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[71.34.25.140]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-536127b5567sm8224761cf.12.2026.10.14.15.08.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 14 Oct 2026 15:08:19 -0700 (PDT) From: Crystal Wood To: Steven Rostedt Cc: Tomas Glozar , John Kacur , linux-trace-kernel@vger.kernel.org, Crystal Wood Subject: [PATCH v4 5/9] tracing/osnoise: start_kthread: Always check OSN_WORKLOAD Date: Wed, 14 Oct 2026 17:07:55 -0500 Message-ID: <20261014220759.908839-6-crwood@redhat.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20261014220759.908839-1-crwood@redhat.com> References: <20261014220759.908839-1-crwood@redhat.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: O458Ia27uMs9Q2R-tohGLYyJrlU31-VYfRxAiDU0Ek0_1792015701 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true We can get here on timerlat with OSN_WORKLOAD cleared via osnoise_hotplug_workfn(). While we're moving this code, remove the pointless compiler barrier immediately before returning from a function. Even if it's inlined, it's not doing anything useful. Signed-off-by: Crystal Wood --- v2: no change --- kernel/trace/trace_osnoise.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c index 202d7b4254bd..3da4f1f095df 100644 --- a/kernel/trace/trace_osnoise.c +++ b/kernel/trace/trace_osnoise.c @@ -2078,16 +2078,17 @@ static int start_kthread(unsigned int cpu) if (osn->kthread) goto out; + /* Can still happen with timerlat via cpu hotplug */ + if (!test_bit(OSN_WORKLOAD, &osnoise_options)) { + if (!timerlat_enabled()) + osn->sampling = true; + goto out; + } + if (timerlat_enabled()) { snprintf(comm, 24, "timerlat/%d", cpu); main = timerlat_main; } else { - /* if no workload, just return */ - if (!test_bit(OSN_WORKLOAD, &osnoise_options)) { - cpu_osn_var(cpu)->sampling = true; - barrier(); - goto out; - } snprintf(comm, 24, "osnoise/%d", cpu); } -- 2.54.0