Split the function so the actual work part can be reused and called from
places which hold rq::lock already.
No functional change.
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
---
kernel/sched/core.c | 64 ++++++++++++++++++++++++++++++----------------------
1 file changed, 38 insertions(+), 26 deletions(-)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1863,34 +1863,17 @@ void do_set_cpus_allowed(struct task_str
set_next_task(rq, p);
}
-/*
- * Change a given task's CPU affinity. Migrate the thread to a
- * proper CPU and schedule it away if the CPU it's executing on
- * is removed from the allowed bitmask.
- *
- * NOTE: the caller must have a valid reference to the task, the
- * task must not exit() & deallocate itself prematurely. The
- * call is not atomic; no spinlocks may be held.
- */
-static int __set_cpus_allowed_ptr(struct task_struct *p,
- const struct cpumask *new_mask, bool check)
+static int set_cpus_allowed_ptr_locked(struct task_struct *p,
+ const struct cpumask *new_mask,
+ bool check,
+ struct rq *rq, struct rq_flags *rf)
{
const struct cpumask *cpu_valid_mask = cpu_active_mask;
unsigned int dest_cpu;
- struct rq_flags rf;
- struct rq *rq;
int ret = 0;
- rq = task_rq_lock(p, &rf);
update_rq_clock(rq);
- if (p->flags & PF_KTHREAD) {
- /*
- * Kernel threads are allowed on online && !active CPUs
- */
- cpu_valid_mask = cpu_online_mask;
- }
-
/*
* Must re-check here, to close a race against __kthread_bind(),
* sched_setaffinity() is not guaranteed to observe the flag.
@@ -1900,8 +1883,12 @@ static int __set_cpus_allowed_ptr(struct
goto out;
}
- if (cpumask_equal(&p->cpus_mask, new_mask))
- goto out;
+ if (p->flags & PF_KTHREAD) {
+ /*
+ * Kernel threads are allowed on online && !active CPUs
+ */
+ cpu_valid_mask = cpu_online_mask;
+ }
/*
* Picking a ~random cpu helps in cases where we are changing affinity
@@ -1933,7 +1920,7 @@ static int __set_cpus_allowed_ptr(struct
if (task_running(rq, p) || p->state == TASK_WAKING) {
struct migration_arg arg = { p, dest_cpu };
/* Need help from migration thread: drop lock and wait. */
- task_rq_unlock(rq, p, &rf);
+ task_rq_unlock(rq, p, rf);
stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
return 0;
} else if (task_on_rq_queued(p)) {
@@ -1941,10 +1928,35 @@ static int __set_cpus_allowed_ptr(struct
* OK, since we're going to drop the lock immediately
* afterwards anyway.
*/
- rq = move_queued_task(rq, &rf, p, dest_cpu);
+ rq = move_queued_task(rq, rf, p, dest_cpu);
}
out:
- task_rq_unlock(rq, p, &rf);
+ task_rq_unlock(rq, p, rf);
+ return ret;
+}
+
+/*
+ * Change a given task's CPU affinity. Migrate the thread to a
+ * proper CPU and schedule it away if the CPU it's executing on
+ * is removed from the allowed bitmask.
+ *
+ * NOTE: the caller must have a valid reference to the task, the
+ * task must not exit() & deallocate itself prematurely. The
+ * call is not atomic; no spinlocks may be held.
+ */
+static int __set_cpus_allowed_ptr(struct task_struct *p,
+ const struct cpumask *new_mask, bool check)
+{
+ struct rq_flags rf;
+ struct rq *rq;
+ int ret = 0;
+
+ rq = task_rq_lock(p, &rf);
+
+ if (cpumask_equal(&p->cpus_mask, new_mask))
+ task_rq_unlock(rq, p, &rf);
+ else
+ ret = set_cpus_allowed_ptr_locked(p, new_mask, check, rq, &rf);
return ret;
}
