From f1e0bb0ad473a32d1b7e6d285ae9f7e47710bb5e Mon Sep 17 00:00:00 2001 From: Yang Yingliang Date: Thu, 24 Sep 2015 17:32:13 +0800 Subject: [PATCH] genirq: Introduce generic irq migration for cpu hotunplug ARM and ARM64 have almost identical code for migrating interrupts on cpu hotunplug. Provide a generic version which can be used by both. The new code addresses a shortcoming in the ARM[64] variants which fails to update the affinity change in some cases. The solution for this is to use the core function irq_do_set_affinity() instead of open coding it. [ tglx: Added copyright notice and license boilerplate. Rewrote subject and changelog. ] Signed-off-by: Yang Yingliang Acked-by: Russell King - ARM Linux Cc: Jiang Liu Cc: Marc Zyngier Cc: Mark Rutland Cc: Will Deacon Cc: Hanjun Guo Cc: Link: http://lkml.kernel.org/r/1443087135-17044-2-git-send-email-yangyingliang@huawei.com Signed-off-by: Thomas Gleixner --- include/linux/irq.h | 2 + kernel/irq/Kconfig | 4 ++ kernel/irq/Makefile | 1 + kernel/irq/cpuhotplug.c | 82 +++++++++++++++++++++++++++++++++++++++++ 4 files changed, 89 insertions(+) create mode 100644 kernel/irq/cpuhotplug.c diff --git a/include/linux/irq.h b/include/linux/irq.h index 11bf09288ddb..45cc7299bb61 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -452,6 +452,8 @@ extern int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *cpumask, bool force); extern int irq_set_vcpu_affinity(unsigned int irq, void *vcpu_info); +extern void irq_migrate_all_off_this_cpu(void); + #if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_PENDING_IRQ) void irq_move_irq(struct irq_data *data); void irq_move_masked_irq(struct irq_data *data); diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig index 9a76e3beda54..3b48dab80164 100644 --- a/kernel/irq/Kconfig +++ b/kernel/irq/Kconfig @@ -30,6 +30,10 @@ config GENERIC_IRQ_LEGACY_ALLOC_HWIRQ config GENERIC_PENDING_IRQ bool +# Support for generic irq migrating off cpu before the cpu is offline. +config GENERIC_IRQ_MIGRATION + bool + # Alpha specific irq affinity mechanism config AUTO_IRQ_AFFINITY bool diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile index d12123526e2b..2fc9cbdf35b6 100644 --- a/kernel/irq/Makefile +++ b/kernel/irq/Makefile @@ -5,5 +5,6 @@ obj-$(CONFIG_GENERIC_IRQ_PROBE) += autoprobe.o obj-$(CONFIG_IRQ_DOMAIN) += irqdomain.o obj-$(CONFIG_PROC_FS) += proc.o obj-$(CONFIG_GENERIC_PENDING_IRQ) += migration.o +obj-$(CONFIG_GENERIC_IRQ_MIGRATION) += cpuhotplug.o obj-$(CONFIG_PM_SLEEP) += pm.o obj-$(CONFIG_GENERIC_MSI_IRQ) += msi.o diff --git a/kernel/irq/cpuhotplug.c b/kernel/irq/cpuhotplug.c new file mode 100644 index 000000000000..80f4f4e56fed --- /dev/null +++ b/kernel/irq/cpuhotplug.c @@ -0,0 +1,82 @@ +/* + * Generic cpu hotunplug interrupt migration code copied from the + * arch/arm implementation + * + * Copyright (C) Russell King + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#include +#include +#include + +#include "internals.h" + +static bool migrate_one_irq(struct irq_desc *desc) +{ + struct irq_data *d = irq_desc_get_irq_data(desc); + const struct cpumask *affinity = d->common->affinity; + struct irq_chip *c; + bool ret = false; + + /* + * If this is a per-CPU interrupt, or the affinity does not + * include this CPU, then we have nothing to do. + */ + if (irqd_is_per_cpu(d) || + !cpumask_test_cpu(smp_processor_id(), affinity)) + return false; + + if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) { + affinity = cpu_online_mask; + ret = true; + } + + c = irq_data_get_irq_chip(d); + if (!c->irq_set_affinity) { + pr_warn_ratelimited("IRQ%u: unable to set affinity\n", d->irq); + } else { + int r = irq_do_set_affinity(d, affinity, false); + if (r) + pr_warn_ratelimited("IRQ%u: set affinity failed(%d).\n", + d->irq, r); + } + + return ret; +} + +/** + * irq_migrate_all_off_this_cpu - Migrate irqs away from offline cpu + * + * The current CPU has been marked offline. Migrate IRQs off this CPU. + * If the affinity settings do not allow other CPUs, force them onto any + * available CPU. + * + * Note: we must iterate over all IRQs, whether they have an attached + * action structure or not, as we need to get chained interrupts too. + */ +void irq_migrate_all_off_this_cpu(void) +{ + unsigned int irq; + struct irq_desc *desc; + unsigned long flags; + + local_irq_save(flags); + + for_each_active_irq(irq) { + bool affinity_broken; + + desc = irq_to_desc(irq); + raw_spin_lock(&desc->lock); + affinity_broken = migrate_one_irq(desc); + raw_spin_unlock(&desc->lock); + + if (affinity_broken) + pr_warn_ratelimited("IRQ%u no longer affine to CPU%u\n", + irq, smp_processor_id()); + } + + local_irq_restore(flags); +} -- 2.20.1