From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755401AbbFLOm7 (ORCPT ); Fri, 12 Jun 2015 10:42:59 -0400 Received: from mga14.intel.com ([192.55.52.115]:14088 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753458AbbFLOm6 convert rfc822-to-8bit (ORCPT ); Fri, 12 Jun 2015 10:42:58 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,602,1427785200"; d="scan'208";a="742183049" From: "Liang, Kan" To: David Ahern , Andi Kleen CC: Arnaldo Carvalho de Melo , "linux-kernel@vger.kernel.org" , "Huang, Ying" Subject: RE: [PATCH 1/1] perf,tools: add time out to force stop endless mmap processing Thread-Topic: [PATCH 1/1] perf,tools: add time out to force stop endless mmap processing Thread-Index: AQHQo44i3glIe3h0sEG/9i/L0QJfWp2m0lUAgAAU7wCAADmvgIAAYMUAgAFtkPA= Date: Fri, 12 Jun 2015 14:42:53 +0000 Message-ID: <37D7C6CF3E00A74B8858931C1DB2F077018767AD@SHSMSX103.ccr.corp.intel.com> References: <1433922364-22580-1-git-send-email-kan.liang@intel.com> <20150611140614.GC2696@kernel.org> <5579A766.4010504@gmail.com> <20150611184737.GU19417@two.firstfloor.org> <557A28F6.8040603@gmail.com> In-Reply-To: <557A28F6.8040603@gmail.com> Accept-Language: zh-CN, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 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 Hi David, I tried the task_diag on my platform, but it shows error message when I run perf top. " Message handling failed: rc -1, errno 25". And it looks perf top failed to get maps information. 20.88% [unknown] [.] 0x00000000004992c4 6.77% [unknown] [.] 0x000000000048f9e7 4.92% [unknown] [.] 0x000000000043789c 4.68% [unknown] [.] 0x0000003002f32918 4.31% [unknown] [.] 0x00000000004992d6 1.85% [kernel] [k] _raw_spin_lock 1.84% [unknown] [.] 0x00000000004d8190 1.84% [unknown] [.] 0x00000000004378ad 1.40% [kernel] [k] clear_page_c_e 1.23% [unknown] [.] 0x00000000004992d0 1.23% [unknown] [.] 0x00000000004378cf I installed the task_diag kernel and libnl3-3.2.22-3. Thanks, Kan