Re: [PATCH 6/6] xen/sched: don't disable scheduler on cpus during suspend

From: Juergen Gross <jgross@suse.com>
To: Dario Faggioli <dfaggioli@suse.com>, xen-devel@lists.xenproject.org
Cc: George Dunlap <george.dunlap@eu.citrix.com>
Subject: Re: [PATCH 6/6] xen/sched: don't disable scheduler on cpus during suspend
Date: Thu, 28 Mar 2019 06:41:27 +0100	[thread overview]
Message-ID: <9a97cb91-6c72-1281-0d1c-55c769f225a6@suse.com> (raw)
In-Reply-To: <cd406cd362b1af495d8f84585b8cff1b706203fe.camel@suse.com>

On 28/03/2019 00:10, Dario Faggioli wrote:
> On Mon, 2019-03-18 at 14:11 +0100, Juergen Gross wrote:
>> Today there is special handling in cpu_disable_scheduler() for
>> suspend
>> by forcing all vcpus to the boot cpu. In fact there is no need for
>> that
>> as during resume the vcpus are put on the correct cpus again.
>>
>> So we can just omit the call of cpu_disable_scheduler() when
>> offlining
>> a cpu due to suspend and on resuming we can omit taking the schedule
>> lock for selecting the new processor.
>>
>> In restore_vcpu_affinity() we should be careful when applying
>> affinity
>> as the cpu might not have come back to life. This in turn enables us
>> to even support affinity_broken across suspend/resume.
>>
>> Avoid all other scheduler dealloc - alloc dance when doing suspend
>> and
>> resume, too. It is enough to react on cpus failing to come up on
>> resume
>> again.
>>
>> Signed-off-by: Juergen Gross <jgross@suse.com>
>>
> Ok, I think this patch is fine.
> 
> Reviewed-by: Dario Faggioli <dfaggioli@suse.com>
> 
> I guess you have tested both cpu off/on-lining and suspend/resume, or
> do you need help with that? (One of my testboxes that I have here,
> should be able to do suspend)

I've tested suspend/resume.

Juergen

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