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 08:43:56 -0800 Message-ID: <20200219164356.GB2935@paulmck-ThinkPad-P72> References: <20200219144724.800607165@infradead.org> <20200219150745.125119627@infradead.org> Reply-To: paulmck@kernel.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20200219150745.125119627@infradead.org> Sender: linux-kernel-owner@vger.kernel.org To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, rostedt@goodmis.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 List-Id: linux-arch.vger.kernel.org On Wed, Feb 19, 2020 at 03:47:37PM +0100, Peter Zijlstra wrote: > Effectively revert commit 865e63b04e9b2 ("tracing: Add back in > rcu_irq_enter/exit_irqson() for rcuidle tracepoints") now that we've > taught perf how to deal with not having an RCU context provided. > > Signed-off-by: Peter Zijlstra (Intel) > --- > include/linux/tracepoint.h | 8 ++------ > 1 file changed, 2 insertions(+), 6 deletions(-) > > --- a/include/linux/tracepoint.h > +++ b/include/linux/tracepoint.h > @@ -179,10 +179,8 @@ static inline struct tracepoint *tracepo Shouldn't we also get rid of this line above? int __maybe_unused __idx = 0; \ Thanx, Paul > * For rcuidle callers, use srcu since sched-rcu \ > * doesn't work from the idle path. \ > */ \ > - if (rcuidle) { \ > + if (rcuidle) \ > __idx = srcu_read_lock_notrace(&tracepoint_srcu);\ > - rcu_irq_enter_irqsave(); \ > - } \ > \ > it_func_ptr = rcu_dereference_raw((tp)->funcs); \ > \ > @@ -194,10 +192,8 @@ static inline struct tracepoint *tracepo > } while ((++it_func_ptr)->func); \ > } \ > \ > - if (rcuidle) { \ > - rcu_irq_exit_irqsave(); \ > + if (rcuidle) \ > srcu_read_unlock_notrace(&tracepoint_srcu, __idx);\ > - } \ > \ > preempt_enable_notrace(); \ > } while (0) > > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:33574 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726551AbgBSQn5 (ORCPT ); Wed, 19 Feb 2020 11:43:57 -0500 Date: Wed, 19 Feb 2020 08:43:56 -0800 From: "Paul E. McKenney" Subject: Re: [PATCH v3 13/22] tracing: Remove regular RCU context for _rcuidle tracepoints (again) Message-ID: <20200219164356.GB2935@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20200219144724.800607165@infradead.org> <20200219150745.125119627@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200219150745.125119627@infradead.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, rostedt@goodmis.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 Message-ID: <20200219164356.oyNkKkYyMR0jcnDxl25ZeW7RNs6izxIa98V_V_QdiIo@z> On Wed, Feb 19, 2020 at 03:47:37PM +0100, Peter Zijlstra wrote: > Effectively revert commit 865e63b04e9b2 ("tracing: Add back in > rcu_irq_enter/exit_irqson() for rcuidle tracepoints") now that we've > taught perf how to deal with not having an RCU context provided. > > Signed-off-by: Peter Zijlstra (Intel) > --- > include/linux/tracepoint.h | 8 ++------ > 1 file changed, 2 insertions(+), 6 deletions(-) > > --- a/include/linux/tracepoint.h > +++ b/include/linux/tracepoint.h > @@ -179,10 +179,8 @@ static inline struct tracepoint *tracepo Shouldn't we also get rid of this line above? int __maybe_unused __idx = 0; \ Thanx, Paul > * For rcuidle callers, use srcu since sched-rcu \ > * doesn't work from the idle path. \ > */ \ > - if (rcuidle) { \ > + if (rcuidle) \ > __idx = srcu_read_lock_notrace(&tracepoint_srcu);\ > - rcu_irq_enter_irqsave(); \ > - } \ > \ > it_func_ptr = rcu_dereference_raw((tp)->funcs); \ > \ > @@ -194,10 +192,8 @@ static inline struct tracepoint *tracepo > } while ((++it_func_ptr)->func); \ > } \ > \ > - if (rcuidle) { \ > - rcu_irq_exit_irqsave(); \ > + if (rcuidle) \ > srcu_read_unlock_notrace(&tracepoint_srcu, __idx);\ > - } \ > \ > preempt_enable_notrace(); \ > } while (0) > >