Messages in this thread | | | Subject | Re: [PATCH 2/2] KVM: selftests: Use getcpu() instead of sched_getcpu() in rseq_test | From | Gavin Shan <> | Date | Wed, 10 Aug 2022 10:45:50 +1000 |
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On 8/10/22 6:53 AM, Sean Christopherson wrote: > 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". >
Yep, I will have something like below in next revision:
/* * We have to perform direct system call for getcpu() because it's not * available until glic 2.29. */
Thanks, Gavin
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