Re: [PATCH 0/7] hv: CPU onlining/offlining fixes and improvements

From: Vitaly Kuznetsov
Date: Mon Jan 02 2017 - 14:51:12 EST


Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> writes:

> Some time ago we forbade CPU offlining for Hyper-V and this was sufficient
> if you boot with all CPUs onlined. Turns out, people may want to limit the
> number online CPUs by passing 'maxcpus=' kernel parameter and we hit a
> crash in Hyper-V code in this case. After some thinking, I think we may not
> only fix the crash but also make the offlining prevention fine-grained: we
> need to prevent from offlining CPUs which have VMBus channels attached
> only. All offlined CPUs may always be onlined.
>
> PATCH1 fixes a bug which is not directly related to the series, I hit it
> while testing hv_vmbus module unload with this series.
>
> Vitaly Kuznetsov (7):
> hv: acquire vmbus_connection.channel_mutex in vmbus_free_channels()
> hv: allocate synic pages for all present CPUs
> hv: init percpu_list in hv_synic_alloc()
> hv: change clockevents unbind tactics
> hv: check all present cpus in vmbus_wait_for_unload()
> hv: switch to cpuhp state machine for synic init/cleanup
> hv: make CPU offlining prevention fine-grained

K. Y.,

it seems that for some reason only patches 1 and 4 from this series made
it upstream (and to char-misc tree). Could you please resend the rest to
Greg? Please let me know if you want me to rebase/retest. Thanks!

--
Vitaly