From 234b8ab6476c5edd5262e2ff563de9498d60044a Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 30 Jul 2021 12:24:36 +0100 Subject: sched: Introduce dl_task_check_affinity() to check proposed affinity In preparation for restricting the affinity of a task during execve() on arm64, introduce a new dl_task_check_affinity() helper function to give an indication as to whether the restricted mask is admissible for a deadline task. Signed-off-by: Will Deacon Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Daniel Bristot de Oliveira Link: https://lore.kernel.org/r/20210730112443.23245-10-will@kernel.org --- kernel/sched/core.c | 46 +++++++++++++++++++++++++++++----------------- 1 file changed, 29 insertions(+), 17 deletions(-) (limited to 'kernel/sched/core.c') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 6ee197049c9c..a22cc3c156ce 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7756,6 +7756,32 @@ out_unlock: return retval; } +#ifdef CONFIG_SMP +int dl_task_check_affinity(struct task_struct *p, const struct cpumask *mask) +{ + int ret = 0; + + /* + * If the task isn't a deadline task or admission control is + * disabled then we don't care about affinity changes. + */ + if (!task_has_dl_policy(p) || !dl_bandwidth_enabled()) + return 0; + + /* + * Since bandwidth control happens on root_domain basis, + * if admission test is enabled, we only admit -deadline + * tasks allowed to run on all the CPUs in the task's + * root_domain. + */ + rcu_read_lock(); + if (!cpumask_subset(task_rq(p)->rd->span, mask)) + ret = -EBUSY; + rcu_read_unlock(); + return ret; +} +#endif + static int __sched_setaffinity(struct task_struct *p, const struct cpumask *mask) { @@ -7773,23 +7799,9 @@ __sched_setaffinity(struct task_struct *p, const struct cpumask *mask) cpuset_cpus_allowed(p, cpus_allowed); cpumask_and(new_mask, mask, cpus_allowed); - /* - * Since bandwidth control happens on root_domain basis, - * if admission test is enabled, we only admit -deadline - * tasks allowed to run on all the CPUs in the task's - * root_domain. - */ -#ifdef CONFIG_SMP - if (task_has_dl_policy(p) && dl_bandwidth_enabled()) { - rcu_read_lock(); - if (!cpumask_subset(task_rq(p)->rd->span, new_mask)) { - retval = -EBUSY; - rcu_read_unlock(); - goto out_free_new_mask; - } - rcu_read_unlock(); - } -#endif + retval = dl_task_check_affinity(p, new_mask); + if (retval) + goto out_free_new_mask; again: retval = __set_cpus_allowed_ptr(p, new_mask, SCA_CHECK | SCA_USER); if (retval) -- cgit v1.2.3-59-g8ed1b