From: Sean Christopherson <seanjc@google.com>
To: Gavin Shan <gshan@redhat.com>
Cc: Florian Weimer <fweimer@redhat.com>,
shan.gavin@gmail.com, kvm@vger.kernel.org, maz@kernel.org,
linux-kernel@vger.kernel.org, andrew.jones@linux.dev,
mathieu.desnoyers@efficios.com, yihyu@redhat.com,
linux-kselftest@vger.kernel.org, pbonzini@redhat.com,
kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH 2/2] KVM: selftests: Use getcpu() instead of sched_getcpu() in rseq_test
Date: Tue, 9 Aug 2022 20:53:36 +0000 [thread overview]
Message-ID: <YvLJUEOcxaZKW0y1@google.com> (raw)
In-Reply-To: <ea2ef1a2-0fd8-448b-d7ca-254603518823@redhat.com>
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".
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next prev parent reply other threads:[~2022-08-09 20:53 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-09 6:06 [PATCH 0/2] kvm/selftests: Two rseq_test fixes Gavin Shan
2022-08-09 6:06 ` [PATCH 1/2] KVM: selftests: Make rseq compatible with glibc-2.35 Gavin Shan
2022-08-09 6:33 ` Florian Weimer
2022-08-09 8:45 ` Gavin Shan
2022-08-09 7:16 ` Florian Weimer
2022-08-09 9:27 ` Gavin Shan
2022-08-09 12:21 ` Mathieu Desnoyers
2022-08-09 13:44 ` Mathieu Desnoyers
2022-08-09 21:38 ` Sean Christopherson
2022-08-10 0:37 ` Gavin Shan
2022-08-10 12:29 ` Mathieu Desnoyers
2022-08-10 12:35 ` Paolo Bonzini
2022-08-10 12:13 ` Mathieu Desnoyers
2022-08-10 23:52 ` Gavin Shan
2022-08-10 9:14 ` Paolo Bonzini
2022-08-10 9:59 ` Gavin Shan
2022-08-10 12:17 ` Mathieu Desnoyers
2022-08-10 12:19 ` Paolo Bonzini
2022-08-10 23:34 ` Gavin Shan
2022-08-09 6:06 ` [PATCH 2/2] KVM: selftests: Use getcpu() instead of sched_getcpu() in rseq_test Gavin Shan
2022-08-09 6:35 ` Florian Weimer
2022-08-09 7:17 ` Florian Weimer
2022-08-09 8:46 ` Gavin Shan
2022-08-09 20:53 ` Sean Christopherson [this message]
2022-08-10 0:45 ` Gavin Shan
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