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authorPeter Zijlstra <peterz@infradead.org>2021-06-11 10:28:13 +0200
committerPeter Zijlstra <peterz@infradead.org>2021-06-18 11:43:07 +0200
commit3ba9f93b12361e005dd65fcc8072b42e3189f4f4 (patch)
treeff7b3224fb4f03ea17ac76b0d1ad0c2431d0a7ab
parentb03fbd4ff24c5f075e58eb19261d5f8b3e40d7c6 (diff)
downloadlinux-3ba9f93b12361e005dd65fcc8072b42e3189f4f4.tar.bz2
sched,perf,kvm: Fix preemption condition
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) <peterz@infradead.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20210611082838.285099381@infradead.org
-rw-r--r--kernel/events/core.c7
-rw-r--r--virt/kvm/kvm_main.c2
2 files changed, 4 insertions, 5 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index fe88d6eea3c2..fd89000c9bf5 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -8682,13 +8682,12 @@ static void perf_event_switch(struct task_struct *task,
},
};
- if (!sched_in && task->state == TASK_RUNNING)
+ if (!sched_in && task->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);
}
/*
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 6a6bc7af0e28..5f166eb8ee2e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -5025,7 +5025,7 @@ static void kvm_sched_out(struct preempt_notifier *pn,
{
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);
}