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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 06726C18E5B for ; Tue, 17 Mar 2020 15:59:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C598120724 for ; Tue, 17 Mar 2020 15:59:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584460740; bh=hhu6XAm/T/wDV6UsKrflTER0XbhUy8RqHGJSqyjTnNE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=QUamchtSXq4CzY1oVE3TWpJX8KAIzpVIzNY4vonIKQ6hHsGOjYTmwcHUD8QovG1Q+ +YhDJRt5OoNbayZw2/hnVQ44fzNA1/fWDr0nEIjuj7tHkLoh4716Cd3t2OSIYrhB8E 8DJgmT5vf4OQ6hxhfE+qlG0eT6YqI9fHJUmG99KM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726680AbgCQP67 (ORCPT ); Tue, 17 Mar 2020 11:58:59 -0400 Received: from mail-wm1-f53.google.com ([209.85.128.53]:51771 "EHLO mail-wm1-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726294AbgCQP67 (ORCPT ); Tue, 17 Mar 2020 11:58:59 -0400 Received: by mail-wm1-f53.google.com with SMTP id a132so22045665wme.1 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=s/Uaqd36AjVrV8nBsVkpbGsBDfXcdWzFUojhtrw1D7euEE1mO9n2yoRC7CnQNJlmfd pb69r8M/E8qGTF4FEm/VWEk6ysxlNTFL0ZdMo6tMSbshc69mbDN0zGlfYy2vSdDyOwVk piGN59Dqm80KyJurDTs8d8FcJlUyutJANScB5m9RJpP61uS6UuREhVjNNskJQJ1GSWuO wUwJG/ks7f4SOAR9hIKVkXpeVj0XOjQO2vHWeq1m2fEg0iiMfUYVVRK0M1B3WZZX7ZcW 4HGy9qsAAV9X3Oyx+jtipXTBdsJt59jaHvIGecAmTNt+KHe1g4v2RQmsHcsDGiPSWuyn 2DiA== X-Gm-Message-State: ANhLgQ0ceDfex/NPjlrcD0L+QiFzkc4+CvAZU/dPRD3s9PbzT1rwC3Uk z+6NFK82Y1eRdG3sENx1snA= 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> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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