From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id 883C36B004D for ; Thu, 2 Apr 2009 16:14:24 -0400 (EDT) Message-ID: <49D51CA9.6090601@redhat.com> Date: Thu, 02 Apr 2009 16:14:33 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [patch 0/6] Guest page hinting version 7. 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> In-Reply-To: <49D518E9.1090001@goop.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit 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: 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