From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: [RFC] Make need_resched() return true when rcu_urgent_qs requested Date: Thu, 19 Jul 2018 10:09:53 -0700 Message-ID: <20180719170953.GA17730@linux.vnet.ibm.com> References: <20180711210828.GD3593@linux.vnet.ibm.com> <1531396842.8759.125.camel@infradead.org> <20180712125351.GP3593@linux.vnet.ibm.com> <20180712161704.GA20726@linux.vnet.ibm.com> <20180716154015.GA21419@linux.vnet.ibm.com> <1531815548.19223.23.camel@infradead.org> <20180717125653.GH12945@linux.vnet.ibm.com> <20180718153628.GA24359@linux.vnet.ibm.com> <1531929711.3414.29.camel@infradead.org> <20180718163712.GB12945@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Christian Borntraeger , Peter Zijlstra , mhillenb@amazon.de, linux-kernel , kvm To: David Woodhouse Return-path: Content-Disposition: inline In-Reply-To: <20180718163712.GB12945@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Wed, Jul 18, 2018 at 09:37:12AM -0700, Paul E. McKenney wrote: > On Wed, Jul 18, 2018 at 06:01:51PM +0200, David Woodhouse wrote: > > On Wed, 2018-07-18 at 08:36 -0700, Paul E. McKenney wrote: > > > And I finally did get some near misses from an earlier commit, so we > > > should consider your patch to be officially off the hook. > > > > Yay, I like it when it's not my fault. I'll redo it with the ifdef > > CONFIG_NO_HZ_FULL. > > Hey, I didn't say it wasn't your fault, only that it -officially- wasn't > your fault. ;-) And I believe that I found my bug in this commit (lots more testing still required, but the preponderance of evidence and all that): 2cc0c7f07143 ("rcu: Eliminate ->rcu_qs_ctr from the rcu_dynticks structure") So it really isn't your fault. Of course, the real reason for the lack of fault on your part will not because I believe I found the bug elsewhere, but instead because I will be dropping your patch (and mine as well) on Frederic's advice. ;-) Thanx, Paul