Commit 66675170 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'sched-urgent-2021-06-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull scheduler fix from Ingo Molnar:
 "A last minute cgroup bandwidth scheduling fix for a recently
  introduced logic fail which triggered a kernel warning by LTP's
  cfs_bandwidth01 test"

* tag 'sched-urgent-2021-06-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Ensure that the CFS parent is added after unthrottling
parents df501100 fdaba61e

kernel/sched/fair.c

+28 −0
Original line number Diff line number Diff line
@@ -3298,6 +3298,31 @@ static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq, int flags) 


#ifdef CONFIG_SMP

#ifdef CONFIG_FAIR_GROUP_SCHED

/*

 * Because list_add_leaf_cfs_rq always places a child cfs_rq on the list

 * immediately before a parent cfs_rq, and cfs_rqs are removed from the list

 * bottom-up, we only have to test whether the cfs_rq before us on the list

 * is our child.

 * If cfs_rq is not on the list, test whether a child needs its to be added to

 * connect a branch to the tree  * (see list_add_leaf_cfs_rq() for details).

 */

static inline bool child_cfs_rq_on_list(struct cfs_rq *cfs_rq)

{

	struct cfs_rq *prev_cfs_rq;

	struct list_head *prev;



	if (cfs_rq->on_list) {

		prev = cfs_rq->leaf_cfs_rq_list.prev;

	} else {

		struct rq *rq = rq_of(cfs_rq);



		prev = rq->tmp_alone_branch;

	}



	prev_cfs_rq = container_of(prev, struct cfs_rq, leaf_cfs_rq_list);



	return (prev_cfs_rq->tg->parent == cfs_rq->tg);

}



static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq)

{
@@ -3313,6 +3338,9 @@ static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq) 
	if (cfs_rq->avg.runnable_sum)

		return false;



	if (child_cfs_rq_on_list(cfs_rq))

		return false;



	return true;

}