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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


  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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