From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754993Ab2F2MZo (ORCPT ); Fri, 29 Jun 2012 08:25:44 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:18733 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752588Ab2F2MZn (ORCPT ); Fri, 29 Jun 2012 08:25:43 -0400 X-Authority-Analysis: v=2.0 cv=IOWA+3TG c=1 sm=0 a=ZycB6UtQUfgMyuk2+PxD7w==:17 a=XQbtiDEiEegA:10 a=2lFTh0urSm0A:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=meVymXHHAAAA:8 a=ayC55rCoAAAA:8 a=1XWaLZrsAAAA:8 a=DhiXXOCnvGlBRRFihSkA:9 a=PUjeQqilurYA:10 a=UTB_XpHje0EA:10 a=ZycB6UtQUfgMyuk2+PxD7w==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.80.29 Message-ID: <1340972741.16702.105.camel@gandalf.stny.rr.com> Subject: Re: [PATCH] tracing: Update entries counter when removing pages From: Steven Rostedt To: Vaibhav Nagarnaik Cc: Justin Teravest , David Sharp , linux-kernel@vger.kernel.org Date: Fri, 29 Jun 2012 08:25:41 -0400 In-Reply-To: <1340046722-11477-1-git-send-email-vnagarnaik@google.com> References: <1340046722-11477-1-git-send-email-vnagarnaik@google.com> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.2.2-1+b1 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 Mon, 2012-06-18 at 12:12 -0700, Vaibhav Nagarnaik wrote: > When removing pages from the ring buffer, its state is not reset. This > means that the counters need to be correctly updated to account for the > pages removed. > > Update the entries counter to reflect the removed events from the > pages just like entries_bytes counter. > > Signed-off-by: Vaibhav Nagarnaik > --- > kernel/trace/ring_buffer.c | 6 +++--- > 1 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c > index 96c2dd1..a2bec4c 100644 > --- a/kernel/trace/ring_buffer.c > +++ b/kernel/trace/ring_buffer.c > @@ -1346,10 +1346,10 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned int nr_pages) > * If something was added to this page, it was full > * since it is not the tail page. So we deduct the > * bytes consumed in ring buffer from here. > - * No need to update overruns, since this page is > - * deleted from ring buffer and its entries are > - * already accounted for. > + * No need to update overruns, since updating > + * 'entries' accounts for that. > */ > + local_sub(page_entries, &cpu_buffer->entries); Actually, I think it would be better to increment overrun instead. As these are lost events, and that is what overrun counts. I just tested it with: local_add(page_entries, &cpu_buffer->overrun); and it works well. Showing the lost events. -- Steve > local_sub(BUF_PAGE_SIZE, &cpu_buffer->entries_bytes); > } >