From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f49.google.com (mail-pa0-f49.google.com [209.85.220.49]) by kanga.kvack.org (Postfix) with ESMTP id 8F298900016 for ; Thu, 4 Jun 2015 14:41:47 -0400 (EDT) Received: by payr10 with SMTP id r10so34846227pay.1 for ; Thu, 04 Jun 2015 11:41:47 -0700 (PDT) Received: from mga03.intel.com (mga03.intel.com. [134.134.136.65]) by mx.google.com with ESMTP id k9si7106623pdp.27.2015.06.04.11.41.46 for ; Thu, 04 Jun 2015 11:41:46 -0700 (PDT) Message-ID: <55709BEA.8030903@intel.com> Date: Thu, 04 Jun 2015 11:41:46 -0700 From: Dave Hansen MIME-Version: 1.0 Subject: Re: [RFC PATCH 08/12] mm: use mirrorable to switch allocate mirrored memory References: <55704A7E.5030507@huawei.com> <55704C79.5060608@huawei.com> In-Reply-To: <55704C79.5060608@huawei.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Xishi Qiu , Andrew Morton , nao.horiguchi@gmail.com, Yinghai Lu , "H. Peter Anvin" , Thomas Gleixner , mingo@elte.hu, Xiexiuqi , Hanjun Guo , "Luck, Tony" Cc: Linux MM , LKML On 06/04/2015 06:02 AM, Xishi Qiu wrote: > Add a new interface in path /proc/sys/vm/mirrorable. When set to 1, it means > we should allocate mirrored memory for both user and kernel processes. That's a pretty dangerously short name. :) How would this end up getting used? It seems like it would be dangerous to use once userspace was very far along. So would the kernel set it to 1 and then let (early??) userspace set it back to 0? That would let important userspace like /bin/init get mirrored memory without having to actually change much in userspace. This definitely needs some good documentation. Also, if it's insane to turn it back *on*, maybe it should be a one-way trip to turn off. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org