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=-3.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 B8CAEC4363D for ; Fri, 2 Oct 2020 13:27:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6580420719 for ; Fri, 2 Oct 2020 13:27:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=cmpxchg-org.20150623.gappssmtp.com header.i=@cmpxchg-org.20150623.gappssmtp.com header.b="Rd2A/Weu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387908AbgJBN1l (ORCPT ); Fri, 2 Oct 2020 09:27:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44962 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726090AbgJBN1k (ORCPT ); Fri, 2 Oct 2020 09:27:40 -0400 Received: from mail-qt1-x841.google.com (mail-qt1-x841.google.com [IPv6:2607:f8b0:4864:20::841]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AA4A9C0613D0 for ; Fri, 2 Oct 2020 06:27:40 -0700 (PDT) Received: by mail-qt1-x841.google.com with SMTP id y11so1127891qtn.9 for ; Fri, 02 Oct 2020 06:27:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=zrpmNv9TwKzBwkVfbm5DOPz5PI+5NOjhq3Gy3n1KaMg=; b=Rd2A/Weuc+n5WsaDOpKuAiVOCTvh1UKrmHrmyJbGKoFiQz/LW/SvNo+v4+f7sKmCT7 Id4WyMVvSTH8unM3e+u6wRqu+AF7Dm/RP4LkDzDjqQJbAbiNJ1Ljx3+QLOLEBXDE2O7n POdrPxccPfAYA4RXPI+x7zUMLyU6Hv5z4vfGuBxlP02x9Yo1xHD9EzDO7jfeaYzoabdY FYI5+8R0g1e0DjA0n/KGkn3miYtkTq4lITpne0IdguBLjyg+h/EPDTeDxxNB+fPDkKxq gjOwy6yjUA31e7yN6fx+JJG2iJ/L+re3SBOrNy4Ik3pC+VnnT/Xmv+K2nfxn4qNipul3 uxMw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=zrpmNv9TwKzBwkVfbm5DOPz5PI+5NOjhq3Gy3n1KaMg=; b=f/Nw0nOcRtFZfa4+ohw38ePvWw46pvYJokDS2dDz+ENqVLdn/IoHQN9pEoCCSApErT TG1XpQhvW7HEBUF/szSyZwWBvZHiX9AdmEauKelKEvLScyiAEvtT5HDm4pqGgjP//olI QuBs34FB5IRmdI3DSoi/vdlk6vwbQSmh46PtHEwC7laO8q2Ls5XJbdb4KkfuEKX/cwXj r8Be6bD+NGsR6e5ZPvTfROWleRsrsoqJtFleWb5BRe7tE0x0fAtsmnBplV1BDJkr7L2r XfB704TEmbUVPN48RMdUumzVBMo+r1uEGuYcfU4iEmYhQ6u5+qK48HigkprVG75lZj8K aoSQ== X-Gm-Message-State: AOAM530Rt9cPlWa+/0Vv/heq5kZT3xu68z5uIAFMlSoDZ9kgZ4LAUXVz 6o8DIKD4kdlmGhqIer1SxWknSQ== X-Google-Smtp-Source: ABdhPJwlVwM9MAnCLAE0xRO4pwEYKddVvRYLA8GvopEROKXDbMOwOrms04uggw9W2U/fDnQvNTYMaQ== X-Received: by 2002:ac8:7613:: with SMTP id t19mr2283473qtq.259.1601645259959; Fri, 02 Oct 2020 06:27:39 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::1:d668]) by smtp.gmail.com with ESMTPSA id g188sm1064288qkf.3.2020.10.02.06.27.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Oct 2020 06:27:39 -0700 (PDT) Date: Fri, 2 Oct 2020 09:25:57 -0400 From: Johannes Weiner To: Michal =?iso-8859-1?Q?Koutn=FD?= Cc: Roman Gushchin , Andrew Morton , Shakeel Butt , Michal Hocko , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel-team@fb.com Subject: Re: [PATCH v4 4/4] mm: convert page kmemcg type to a page memcg flag Message-ID: <20201002132557.GA525590@cmpxchg.org> References: <20201001002710.748166-1-guro@fb.com> <20201001002710.748166-5-guro@fb.com> <20201001170036.GA29848@blackbook> <20201001172713.GA500308@cmpxchg.org> <20201002100350.GC24008@blackbody.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20201002100350.GC24008@blackbody.suse.cz> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 02, 2020 at 12:03:50PM +0200, Michal Koutný wrote: > On Thu, Oct 01, 2020 at 01:27:13PM -0400, Johannes Weiner wrote: > > I do think there is a bug, though: mem_cgroup_move_account() should > > use WRITE_ONCE() on page->mem_cgroup. > If this were a bug, wouldn't be the proper approach > rcu_assign_pointer()/rcu_dereference() pair? Yes, you're right. I'll double check these code paths and follow up with a patch if necessary.