From bc06a9e0874239cb6d4eebcb0ecd1a91ad9272db Mon Sep 17 00:00:00 2001 From: Shanker Donthineni Date: Fri, 19 May 2023 08:49:00 -0500 Subject: [PATCH] genirq: Use hlist for managing resend handlers The current implementation utilizes a bitmap for managing interrupt resend handlers, which is allocated based on the SPARSE_IRQ/NR_IRQS macros. However, this method may not efficiently utilize memory during runtime, particularly when IRQ_BITMAP_BITS is large. Address this issue by using an hlist to manage interrupt resend handlers instead of relying on a static bitmap memory allocation. Additionally, a new function, clear_irq_resend(), is introduced and called from irq_shutdown to ensure a graceful teardown of the interrupt. Signed-off-by: Shanker Donthineni Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20230519134902.1495562-2-sdonthineni@nvidia.com --- include/linux/irqdesc.h | 3 +++ kernel/irq/chip.c | 1 + kernel/irq/internals.h | 2 ++ kernel/irq/irqdesc.c | 2 ++ kernel/irq/resend.c | 47 ++++++++++++++++++++++++++++++----------------- 5 files changed, 38 insertions(+), 17 deletions(-) diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h index 844a8e3..d9451d4 100644 --- a/include/linux/irqdesc.h +++ b/include/linux/irqdesc.h @@ -102,6 +102,9 @@ struct irq_desc { int parent_irq; struct module *owner; const char *name; +#ifdef CONFIG_HARDIRQS_SW_RESEND + struct hlist_node resend_node; +#endif } ____cacheline_internodealigned_in_smp; #ifdef CONFIG_SPARSE_IRQ diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index 49e7bc8..2eac5532 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -306,6 +306,7 @@ static void __irq_disable(struct irq_desc *desc, bool mask); void irq_shutdown(struct irq_desc *desc) { if (irqd_is_started(&desc->irq_data)) { + clear_irq_resend(desc); desc->depth = 1; if (desc->irq_data.chip->irq_shutdown) { desc->irq_data.chip->irq_shutdown(&desc->irq_data); diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h index 5fdc0b5..51fc8c4 100644 --- a/kernel/irq/internals.h +++ b/kernel/irq/internals.h @@ -113,6 +113,8 @@ irqreturn_t handle_irq_event(struct irq_desc *desc); /* Resending of interrupts :*/ int check_irq_resend(struct irq_desc *desc, bool inject); +void clear_irq_resend(struct irq_desc *desc); +void irq_resend_init(struct irq_desc *desc); bool irq_wait_for_poll(struct irq_desc *desc); void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action); diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c index 240e145..b401b89 100644 --- a/kernel/irq/irqdesc.c +++ b/kernel/irq/irqdesc.c @@ -415,6 +415,7 @@ static struct irq_desc *alloc_desc(int irq, int node, unsigned int flags, desc_set_defaults(irq, desc, node, affinity, owner); irqd_set(&desc->irq_data, flags); kobject_init(&desc->kobj, &irq_kobj_type); + irq_resend_init(desc); return desc; @@ -581,6 +582,7 @@ int __init early_irq_init(void) mutex_init(&desc[i].request_mutex); init_waitqueue_head(&desc[i].wait_for_threads); desc_set_defaults(i, &desc[i], node, NULL, NULL); + irq_resend_init(desc); } return arch_early_irq_init(); } diff --git a/kernel/irq/resend.c b/kernel/irq/resend.c index 0c46e9f..edec335 100644 --- a/kernel/irq/resend.c +++ b/kernel/irq/resend.c @@ -21,8 +21,9 @@ #ifdef CONFIG_HARDIRQS_SW_RESEND -/* Bitmap to handle software resend of interrupts: */ -static DECLARE_BITMAP(irqs_resend, IRQ_BITMAP_BITS); +/* hlist_head to handle software resend of interrupts: */ +static HLIST_HEAD(irq_resend_list); +static DEFINE_RAW_SPINLOCK(irq_resend_lock); /* * Run software resends of IRQ's @@ -30,18 +31,17 @@ static DECLARE_BITMAP(irqs_resend, IRQ_BITMAP_BITS); static void resend_irqs(struct tasklet_struct *unused) { struct irq_desc *desc; - int irq; - - while (!bitmap_empty(irqs_resend, nr_irqs)) { - irq = find_first_bit(irqs_resend, nr_irqs); - clear_bit(irq, irqs_resend); - desc = irq_to_desc(irq); - if (!desc) - continue; - local_irq_disable(); + + raw_spin_lock_irq(&irq_resend_lock); + while (!hlist_empty(&irq_resend_list)) { + desc = hlist_entry(irq_resend_list.first, struct irq_desc, + resend_node); + hlist_del_init(&desc->resend_node); + raw_spin_unlock(&irq_resend_lock); desc->handle_irq(desc); - local_irq_enable(); + raw_spin_lock(&irq_resend_lock); } + raw_spin_unlock_irq(&irq_resend_lock); } /* Tasklet to handle resend: */ @@ -49,8 +49,6 @@ static DECLARE_TASKLET(resend_tasklet, resend_irqs); static int irq_sw_resend(struct irq_desc *desc) { - unsigned int irq = irq_desc_get_irq(desc); - /* * Validate whether this interrupt can be safely injected from * non interrupt context @@ -70,16 +68,31 @@ static int irq_sw_resend(struct irq_desc *desc) */ if (!desc->parent_irq) return -EINVAL; - irq = desc->parent_irq; } - /* Set it pending and activate the softirq: */ - set_bit(irq, irqs_resend); + /* Add to resend_list and activate the softirq: */ + raw_spin_lock(&irq_resend_lock); + hlist_add_head(&desc->resend_node, &irq_resend_list); + raw_spin_unlock(&irq_resend_lock); tasklet_schedule(&resend_tasklet); return 0; } +void clear_irq_resend(struct irq_desc *desc) +{ + raw_spin_lock(&irq_resend_lock); + hlist_del_init(&desc->resend_node); + raw_spin_unlock(&irq_resend_lock); +} + +void irq_resend_init(struct irq_desc *desc) +{ + INIT_HLIST_NODE(&desc->resend_node); +} #else +void clear_irq_resend(struct irq_desc *desc) {} +void irq_resend_init(struct irq_desc *desc) {} + static int irq_sw_resend(struct irq_desc *desc) { return -EINVAL; -- 2.7.4