From: Peter Zijlstra <peterz@infradead.org>
Date: Fri, 26 Apr 2024 11:00:50 +0000 (+0200)
Subject: sched/eevdf: Fixup PELT vs DELAYED_DEQUEUE
X-Git-Tag: v6.12-rc1~120^2~25
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=fc1892becd56;p=thirdparty%2Flinux.git

sched/eevdf: Fixup PELT vs DELAYED_DEQUEUE

Note that tasks that are kept on the runqueue to burn off negative
lag, are not in fact runnable anymore, they'll get dequeued the moment
they get picked.

As such, don't count this time towards runnable.

Thanks to Valentin for spotting I had this backwards initially.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Tested-by: Valentin Schneider <vschneid@redhat.com>
Link: https://lkml.kernel.org/r/20240727105030.514088302@infradead.org
---

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 1a593393e3088..0eb1bbf7f2697 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5402,6 +5402,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
 		    !entity_eligible(cfs_rq, se)) {
 			if (cfs_rq->next == se)
 				cfs_rq->next = NULL;
+			update_load_avg(cfs_rq, se, 0);
 			se->sched_delayed = 1;
 			return false;
 		}
@@ -6841,6 +6842,7 @@ requeue_delayed_entity(struct sched_entity *se)
 		}
 	}
 
+	update_load_avg(cfs_rq, se, 0);
 	se->sched_delayed = 0;
 }
 
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 263b4ded2b47d..2f5d658c0631f 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -820,6 +820,9 @@ static inline void se_update_runnable(struct sched_entity *se)
 
 static inline long se_runnable(struct sched_entity *se)
 {
+	if (se->sched_delayed)
+		return false;
+
 	if (entity_is_task(se))
 		return !!se->on_rq;
 	else
@@ -834,6 +837,9 @@ static inline void se_update_runnable(struct sched_entity *se) { }
 
 static inline long se_runnable(struct sched_entity *se)
 {
+	if (se->sched_delayed)
+		return false;
+
 	return !!se->on_rq;
 }