[PATCH 07/11] sched_ext: Move sanity check and dsq_mod_nr() into task_unlink_from_dsq()

Tejun Heo
2024-08-30T11:04:32Z

All task_unlink_from_dsq() users are doing dsq_mod_nr(dsq, -1). Move it into
task_unlink_from_dsq(). Also move sanity check into it.

No functional changes intended.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/sched/ext.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 620cc0586c4b..9befa2bd1eb0 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -1641,6 +1641,8 @@ static void dispatch_enqueue(struct scx_dispatch_q *dsq, struct task_struct *p,
static void task_unlink_from_dsq(struct task_struct *p,
struct scx_dispatch_q *dsq)
{
+ WARN_ON_ONCE(list_empty(&p->scx.dsq_list.node));
+
if (p->scx.dsq_flags & SCX_TASK_DSQ_ON_PRIQ) {
rb_erase(&p->scx.dsq_priq, &dsq->priq);
RB_CLEAR_NODE(&p->scx.dsq_priq);
@@ -1648,6 +1650,7 @@ static void task_unlink_from_dsq(struct task_struct *p,
}

list_del_init(&p->scx.dsq_list.node);
+ dsq_mod_nr(dsq, -1);
}

static void dispatch_dequeue(struct rq *rq, struct task_struct *p)
@@ -1684,9 +1687,7 @@ static void dispatch_dequeue(struct rq *rq, struct task_struct *p)
*/
if (p->scx.holding_cpu < 0) {
/* @p must still be on @dsq, dequeue */
- WARN_ON_ONCE(list_empty(&p->scx.dsq_list.node));
task_unlink_from_dsq(p, dsq);
- dsq_mod_nr(dsq, -1);
} else {
/*
* We're racing against dispatch_to_local_dsq() which already
@@ -2148,7 +2149,6 @@ static void consume_local_task(struct task_struct *p,
WARN_ON_ONCE(p->scx.holding_cpu >= 0);
task_unlink_from_dsq(p, dsq);
list_add_tail(&p->scx.dsq_list.node, &rq->scx.local_dsq.list);
- dsq_mod_nr(dsq, -1);
dsq_mod_nr(&rq->scx.local_dsq, 1);
p->scx.dsq = &rq->scx.local_dsq;
raw_spin_unlock(&dsq->lock);
@@ -2238,7 +2238,6 @@ static bool unlink_dsq_and_lock_task_rq(struct task_struct *p,

WARN_ON_ONCE(p->scx.holding_cpu >= 0);
task_unlink_from_dsq(p, dsq);
- dsq_mod_nr(dsq, -1);
p->scx.holding_cpu = cpu;

raw_spin_unlock(&dsq->lock);
--
2.46.0