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 X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1C3EFC43331 for ; Thu, 2 Apr 2020 16:57:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D90B02078E for ; Thu, 2 Apr 2020 16:57:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585846659; bh=X3PlfBlbIWLeP0CMCgHZC7mjUaCakvnwr6GNUHzqNcM=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=j/8K//cX9ATPFv1bryc9jUM/cseSpxQ2puODoTX+0YQ6FFO7cEd9p9goWq+lPtprZ yNHTrb/76zDV8UuPAp6kLtnbVsMLl7bWR99ZB/L2jE7DCMrjhy775+bwjY44s9rZVy DXg57PgsXd8mij4bHmhT93fFdbbt6PEsrug4vAao= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389949AbgDBQ5i (ORCPT ); Thu, 2 Apr 2020 12:57:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:42514 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387700AbgDBQ5i (ORCPT ); Thu, 2 Apr 2020 12:57:38 -0400 Received: from paulmck-ThinkPad-P72.home (50-39-105-78.bvtn.or.frontiernet.net [50.39.105.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B277420737; Thu, 2 Apr 2020 16:57:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585846657; bh=X3PlfBlbIWLeP0CMCgHZC7mjUaCakvnwr6GNUHzqNcM=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=J4YVuxmJ6og07F0T/oP2MNLLaNO5WKhKFTnErKaZYhoAS/KPlPlGtkMRteYfzQT0a OY8qmQQqBdRXMD8fXMSSEB72DF62PW2I9oc9v8Rjf9qP4TtR1MycHOKYLqwMRakYMW i050cCPPsNykKhgYT4mE9Y+omVEAs6NhHLK7NQjY= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id 7FADD3521885; Thu, 2 Apr 2020 09:57:37 -0700 (PDT) Date: Thu, 2 Apr 2020 09:57:37 -0700 From: "Paul E. McKenney" To: Qian Cai Cc: Michael Ellerman , Peter Zijlstra , Ingo Molnar , juri.lelli@redhat.com, dietmar.eggemann@arm.com, vincent.guittot@linaro.org, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, tglx@linutronix.de, "James.Bottomley@hansenpartnership.com" , deller@gmx.de, linuxppc-dev@lists.ozlabs.org, linux-parisc@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Nicholas Piggin Subject: Re: [PATCH v2] sched/core: fix illegal RCU from offline CPUs Message-ID: <20200402165737.GQ19865@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20200402155406.GP19865@paulmck-ThinkPad-P72> <4134872A-3D1D-4860-9C1B-2FD9C00272BB@lca.pw> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4134872A-3D1D-4860-9C1B-2FD9C00272BB@lca.pw> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 02, 2020 at 12:19:54PM -0400, Qian Cai wrote: > > > > On Apr 2, 2020, at 11:54 AM, Paul E. McKenney wrote: > > > > I do run this combination quite frequently, but only as part of > > rcutorture, which might not be a representative workload. For one thing, > > it has a minimal userspace consisting only of a trivial init program. > > I don't recall having ever seen this. (I have seen one recent complaint > > about an IPI being sent to an offline CPU, but I cannot prove that this > > was not due to RCU bugs that I was chasing at the time.) > > Yes, a trivial init is tough while running systemd should be able to catch it as it will use cgroup. Not planning to add systemd to my rcutorture runs. ;-) Thanx, Paul