From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rik van Riel Subject: Re: [RFC PATCH 2/3] sched: add yield_to function Date: Fri, 03 Dec 2010 12:09:01 -0500 Message-ID: <4CF9242D.4090007@redhat.com> References: <20101202144129.4357fe00@annuminas.surriel.com> <20101202144423.3ad1908d@annuminas.surriel.com> <1291355656.7633.124.camel@marge.simson.net> <20101203134618.GG27994@linux.vnet.ibm.com> <1291387511.7992.15.camel@marge.simson.net> <4CF90341.4020101@redhat.com> <1291388987.7992.27.camel@marge.simson.net> <4CF90E3D.7090103@redhat.com> <20101203162003.GA13515@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Mike Galbraith , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Avi Kiviti , Peter Zijlstra , Ingo Molnar , Anthony Liguori To: vatsa@linux.vnet.ibm.com Return-path: In-Reply-To: <20101203162003.GA13515@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 12/03/2010 11:20 AM, Srivatsa Vaddagiri wrote: > On Fri, Dec 03, 2010 at 10:35:25AM -0500, Rik van Riel wrote: >> Do you have suggestions on what I should do to make >> this yield_to functionality work? > > Keeping in mind the complications of yield_to, I had suggested we do something > suggested below: > > http://marc.info/?l=kvm&m=129122645006996&w=2 > > Essentially yield to other tasks on your own runqueue and when you get to run > again, try reclaiming what you gave up earlier (with a cap on how much one can > feedback this relinquished time). It can be accomplished via a special form of > yield(), available only to in-kernel users, kvm in this case. I don't see how that is going to help get the lock released, when the VCPU holding the lock is on another CPU. -- All rights reversed