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 2F4D4C4332E for ; Fri, 20 Mar 2020 16:27:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0628D2078C for ; Fri, 20 Mar 2020 16:27:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584721654; bh=gwsNsin4/SYg1Xj0KQ+zV+B8Z3aO3Bg8kEnqtbQn7Oc=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=kVAwT3Bk9f0kJkKw4+GsKtshs9vg9ONNwTt/wUmH8ad5ydDnU7BCYUthJzWvroNB3 JP0+BYCa7sB39XY4TIr+l+OiFFuJ8+gpJcGI1qSti/ONXfeu0ERsiMRj95/O2IC1TF oAM4Ha7JBOoTNryFDNVQ81sb33L9QQjjil+5Tit8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727497AbgCTQ1c (ORCPT ); Fri, 20 Mar 2020 12:27:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:52950 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727464AbgCTQ1c (ORCPT ); Fri, 20 Mar 2020 12:27:32 -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 E5E6520724; Fri, 20 Mar 2020 16:27:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584721651; bh=gwsNsin4/SYg1Xj0KQ+zV+B8Z3aO3Bg8kEnqtbQn7Oc=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=sYpq5idgbfPCkOXvP9v10jUWhgcWOkAqCS6lMIHDNrKY4kHXbxslXyhOsVlWwOIEg NsSPGQsIJGjWY0qvwWsQrO01v2+BmXBzVBKTeKmUh+3Fcs2XEPfCaT0FJtJC8qjXDI 8TtwLtKyYaJzXtwo3R9/8oiPfAcH+1X00W0867sg= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id C0E0135226B4; Fri, 20 Mar 2020 09:27:31 -0700 (PDT) Date: Fri, 20 Mar 2020 09:27:31 -0700 From: "Paul E. McKenney" To: Steven Rostedt 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: <20200320162731.GQ3199@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org 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> <20200319230945.3f4701ed@oasis.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200319230945.3f4701ed@oasis.local.home> 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, Mar 19, 2020 at 11:09:45PM -0400, Steven Rostedt wrote: > 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. Sounds good, and again thank you for looking this over! Thanx, Paul