[PATCH 6.18 276/277] sched_ext: Refactor do_enqueue_task() local and global DSQ paths

Greg Kroah-Hartman
2026-04-08T18:39:12Z

From: Tejun Heo <tj@kernel.org>

[ Upstream commit 3546119f18647d7ddbba579737d8a222b430cb1c ]

The local and global DSQ enqueue paths in do_enqueue_task() share the same
slice refill logic. Factor out the common code into a shared enqueue label.
This makes adding new enqueue cases easier. No functional changes.

Reviewed-by: Andrea Righi <arighi@nvidia.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Stable-dep-of: 7e0ffb72de8a ("sched_ext: Fix stale direct dispatch state in ddsp_dsq_id")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/sched/ext.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)

--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -1243,6 +1243,7 @@ static void do_enqueue_task(struct rq *r
{
struct scx_sched *sch = scx_root;
struct task_struct **ddsp_taskp;
+ struct scx_dispatch_q *dsq;
unsigned long qseq;

WARN_ON_ONCE(!(p->scx.flags & SCX_TASK_QUEUED));
@@ -1310,8 +1311,17 @@ static void do_enqueue_task(struct rq *r
direct:
direct_dispatch(sch, p, enq_flags);
return;
-
+local_norefill:
+ dispatch_enqueue(sch, &rq->scx.local_dsq, p, enq_flags);
+ return;
local:
+ dsq = &rq->scx.local_dsq;
+ goto enqueue;
+global:
+ dsq = find_global_dsq(sch, p);
+ goto enqueue;
+
+enqueue:
/*
* For task-ordering, slice refill must be treated as implying the end
* of the current slice. Otherwise, the longer @p stays on the CPU, the
@@ -1319,14 +1329,7 @@ local:
*/
touch_core_sched(rq, p);
refill_task_slice_dfl(sch, p);
-local_norefill:
- dispatch_enqueue(sch, &rq->scx.local_dsq, p, enq_flags);
- return;
-
-global:
- touch_core_sched(rq, p); /* see the comment in local: */
- refill_task_slice_dfl(sch, p);
- dispatch_enqueue(sch, find_global_dsq(sch, p), p, enq_flags);
+ dispatch_enqueue(sch, dsq, p, enq_flags);
}

static bool task_runnable(const struct task_struct *p)