From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932601AbbAIJxA (ORCPT ); Fri, 9 Jan 2015 04:53:00 -0500 Received: from foss-mx-na.foss.arm.com ([217.140.108.86]:58492 "EHLO foss-mx-na.foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932202AbbAIJw5 (ORCPT ); Fri, 9 Jan 2015 04:52:57 -0500 Message-ID: <54AFA4EE.5080906@arm.com> Date: Fri, 09 Jan 2015 09:52:46 +0000 From: Marc Zyngier User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.3.0 MIME-Version: 1.0 To: Jiang Liu , Thomas Gleixner CC: "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 0/2] genirq: Make irqchip flags work with stacked irq domains References: <1420738365-22063-1-git-send-email-marc.zyngier@arm.com> <54AF45E0.2080803@linux.intel.com> In-Reply-To: <54AF45E0.2080803@linux.intel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jiang, On 09/01/15 03:07, Jiang Liu wrote: > On 2015/1/9 1:32, Marc Zyngier wrote: >> With the landing of stacked irq domains in 3.19, we have ended up in a >> situation where we have a stack of IRQ controllers, each with their >> set of flags, but the core code is only able to look at the top-most, >> which is not very helpful. This small series is trying to fix this. >> >> The first patch converts all access to desc->irq_data.chip->flags to >> using an accessor, without changing anything else. The second patch >> adds some logic to combine these flags as we allocate the interrupts, >> ultimately storing the resulting set as part of the irq_desc >> structure. >> >> We end-up with a configuration where the flags can either be located >> in the irq_chip structure (non stacked case), or in the irq_desc >> (stacked case). While this isn't really ideal, this gives at least the >> right level of information to the rest of the IRQ framework. > Hi Mark, > By this way, we need to aggregate irq_chip flags for every > irq. How about changing irq_desc_get_chip_flags(struct irq_desc *desc) > to irq_desc_check_chip_flags(struct irq_desc *desc, unsigned int flags) > which dynamically walks the stacked irqchips? That was the other option, but I felt that going through the list of irqchips was not a very nice idea performance wise. This is used is some moderately hot paths (cond_unmask_eoi_irq, for example), and I wondered if we wanted to pay this price at runtime... Thoughts? Thanks, M. -- Jazz is not dead. It just smells funny...