diff options
Diffstat (limited to 'sys/kern/sched_ule.c')
| -rw-r--r-- | sys/kern/sched_ule.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/sys/kern/sched_ule.c b/sys/kern/sched_ule.c index a655440..961f80d 100644 --- a/sys/kern/sched_ule.c +++ b/sys/kern/sched_ule.c @@ -1037,6 +1037,14 @@ tdq_notify(struct tdq *tdq, struct thread *td) ctd = pcpu_find(cpu)->pc_curthread; if (!sched_shouldpreempt(pri, ctd->td_priority, 1)) return; + + /* + * Make sure that tdq_load updated before calling this function + * is globally visible before we read tdq_cpu_idle. Idle thread + * accesses both of them without locks, and the order is important. + */ + mb(); + if (TD_IS_IDLETHREAD(ctd)) { /* * If the MD code has an idle wakeup routine try that before @@ -2645,6 +2653,12 @@ sched_idletd(void *dummy) /* Run main MD idle handler. */ tdq->tdq_cpu_idle = 1; + /* + * Make sure that tdq_cpu_idle update is globally visible + * before cpu_idle() read tdq_load. The order is important + * to avoid race with tdq_notify. + */ + mb(); cpu_idle(switchcnt * 4 > sched_idlespinthresh); tdq->tdq_cpu_idle = 0; |
