From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-6.0 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id A606E7D08A for ; Wed, 16 Jan 2019 21:05:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727109AbfAPVFJ (ORCPT ); Wed, 16 Jan 2019 16:05:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:38474 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726803AbfAPVFJ (ORCPT ); Wed, 16 Jan 2019 16:05:09 -0500 Received: from gandalf.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 0685920652; Wed, 16 Jan 2019 21:05:07 +0000 (UTC) Date: Wed, 16 Jan 2019 16:05:06 -0500 From: Steven Rostedt To: Changbin Du Cc: mingo@redhat.com, corbet@lwn.net, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] sched/tracing: Show stacktrace for wakeup tracers Message-ID: <20190116160506.0d56e027@gandalf.local.home> In-Reply-To: <20190116160249.7554-1-changbin.du@gmail.com> References: <20190116160249.7554-1-changbin.du@gmail.com> X-Mailer: Claws Mail 3.16.0 (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-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Thu, 17 Jan 2019 00:02:49 +0800 Changbin Du wrote: > This align the behavior of wakeup tracers with irqsoff latency tracer > that we record stacktrace at the beginning and end of waking up. The > stacktrace shows us what is happening in the kernel. > > Signed-off-by: Changbin Du I've applied your patch, but it may be a while before you see it in linux-next. I'll be traveling for a bit and wont be able to do the full tests which I do before pushing to my linux-next branch. You may see them soon in my ftrace/core branch on kernel.org. -- Steve > --- > kernel/trace/trace_sched_wakeup.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c > index da5b6e012840..f4fe7d1781e9 100644 > --- a/kernel/trace/trace_sched_wakeup.c > +++ b/kernel/trace/trace_sched_wakeup.c > @@ -475,6 +475,7 @@ probe_wakeup_sched_switch(void *ignore, bool preempt, > > __trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, flags, pc); > tracing_sched_switch_trace(wakeup_trace, prev, next, flags, pc); > + __trace_stack(wakeup_trace, flags, 0, pc); > > T0 = data->preempt_timestamp; > T1 = ftrace_now(cpu); > @@ -586,6 +587,7 @@ probe_wakeup(void *ignore, struct task_struct *p) > data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu); > data->preempt_timestamp = ftrace_now(cpu); > tracing_sched_wakeup_trace(wakeup_trace, p, current, flags, pc); > + __trace_stack(wakeup_trace, flags, 0, pc); > > /* > * We must be careful in using CALLER_ADDR2. But since wake_up