Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755056AbbHXQ24 (ORCPT ); Mon, 24 Aug 2015 12:28:56 -0400 Received: from mail-ig0-f178.google.com ([209.85.213.178]:35162 "EHLO mail-ig0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752983AbbHXQ2y (ORCPT ); Mon, 24 Aug 2015 12:28:54 -0400 MIME-Version: 1.0 In-Reply-To: <55DB205E.9070205@arm.com> References: <20150822131050.GK1820@rric.localdomain> <55DAEF3C.5090303@arm.com> <55DB11F3.1070604@arm.com> <55DB205E.9070205@arm.com> Date: Mon, 24 Aug 2015 21:58:53 +0530 Message-ID: Subject: Re: [PATCH] irqchip, gicv3-its, numa: Workaround for Cavium ThunderX erratum 23144 From: Ganapatrao Kulkarni To: Marc Zyngier Cc: Robert Richter , Will Deacon , Thomas Gleixner , Jason Cooper , "linux-arm-kernel@lists.infradead.org" , Tirumalesh Chalamarla , Robert Richter , "linux-kernel@vger.kernel.org" , Ganapatrao Kulkarni Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2466 Lines: 65 Hi Marc, thanks for the suggestions. On Mon, Aug 24, 2015 at 7:17 PM, Marc Zyngier wrote: > On 24/08/15 14:27, Ganapatrao Kulkarni wrote: >> On Mon, Aug 24, 2015 at 6:15 PM, Marc Zyngier wrote: > >>>>>> static void its_enable_cavium_thunderx(void *data) >>>>>> { >>>>>> - struct its_node *its = data; >>>>>> + struct its_node __maybe_unused *its = data; >>>>>> >>>>>> - its->flags |= ITS_FLAGS_CAVIUM_THUNDERX; >>>>>> +#ifdef CONFIG_CAVIUM_ERRATUM_22375 >>>>>> + its->flags |= ITS_WORKAROUND_CAVIUM_22375; >>>>>> + pr_info("ITS: Enabling workaround for 22375, 24313\n"); >>>>>> +#endif >>>>>> + >>>>>> +#ifdef CONFIG_CAVIUM_ERRATUM_23144 >>>>>> + if (num_possible_nodes() > 1) { >>>>>> + its->numa_node = its_get_node_thunderx(its); >>>>> >>>>> I'd rather see numa_node being always initialized to something useful. >>>>> If you're adding numa support, why can't this be initialized via >>>>> standard topology bindings? >>>> IIUC, topology defines only cpu topology. >>> >>> Well, welcome to a much more complex system where both your CPUs and >>> your IOs have some degree of affinity. This needs to be described >>> properly, and not hacked on the side. >> ok, will add description for the function. > > I sense that you misunderstood what I meant. What I'd like to see is > some topology information coming from DT, showing the relationship > between a device (your ITS) and a given node (your socket). This can > then be used from two purposes: sure will post next version with changes as per you comments. > > - find the optimal affinity for a MSI so that it doesn't default to a > foreign node (a reasonable performance expectation), this can be done by adding dt associativity property to its node. i can send in next version of patch. > - work around implementation bugs where an LPI cannot be routed to a > redistributor that is on a foreign node. > > I really don't feel like adding a hack just for the second point, and > I'd rather get the big picture right so that your workaround is just a > special case of the generic one. > > Thanks, > > M. > -- > Jazz is not dead. It just smells funny... thanks Ganapat -- 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/