From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754997AbXGHNxS (ORCPT ); Sun, 8 Jul 2007 09:53:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752783AbXGHNxJ (ORCPT ); Sun, 8 Jul 2007 09:53:09 -0400 Received: from il.qumranet.com ([82.166.9.18]:38922 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751474AbXGHNxI (ORCPT ); Sun, 8 Jul 2007 09:53:08 -0400 Message-ID: <4690EC47.6060904@qumranet.com> Date: Sun, 08 Jul 2007 16:53:11 +0300 From: Avi Kivity User-Agent: Thunderbird 2.0.0.0 (X11/20070419) MIME-Version: 1.0 To: Ingo Molnar CC: kvm-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, shaohua.li@intel.com Subject: Re: [PATCH][RFC] kvm-scheduler integration References: <11838994974161-git-send-email-avi@qumranet.com> <20070708133539.GA12597@elte.hu> <4690E973.7000606@qumranet.com> <20070708134850.GB22911@elte.hu> In-Reply-To: <20070708134850.GB22911@elte.hu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > * Avi Kivity wrote: > > >>>> +#ifdef CONFIG_SCHED_KVM >>>> +static __read_mostly struct sched_kvm_hooks kvm_hooks; >>>> +#endif >>>> >>> please just add a current->put_vcpu() function pointer instead of >>> this hooks thing. >>> >> Won't that increase task_struct (16 bytes on 64-bit) unnecessarily? >> The function pointers are common to all virtual machines. >> > > well, this function pointer could then be reused by other virtual > machines as well, couldnt it? I don't get this. If we add a couple of members to task_struct, it can't be reused. The values will be the same across all tasks, but the memory will be gone (including tasks which aren't virtual machines). > If the task struct overhead is a problem > (it really isnt, and it's dependent on CONFIG_KVM) then we could switch > it around to a notifier-alike mechanism. > I'm hoping that CONFIG_KVM will be enabled on most distro kernels, so we need to optimize for that case as well. -- error compiling committee.c: too many arguments to function