From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5409DC282DD for ; Wed, 8 Jan 2020 21:54:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E875206DB for ; Wed, 8 Jan 2020 21:54:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727351AbgAHVym (ORCPT ); Wed, 8 Jan 2020 16:54:42 -0500 Received: from mga09.intel.com ([134.134.136.24]:5184 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726390AbgAHVyl (ORCPT ); Wed, 8 Jan 2020 16:54:41 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Jan 2020 13:54:41 -0800 X-IronPort-AV: E=Sophos;i="5.69,411,1571727600"; d="scan'208";a="223053020" Received: from rchatre-mobl.amr.corp.intel.com (HELO [10.24.14.130]) ([10.24.14.130]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 08 Jan 2020 13:54:41 -0800 Subject: Re: [bug report] resctrl high memory comsumption To: Fenghua Yu Cc: Shakeel Butt , Borislav Petkov , LKML , Thomas Gleixner , Ingo Molnar , x86@kernel.org References: <20200108202311.GA40461@romley-ivt3.sc.intel.com> <20200108214250.GB40461@romley-ivt3.sc.intel.com> From: Reinette Chatre Message-ID: Date: Wed, 8 Jan 2020 13:54:39 -0800 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.2.1 MIME-Version: 1.0 In-Reply-To: <20200108214250.GB40461@romley-ivt3.sc.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Fenghua, On 1/8/2020 1:42 PM, Fenghua Yu wrote: > On Wed, Jan 08, 2020 at 12:42:17PM -0800, Reinette Chatre wrote: >> Hi Fenghua, >> On 1/8/2020 12:23 PM, Fenghua Yu wrote: >>> On Wed, Jan 08, 2020 at 09:07:41AM -0800, Shakeel Butt wrote: >>>> Recently we had a bug in the system software writing the same pids to >>>> the tasks file of resctrl group multiple times. The resctrl code >>> Subject: [RFC PATCH] x86/resctrl: Fix redundant task movements >> I think your fix would address this specific use case but a slightly >> different use case will still encounter the problem of high memory >> consumption. If for example, sleeping tasks are moved (many times) >> between resource or monitoring groups then their task_works queue would >> just keep growing. It seems that a call to task_work_cancel() before >> adding a new work item should address all these cases? > > The checking code in this patch is also helpful to avoid redundant > task move preparation (kzalloc(), task_work_add(), etc) in the same > rdtgroup. Indeed. > > How about adding both the checking code and task_work_cancel()? That does sound good to me. There is something in the current implementation that I would appreciate your feedback on: Currently the task's closid and rmid are initialized _after_ the call to task_work_add() succeeds. Should these not be initialized before the call to task_work_add()? Thank you Reinette