From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rik van Riel Subject: Re: [patch 0/6] Guest page hinting version 7. Date: Thu, 02 Apr 2009 16:14:33 -0400 Message-ID: <49D51CA9.6090601@redhat.com> References: <20090327150905.819861420@de.ibm.com> <200903281705.29798.rusty@rustcorp.com.au> <20090329162336.7c0700e9@skybase> <200904022232.02185.nickpiggin@yahoo.com.au> <20090402175249.3c4a6d59@skybase> <49D50CB7.2050705@redhat.com> <49D518E9.1090001@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <49D518E9.1090001@goop.org> Sender: owner-linux-mm@kvack.org To: Jeremy Fitzhardinge Cc: Martin Schwidefsky , akpm@osdl.org, Nick Piggin , frankeh@watson.ibm.com, virtualization@lists.osdl.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-mm@kvack.org, hugh@veritas.com, Xen-devel List-Id: virtualization@lists.linuxfoundation.org Jeremy Fitzhardinge wrote: > The more complex host policy decisions of how to balance overall > memory use system-wide are much in the same for both mechanisms. Not at all. Page hinting is just an optimization to host swapping, where IO can be avoided on many of the pages that hit the end of the LRU. No decisions have to be made at all about balancing memory use between guests, it just happens through regular host LRU aging. Automatic ballooning requires that something on the host figures out how much memory each guest needs and sizes the guests appropriately. All the proposed policies for that which I have seen have some nasty corner cases or are simply very limited in scope. -- 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