Re: [PATCH v3 0/4] implement vcpu preempted check

From: Christian Borntraeger
Date: Thu Sep 29 2016 - 06:23:41 EST

On 09/29/2016 12:10 PM, Peter Zijlstra wrote:
> On Thu, Jul 21, 2016 at 07:45:10AM -0400, Pan Xinhui wrote:
>> change from v2:
>> no code change, fix typos, update some comments
>> change from v1:
>> a simplier definition of default vcpu_is_preempted
>> skip mahcine type check on ppc, and add config. remove dedicated macro.
>> add one patch to drop overload of rwsem_spin_on_owner and mutex_spin_on_owner.
>> add more comments
>> thanks boqun and Peter's suggestion.
>> This patch set aims to fix lock holder preemption issues.
> So I really like the concept, but I would also really like to see
> support for more hypervisors included before we can move forward with
> this.
> Please consider s390 and (x86/arm) KVM. Once we have a few, more can
> follow later, but I think its important to not only have PPC support for
> this.

Actually the s390 preemted check via sigp sense running is available for
all hypervisors (z/VM, LPAR and KVM) which implies everywhere as you can no
longer buy s390 systems without LPAR.

As Heiko already pointed out we could simply use a small inline function
that calls cpu_is_preempted from arch/s390/lib/spinlock (or smp_vcpu_scheduled from smp.c)