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,UNPARSEABLE_RELAY,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 A0275C76195 for ; Mon, 15 Jul 2019 16:58:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7BDFC2080A for ; Mon, 15 Jul 2019 16:58:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731438AbfGOQ6Z (ORCPT ); Mon, 15 Jul 2019 12:58:25 -0400 Received: from out30-131.freemail.mail.aliyun.com ([115.124.30.131]:51743 "EHLO out30-131.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729533AbfGOQ6Y (ORCPT ); Mon, 15 Jul 2019 12:58:24 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R391e4;CH=green;DM=||false|;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04420;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0TX.M-FQ_1563209898; Received: from US-143344MP.local(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0TX.M-FQ_1563209898) by smtp.aliyun-inc.com(127.0.0.1); Tue, 16 Jul 2019 00:58:20 +0800 Subject: Re: [PATCH] mm: page_alloc: document kmemleak's non-blockable __GFP_NOFAIL case To: Qian Cai , Catalin Marinas , Michal Hocko Cc: "dvyukov@google.com" , "akpm@linux-foundation.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" References: <1562964544-59519-1-git-send-email-yang.shi@linux.alibaba.com> <20190715131732.GX29483@dhcp22.suse.cz> <1563203882.4610.1.camel@lca.pw> From: Yang Shi Message-ID: <82cbc350-c2a8-e653-208a-a533771fe653@linux.alibaba.com> Date: Mon, 15 Jul 2019 09:58:14 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <1563203882.4610.1.camel@lca.pw> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/15/19 8:18 AM, Qian Cai wrote: > On Mon, 2019-07-15 at 10:01 -0500, Catalin Marinas wrote: >> On 15 Jul 2019, at 08:17, Michal Hocko wrote: >>> On Sat 13-07-19 04:49:04, Yang Shi wrote: >>>> When running ltp's oom test with kmemleak enabled, the below warning was >>>> triggerred since kernel detects __GFP_NOFAIL & ~__GFP_DIRECT_RECLAIM is >>>> passed in: >>> kmemleak is broken and this is a long term issue. I thought that >>> Catalin had something to address this. >> What needs to be done in the short term is revert commit >> d9570ee3bd1d4f20ce63485f5ef05663866fe6c0. Longer term the solution is to embed >> kmemleak metadata into the slab so that we don’t have the situation where the >> primary slab allocation success but the kmemleak metadata fails. >> >> I’m on holiday for one more week with just a phone to reply from but feel free >> to revert the above commit. I’ll follow up with a better solution. > Well, the reverting will only make the situation worst for the kmemleak under > memory pressure. In the meantime, if someone wants to push for the mempool I think this is expected by reverting that commit since kmemleak metadata could fail. But, it could fail too even though that commit is not reverted if the context is non-blockable. > solution with tunable pool sizes along with the reverting, that could be an > improvement. > > https://lore.kernel.org/linux-mm/20190328145917.GC10283@arrakis.emea.arm.com/