From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f199.google.com (mail-wr0-f199.google.com [209.85.128.199]) by kanga.kvack.org (Postfix) with ESMTP id 1AF626B0033 for ; Mon, 23 Oct 2017 13:49:08 -0400 (EDT) Received: by mail-wr0-f199.google.com with SMTP id k15so10422544wrc.1 for ; Mon, 23 Oct 2017 10:49:08 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id 60si5741698wrp.1.2017.10.23.10.49.06 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 23 Oct 2017 10:49:06 -0700 (PDT) Date: Mon, 23 Oct 2017 19:49:05 +0200 From: Michal Hocko Subject: Re: [PATCH] mm: fix movable_node kernel command-line Message-ID: <20171023174905.ap4uz6puggeqnz3s@dhcp22.suse.cz> References: <20171023125213.whdiev6bjxr72gow@dhcp22.suse.cz> <20171023160314.GA11853@linux.intel.com> <20171023161554.zltjcls34kr4234m@dhcp22.suse.cz> <20171023171435.GA12025@linux.intel.com> <20171023172008.kr6dzpe63nfpgps7@dhcp22.suse.cz> <20171023173544.GA12198@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171023173544.GA12198@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Sharath Kumar Bhat Cc: linux-mm@kvack.org, akpm@linux-foundation.org On Mon 23-10-17 10:35:44, Sharath Kumar Bhat wrote: > On Mon, Oct 23, 2017 at 07:20:08PM +0200, Michal Hocko wrote: > > On Mon 23-10-17 10:14:35, Sharath Kumar Bhat wrote: > > [...] > > > This lets admin to configure the kernel to have movable memory > size of > > > hotpluggable memories and at the same time hotpluggable nodes have only > > > movable memory. > > > > Put aside that I believe that having too much of movable memory is > > dangerous and people are not very prepared for that fact, what is the > > specific usecase. Allowing users something is nice but as I've said the > > interface is ugly already and putting more on top is not very desirable. > > > > > This is useful because it lets user to have more movable > > > memory in the system that can be offlined/onlined. When the same hardware > > > is shared between two OS's then this helps to dynamically provision the > > > physical memory between them by offlining/onlining as and when the > > > application/user need changes. > > > > just use hotplugable memory for that purpose. The latest memory hotplug > > code allows you to online memory into a kernel or movable zone as per > > admin policy without the previously hardcoded zone ordering. So I really > > fail to see why to mock with the command line parameter at all. > > Yes, but it won't let us offline the memory blocks if they are already > in use by kernel allocations. This is more likely over a long period of > uptime. The command-line ensures that the memory blocks are movable all > the time as reserved by the admin from the boot. I am really confused about your usecase then. Why do you want to make non-hotplugable memory to be movable then? -- Michal Hocko SUSE Labs -- 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