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=-8.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=ham 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 25674C43444 for ; Thu, 3 Jan 2019 09:32:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DE7C821019 for ; Thu, 3 Jan 2019 09:32:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546507925; bh=yinMsv5fbA3tVu+bujFnkgPhBEVGk6j/t0S0fTCPMoI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=VJHIErpAMdwoAIy5/NSd2xGinODhkUM5oj4bxEgxO3rYFkzeQAeRrOXnMQ1y1C4UO PAEAbTudL6cB2ToXC91Sf61lHJiR8vAR5Avc5I6WTcQuaSLPcuyzcb7GYFMTaNO1qk VQKVBzY9OBt97d/vYfEegyjWP0gTOF4+rZMlg8lw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730491AbfACJcE (ORCPT ); Thu, 3 Jan 2019 04:32:04 -0500 Received: from mx2.suse.de ([195.135.220.15]:44016 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726152AbfACJcE (ORCPT ); Thu, 3 Jan 2019 04:32:04 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 95914AE18; Thu, 3 Jan 2019 09:32:02 +0000 (UTC) Date: Thu, 3 Jan 2019 10:32:01 +0100 From: Michal Hocko To: Qian Cai Cc: catalin.marinas@arm.com, akpm@linux-foundation.org, cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] kmemleak: survive in a low-memory situation Message-ID: <20190103093201.GB31793@dhcp22.suse.cz> References: <20190102165931.GB6584@arrakis.emea.arm.com> <20190102180619.12392-1-cai@lca.pw> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190102180619.12392-1-cai@lca.pw> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 02-01-19 13:06:19, Qian Cai wrote: [...] > diff --git a/mm/kmemleak.c b/mm/kmemleak.c > index f9d9dc250428..9e1aa3b7df75 100644 > --- a/mm/kmemleak.c > +++ b/mm/kmemleak.c > @@ -576,6 +576,16 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size, > struct rb_node **link, *rb_parent; > > object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp)); > +#ifdef CONFIG_PREEMPT_COUNT > + if (!object) { > + /* last-ditch effort in a low-memory situation */ > + if (irqs_disabled() || is_idle_task(current) || in_atomic()) > + gfp = GFP_ATOMIC; > + else > + gfp = gfp_kmemleak_mask(gfp) | __GFP_DIRECT_RECLAIM; > + object = kmem_cache_alloc(object_cache, gfp); > + } > +#endif I do not get it. How can this possibly help when gfp_kmemleak_mask() adds __GFP_NOFAIL modifier to the given gfp mask? Or is this not the case anymore in some tree? -- Michal Hocko SUSE Labs