From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755386Ab2ECM5Y (ORCPT ); Thu, 3 May 2012 08:57:24 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:10852 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752041Ab2ECM5W (ORCPT ); Thu, 3 May 2012 08:57:22 -0400 X-Authority-Analysis: v=2.0 cv=bcnpoZzB c=1 sm=0 a=ZycB6UtQUfgMyuk2+PxD7w==:17 a=XQbtiDEiEegA:10 a=YECtLpki0LgA:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=meVymXHHAAAA:8 a=oh7p09fDAAAA:8 a=Zm_B_Y7Yb7E_A1nUUXIA:9 a=PUjeQqilurYA:10 a=S4qrOZZe1UsA:10 a=jeBq3FmKZ4MA:10 a=ZycB6UtQUfgMyuk2+PxD7w==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.80.29 Message-ID: <1336049840.14207.82.camel@gandalf.stny.rr.com> Subject: Re: [PATCH v6 1/3] trace: Make removal of ring buffer pages atomic From: Steven Rostedt To: Vaibhav Nagarnaik Cc: Frederic Weisbecker , Ingo Molnar , Laurent Chavey , Justin Teravest , David Sharp , linux-kernel@vger.kernel.org Date: Thu, 03 May 2012 08:57:20 -0400 In-Reply-To: References: <1328212844-11889-2-git-send-email-vnagarnaik@google.com> <1335388704-26790-1-git-send-email-vnagarnaik@google.com> <1336010118.14207.75.camel@gandalf.stny.rr.com> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.2.2-1 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2012-05-02 at 23:40 -0700, Vaibhav Nagarnaik wrote: > On Wed, May 2, 2012 at 6:55 PM, Steven Rostedt wrote: > > Hmm, something in this patch breaks buffers_size_kb and friends. > > I checked and I guess you are referring to the initial state of the > buffer_size_kb, which returns: > 0 (expanded: 1408) > instead of: > 7 (expanded: 1408) > No I realized that. That changed with your other patch. > I found this got in with the earlier patch which added per-cpu > buffer_size_kb. I will send a small fix-up patch for it. Yeah, probably should send a fix for that. > > After expanding the ring buffer to various sizes, I couldn't find any > other breakage. Is there any other behavior that you saw as odd? The issue I see seems to trigger with trace-cmd: [root@ixf ~]# cat /debug/tracing/buffer_size_kb 0 (expanded: 1408) [root@ixf ~]# trace-cmd start -e sched /debug/tracing/events/sched/filter /debug/tracing/events/*/sched/filter [root@ixf ~]# cat /debug/tracing/buffer_size_kb 0 But if I enable it via the command line it works: [root@ixf ~]# cat /debug/tracing/buffer_size_kb 0 (expanded: 1408) [root@ixf ~]# echo 1 > /debug/tracing/events/sched/enable [root@ixf ~]# cat /debug/tracing/buffer_size_kb 1408 Without your patch: [root@ixf ~]# cat /debug/tracing/buffer_size_kb 0 (expanded: 1408) [root@ixf ~]# trace-cmd start -e sched /debug/tracing/events/sched/filter /debug/tracing/events/*/sched/filter [root@ixf ~]# cat /debug/tracing/buffer_size_kb 1408 So it seems to be trace-cmd doing something different that prevents the expand from happening. Not sure what it is. If I get time, I'll investigate it a little more. Thanks, -- Steve