From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F0B77C433F5 for ; Thu, 28 Apr 2022 18:39:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351184AbiD1SnM (ORCPT ); Thu, 28 Apr 2022 14:43:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55158 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232896AbiD1SnL (ORCPT ); Thu, 28 Apr 2022 14:43:11 -0400 Received: from ms.lwn.net (ms.lwn.net [45.79.88.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 09DCEBE9F5; Thu, 28 Apr 2022 11:39:55 -0700 (PDT) Received: from localhost (unknown [IPv6:2601:281:8300:3d::5f6]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ms.lwn.net (Postfix) with ESMTPSA id 71CC137A; Thu, 28 Apr 2022 18:39:55 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 ms.lwn.net 71CC137A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lwn.net; s=20201203; t=1651171195; bh=fxw3rNrkfLA2emenBhZ8L7bdgypypZpUWtQbyeBbAl8=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=G84Kt3DbbfUzzepGREd8nWnTW9WwCy231V3+AEwXL7wKFJxLer3Ya3dXEZ2o9bQMm 70kAjxtBCWiaFuj2nenIbd9Uh1mY6EGSGBM2TMnq943D0cGF3H/zyZaog5Lrvf8vXT e+7bex7EKjDXYQYW9XrNCaawpbj65EYOBQGmbi0pAp0iZVzk0clTeQ/veu+ModTV/D YFcY0LAux0tv7Y0bK15RF7LLN9hJj94KuRFaPuTwfyXrioSKj1EHCziccYZRstExE4 uol3LxVzsTUxoI8vDqonSUrojaRvywPd+PvhZviGOr1c3NDUQLaWV6lc2hCjQ4PtJ6 m0a5Fj3Nb0YCg== From: Jonathan Corbet To: Joel Savitz , linux-kernel Cc: Andrew Morton , Huang Ying , Eric Biggers , Dominik Brodowski , Mauro Carvalho Chehab , Rasmus Villemoes , "Jason A. Donenfeld" , Daniel Borkmann , Rob Herring , Wang Qing , linux-doc@vger.kernel.org, chao , "Paul E. McKenney" Subject: Re: [PATCH] Documentation/sysctl: document max_rcu_stall_to_panic In-Reply-To: References: <20220324221156.44813-1-jsavitz@redhat.com> Date: Thu, 28 Apr 2022 12:39:54 -0600 Message-ID: <87levp59xh.fsf@meer.lwn.net> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Joel Savitz writes: > Friendly ping. This was waiting for an ack from an RCU person. Looking now, though, I see that you didn't copy any RCU people. Adding Paul and the author of the patch you reference (and appending patch below). Thanks, jon Joel Savitz (March 24) (kernel lwn) Subject: [PATCH] Documentation/sysctl: document max_rcu_stall_to_panic To: linux-kernel@vger.kernel.org Cc: Joel Savitz , Jonathan Corbet , Andrew Morton , Huang Ying , Eric Biggers , Dominik Brodowski , Mauro Carvalho Chehab , Rasmus Villemoes , "Jason A. Donenfeld" , Daniel Borkmann , Rob Herring , Wang Qing , linux-doc@vger.kernel.org Date: Thu, 24 Mar 2022 18:11:56 -0400 commit dfe564045c65 ("rcu: Panic after fixed number of stalls") introduced a new systctl but no accompanying documentation. Add a simple entry to the documentation. Signed-off-by: Joel Savitz --- Documentation/admin-guide/sysctl/kernel.rst | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index 803c60bf21d3..4e48139b9a34 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -781,6 +781,13 @@ is useful to define the root cause of RCU stalls using a vmcore. 1 panic() after printing RCU stall messages. = ============================================================ +max_rcu_stall_to_panic +====================== + +When ``panic_on_rcu_stall`` is set to 1, this value determines the +number of times that RCU can stall before panic() is called. + +When ``panic_on_rcu_stall`` is set to 0, this value is has no effect. perf_cpu_time_max_percent =========================