The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x 530b6637c79e728d58f1d9b66bd4acf4b735b86d # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025122922-chubby-doctrine-9c07@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 530b6637c79e728d58f1d9b66bd4acf4b735b86d Mon Sep 17 00:00:00 2001 From: Tejun Heo tj@kernel.org Date: Thu, 11 Dec 2025 15:45:03 -1000 Subject: [PATCH] sched_ext: Factor out local_dsq_post_enq() from dispatch_enqueue()
Factor out local_dsq_post_enq() which performs post-enqueue handling for local DSQs - triggering resched_curr() if SCX_ENQ_PREEMPT is specified or if the current CPU is idle. No functional change.
This will be used by the next patch to fix move_local_task_to_local_dsq().
Cc: stable@vger.kernel.org # v6.12+ Reviewed-by: Andrea Righi arighi@nvidia.com Reviewed-by: Emil Tsalapatis emil@etsalapatis.com Signed-off-by: Tejun Heo tj@kernel.org
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index c4465ccefea4..c78efa99406f 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -982,6 +982,22 @@ static void refill_task_slice_dfl(struct scx_sched *sch, struct task_struct *p) __scx_add_event(sch, SCX_EV_REFILL_SLICE_DFL, 1); }
+static void local_dsq_post_enq(struct scx_dispatch_q *dsq, struct task_struct *p, + u64 enq_flags) +{ + struct rq *rq = container_of(dsq, struct rq, scx.local_dsq); + bool preempt = false; + + if ((enq_flags & SCX_ENQ_PREEMPT) && p != rq->curr && + rq->curr->sched_class == &ext_sched_class) { + rq->curr->scx.slice = 0; + preempt = true; + } + + if (preempt || sched_class_above(&ext_sched_class, rq->curr->sched_class)) + resched_curr(rq); +} + static void dispatch_enqueue(struct scx_sched *sch, struct scx_dispatch_q *dsq, struct task_struct *p, u64 enq_flags) { @@ -1093,22 +1109,10 @@ static void dispatch_enqueue(struct scx_sched *sch, struct scx_dispatch_q *dsq, if (enq_flags & SCX_ENQ_CLEAR_OPSS) atomic_long_set_release(&p->scx.ops_state, SCX_OPSS_NONE);
- if (is_local) { - struct rq *rq = container_of(dsq, struct rq, scx.local_dsq); - bool preempt = false; - - if ((enq_flags & SCX_ENQ_PREEMPT) && p != rq->curr && - rq->curr->sched_class == &ext_sched_class) { - rq->curr->scx.slice = 0; - preempt = true; - } - - if (preempt || sched_class_above(&ext_sched_class, - rq->curr->sched_class)) - resched_curr(rq); - } else { + if (is_local) + local_dsq_post_enq(dsq, p, enq_flags); + else raw_spin_unlock(&dsq->lock); - } }
static void task_unlink_from_dsq(struct task_struct *p,