Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752293AbbFZMiU (ORCPT ); Fri, 26 Jun 2015 08:38:20 -0400 Received: from www.linutronix.de ([62.245.132.108]:52099 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752475AbbFZMiM (ORCPT ); Fri, 26 Jun 2015 08:38:12 -0400 Date: Fri, 26 Jun 2015 14:38:10 +0200 (CEST) From: Thomas Gleixner To: Preeti U Murthy cc: Sudeep Holla , "linux-kernel@vger.kernel.org" , Suzuki Poulose , Lorenzo Pieralisi , Catalin Marinas , "Rafael J. Wysocki" Subject: Re: [PATCH] clockevents: return error from tick_broadcast_oneshot_control if !GENERIC_CLOCKEVENTS_BROADCAST In-Reply-To: <558D46C5.8080307@linux.vnet.ibm.com> Message-ID: References: <1435228065-2428-1-git-send-email-sudeep.holla@arm.com> <558C1E97.4020206@arm.com> <558CDE57.3050008@linux.vnet.ibm.com> <558D46C5.8080307@linux.vnet.ibm.com> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1446 Lines: 34 On Fri, 26 Jun 2015, Preeti U Murthy wrote: > On 06/26/2015 01:17 PM, Thomas Gleixner wrote: > > if (state == TICK_BROADCAST_ENTER) { > > + /* > > + * If the current CPU owns the hrtimer broadcast > > + * mechanism, it cannot go deep idle and we do not add > > + * the CPU to the broadcast mask. We don't have to go > > + * through the EXIT path as the local timer is not > > + * shutdown. > > + */ > > + ret = broadcast_needs_cpu(bc, cpu); > > + > > + /* > > + * If the hrtimer broadcast check tells us that the > > + * cpu cannot go deep idle, or if the broadcast device > > + * is in periodic mode, we just return. > > + */ > > + if (ret || tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) > > + goto out; > > The check on PERIODIC mode is good, but I don't see the point of moving > broadcast_needs_cpu() up above. broadcast_shutdown_local() calls > broadcast_needs_cpu() internally. > > Besides, by jumping to 'out', we will miss programming the broadcast > hrtimer in tick_broadcast_set_event() below, if the cpu happen to be the > broadcast cpu(which is why it was not allowed to go to deep idle). Hmm. Need to think a bit more about this convoluted maze ... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/