From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1170083AbdDXMoK (ORCPT ); Mon, 24 Apr 2017 08:44:10 -0400 Received: from mail.kernel.org ([198.145.29.136]:37488 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1168918AbdDXMoC (ORCPT ); Mon, 24 Apr 2017 08:44:02 -0400 Date: Mon, 24 Apr 2017 08:43:57 -0400 From: Steven Rostedt To: Peter Zijlstra Cc: LKML , Thomas Gleixner , Ingo Molnar , Clark Williams , Daniel Bristot de Oliveira , John Kacur Subject: Re: [RFC][PATCH tip/sched/core] sched/rt: Simplify the IPI rt balancing logic Message-ID: <20170424084357.645d6f18@gandalf.local.home> In-Reply-To: <20170424085700.vm2wpn5gac57vb2n@hirez.programming.kicks-ass.net> References: <20170421224929.1a4bbeec@gandalf.local.home> <20170424085700.vm2wpn5gac57vb2n@hirez.programming.kicks-ass.net> X-Mailer: Claws Mail 3.14.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 24 Apr 2017 10:57:00 +0200 Peter Zijlstra wrote: > On Fri, Apr 21, 2017 at 10:49:29PM -0400, Steven Rostedt wrote: > > +#ifdef HAVE_RT_PUSH_IPI > > + /* > > + * For IPI pull requests, loop across the rto_mask. > > + */ > > + struct irq_work rto_push_work; > > + raw_spinlock_t rto_lock; > > + /* These atomics are updated outside of a lock */ > > + atomic_t rto_loop_next; > > + atomic_t rto_loop_start; > > + /* These are only updated and read withn rto_lock */ > > + int rto_loop; > > + int rto_cpu; > > +#endif > > Don't you think it would make sense to place the rto_lock near the > variables it protects? And if those atomics are supposed to increase > performance, do they want to share the same cacheline with the lock? Good point! I'll update. -- Steve