From e4099a5e929435cd6349343f002583f29868c900 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 17 Dec 2013 10:03:34 +0100 Subject: [PATCH] sched/deadline: Fix up the smp-affinity mask tests For now deadline tasks are not allowed to set smp affinity; however the current tests are wrong, cure this. The test in __sched_setscheduler() also uses an on-stack cpumask_t which is a no-no. Change both tests to use cpumask_subset() such that we test the root domain span to be a subset of the cpus_allowed mask. This way we're sure the tasks can always run on all CPUs they can be balanced over, and have no effective affinity constraints. Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/n/tip-fyqtb1lapxca3lhsxv9cumdc@git.kernel.org Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 28 +++++++++------------------- 1 file changed, 9 insertions(+), 19 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index e30356d6..27c6375 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3384,23 +3384,14 @@ change: #ifdef CONFIG_SMP if (dl_bandwidth_enabled() && dl_policy(policy)) { cpumask_t *span = rq->rd->span; - cpumask_t act_affinity; - - /* - * cpus_allowed mask is statically initialized with - * CPU_MASK_ALL, span is instead dynamic. Here we - * compute the "dynamic" affinity of a task. - */ - cpumask_and(&act_affinity, &p->cpus_allowed, - cpu_active_mask); /* * Don't allow tasks with an affinity mask smaller than * the entire root_domain to become SCHED_DEADLINE. We * will also fail if there's no bandwidth available. */ - if (!cpumask_equal(&act_affinity, span) || - rq->rd->dl_bw.bw == 0) { + if (!cpumask_subset(span, &p->cpus_allowed) || + rq->rd->dl_bw.bw == 0) { task_rq_unlock(rq, p, &flags); return -EPERM; } @@ -3420,8 +3411,7 @@ change: * of a SCHED_DEADLINE task) we need to check if enough bandwidth * is available. */ - if ((dl_policy(policy) || dl_task(p)) && - dl_overflow(p, policy, attr)) { + if ((dl_policy(policy) || dl_task(p)) && dl_overflow(p, policy, attr)) { task_rq_unlock(rq, p, &flags); return -EBUSY; } @@ -3860,6 +3850,10 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) if (retval) goto out_unlock; + + cpuset_cpus_allowed(p, cpus_allowed); + cpumask_and(new_mask, in_mask, cpus_allowed); + /* * Since bandwidth control happens on root_domain basis, * if admission test is enabled, we only admit -deadline @@ -3870,16 +3864,12 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) if (task_has_dl_policy(p)) { const struct cpumask *span = task_rq(p)->rd->span; - if (dl_bandwidth_enabled() && - !cpumask_equal(in_mask, span)) { + if (dl_bandwidth_enabled() && !cpumask_subset(span, new_mask)) { retval = -EBUSY; goto out_unlock; } } #endif - - cpuset_cpus_allowed(p, cpus_allowed); - cpumask_and(new_mask, in_mask, cpus_allowed); again: retval = set_cpus_allowed_ptr(p, new_mask); @@ -4535,7 +4525,7 @@ EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); * When dealing with a -deadline task, we have to check if moving it to * a new CPU is possible or not. In fact, this is only true iff there * is enough bandwidth available on such CPU, otherwise we want the - * whole migration progedure to fail over. + * whole migration procedure to fail over. */ static inline bool set_task_cpu_dl(struct task_struct *p, unsigned int cpu) -- 2.7.4