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Peter Anvin" , Joel Fernandes , netdev@vger.kernel.org, Jiri Olsa , Alasdair Kergon , Daniel Thompson , Davidlohr Bueso , kvm@vger.kernel.org, Will Deacon , cgroups@vger.kernel.org, x86@kernel.org, Jakub Kicinski , John Stultz , "Paul E. McKenney" , linux-pm@vger.kernel.org, Boqun Feng , Johannes Weiner , Josh Triplett , Arnaldo Carvalho de Melo , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, Borislav Petkov , Alexander Viro , Waiman Long , Namhyung Kim , Jens Axboe , Felipe Balbi , Stephen Boyd , Greg Kroah-Hartman , linux-usb@vger.kernel.org, "Rafael J. Wysocki" , Douglas Anderson , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Jason Wessel , Tejun Heo , Mathieu Desnoyers , Andrew Morton , rcu@vger.kernel.org, "David S. Miller" Subject: [dm-devel] [PATCH 3/6] sched,perf,kvm: Fix preemption condition X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit When ran from the sched-out path (preempt_notifier or perf_event), p->state is irrelevant to determine preemption. You can get preempted with !task_is_running() just fine. The right indicator for preemption is if the task is still on the runqueue in the sched-out path. Signed-off-by: Peter Zijlstra (Intel) --- kernel/events/core.c | 7 +++---- virt/kvm/kvm_main.c | 2 +- 2 files changed, 4 insertions(+), 5 deletions(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8568,13 +8568,12 @@ static void perf_event_switch(struct tas }, }; - if (!sched_in && task->state == TASK_RUNNING) + if (!sched_in && current->on_rq) { switch_event.event_id.header.misc |= PERF_RECORD_MISC_SWITCH_OUT_PREEMPT; + } - perf_iterate_sb(perf_event_switch_output, - &switch_event, - NULL); + perf_iterate_sb(perf_event_switch_output, &switch_event, NULL); } /* --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -4869,7 +4869,7 @@ static void kvm_sched_out(struct preempt { struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn); - if (current->state == TASK_RUNNING) { + if (current->on_rq) { WRITE_ONCE(vcpu->preempted, true); WRITE_ONCE(vcpu->ready, true); } -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel