id() consistently after ~1500 cores are online.
Reverting the only directly related changes I could find [1,2] doesn't help. Debugging indicates there is a race where the created thread is quickly migrated to core 0 when this occurs, since smp_processor_id returns 0 in these cases. Thomas introduced a thread parked state to fix related issues a year back. Linux 3.14(.13) boots just nice.
Full boot output is at: https://resources.numascale.com/linux-315-thread-mig.txt
Any theories so far? I'll start bisecting when I have full access to the system again in a week and I'll do some more debugging with intermittent access before then.
Thanks, Daniel
-- [1]
commit 81c98869faa5f3a9457c93efef908ef476326b31 Author: Nishanth Aravamudan <nacc@linux.vnet.ibm.com> Date: Thu Apr 3 14:46:25 2014 -0700 kthread: ensure locality of task_struct allocations
-- [2]
commit 89f898c1e195fa6235c869bb457e500b7b3ac49d Author: Igor Mammedov <imammedo@redhat.com> Date: Thu Jun 5 15:42:43 2014 +0200
x86: Fix list/memory corruption on CPU hotplug -- Daniel J Blueman Principal Software Engineer, Numascale
| |