[SRU][F/aws][PATCH 0/2] aws: proper fix for c5.18xlarge hibernation issues

[Colin Ian King]

On 23/03/2021 16:15, Andrea Righi wrote:
> BugLink: https://bugs.launchpad.net/bugs/1920944
> 
> [Impact]
> 
> In LP: #1918694 we applied a fix and a workaround to solve the
> hibernation issues on c5.18xlarge. The workaround was in the form of a
> SAUCE patch:
> 
>   "UBUNTU: SAUCE: aws: kvm: double the size of hv_clock_boot"
> 
> It looks like we can replace this workaround with a proper fix, by
> applying this patch:
> https://lore.kernel.org/kvm/87sg4t7vqy.fsf@vitty.brq.redhat.com/T/#m7533e1d1e551bff425da029fd401bd87935edc33
> 
> [Test plan]
> 
> Create a c5.18xlarge instance, run the memory stress test script (the
> same test script that we are using to stress test hibernation), trigger
> the hibernate event, trigger the resume event. Repeat a couple of times
> and the problem is very likely to happen.
> 
> [Fix]
> 
> Replace "UBUNTU: SAUCE: aws: kvm: double the size of hv_clock_boot"
> with:
> 
> https://lore.kernel.org/kvm/87sg4t7vqy.fsf@vitty.brq.redhat.com/T/#m7533e1d1e551bff425da029fd401bd87935edc33

There has been a follow-up comment on this fix:

https://lore.kernel.org/kvm/87sg4t7vqy.fsf@vitty.brq.redhat.com/T/#e7533e1d1e551bff425da029fd401bd87935edc33

should we wait for a V2 of this fix?

> 
> The fix has been tested extensively in the AWS infrastructure with
> positive results.
> 
> [Regression potential]
> 
> This new code introduced by the fix can be executed also when a CPU is
> put offline, so we may see potential regressions in the KVM CPU
> hotplugging.
> 
>