From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A24C63C0633; Thu, 9 Jul 2026 22:51:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783637463; cv=none; b=PTh2KLd/jFPHkXvEBo4MZA9iROF+R/ensdTxtpP8MGKiGtGxZpuGt9fTHx72yd4ip9OMm5sjV4o0zjKt6z0m6IcX/vde7RSU9TC2KBmeamD2Tls6gHG7z/c2c7Koz3APkerOik1m82QUPI/EsRS9N0ZciSPfXxbRE6JwyxBj2VQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783637463; c=relaxed/simple; bh=Qvlq+G+yo8cBl0fVU+u6ihmyZY349289MLhJXnk2OYs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gZ3vu2/bY1uQLd3M+uJ3cA33qW4071eHio35LjWFNy5+emrGadt8dO6o7H8jwmrxE4ZcgzGZh84DtLs0W9R7vyWvkjj+gR5qSYCuM28z/o1wg1/BqIYSVloGHp/CA7/lJ2dIEjjlDGrX9d0C2vu4JowZ7iIUgwCe6CoyciCq77o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MtSLT3NC; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="MtSLT3NC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5B0061F000E9; Thu, 9 Jul 2026 22:51:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783637461; bh=9/RWg2GecaryKN0shBEpzoGthIrosBf7BftgLAo1RSw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=MtSLT3NCq54/8AyLPxXcZsLACdKfUbM0nkxKJX9dDpk5TCJOrP27EQTiVjZSgYpwb pGwRRbhbXJnKVFpkSz5Jp61zF3f8RARDD2n2G8pMkFnzoiwisQuMPFLiJCoLDSgOuH nSFMSg0pk2Mq3a8JRYw6iAllFjg/4aZrkp3vpimqzcAPep1XuMMN+aviFRGNS9XElP 7cNgc+Ufjqelh5eQXSUREk93AWEruFRNF9jlbqNO1KsYl4rl3SRFgTDVYMCn0VTgWD 7NclD4XSqz5WgwPrzGIoEMLGkZB4XbZfI1ll7rpz2HVmgd3rL1fYRKlYP5SM9EOrJO FVIiCVxI5kIbA== From: Tejun Heo To: David Vernet , Andrea Righi , Changwoo Min Cc: sched-ext@lists.linux.dev, Emil Tsalapatis , linux-kernel@vger.kernel.org, Tejun Heo Subject: [PATCH v5 sched_ext/for-7.3 17/33] sched_ext: Generalize local-DSQ handling to rq-owned DSQs Date: Thu, 9 Jul 2026 12:50:25 -1000 Message-ID: <20260709225041.1695495-18-tj@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260709225041.1695495-1-tj@kernel.org> References: <20260709225041.1695495-1-tj@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The local DSQ is synchronized by the containing rq lock rather than its own dsq->lock. A later patch adds a second such DSQ. In preparation, factor the "rq owns the lock" test into dsq_is_rq_owned() and rename local_dsq_post_enq() to rq_owned_post_enq(), taking @rq explicitly. No behavior change. Signed-off-by: Tejun Heo --- kernel/sched/ext/ext.c | 34 ++++++++++++++++++++++------------ 1 file changed, 22 insertions(+), 12 deletions(-) diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c index 9d111bdd05e9..f58cf7c39b6e 100644 --- a/kernel/sched/ext/ext.c +++ b/kernel/sched/ext/ext.c @@ -96,6 +96,17 @@ static atomic_long_t scx_hotplug_seq = ATOMIC_LONG_INIT(0); /* Global cursor for the per-CPU tid allocator. Starts at 1; tid 0 is reserved. */ static atomic64_t scx_tid_cursor = ATOMIC64_INIT(1); +/* is @dsq synchronized by the containing rq lock instead of dsq->lock? */ +static bool dsq_is_rq_owned(struct scx_dispatch_q *dsq) +{ + switch (dsq->id) { + case SCX_DSQ_LOCAL: + return true; + default: + return false; + } +} + #ifdef CONFIG_EXT_SUB_SCHED /* * The sub sched being enabled. Used by scx_disable_and_exit_task() to exit @@ -1270,11 +1281,10 @@ static void call_task_dequeue(struct scx_sched *sch, struct rq *rq, p->scx.flags &= ~SCX_TASK_IN_CUSTODY; } -static void local_dsq_post_enq(struct scx_sched *sch, struct scx_dispatch_q *dsq, - struct task_struct *p, u64 enq_flags) +static void rq_owned_post_enq(struct scx_sched *sch, struct rq *rq, + struct scx_dispatch_q *dsq, struct task_struct *p, + u64 enq_flags) { - struct rq *rq = container_of(dsq, struct rq, scx.local_dsq); - call_task_dequeue(sch, rq, p, 0); /* @@ -1334,13 +1344,13 @@ static void scx_dispatch_enqueue(struct scx_sched *sch, struct rq *rq, struct scx_dispatch_q *dsq, struct task_struct *p, u64 enq_flags) { - bool is_local = dsq->id == SCX_DSQ_LOCAL; + bool is_rq_owned = dsq_is_rq_owned(dsq); WARN_ON_ONCE(p->scx.dsq || !list_empty(&p->scx.dsq_list.node)); WARN_ON_ONCE((p->scx.dsq_flags & SCX_TASK_DSQ_ON_PRIQ) || !RB_EMPTY_NODE(&p->scx.dsq_priq)); - if (!is_local) { + if (!is_rq_owned) { raw_spin_lock_nested(&dsq->lock, (enq_flags & SCX_ENQ_NESTED) ? SINGLE_DEPTH_NESTING : 0); @@ -1435,8 +1445,8 @@ static void scx_dispatch_enqueue(struct scx_sched *sch, struct rq *rq, * ops_state first, both sides would modify p->scx.flags * concurrently in a non-atomic way. */ - if (is_local) { - local_dsq_post_enq(sch, dsq, p, enq_flags); + if (is_rq_owned) { + rq_owned_post_enq(sch, rq, dsq, p, enq_flags); } else { /* * Global and bypass DSQs are terminal - the task leaves the @@ -1487,7 +1497,7 @@ static void task_unlink_from_dsq(struct task_struct *p, static void scx_dispatch_dequeue(struct rq *rq, struct task_struct *p) { struct scx_dispatch_q *dsq = p->scx.dsq; - bool is_local = dsq == &rq->scx.local_dsq; + bool is_rq_owned = dsq && dsq_is_rq_owned(dsq); lockdep_assert_rq_held(rq); @@ -1511,7 +1521,7 @@ static void scx_dispatch_dequeue(struct rq *rq, struct task_struct *p) return; } - if (!is_local) + if (!is_rq_owned) raw_spin_lock(&dsq->lock); /* @@ -1533,7 +1543,7 @@ static void scx_dispatch_dequeue(struct rq *rq, struct task_struct *p) } p->scx.dsq = NULL; - if (!is_local) + if (!is_rq_owned) raw_spin_unlock(&dsq->lock); } @@ -2085,7 +2095,7 @@ static void move_local_task_to_local_dsq(struct scx_sched *sch, dsq_inc_nr(dst_dsq, p, enq_flags); p->scx.dsq = dst_dsq; - local_dsq_post_enq(sch, dst_dsq, p, enq_flags); + rq_owned_post_enq(sch, dst_rq, dst_dsq, p, enq_flags); } /** -- 2.55.0