[PATCH 6/6] sched: Simplify ttwu_runnable()

From: Peter Zijlstra

Date: Tue May 26 2026 - 07:38:54 EST


Note that both proxy and delayed tasks have ->is_blocked set. Use this one
condition to guard both paths.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
kernel/sched/core.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3764,9 +3764,6 @@ static inline void proxy_reset_donor(str
*/
static inline bool proxy_needs_return(struct rq *rq, struct task_struct *p)
{
- if (!p->is_blocked)
- return false;
-
scoped_guard(raw_spinlock, &p->blocked_lock) {
/* Task is waking up; clear any blocked_on relationship */
__clear_task_blocked_on(p, NULL);
@@ -3860,10 +3857,12 @@ static int ttwu_runnable(struct task_str
return 0;

update_rq_clock(rq);
- if (p->se.sched_delayed)
- enqueue_task(rq, p, ENQUEUE_NOCLOCK | ENQUEUE_DELAYED);
- if (proxy_needs_return(rq, p))
- return 0;
+ if (p->is_blocked) {
+ if (p->se.sched_delayed)
+ enqueue_task(rq, p, ENQUEUE_NOCLOCK | ENQUEUE_DELAYED);
+ if (proxy_needs_return(rq, p))
+ return 0;
+ }
if (!task_on_cpu(rq, p)) {
/*
* When on_rq && !on_cpu the task is preempted, see if