From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [Xen-devel] [PATCH 07/10] xen/mmu: Work with 1-1 mappings when allocating new top/middle entries. Date: Wed, 22 Dec 2010 12:47:28 -0500 Message-ID: <20101222174728.GA24483@dumpdata.com> References: <1292967460-15709-1-git-send-email-konrad.wilk@oracle.com> <1292967460-15709-8-git-send-email-konrad.wilk@oracle.com> <1293008071.3998.41.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1293008071.3998.41.camel@localhost.localdomain> Sender: linux-kernel-owner@vger.kernel.org To: Ian Campbell Cc: "linux-kernel@vger.kernel.org" , "jeremy@goop.org" , "hpa@zytor.com" , Konrad Rzeszutek Wilk , "xen-devel@lists.xensource.com" , Jan Beulich List-Id: xen-devel@lists.xenproject.org On Wed, Dec 22, 2010 at 08:54:31AM +0000, Ian Campbell wrote: > On Tue, 2010-12-21 at 21:37 +0000, Konrad Rzeszutek Wilk wrote: > > We were not properly taking under advisement the 1-1 mappings > > when a large area of memory was ballooned out. > > Are we lazily allocating the p2m tree nodes for regions initially > covered by the balloon? (perhaps we have always done this and it isn't > new with this series) Before: Yes Now: Yes. > > Would it be simpley to always populate enough tree nodes to cover the > ballooned area as well as nr_pages at start of day and therefore avoid > worrying about it later on (except for memory hotplug which is special > in this way already)? Tried that, ran out of reserved_brk space :-) But not sure what we would gain for this - it is not always guaranteed that we will populate up to the memory 'maxmem' region.