From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752192AbdIFScs (ORCPT ); Wed, 6 Sep 2017 14:32:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:39900 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751212AbdIFScr (ORCPT ); Wed, 6 Sep 2017 14:32:47 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 885F721E92 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=rostedt@goodmis.org Date: Wed, 6 Sep 2017 14:32:43 -0400 From: Steven Rostedt To: Tom Zanussi Cc: tglx@linutronix.de, mhiramat@kernel.org, namhyung@kernel.org, vedang.patel@intel.com, bigeasy@linutronix.de, joel.opensrc@gmail.com, joelaf@google.com, mathieu.desnoyers@efficios.com, baohong.liu@intel.com, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org Subject: Re: [PATCH v2 02/40] tracing: Add support to detect and avoid duplicates Message-ID: <20170906143243.381a38df@gandalf.local.home> In-Reply-To: <7f3ca68455bdac47285ed45d608075a4af287362.1504642143.git.tom.zanussi@linux.intel.com> References: <7f3ca68455bdac47285ed45d608075a4af287362.1504642143.git.tom.zanussi@linux.intel.com> X-Mailer: Claws Mail 3.14.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 5 Sep 2017 16:57:14 -0500 Tom Zanussi wrote: > From: Vedang Patel > > A duplicate in the tracing_map hash table is when 2 different entries > have the same key and, as a result, the key_hash. This is possible due > to a race condition in the algorithm. This race condition is inherent to > the algorithm and not a bug. This was fine because, until now, we were > only interested in the sum of all the values related to a particular > key (the duplicates are dealt with in tracing_map_sort_entries()). But, > with the inclusion of variables[1], we are interested in individual > values. So, it will not be clear what value to choose when > there are duplicates. So, the duplicates need to be removed. > > [1] - https://lkml.org/lkml/2017/6/26/751 FYI, something like this should have: Link: http://lkml.kernel.org/r/cover.1498510759.git.tom.zanussi@linux.intel.com And avoid any non kernel.org archiving system. -- Steve > > Signed-off-by: Vedang Patel > --- >