Subject: sched, rt: Fix migrate_enable() thinko From: Mike Galbraith Date: Tue, 23 Aug 2011 16:12:43 +0200 Assigning mask = tsk_cpus_allowed(p) after p->migrate_disable = 0 ensures that we won't see a mask change.. no push/pull, we stack tasks on one CPU. Also add a couple fields to sched_debug for the next guy. [ Build fix from Stratos Psomadakis ] Signed-off-by: Mike Galbraith Cc: Paul E. McKenney Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1314108763.6689.4.camel@marge.simson.net Signed-off-by: Thomas Gleixner --- kernel/sched/core.c | 4 +++- kernel/sched/debug.c | 7 +++++++ 2 files changed, 10 insertions(+), 1 deletion(-) Index: linux-stable/kernel/sched/core.c =================================================================== --- linux-stable.orig/kernel/sched/core.c +++ linux-stable/kernel/sched/core.c @@ -5355,12 +5355,14 @@ void migrate_enable(void) */ rq = this_rq(); raw_spin_lock_irqsave(&rq->lock, flags); - p->migrate_disable = 0; mask = tsk_cpus_allowed(p); + p->migrate_disable = 0; WARN_ON(!cpumask_test_cpu(smp_processor_id(), mask)); if (!cpumask_equal(&p->cpus_allowed, mask)) { + /* Get the mask now that migration is enabled */ + mask = tsk_cpus_allowed(p); if (p->sched_class->set_cpus_allowed) p->sched_class->set_cpus_allowed(p, mask); p->nr_cpus_allowed = cpumask_weight(mask); Index: linux-stable/kernel/sched/debug.c =================================================================== --- linux-stable.orig/kernel/sched/debug.c +++ linux-stable/kernel/sched/debug.c @@ -237,6 +237,9 @@ void print_rt_rq(struct seq_file *m, int P(rt_throttled); PN(rt_time); PN(rt_runtime); +#ifdef CONFIG_SMP + P(rt_nr_migratory); +#endif #undef PN #undef P @@ -491,6 +494,10 @@ void proc_sched_show_task(struct task_st P(se.load.weight); P(policy); P(prio); +#ifdef CONFIG_PREEMPT_RT_FULL + P(migrate_disable); +#endif + P(nr_cpus_allowed); #undef PN #undef __PN #undef P