From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757060Ab0LRRIk (ORCPT ); Sat, 18 Dec 2010 12:08:40 -0500 Received: from mx1.redhat.com ([209.132.183.28]:11512 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756884Ab0LRRIj (ORCPT ); Sat, 18 Dec 2010 12:08:39 -0500 Message-ID: <4D0CEA7F.9080603@redhat.com> Date: Sat, 18 Dec 2010 19:08:15 +0200 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.13) Gecko/20101209 Fedora/3.1.7-0.35.b3pre.fc14 Thunderbird/3.1.7 MIME-Version: 1.0 To: Mike Galbraith CC: Rik van Riel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Srivatsa Vaddagiri , Peter Zijlstra , Chris Wright Subject: Re: [RFC -v2 PATCH 2/3] sched: add yield_to function References: <20101213224434.7495edb2@annuminas.surriel.com> <20101213224657.7e141746@annuminas.surriel.com> <1292306896.7448.157.camel@marge.simson.net> <4D0A6D34.6070806@redhat.com> <1292569018.7772.75.camel@marge.simson.net> <1292570143.7772.84.camel@marge.simson.net> In-Reply-To: <1292570143.7772.84.camel@marge.simson.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/17/2010 09:15 AM, Mike Galbraith wrote: > BTW, with this vruntime donation thingy, what prevents a task from > forking off accomplices who do nothing but wait for a wakeup and > yield_to(exploit)? > What's the difference between that and forking off accomplices who run(exploit) directly? Many threads dominating the scheduler has been solved by group scheduling. We need to make sure directed yield doesn't violate that, but I don't see new problems. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.