diff options
author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2010-10-31 12:37:04 +0100 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2010-11-11 14:37:23 +0100 |
commit | 1e5a74059f9059d330744eac84873b1b99657008 (patch) | |
tree | f32f8ac76d5a6c49c1b4cd8f83155af00007fac0 /kernel/sched.c | |
parent | 2d46709082c062cae7cce1a15f8cd4cd81b92d88 (diff) | |
download | op-kernel-dev-1e5a74059f9059d330744eac84873b1b99657008.zip op-kernel-dev-1e5a74059f9059d330744eac84873b1b99657008.tar.gz |
sched: Fix cross-sched-class wakeup preemption
Instead of dealing with sched classes inside each check_preempt_curr()
implementation, pull out this logic into the generic wakeup preemption
path.
This fixes a hang in KVM (and others) where we are waiting for the
stop machine thread to run ...
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Tested-by: Marcelo Tosatti <mtosatti@redhat.com>
Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1288891946.2039.31.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r-- | kernel/sched.c | 37 |
1 files changed, 26 insertions, 11 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 36a0880..dc91a4d 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -560,18 +560,8 @@ struct rq { static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); -static inline -void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) -{ - rq->curr->sched_class->check_preempt_curr(rq, p, flags); - /* - * A queue event has occurred, and we're going to schedule. In - * this case, we can save a useless back to back clock update. - */ - if (test_tsk_need_resched(p)) - rq->skip_clock_update = 1; -} +static void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags); static inline int cpu_of(struct rq *rq) { @@ -2118,6 +2108,31 @@ static inline void check_class_changed(struct rq *rq, struct task_struct *p, p->sched_class->prio_changed(rq, p, oldprio, running); } +static void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) +{ + const struct sched_class *class; + + if (p->sched_class == rq->curr->sched_class) { + rq->curr->sched_class->check_preempt_curr(rq, p, flags); + } else { + for_each_class(class) { + if (class == rq->curr->sched_class) + break; + if (class == p->sched_class) { + resched_task(rq->curr); + break; + } + } + } + + /* + * A queue event has occurred, and we're going to schedule. In + * this case, we can save a useless back to back clock update. + */ + if (test_tsk_need_resched(rq->curr)) + rq->skip_clock_update = 1; +} + #ifdef CONFIG_SMP /* * Is this task likely cache-hot: |