2.6.32-longterm review patch. If anyone has any objections, please let us know.
------------------ Commit: 1e5a74059f9059d330744eac84873b1b99657008 upstream 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 <[email protected]> Tested-by: Marcelo Tosatti <[email protected]> Tested-by: Sergey Senozhatsky <[email protected]> Signed-off-by: Peter Zijlstra <[email protected]> LKML-Reference: <1288891946.2039.31.camel@laptop> Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Mike Galbraith <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- kernel/sched.c | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) --- a/kernel/sched.c +++ b/kernel/sched.c @@ -594,11 +594,7 @@ 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); -} +static void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags); static inline int cpu_of(struct rq *rq) { @@ -2392,6 +2388,24 @@ void task_oncpu_function_call(struct tas preempt_enable(); } +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; + } + } + } +} + #ifdef CONFIG_SMP /* * ->cpus_allowed is protected by either TASK_WAKING or rq->lock held. _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
