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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 41F09C3F2C6 for ; Wed, 4 Mar 2020 00:29:52 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 007FC2072A for ; Wed, 4 Mar 2020 00:29:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="nYFseDo0" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 007FC2072A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 688D86B0003; Tue, 3 Mar 2020 19:29:51 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 639A76B000C; Tue, 3 Mar 2020 19:29:51 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 528466B000D; Tue, 3 Mar 2020 19:29:51 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0062.hostedemail.com [216.40.44.62]) by kanga.kvack.org (Postfix) with ESMTP id 3AEDC6B0003 for ; Tue, 3 Mar 2020 19:29:51 -0500 (EST) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id D724912F22 for ; Wed, 4 Mar 2020 00:29:50 +0000 (UTC) X-FDA: 76555796940.14.bite22_7308c3817790a X-HE-Tag: bite22_7308c3817790a X-Filterd-Recvd-Size: 3697 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf45.hostedemail.com (Postfix) with ESMTP for ; Wed, 4 Mar 2020 00:29:50 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4352B2064A; Wed, 4 Mar 2020 00:29:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583281789; bh=HnJHpFDOLod4KqNGlrwVWos5lTr6U52W7IZXOQnTJjM=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=nYFseDo0hzSCyqy3bvp1iv6AiEwp96Vh3BO3avrsSP6bnKuKgRm0OeqN21UV/6qfS cgBJxF5Fc9YEkB75tTg8eULhRmlEU4UTwmP4U2fStpFrOxYilkOS2oj1fI2419uRyG Bm7yM/4q6+KQMJDwPYFP7YvHptN66+UThXdXgtSY= Date: Tue, 3 Mar 2020 16:29:48 -0800 From: Andrew Morton To: Shakeel Butt Cc: Johannes Weiner , Yang Shi , Tetsuo Handa , Naresh Kamboju , linux-mm , Mel Gorman , Michal Hocko , Dan Schatzberg Subject: Re: fs/buffer.c: WARNING: alloc_page_buffers while mke2fs Message-Id: <20200303162948.a383cb88c4a1b0bfd3817798@linux-foundation.org> In-Reply-To: References: <0a37bb7d-18a7-c43c-52a5-f13a34decf69@i-love.sakura.ne.jp> <20200303202623.GA68565@cmpxchg.org> <20200303210632.GC68565@cmpxchg.org> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, 3 Mar 2020 15:22:00 -0800 Shakeel Butt wrote: > > doesn't corrupt its state. > > > > I.e. this is safe: > > > > process: interrupt: > > old = current->active_memcg > > old = current->active_memcg > > current->active_memcg = new > > allocate > > current->active_memcg = old > > current->active_memcg = new > > return old > > > > This is safe as well: > > > > process: interrupt: > > old = current->active_memcg > > current->active_memcg = new > > old = current->active_memcg > > current->active_memcg = new > > allocate > > current->active_memcg = old > > return old > > Yes, you are right. Thanks for the explanation. Thanks, all. Dan, I dropped the three-patch series loop-use-worker-per-cgroup-instead-of-kworker.patch mm-charge-active-memcg-when-no-mm-is-set.patch loop-charge-i-o-to-mem-and-blk-cg.patch When convenient, could you please prepend Johannes' patch to the series, retest and resend? While doing so, please figure out why you didn't also see this warning in your testing and make the appropriate changes! Thanks.