From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f174.google.com ([209.85.214.174]:47871 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932473Ab2CZOdk (ORCPT ); Mon, 26 Mar 2012 10:33:40 -0400 Message-ID: <4F707E39.50502@gmail.com> Date: Mon, 26 Mar 2012 22:33:29 +0800 From: Jiang Liu MIME-Version: 1.0 To: Bjorn Helgaas CC: Yevgeny Petrilin , linux-pci@vger.kernel.org, Thomas Gleixner , linux-kernel@vger.kernel.org Subject: Re: IRQ affinity enforced only after first interrupt. References: <4F7031A4.70601@mellanox.co.il> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-pci-owner@vger.kernel.org List-ID: The architecture specific code will determine whether the IRQ could be migrated in process context. For example, the IRQ_MOVE_PCNTXT flag will be set on x86 systems if interrupt remapping is enabled. On 03/26/2012 10:28 PM, Bjorn Helgaas wrote: > [This is not really a PCI question, so +cc Thomas, LKML.] > > On Mon, Mar 26, 2012 at 3:06 AM, Yevgeny Petrilin > wrote: >> Hello, >> >> I'm working on an issue where affinity changes to IRQ only have effect after the first interrupt which still happens on the original core. >> I understand that the decision regarding it takes place in this code: >> >> if (irq_can_move_pcntxt(data)) { >> ret = chip->irq_set_affinity(data, mask, false); >> switch (ret) { >> case IRQ_SET_MASK_OK: >> cpumask_copy(data->affinity, mask); >> case IRQ_SET_MASK_OK_NOCOPY: >> irq_set_thread_affinity(desc); >> ret = 0; >> } >> } else { >> irqd_set_move_pending(data); >> irq_copy_pending(desc, mask); >> } >> >> Which means that the "IRQD_MOVE_PCNTXT" flag is not set in irq_data->state_use_accessors. >> I was able to add this flag using irq_modify_status(), which is probably not the way to go. >> This option also doesn't exist in older kernels (2.6.32) >> >> So the question is, when irq_desc is created, how is it determined that "IRQD_MOVE_PCNTXT" flag is set? >> >> Thanks, >> Yevgeny >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-pci" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html