From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1167307AbdDXI5Q (ORCPT ); Mon, 24 Apr 2017 04:57:16 -0400 Received: from merlin.infradead.org ([205.233.59.134]:47370 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1167160AbdDXI5J (ORCPT ); Mon, 24 Apr 2017 04:57:09 -0400 Date: Mon, 24 Apr 2017 10:57:00 +0200 From: Peter Zijlstra To: Steven Rostedt 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: <20170424085700.vm2wpn5gac57vb2n@hirez.programming.kicks-ass.net> References: <20170421224929.1a4bbeec@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170421224929.1a4bbeec@gandalf.local.home> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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?