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=-1.0 required=3.0 tests=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 33EA2C10F29 for ; Tue, 17 Mar 2020 15:59:00 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F14F520724 for ; Tue, 17 Mar 2020 15:58:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F14F520724 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 8C75D6B0005; Tue, 17 Mar 2020 11:58:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8504B6B0006; Tue, 17 Mar 2020 11:58:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 717EE6B0007; Tue, 17 Mar 2020 11:58:59 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0197.hostedemail.com [216.40.44.197]) by kanga.kvack.org (Postfix) with ESMTP id 56F576B0005 for ; Tue, 17 Mar 2020 11:58:59 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 4A1661EFF for ; Tue, 17 Mar 2020 15:58:59 +0000 (UTC) X-FDA: 76605312798.20.unit29_6b8ab569d5500 X-HE-Tag: unit29_6b8ab569d5500 X-Filterd-Recvd-Size: 3384 Received: from mail-wm1-f53.google.com (mail-wm1-f53.google.com [209.85.128.53]) by imf37.hostedemail.com (Postfix) with ESMTP for ; Tue, 17 Mar 2020 15:58:58 +0000 (UTC) Received: by mail-wm1-f53.google.com with SMTP id f7so22608818wml.4 for ; Tue, 17 Mar 2020 08:58:58 -0700 (PDT) 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:in-reply-to; bh=FYhH5q4WEl1FEeszV9WnzdrzRhQsi77Q0fjkKyiS8K8=; b=GcXIrt15tRNlocOjlXhZ4st6lPFDAFEVJ+W4PW9J/jLpw2zO+63hNixi/RcFRpg5W+ VJAJA2Hea4xlWY6Ljpwm4du4jVb1XIEFd9FXO9yvvM7iYbB7ViaAtJBJZMt+koGlfkdj KhvvKxAF1rNhRH+uEq5WXu6Zg/QXaUEKx4CU6kdM4Cm7IEc6uPxfxeGHjzumYGtGP7zk Evjny9k157n99X1/FwxMdCsuv+qQ3bMDtibyBHA10SkEGArH9AtiNHX8aEa3ASWBrBhl y/WCN3KN/2VP4+6ZSGeNY8BjctgC45D6BUmLCImWpIDE6FUt/JK+DPOvz8FZ8J7+IPNo U6zw== X-Gm-Message-State: ANhLgQ11ETKfKSbNzkIjaUD9VFjRiX/EfEb0DZQTe9Fr8XO0MBI/BQAq fQd0gR49n2diIy/Gv8YYbBM= X-Google-Smtp-Source: ADFU+vtXMrtZwl2B9c9BXLxh92KX3GuxYzjcrVUmZMxyVywjJwgO8Q2gOZ17aY6Ccxd+xD91MfQb7w== X-Received: by 2002:a05:600c:2250:: with SMTP id a16mr5756585wmm.57.1584460737542; Tue, 17 Mar 2020 08:58:57 -0700 (PDT) Received: from localhost (ip-37-188-255-121.eurotel.cz. [37.188.255.121]) by smtp.gmail.com with ESMTPSA id w7sm5368320wrr.60.2020.03.17.08.58.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Mar 2020 08:58:56 -0700 (PDT) Date: Tue, 17 Mar 2020 16:58:55 +0100 From: Michal Hocko To: Minchan Kim Cc: Jann Horn , Linux-MM , kernel list , Daniel Colascione , Dave Hansen , "Joel Fernandes (Google)" , Andrew Morton Subject: Re: interaction of MADV_PAGEOUT with CoW anonymous mappings? Message-ID: <20200317155855.GS26018@dhcp22.suse.cz> References: <20200312082248.GS23944@dhcp22.suse.cz> <20200312201602.GA68817@google.com> <20200312204155.GE23944@dhcp22.suse.cz> <20200313020851.GD68817@google.com> <20200313080546.GA21007@dhcp22.suse.cz> <20200313205941.GA78185@google.com> <20200316092052.GD11482@dhcp22.suse.cz> <20200317014340.GA73302@google.com> <20200317071239.GB26018@dhcp22.suse.cz> <20200317150055.GC73302@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200317150055.GC73302@google.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000122, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue 17-03-20 08:00:55, Minchan Kim wrote: > On Tue, Mar 17, 2020 at 08:12:39AM +0100, Michal Hocko wrote: [...] > > Just to make it clear, are you really suggesting to special case > > page_check_references for madvise path? > > > > No, (page_mapcount() > 1) checks *effectively* fixes the performance > bug as well as vulnerability issue. Ahh, ok then we are on the same page. You were replying to the part where I have pointed out that you can control aging by these calls and your response suggested that this is somehow undesirable behavior or even a bug. -- Michal Hocko SUSE Labs