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| author | Will Deacon <will@kernel.org> | 2021-07-30 12:24:36 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-08-20 12:33:00 +0200 |
| commit | 234b8ab6476c5edd5262e2ff563de9498d60044a (patch) | |
| tree | 0aef76cf961a22e3f622d17824cc532745609604 | |
| parent | 07ec77a1d4e82526e1588979fff2f024f8e96df2 (diff) | |
| download | lwn-234b8ab6476c5edd5262e2ff563de9498d60044a.tar.gz lwn-234b8ab6476c5edd5262e2ff563de9498d60044a.zip | |
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 <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Link: https://lore.kernel.org/r/20210730112443.23245-10-will@kernel.org
| -rw-r--r-- | include/linux/sched.h | 6 | ||||
| -rw-r--r-- | kernel/sched/core.c | 46 |
2 files changed, 35 insertions, 17 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index ce2d5cfc331e..3bb9fecfdaa1 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1709,6 +1709,7 @@ extern void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new extern int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask); extern int dup_user_cpus_ptr(struct task_struct *dst, struct task_struct *src, int node); extern void release_user_cpus_ptr(struct task_struct *p); +extern int dl_task_check_affinity(struct task_struct *p, const struct cpumask *mask); extern void force_compatible_cpus_allowed_ptr(struct task_struct *p); extern void relax_compatible_cpus_allowed_ptr(struct task_struct *p); #else @@ -1731,6 +1732,11 @@ static inline void release_user_cpus_ptr(struct task_struct *p) { WARN_ON(p->user_cpus_ptr); } + +static inline int dl_task_check_affinity(struct task_struct *p, const struct cpumask *mask) +{ + return 0; +} #endif extern int yield_to(struct task_struct *p, bool preempt); 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) |