Messages in this thread | | | Date | Thu, 6 Mar 2014 14:32:11 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] abort secondary CPU bring-up gracefully if do_boot_cpu timed out on cpu_callin_mask |
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* Igor Mammedov <imammedo@redhat.com> wrote:
> 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.
Okay, cool - please update the patch description with that and resubmit.
Thanks,
Ingo
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