From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [RFC v2 03/20] memory: merge adjacent segments of a single memory region Date: Mon, 27 Jun 2011 17:11:52 +0300 Message-ID: <4E088FA8.8010705@redhat.com> References: <1309180927-19003-1-git-send-email-avi@redhat.com> <1309180927-19003-4-git-send-email-avi@redhat.com> <4E088C08.3090408@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org To: Jan Kiszka Return-path: Received: from mx1.redhat.com ([209.132.183.28]:50073 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751784Ab1F0OL7 (ORCPT ); Mon, 27 Jun 2011 10:11:59 -0400 In-Reply-To: <4E088C08.3090408@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: On 06/27/2011 04:56 PM, Jan Kiszka wrote: > On 2011-06-27 15:21, Avi Kivity wrote: > > Simple implementations of memory routers, for example the Cirrus VGA memory banks > > or the 440FX PAM registers can generate adjacent memory regions which are contiguous. > > Detect these and merge them; this saves kvm memory slots and shortens lookup times. > > That reminds me of KVM_CAP_JOIN_MEMORY_REGIONS_WORKS. Have you checked > if things still work in the absence of the feature or if we need to lift > our requirements on the host kernel (would be 2.6.30, not that problematic)? Good catch. We should probably disable merging if it doesn't work. Or we should declare that a kernel bug should be fixed in the kernel, not userspace, and backport the fix to 2.6.27.whatever. -- error compiling committee.c: too many arguments to function