From patchwork Mon Mar 10 18:38:07 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Paul E. McKenney" X-Patchwork-Id: 14010546 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 B469C235C15; Mon, 10 Mar 2025 18:38:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741631892; cv=none; b=kG8uT+feaHi946U2e03WUGTMxMwyqhvukZZSyBbOVVbmeAJSZY6zpA9x25JzA4Td0xGPiZiTznYUvc1NNXkuAETDac5seX96rQ2kG5SYR2IotYPX0mhx8dpiwVa0NmQSboBz28dTHhclrzUM8zP8OSXBBb03jhXWPV48A8MJCsk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741631892; c=relaxed/simple; bh=58Vf7rQ9Ye1ZnF11F3AKbtRYHEgqBK/0woCbX8EkJYc=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=PpmjGXXxM+v6eMhWruYiWy+ubudGLpn+4hYans6jD2VcmtSZJeplHCtrzro8xLLUStdZ394b/uDXWIKsQc41Eel/NMdvkmIwNeiP8UyWunM1Wm1hX7V8Ric0XOu7GdO6R4SfbOpF+IyHpwlvUFWhTixlWOMXn21GUc73XfMSC8I= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=P5m6LcCY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="P5m6LcCY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D084C4CEF6; Mon, 10 Mar 2025 18:38:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741631892; bh=58Vf7rQ9Ye1ZnF11F3AKbtRYHEgqBK/0woCbX8EkJYc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=P5m6LcCY0fMTsbvQBiYf/XRYgqwdq8ytPquDE20krnwpOaMuDoNA3pU22YsjdDDnZ qZXcgvsjhtD+gBnQ8yDYjS4VS6fjlWdJl6rB5AULiAk+z6VU7XRZ1Erge+x3cg8QZ+ EauQkjvmZHffohcA36ck217NllK1h3t+XMzy//q5dO28AHqw8Z0xOpCEv0PyyYc3q5 n0KfEYbJrbBQVyMkmn23Msfg6NKF0jum/ogCx79YAMGx8lSCX2c4/IsjUyGDzJXMq9 ezhz6fIZr5+49jOKebZnnkMOlyezx6eL3B/CSfbVT/+86jhNLL1nOIKIHKNXep3/VQ /4JxIbu5B11ww== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 9EE36CE1389; Mon, 10 Mar 2025 11:38:11 -0700 (PDT) From: "Paul E. McKenney" To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, rostedt@goodmis.org, "Paul E. McKenney" Subject: [PATCH 7/9] rcutorture: Comment invocations of tick_dep_set_task() Date: Mon, 10 Mar 2025 11:38:07 -0700 Message-Id: <20250310183809.3576320-7-paulmck@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <4bf081c8-9299-4ee3-b337-d5b751cef6be@paulmck-laptop> References: <4bf081c8-9299-4ee3-b337-d5b751cef6be@paulmck-laptop> Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The rcu_torture_reader() and rcu_torture_fwd_prog_cr() functions run CPU-bound for extended periods of time (tens or even hundreds of milliseconds), so they invoke tick_dep_set_task() and tick_dep_clear_task() to ensure that the scheduling-clock tick helps move grace periods forward. So why doesn't rcu_torture_fwd_prog_nr() also invoke tick_dep_set_task() and tick_dep_clear_task()? Because the point of this function is to test RCU's ability to (eventually) force grace periods forward even when the tick has been disabled during long CPU-bound kernel execution. Signed-off-by: Paul E. McKenney --- kernel/rcu/rcutorture.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 6d808c70349c4..3042a7950fe23 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -2410,7 +2410,7 @@ rcu_torture_reader(void *arg) set_user_nice(current, MAX_NICE); if (irqreader && cur_ops->irq_capable) timer_setup_on_stack(&t, rcu_torture_timer, 0); - tick_dep_set_task(current, TICK_DEP_BIT_RCU); + tick_dep_set_task(current, TICK_DEP_BIT_RCU); // CPU bound, so need tick. do { if (irqreader && cur_ops->irq_capable) { if (!timer_pending(&t)) @@ -3260,7 +3260,7 @@ static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp) cver = READ_ONCE(rcu_torture_current_version); gps = cur_ops->get_gp_seq(); rfp->rcu_launder_gp_seq_start = gps; - tick_dep_set_task(current, TICK_DEP_BIT_RCU); + tick_dep_set_task(current, TICK_DEP_BIT_RCU); // CPU bound, so need tick. while (time_before(jiffies, stopat) && !shutdown_time_arrived() && !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {