From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [PATCH V3 2/2] mm: Extend memory hotplug API to allow memory hotplug in virtual machines Date: Thu, 19 May 2011 16:01:43 -0700 Message-ID: <20110519160143.02163f36.akpm@linux-foundation.org> References: <20110517213858.GC30232@router-fw-old.local.net-space.pl> <20110519204509.GD27202@router-fw-old.local.net-space.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20110519204509.GD27202@router-fw-old.local.net-space.pl> Sender: owner-linux-mm@kvack.org To: Daniel Kiper Cc: David Rientjes , ian.campbell@citrix.com, haicheng.li@linux.intel.com, fengguang.wu@intel.com, jeremy@goop.org, konrad.wilk@oracle.com, dan.magenheimer@oracle.com, v.tolstov@selfip.ru, pasik@iki.fi, dave@linux.vnet.ibm.com, wdauchy@gmail.com, xen-devel@lists.xensource.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org List-Id: xen-devel@lists.xenproject.org On Thu, 19 May 2011 22:45:09 +0200 Daniel Kiper wrote: > On Wed, May 18, 2011 at 08:36:02PM -0700, David Rientjes wrote: > > On Tue, 17 May 2011, Daniel Kiper wrote: > > > > > This patch contains online_page_callback and apropriate functions for > > > setting/restoring online page callbacks. It allows to do some machine > > > specific tasks during online page stage which is required to implement > > > memory hotplug in virtual machines. Additionally, __online_page_set_limits(), > > > __online_page_increment_counters() and __online_page_free() function > > > was added to ease generic hotplug operation. > > > > There are several issues with this. > > > > First, this is completely racy and only allows one global callback to be > > in use at a time without looping, which is probably why you had to pass an > > One callback is allowed by design. Currently I do not see > any real usage for more than one callback. I'd suggest that you try using the notifier.h tools here and remove the restriction. Sure, we may never use the capability but I expect the code will look nice and simple and once it's done, it's done. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org