linux/kernel/irq/handle.c
Mike Travis 0fa0ebbf15 irq: allocate irq_desc_ptrs array based on nr_irqs
Impact: allocate irq_desc_ptrs in preparation for making it variable-sized.

This addresses this memory usage bump when NR_CPUS bumped from 128 to 4096:

    34816   +229376    264192  +658%  irq_desc_ptrs(.data.read_mostly)

The patch is split into two parts, the first simply allocates the
irq_desc_ptrs array.  Then next will deal with making it variable.
This is only when CONFIG_SPARSE_IRQS=y.

Signed-off-by: Mike Travis <travis@sgi.com>
2009-01-11 19:13:35 +01:00

469 lines
10 KiB
C

/*
* linux/kernel/irq/handle.c
*
* Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
* Copyright (C) 2005-2006, Thomas Gleixner, Russell King
*
* This file contains the core interrupt handling code.
*
* Detailed information is available in Documentation/DocBook/genericirq
*
*/
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/rculist.h>
#include <linux/hash.h>
#include <linux/bootmem.h>
#include "internals.h"
/*
* lockdep: we want to handle all irq_desc locks as a single lock-class:
*/
struct lock_class_key irq_desc_lock_class;
/**
* handle_bad_irq - handle spurious and unhandled irqs
* @irq: the interrupt number
* @desc: description of the interrupt
*
* Handles spurious and unhandled IRQ's. It also prints a debugmessage.
*/
void handle_bad_irq(unsigned int irq, struct irq_desc *desc)
{
print_irq_desc(irq, desc);
kstat_incr_irqs_this_cpu(irq, desc);
ack_bad_irq(irq);
}
/*
* Linux has a controller-independent interrupt architecture.
* Every controller has a 'controller-template', that is used
* by the main code to do the right thing. Each driver-visible
* interrupt source is transparently wired to the appropriate
* controller. Thus drivers need not be aware of the
* interrupt-controller.
*
* The code is designed to be easily extended with new/different
* interrupt controllers, without having to do assembly magic or
* having to touch the generic code.
*
* Controller mappings for all interrupt sources:
*/
int nr_irqs = NR_IRQS;
EXPORT_SYMBOL_GPL(nr_irqs);
#ifdef CONFIG_SPARSE_IRQ
static struct irq_desc irq_desc_init = {
.irq = -1,
.status = IRQ_DISABLED,
.chip = &no_irq_chip,
.handle_irq = handle_bad_irq,
.depth = 1,
.lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
};
void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr)
{
unsigned long bytes;
char *ptr;
int node;
/* Compute how many bytes we need per irq and allocate them */
bytes = nr * sizeof(unsigned int);
node = cpu_to_node(cpu);
ptr = kzalloc_node(bytes, GFP_ATOMIC, node);
printk(KERN_DEBUG " alloc kstat_irqs on cpu %d node %d\n", cpu, node);
if (ptr)
desc->kstat_irqs = (unsigned int *)ptr;
}
static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
{
memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
spin_lock_init(&desc->lock);
desc->irq = irq;
#ifdef CONFIG_SMP
desc->cpu = cpu;
#endif
lockdep_set_class(&desc->lock, &irq_desc_lock_class);
init_kstat_irqs(desc, cpu, nr_cpu_ids);
if (!desc->kstat_irqs) {
printk(KERN_ERR "can not alloc kstat_irqs\n");
BUG_ON(1);
}
if (!init_alloc_desc_masks(desc, cpu, false)) {
printk(KERN_ERR "can not alloc irq_desc cpumasks\n");
BUG_ON(1);
}
arch_init_chip_data(desc, cpu);
}
/*
* Protect the sparse_irqs:
*/
DEFINE_SPINLOCK(sparse_irq_lock);
struct irq_desc **irq_desc_ptrs __read_mostly;
static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
[0 ... NR_IRQS_LEGACY-1] = {
.irq = -1,
.status = IRQ_DISABLED,
.chip = &no_irq_chip,
.handle_irq = handle_bad_irq,
.depth = 1,
.lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
}
};
/* FIXME: use bootmem alloc ...*/
static unsigned int kstat_irqs_legacy[NR_IRQS_LEGACY][NR_CPUS];
int __init early_irq_init(void)
{
struct irq_desc *desc;
int legacy_count;
int i;
printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d\n", NR_IRQS, nr_irqs);
desc = irq_desc_legacy;
legacy_count = ARRAY_SIZE(irq_desc_legacy);
/* allocate irq_desc_ptrs array based on nr_irqs */
irq_desc_ptrs = alloc_bootmem(nr_irqs * sizeof(void *));
for (i = 0; i < legacy_count; i++) {
desc[i].irq = i;
desc[i].kstat_irqs = kstat_irqs_legacy[i];
lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
init_alloc_desc_masks(&desc[i], 0, true);
irq_desc_ptrs[i] = desc + i;
}
for (i = legacy_count; i < nr_irqs; i++)
irq_desc_ptrs[i] = NULL;
return arch_early_irq_init();
}
struct irq_desc *irq_to_desc(unsigned int irq)
{
if (irq_desc_ptrs && irq < nr_irqs)
return irq_desc_ptrs[irq];
return NULL;
}
struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
{
struct irq_desc *desc;
unsigned long flags;
int node;
if (irq >= nr_irqs) {
WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_desc_alloc\n",
irq, nr_irqs);
return NULL;
}
desc = irq_desc_ptrs[irq];
if (desc)
return desc;
spin_lock_irqsave(&sparse_irq_lock, flags);
/* We have to check it to avoid races with another CPU */
desc = irq_desc_ptrs[irq];
if (desc)
goto out_unlock;
node = cpu_to_node(cpu);
desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
printk(KERN_DEBUG " alloc irq_desc for %d on cpu %d node %d\n",
irq, cpu, node);
if (!desc) {
printk(KERN_ERR "can not alloc irq_desc\n");
BUG_ON(1);
}
init_one_irq_desc(irq, desc, cpu);
irq_desc_ptrs[irq] = desc;
out_unlock:
spin_unlock_irqrestore(&sparse_irq_lock, flags);
return desc;
}
#else /* !CONFIG_SPARSE_IRQ */
struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
[0 ... NR_IRQS-1] = {
.status = IRQ_DISABLED,
.chip = &no_irq_chip,
.handle_irq = handle_bad_irq,
.depth = 1,
.lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
}
};
int __init early_irq_init(void)
{
struct irq_desc *desc;
int count;
int i;
printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
desc = irq_desc;
count = ARRAY_SIZE(irq_desc);
for (i = 0; i < count; i++) {
desc[i].irq = i;
init_alloc_desc_masks(&desc[i], 0, true);
}
return arch_early_irq_init();
}
struct irq_desc *irq_to_desc(unsigned int irq)
{
return (irq < NR_IRQS) ? irq_desc + irq : NULL;
}
struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
{
return irq_to_desc(irq);
}
#endif /* !CONFIG_SPARSE_IRQ */
/*
* What should we do if we get a hw irq event on an illegal vector?
* Each architecture has to answer this themself.
*/
static void ack_bad(unsigned int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
print_irq_desc(irq, desc);
ack_bad_irq(irq);
}
/*
* NOP functions
*/
static void noop(unsigned int irq)
{
}
static unsigned int noop_ret(unsigned int irq)
{
return 0;
}
/*
* Generic no controller implementation
*/
struct irq_chip no_irq_chip = {
.name = "none",
.startup = noop_ret,
.shutdown = noop,
.enable = noop,
.disable = noop,
.ack = ack_bad,
.end = noop,
};
/*
* Generic dummy implementation which can be used for
* real dumb interrupt sources
*/
struct irq_chip dummy_irq_chip = {
.name = "dummy",
.startup = noop_ret,
.shutdown = noop,
.enable = noop,
.disable = noop,
.ack = noop,
.mask = noop,
.unmask = noop,
.end = noop,
};
/*
* Special, empty irq handler:
*/
irqreturn_t no_action(int cpl, void *dev_id)
{
return IRQ_NONE;
}
/**
* handle_IRQ_event - irq action chain handler
* @irq: the interrupt number
* @action: the interrupt action chain for this irq
*
* Handles the action chain of an irq event
*/
irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
{
irqreturn_t ret, retval = IRQ_NONE;
unsigned int status = 0;
if (!(action->flags & IRQF_DISABLED))
local_irq_enable_in_hardirq();
do {
ret = action->handler(irq, action->dev_id);
if (ret == IRQ_HANDLED)
status |= action->flags;
retval |= ret;
action = action->next;
} while (action);
if (status & IRQF_SAMPLE_RANDOM)
add_interrupt_randomness(irq);
local_irq_disable();
return retval;
}
#ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
/**
* __do_IRQ - original all in one highlevel IRQ handler
* @irq: the interrupt number
*
* __do_IRQ handles all normal device IRQ's (the special
* SMP cross-CPU interrupts have their own specific
* handlers).
*
* This is the original x86 implementation which is used for every
* interrupt type.
*/
unsigned int __do_IRQ(unsigned int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
struct irqaction *action;
unsigned int status;
kstat_incr_irqs_this_cpu(irq, desc);
if (CHECK_IRQ_PER_CPU(desc->status)) {
irqreturn_t action_ret;
/*
* No locking required for CPU-local interrupts:
*/
if (desc->chip->ack) {
desc->chip->ack(irq);
/* get new one */
desc = irq_remap_to_desc(irq, desc);
}
if (likely(!(desc->status & IRQ_DISABLED))) {
action_ret = handle_IRQ_event(irq, desc->action);
if (!noirqdebug)
note_interrupt(irq, desc, action_ret);
}
desc->chip->end(irq);
return 1;
}
spin_lock(&desc->lock);
if (desc->chip->ack) {
desc->chip->ack(irq);
desc = irq_remap_to_desc(irq, desc);
}
/*
* REPLAY is when Linux resends an IRQ that was dropped earlier
* WAITING is used by probe to mark irqs that are being tested
*/
status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
status |= IRQ_PENDING; /* we _want_ to handle it */
/*
* If the IRQ is disabled for whatever reason, we cannot
* use the action we have.
*/
action = NULL;
if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
action = desc->action;
status &= ~IRQ_PENDING; /* we commit to handling */
status |= IRQ_INPROGRESS; /* we are handling it */
}
desc->status = status;
/*
* If there is no IRQ handler or it was disabled, exit early.
* Since we set PENDING, if another processor is handling
* a different instance of this same irq, the other processor
* will take care of it.
*/
if (unlikely(!action))
goto out;
/*
* Edge triggered interrupts need to remember
* pending events.
* This applies to any hw interrupts that allow a second
* instance of the same irq to arrive while we are in do_IRQ
* or in the handler. But the code here only handles the _second_
* instance of the irq, not the third or fourth. So it is mostly
* useful for irq hardware that does not mask cleanly in an
* SMP environment.
*/
for (;;) {
irqreturn_t action_ret;
spin_unlock(&desc->lock);
action_ret = handle_IRQ_event(irq, action);
if (!noirqdebug)
note_interrupt(irq, desc, action_ret);
spin_lock(&desc->lock);
if (likely(!(desc->status & IRQ_PENDING)))
break;
desc->status &= ~IRQ_PENDING;
}
desc->status &= ~IRQ_INPROGRESS;
out:
/*
* The ->end() handler has to deal with interrupts which got
* disabled while the handler was running.
*/
desc->chip->end(irq);
spin_unlock(&desc->lock);
return 1;
}
#endif
void early_init_irq_lock_class(void)
{
struct irq_desc *desc;
int i;
for_each_irq_desc(i, desc) {
lockdep_set_class(&desc->lock, &irq_desc_lock_class);
}
}
#ifdef CONFIG_SPARSE_IRQ
unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
{
struct irq_desc *desc = irq_to_desc(irq);
return desc ? desc->kstat_irqs[cpu] : 0;
}
#endif
EXPORT_SYMBOL(kstat_irqs_cpu);