Messages in this thread | | | Date | Thu, 6 Mar 2014 10:10:09 +0100 | From | Igor Mammedov <> | Subject | Re: [PATCH] abort secondary CPU bring-up gracefully if do_boot_cpu timed out on cpu_callin_mask |
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On Thu, 6 Mar 2014 08:08:32 +0100 Ingo Molnar <mingo@kernel.org> wrote:
> > * Igor Mammedov <imammedo@redhat.com> wrote: > > > Master CPU may timeout before cpu_callin_mask is set and cancel > > booting CPU, but being onlined CPU still continues to boot, sets > > cpu_active_mask (CPU_STARTING notifiers) and spins in > > check_tsc_sync_target() for master cpu to arrive. Following attempt > > to online another cpu hangs in stop_machine, initiated from here: > > The changelog needs to prominently contain a description of the > practical relevance of this patch: has the hang triggered on any > system and under what circumstances, and did the patch resolve the > hang, etc.?
Hang is observed on virtual machines during CPU hotplug, especially in big guests with many CPUs. (It happens more often if host is over-committed).
Similar patch is carried in RHEL6 since 2012 and it fixes issue there, when applied to upstream kernel it also fixes issue.
> > Thanks, > > Ingo
Thanks, Igor.
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