From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753293AbbFLAeG (ORCPT ); Thu, 11 Jun 2015 20:34:06 -0400 Received: from mail-qk0-f182.google.com ([209.85.220.182]:34109 "EHLO mail-qk0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752216AbbFLAeB (ORCPT ); Thu, 11 Jun 2015 20:34:01 -0400 Message-ID: <557A28F6.8040603@gmail.com> Date: Thu, 11 Jun 2015 18:33:58 -0600 From: David Ahern User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Andi Kleen CC: Arnaldo Carvalho de Melo , kan.liang@intel.com, linux-kernel@vger.kernel.org, ying.huang@intel.com Subject: Re: [PATCH 1/1] perf,tools: add time out to force stop endless mmap processing References: <1433922364-22580-1-git-send-email-kan.liang@intel.com> <20150611140614.GC2696@kernel.org> <5579A766.4010504@gmail.com> <20150611184737.GU19417@two.firstfloor.org> In-Reply-To: <20150611184737.GU19417@two.firstfloor.org> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/11/15 12:47 PM, Andi Kleen wrote: >> Can you elaborate on an example? I don't see how this can happen >> reading a maps file. And it does not read maps for all threads only >> thread group leaders. > > This is with a stress test case that generates lots of small mappings > at very high speed and frees them again. So the maps file keeps changing > faster than the proc reader can keep it and it can end up with > a live lock. Can you pass it along? I'd like to see how the task_diag proposal handles it. https://github.com/dsahern/linux/commits/task_diag-wip