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 D785323392A; Sat, 19 Sep 2026 00:01:00 +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=1789776062; cv=none; b=rVj+Cf6xDsevRb33rTiIx9+Q5zUR1doTZ1JtOaw6Q3Uh81Y5V4XuTTVeJs0oxHbCJwt07YHrKBHenOAw5tQrehM7Wzium9rfiBZtIhLVVIHf5HNcx8thNzb6go0VUMvmN0Y4cyTFvx7VWLjFV/hb1XQeBSWJQhH3X9vKsKbrMQ0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789776062; c=relaxed/simple; bh=5NmpaBgZZTNdCVrDtYsCo3NWBPDoDOvVSihJo28UyCg=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=tRjrEZE6bJIh3reHdJBMP3faRQUX42HXFJENGeQIsslUeOc+VXELL/0SBm8/I0rZq0EvVMFliV7VJx0C1eG/qXag9jbYH+94GOzBsbED5UWA5kZG3Sj8JkJ7vqHm8bgZ2XADQYOdU9W/MRDq+YHCgG6WdAlPk4m8Hc5kQxZ1UV0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EQaV5A5W; 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="EQaV5A5W" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C1DF91F0089D; Sat, 19 Sep 2026 00:00:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789776059; bh=9iImI7pge0zj7YnIYJa7VF9XuKWLcrJ8NdsyV1nJzqk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=EQaV5A5WXM8PP7BxTaGj3bX+X88l+2plhBDCB+JrEz2R2Rlw1jMMPYe2qskFpyBzp 6qXaLGRrLg0ru0jBZ3/R0DSLID351D8QtljjSWVjFjM0HXVpwULTeXmXOB92fCfx7V ToQaaVEp2iEq8OLuqW96wfHqg8D5qhMkBKVGxwOs60x8bbd8zCrRsI9tu0LXoZP6fa PXLFyq/dW95mWmdDOjBuEJ9r+I5I/HQ0WntG6eU99jhvrKN9x85oHGlVvZq+0V9pRx x1JPanmo91benNwc82/KCt/xoLk28wiTA+rOwhTTvLqyuItf0Lc3GWUEIUgNxaUWCJ jx3Q7u2rfGxJQ== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 5A935CE0A73; Fri, 18 Sep 2026 17:00:59 -0700 (PDT) From: "Paul E. McKenney" To: rcu@vger.kernel.org, linux-kernel@vger.kernel.org Cc: kernel-team@meta.com, Mathieu Desnoyers , Boqun Feng , Steven Rostedt , lkmm@lists.linux.dev, Zqiang , Wang Lian , Kunwu Chan , Bradley Morgan , "Paul E. McKenney" Subject: [PATCH 06/28] hazptrtorture: Enable system-independent CPU overcommit Date: Fri, 18 Sep 2026 17:00:34 -0700 Message-Id: <20260919000056.3132131-6-paulmck@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit This commit interprets negative values of the nreaders module parameter as a number of readers per CPU, so that hazptrtorture.nreaders=-5 would spawn five hazard-pointer reader kthreads per CPU. As CPUs go offline, a number of readers determined by the overcommit are idled, so that again when hazptrtorture.nreaders=-5, five readers would be idled for each offline CPU. Signed-off-by: Paul E. McKenney Cc: Boqun Feng Cc: Mathieu Desnoyers Cc: Cc: --- kernel/rcu/hazptrtorture.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/hazptrtorture.c b/kernel/rcu/hazptrtorture.c index 9ecb86520551..e9ba25f156ac 100644 --- a/kernel/rcu/hazptrtorture.c +++ b/kernel/rcu/hazptrtorture.c @@ -362,7 +362,7 @@ static int hazptr_torture_reader(void *arg) struct hazptr_torture *htp; unsigned long lastsleep = jiffies; long myid = (long)arg; - int mynumonline = myid; + int mynumonline = myid % nr_cpu_ids; int pipe_count; DEFINE_TORTURE_RANDOM(rand); @@ -622,7 +622,7 @@ static int __init hazptr_torture_init(void) if (nreaders >= 0) { nrealreaders = nreaders; } else { - nrealreaders = num_online_cpus() - 2 - nreaders; + nrealreaders = num_online_cpus() * -nreaders; if (nrealreaders <= 0) nrealreaders = 1; } -- 2.40.1