From: Tejun Heo <tj@kernel.org>
To: David Vernet <void@manifault.com>,
Andrea Righi <arighi@nvidia.com>,
Changwoo Min <changwoo@igalia.com>
Cc: sched-ext@lists.linux.dev, Emil Tsalapatis <emil@etsalapatis.com>,
linux-kernel@vger.kernel.org, Tejun Heo <tj@kernel.org>
Subject: [PATCH 4/4] sched_ext: Drop the dead SCX_DEQ_CORE_SCHED_EXEC test in dequeue_task_scx()
Date: Sat, 15 Aug 2026 14:05:27 -1000 [thread overview]
Message-ID: <20260816000527.988170-5-tj@kernel.org> (raw)
In-Reply-To: <20260816000527.988170-1-tj@kernel.org>
dequeue_task_scx() masks SCX_DEQ_CORE_SCHED_EXEC out of the
SCX_DEQ_SCHED_CHANGE decision, but the test can never fire: the incoming
flags are an int of generic DEQUEUE_* bits while the flag is bit 32, and the
core-sched execute path never goes through class dequeue anyway -
set_next_task_scx() calls ops_dequeue() with the flag directly. The test was
live when the SCX_DEQ_SCHED_CHANGE computation sat in ops_dequeue() and
became dead when 03f5304aad0f ("sched_ext: Pass full dequeue flags to
ops.quiescent()") moved the computation here. Drop it.
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/sched/ext/ext.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c
index f14e3fc69644..395d8f5aaaa8 100644
--- a/kernel/sched/ext/ext.c
+++ b/kernel/sched/ext/ext.c
@@ -2267,9 +2267,9 @@ static bool dequeue_task_scx(struct rq *rq, struct task_struct *p, int core_deq_
/*
* Set %SCX_DEQ_SCHED_CHANGE when the dequeue is due to a property
- * change (not sleep or core-sched pick).
+ * change (not sleep).
*/
- if (!(deq_flags & (DEQUEUE_SLEEP | SCX_DEQ_CORE_SCHED_EXEC)))
+ if (!(deq_flags & DEQUEUE_SLEEP))
deq_flags |= SCX_DEQ_SCHED_CHANGE;
if (!(p->scx.flags & SCX_TASK_QUEUED)) {
--
2.55.0
next prev parent reply other threads:[~2026-08-16 0:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-16 0:05 [PATCHSET sched_ext/for-7.3] sched_ext: Update core-sched task ordering for scheduler hierarchies Tejun Heo
2026-08-16 0:05 ` [PATCH 1/4] sched_ext: Fix inverted ops.core_sched_before() invocation Tejun Heo
2026-08-16 0:05 ` [PATCH 2/4] sched_ext: Use runnable_at for the default core-sched task ordering Tejun Heo
2026-08-16 0:05 ` [PATCH 3/4] sched_ext: Make core-sched task ordering hierarchy-aware Tejun Heo
2026-08-16 0:05 ` Tejun Heo [this message]
2026-08-16 2:13 ` [PATCHSET sched_ext/for-7.3] sched_ext: Update core-sched task ordering for scheduler hierarchies Tejun Heo
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