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Tue, 30 Dec 2025 06:28:28 -0800 (PST) Received: from linux.fritz.box ([2a00:6d43:105:c401:e307:1a37:2e76:ce91]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4324ea1b1b1sm68145648f8f.3.2025.12.30.06.28.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Dec 2025 06:28:28 -0800 (PST) From: Marco Crivellari To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: Tejun Heo , Lai Jiangshan , Frederic Weisbecker , Sebastian Andrzej Siewior , Marco Crivellari , Michal Hocko , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers Subject: [PATCH v2] tracing: Replace use of system_wq with system_dfl_wq Date: Tue, 30 Dec 2025 15:28:20 +0100 Message-ID: <20251230142820.173712-1-marco.crivellari@suse.com> X-Mailer: git-send-email 2.52.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This patch continues the effort to refactor workqueue APIs, which has begun with the changes introducing new workqueues and a new alloc_workqueue flag: commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq") commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag") The point of the refactoring is to eventually alter the default behavior of workqueues to become unbound by default so that their workload placement is optimized by the scheduler. Before that to happen after a careful review and conversion of each individ= ual case, workqueue users must be converted to the better named new workqueues = with no intended behaviour changes: system_wq -> system_percpu_wq system_unbound_wq -> system_dfl_wq This specific workflow has no benefits being per-cpu, so instead of system_percpu_wq the new unbound workqueue has been used (system_dfl_wq). This way the old obsolete workqueues (system_wq, system_unbound_wq) can be removed in the future. Suggested-by: Tejun Heo Signed-off-by: Marco Crivellari Acked-by: Steven Rostedt (Google) --- Changes in v2: - use system_dfl_wq instead of system_percpu_wq because this workload has no benefits being per-cpu. - rebase on v6.19-rc3. kernel/trace/trace_events_filter.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events= _filter.c index 385af8405392..7001e34476ee 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -1375,7 +1375,7 @@ static void free_filter_list_tasks(struct rcu_head *r= hp) struct filter_head *filter_list =3D container_of(rhp, struct filter_head,= rcu); =20 INIT_RCU_WORK(&filter_list->rwork, free_filter_list_work); - queue_rcu_work(system_wq, &filter_list->rwork); + queue_rcu_work(system_dfl_wq, &filter_list->rwork); } =20 /* --=20 2.52.0