From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754111AbbJIUyw (ORCPT ); Fri, 9 Oct 2015 16:54:52 -0400 Received: from terminus.zytor.com ([198.137.202.10]:53860 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751047AbbJIUyu (ORCPT ); Fri, 9 Oct 2015 16:54:50 -0400 Date: Fri, 9 Oct 2015 13:54:35 -0700 From: tip-bot for Mika Westerberg Message-ID: Cc: hpa@zytor.com, jiang.liu@linux.intel.com, tglx@linutronix.de, mingo@kernel.org, linux-kernel@vger.kernel.org, mika.westerberg@linux.intel.com Reply-To: mingo@kernel.org, linux-kernel@vger.kernel.org, mika.westerberg@linux.intel.com, jiang.liu@linux.intel.com, tglx@linutronix.de, hpa@zytor.com In-Reply-To: <1444039935-30475-1-git-send-email-mika.westerberg@linux.intel.com> References: <1444039935-30475-1-git-send-email-mika.westerberg@linux.intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:irq/core] genirq: Allow migration of chained interrupts by installing default action Git-Commit-ID: e509bd7da149dc34916037484cd7545b2d48a2b0 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: e509bd7da149dc34916037484cd7545b2d48a2b0 Gitweb: http://git.kernel.org/tip/e509bd7da149dc34916037484cd7545b2d48a2b0 Author: Mika Westerberg AuthorDate: Mon, 5 Oct 2015 13:12:15 +0300 Committer: Thomas Gleixner CommitDate: Fri, 9 Oct 2015 22:47:27 +0200 genirq: Allow migration of chained interrupts by installing default action When a CPU is offlined all interrupts that have an action are migrated to other still online CPUs. However, if the interrupt has chained handler installed this is not done. Chained handlers are used by GPIO drivers which support interrupts, for instance. When the affinity is not corrected properly we end up in situation where most interrupts are not arriving to the online CPUs anymore. For example on Intel Braswell system which has SD-card card detection signal connected to a GPIO the IO-APIC routing entries look like below after CPU1 is offlined: pin30, enabled , level, low , V(52), IRR(0), S(0), logical , D(03), M(1) pin31, enabled , level, low , V(42), IRR(0), S(0), logical , D(03), M(1) pin32, enabled , level, low , V(62), IRR(0), S(0), logical , D(03), M(1) pin5b, enabled , level, low , V(72), IRR(0), S(0), logical , D(03), M(1) The problem here is that the destination mask still contains both CPUs even if CPU1 is already offline. This means that the IO-APIC still routes interrupts to the other CPU as well. We solve the problem by providing a default action for chained interrupts. This action allows the migration code to correct affinity (as it finds desc->action != NULL). Also make the default action handler to emit a warning if for some reason a chained handler ends up calling it. Signed-off-by: Mika Westerberg Cc: Jiang Liu Link: http://lkml.kernel.org/r/1444039935-30475-1-git-send-email-mika.westerberg@linux.intel.com Signed-off-by: Thomas Gleixner --- kernel/irq/chip.c | 17 +++++++++++++++++ kernel/irq/internals.h | 2 ++ kernel/irq/proc.c | 2 +- 3 files changed, 20 insertions(+), 1 deletion(-) diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index 46f1fb5..4aa00d3 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -21,6 +21,20 @@ #include "internals.h" +static irqreturn_t bad_chained_irq(int irq, void *dev_id) +{ + WARN_ONCE(1, "Chained irq %d should not call an action\n", irq); + return IRQ_NONE; +} + +/* + * Chained handlers should never call action on their IRQ. This default + * action will emit warning if such thing happens. + */ +struct irqaction chained_action = { + .handler = bad_chained_irq, +}; + /** * irq_set_chip - set the irq chip for an irq * @irq: irq number @@ -746,6 +760,8 @@ __irq_do_set_handler(struct irq_desc *desc, irq_flow_handler_t handle, if (desc->irq_data.chip != &no_irq_chip) mask_ack_irq(desc); irq_state_set_disabled(desc); + if (is_chained) + desc->action = NULL; desc->depth = 1; } desc->handle_irq = handle; @@ -755,6 +771,7 @@ __irq_do_set_handler(struct irq_desc *desc, irq_flow_handler_t handle, irq_settings_set_noprobe(desc); irq_settings_set_norequest(desc); irq_settings_set_nothread(desc); + desc->action = &chained_action; irq_startup(desc, true); } } diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h index cd60bb4..05c2188 100644 --- a/kernel/irq/internals.h +++ b/kernel/irq/internals.h @@ -18,6 +18,8 @@ extern bool noirqdebug; +extern struct irqaction chained_action; + /* * Bits used by threaded handlers: * IRQTF_RUNTHREAD - signals that the interrupt handler thread should run diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index e3a8c95..7d60905 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -460,7 +460,7 @@ int show_interrupts(struct seq_file *p, void *v) for_each_online_cpu(j) any_count |= kstat_irqs_cpu(i, j); action = desc->action; - if (!action && !any_count) + if ((!action || action == &chained_action) && !any_count) goto out; seq_printf(p, "%*d: ", prec, i);