Re: [PATCH 2/2] KVM: selftests: Use getcpu() instead of sched_getcpu() in rseq_test

From: Sean Christopherson
Date: Tue Aug 09 2022 - 16:54:41 EST


On Tue, Aug 09, 2022, Gavin Shan wrote:
> On 8/9/22 5:17 PM, Florian Weimer wrote:
> > * Florian Weimer:
> >
> > > * Gavin Shan:
> > >
> > > > sched_getcpu() is glibc dependent and it can simply return the CPU
> > > > ID from the registered rseq information, as Florian Weimer pointed.
> > > > In this case, it's pointless to compare the return value from
> > > > sched_getcpu() and that fetched from the registered rseq information.
> > > >
> > > > Fix the issue by replacing sched_getcpu() with getcpu(), as Florian
> > > > suggested. The comments are modified accordingly.
> > >
> > > Note that getcpu was added in glibc 2.29, so perhaps you need to perform
> > > a direct system call?
> >
> > One more thing: syscall(__NR_getcpu) also has the advantage that it
> > wouldn't have to be changed again if node IDs become available via rseq
> > and getcpu is implemented using that.
> >
> > Thanks,
> > Florian
> >
>
> Thanks, Florian. It makes sense to me to use syscall(__NR_getcpu) in
> next revision. Thanks for your quick review :)

+1, and definitely add a comment to prevent future "cleanup".