From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f69.google.com (mail-pl0-f69.google.com [209.85.160.69]) by kanga.kvack.org (Postfix) with ESMTP id 999076B000A for ; Mon, 23 Jul 2018 16:31:11 -0400 (EDT) Received: by mail-pl0-f69.google.com with SMTP id d10-v6so1130313pll.22 for ; Mon, 23 Jul 2018 13:31:11 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id 17-v6sor2398633pgp.145.2018.07.23.13.31.10 for (Google Transport Security); Mon, 23 Jul 2018 13:31:10 -0700 (PDT) Date: Mon, 23 Jul 2018 13:31:08 -0700 (PDT) From: David Rientjes Subject: Re: [PATCH] mm: thp: remove use_zero_page sysfs knob In-Reply-To: <3118b646-681e-a2aa-dc7b-71d4821fa50f@linux.alibaba.com> Message-ID: References: <1532110430-115278-1-git-send-email-yang.shi@linux.alibaba.com> <20180720210626.5bnyddmn4avp2l3x@kshutemo-mobl1> <3118b646-681e-a2aa-dc7b-71d4821fa50f@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Yang Shi Cc: "Kirill A. Shutemov" , hughd@google.com, aaron.lu@intel.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org On Fri, 20 Jul 2018, Yang Shi wrote: > I agree to keep it for a while to let that security bug cool down, however, if > there is no user anymore, it sounds pointless to still keep a dead knob. > It's not a dead knob. We use it, and for reasons other than CVE-2017-1000405. To mitigate the cost of constantly compacting memory to allocate it after it has been freed due to memry pressure, we can either continue to disable it, allow it to be persistently available, or use a new value for use_zero_page to specify it should be persistently available.