From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751517AbaEZHU0 (ORCPT ); Mon, 26 May 2014 03:20:26 -0400 Received: from mail7.hitachi.co.jp ([133.145.228.42]:60340 "EHLO mail7.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751186AbaEZHUZ (ORCPT ); Mon, 26 May 2014 03:20:25 -0400 X-AuditID: 85900ec0-d1328b9000001514-e9-5382eb36736c Message-ID: <5382EB36.2060501@hitachi.com> Date: Mon, 26 May 2014 16:20:22 +0900 From: Yoshihiro YUNOMAE User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:13.0) Gecko/20120604 Thunderbird/13.0 MIME-Version: 1.0 To: Steven Rostedt Cc: Namhyung Kim , linux-kernel@vger.kernel.org, Hidehiro Kawai , Frederic Weisbecker , Masami Hiramatsu , Ingo Molnar , yrl.pp-manager.tt@hitachi.com Subject: Re: [PATCH V2 0/2] ftrace: Introduce the new I/F "nr_saved_cmdlines" References: <20140220084428.3839.59555.stgit@yunodevel> In-Reply-To: <20140220084428.3839.59555.stgit@yunodevel> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Steven, Would you review this patch set? Thanks, Yoshihiro YUNOMAE (2014/02/20 17:44), Yoshihiro YUNOMAE wrote: > Hi, > > This patch set introduces the new I/F "nr_saved_cmdlines" for increasing > the number of saved cmdlines. Current saved_cmdlines can store just 128 command > names and PIDs, but process names are often lost like <...> when we read trace > data. If the process exists, we can get the name by using ps command. However, > if the process already has not existed, we cannot get the name. > > To solve this issue, we introduce the new I/F "nr_saved_cmdlines" to expand > the max number of saved command line names. This I/F is very simple. > If we write a number to nr_saved_cmdlines, the number of command name will be > stored. And, if we read the I/F, we can get current maximum number of command > name. The default number is 128 which is current default number, so this patch > does not change the usage of memory for saved_cmdlines when we boot kernel. > > Thanks! > > Changes in V2: > - Fix a racing problem of savedcmd between saved_cmdlines I/F and > nr_saved_cmdlines I/F. If one reads saved_cmdlines and writes a value to > nr_saved_cmdlines at the same time, then the write returns -EBUSY. [2/2] > > --- > > Yoshihiro YUNOMAE (2): > ftrace: Make saved_cmdlines use seq_read > ftrace: Introduce nr_saved_cmdlines I/F > > > kernel/trace/trace.c | 316 +++++++++++++++++++++++++++++++++++++++++--------- > 1 file changed, 261 insertions(+), 55 deletions(-) > -- Yoshihiro YUNOMAE Software Platform Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: yoshihiro.yunomae.ez@hitachi.com