From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: [PATCH v3 13/22] tracing: Remove regular RCU context for _rcuidle tracepoints (again) Date: Wed, 19 Feb 2020 11:05:21 -0800 Message-ID: <20200219190521.GO2935@paulmck-ThinkPad-P72> References: <20200219144724.800607165@infradead.org> <20200219150745.125119627@infradead.org> <20200219164356.GB2935@paulmck-ThinkPad-P72> <20200219164736.GL18400@hirez.programming.kicks-ass.net> <20200219170507.GH14946@hirez.programming.kicks-ass.net> <20200219122116.7aeaf230@gandalf.local.home> <20200219174025.GJ2935@paulmck-ThinkPad-P72> <20200219130012.116670fd@gandalf.local.home> Reply-To: paulmck@kernel.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail.kernel.org ([198.145.29.99]:41706 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726613AbgBSTFW (ORCPT ); Wed, 19 Feb 2020 14:05:22 -0500 Content-Disposition: inline In-Reply-To: <20200219130012.116670fd@gandalf.local.home> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Steven Rostedt Cc: Peter Zijlstra , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, mingo@kernel.org, joel@joelfernandes.org, gregkh@linuxfoundation.org, gustavo@embeddedor.com, tglx@linutronix.de, josh@joshtriplett.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, luto@kernel.org, tony.luck@intel.com, frederic@kernel.org, dan.carpenter@oracle.com, mhiramat@kernel.org On Wed, Feb 19, 2020 at 01:00:12PM -0500, Steven Rostedt wrote: > On Wed, 19 Feb 2020 09:40:25 -0800 > "Paul E. McKenney" wrote: > > > > Correct, and if rcuidle is not set, and this is a macro, the SRCU > > > portion is compiled out. > > > > Sigh! Apologies for the noise! > > > > If we are using SRCU, we don't care whether or not RCU is watching. OK, > > maybe finally catching up -- the whole point was use of RCU in other > > tracing code, wasn't it? > > Some callbacks (namely perf) might use RCU, but then the callbacks > need to make sure rcu is watching. Got it, thank you! Thanx, Paul