Received: by 2002:a25:6193:0:0:0:0:0 with SMTP id v141csp212555ybb; Thu, 19 Mar 2020 20:11:05 -0700 (PDT) X-Google-Smtp-Source: ADFU+vvKrKUyYhEEciC35aWKIN/qZoAtHxFNIiyVPxx27tOukq/WjM6bUF6pKGXGpjegSFHFpgBF X-Received: by 2002:aca:be57:: with SMTP id o84mr4918430oif.138.1584673865738; Thu, 19 Mar 2020 20:11:05 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1584673865; cv=none; d=google.com; s=arc-20160816; b=QXnZq0ydIGk0I7ReZ83Ub5YxMlHJoXWq5rhTHSQXjVPCxGpt2oLFuPtma3B/vhy2cZ Ha7wl/WowGxdD/SJRWoaVkYL2Tk1XOIFyyZPJ6L6MQLMKW3vxPeGx/mPVmFMofCGzl5O Ww4/3i77Pcy6VcFGmF3m+NqeqABrtB+Q4S8QCojvKFigxIoiRynxSbaRj+C+T2V1Aibl H1KhopoV/VWItssjW5PypLXVDnb/A0S3D2EHyMJWQ3bVudzR7HV4R/EUTcEHHCzLQRyG QxPkIl/uybDvYK6IAz/aYfFizNy/KLu0U8NfKebNWBvTwf1RCsu6VoOuTSfbYjCXnhCW 644g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:subject:cc:to:from:date; bh=MHmmiWREZIwdb6e1ytNVC7VYn/aoXxfXUKp9LqPTejw=; b=juVkESireGQQdrSjqSwwiUde5TaEtALEafHPuutCerPNtjB66S3/kvo9HxQr2zJD/8 taQ5Dqe+GY6XEDFQKMXHWLKOQCuZDOoNoIV6IKqqEucbEYuPSpbCspNVE30YgJLB0+aB 6dvvQjMwR/YmHoYdvKrcssFvdsBnlOr3NfI4cpktHyhM0pjZbxUTEk37lCbXDfEsOO/k WsHzMzWLC4S6l8i6vLcLjS6R6tAbc7rwxPqK3fci0d/yz/UxzAWSiyI0cL7o3ptC0VvI BiOQ495A5g6d4ufqvOYqbxaly5hObPprkdVxHruzzNEYd3R6spmL3xt9YI+IWCYq/imv goDQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id p15si2350586otq.4.2020.03.19.20.10.53; Thu, 19 Mar 2020 20:11:05 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726956AbgCTDJt (ORCPT + 99 others); Thu, 19 Mar 2020 23:09:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:36386 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726614AbgCTDJt (ORCPT ); Thu, 19 Mar 2020 23:09:49 -0400 Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (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 DD12B2070A; Fri, 20 Mar 2020 03:09:46 +0000 (UTC) Date: Thu, 19 Mar 2020 23:09:45 -0400 From: Steven Rostedt To: "Paul E. McKenney" Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org, Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Ben Segall , Mel Gorman Subject: Re: [PATCH RFC v2 tip/core/rcu 01/22] sched/core: Add function to sample state of locked-down task Message-ID: <20200319230945.3f4701ed@oasis.local.home> In-Reply-To: <20200320024943.GA29649@paulmck-ThinkPad-P72> References: <20200319001024.GA28798@paulmck-ThinkPad-P72> <20200319001100.24917-1-paulmck@kernel.org> <20200319132238.75a034c3@gandalf.local.home> <20200319173525.GI3199@paulmck-ThinkPad-P72> <20200320024943.GA29649@paulmck-ThinkPad-P72> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 19 Mar 2020 19:49:43 -0700 "Paul E. McKenney" wrote: > > The current setup is very convenient for the use cases thus far. It > > allows the function to say "Yeah, I was called, but I couldn't do > > anything", thus allowing the caller to make exactly one check to know > > that corrective action is required. > > And here is another use case that led me to take this approach. > The trc_inspect_reader_notrunning() function in the patch below is passed > to try_invoke_on_locked_down_task() whose caller can continue testing > just the return value from try_invoke_on_locked_down_task() to work out > what to do next. > > Thoughts? Other use cases? Note, I made this comment before looking at the use cases in the later patches. I was looking at it for a more generic purpose, but I'm not sure there is one. It's fine as is for now. -- Steve