In preparation for restricting the affinity of a task during execve()
on arm64, introduce a new task_cpus_dl_admissible() helper function to
give an indication as to whether the restricted mask is admissible for
a deadline task.
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
---
include/linux/sched.h | 6 ++++++
kernel/sched/core.c | 44 +++++++++++++++++++++++++++----------------
2 files changed, 34 insertions(+), 16 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 91a6cfeae242..9b17d8cfa6ef 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1691,6 +1691,7 @@ 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 bool task_cpus_dl_admissible(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
@@ -1713,6 +1714,11 @@ static inline void release_user_cpus_ptr(struct task_struct *p)
{
WARN_ON(p->user_cpus_ptr);
}
+
+static inline bool task_cpus_dl_admissible(struct task_struct *p, const struct cpumask *mask)
+{
+ return true;
+}
#endif
extern int yield_to(struct task_struct *p, bool preempt);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 998ed1dbfd4f..42e2aecf087c 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6925,6 +6925,31 @@ SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
return retval;
}
+#ifdef CONFIG_SMP
+bool task_cpus_dl_admissible(struct task_struct *p, const struct cpumask *mask)
+{
+ bool ret;
+
+ /*
+ * 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 true;
+
+ /*
+ * 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();
+ ret = cpumask_subset(task_rq(p)->rd->span, mask);
+ rcu_read_unlock();
+ return ret;
+}
+#endif
+
static int
__sched_setaffinity(struct task_struct *p, const struct cpumask *mask)
{
@@ -6942,23 +6967,10 @@ __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();
+ if (!task_cpus_dl_admissible(p, new_mask)) {
+ retval = -EBUSY;
+ goto out_free_new_mask;
}
-#endif
again:
retval = __set_cpus_allowed_ptr(p, new_mask, SCA_CHECK | SCA_USER);
if (retval)
--
2.31.1.818.g46aad6cb9e-goog
