Commit d723f36e authored by Tejun Heo's avatar Tejun Heo
Browse files

sched_ext: Minor cleanups to scx_task_iter 



- Use memset() in scx_task_iter_start() instead of zeroing fields individually.

- In scx_task_iter_next(), move __scx_task_iter_maybe_relock() after the batch
  check which is simpler.

- Update comment to reflect that tasks are removed from scx_tasks when dead
  (commit 7900aa69 ("sched_ext: Fix cgroup exit ordering by moving
  sched_ext_free() to finish_task_switch()")).

No functional changes.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 023af03c

kernel/sched/ext.c

+5 −6
Original line number Diff line number Diff line
@@ -470,16 +470,16 @@ struct scx_task_iter { 
 * RCU read lock or obtaining a reference count.

 *

 * All tasks which existed when the iteration started are guaranteed to be

 * visited as long as they still exist.

 * visited as long as they are not dead.

 */

static void scx_task_iter_start(struct scx_task_iter *iter)

{

	memset(iter, 0, sizeof(*iter));



	spin_lock_irq(&scx_tasks_lock);



	iter->cursor = (struct sched_ext_entity){ .flags = SCX_TASK_CURSOR };

	list_add(&iter->cursor.tasks_node, &scx_tasks);

	iter->locked_task = NULL;

	iter->cnt = 0;

	iter->list_locked = true;

}
@@ -545,14 +545,13 @@ static struct task_struct *scx_task_iter_next(struct scx_task_iter *iter) 
	struct list_head *cursor = &iter->cursor.tasks_node;

	struct sched_ext_entity *pos;



	__scx_task_iter_maybe_relock(iter);



	if (!(++iter->cnt % SCX_TASK_ITER_BATCH)) {

		scx_task_iter_unlock(iter);

		cond_resched();

		__scx_task_iter_maybe_relock(iter);

	}



	__scx_task_iter_maybe_relock(iter);



	list_for_each_entry(pos, cursor, tasks_node) {

		if (&pos->tasks_node == &scx_tasks)

			return NULL;