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Commit 8cd809c5 authored by Takashi Iwai's avatar Takashi Iwai Committed by Linus Torvalds
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[PATCH] Fix the unnecessary entropy call in the irq handler 

Currently add_interrupt_randomness() is called at each interrupt when one
of the handlers has SA_SAMPLE_RANDOM flag, regardless whether the interrupt
is processed by that handler or not.  This results in the higher latency
and perfomance loss.

The patch fixes this behavior to avoid the unnecessary call by checking the
return value from each handler.
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent b08e7589
Hide whitespace changes
Inline Side-by-side
Showing with 67 additions and 38 deletions
arch/alpha/kernel/irq.c
View file @ 8cd809c5
......@@ -83,6 +83,7 @@ handle_IRQ_event(unsigned int irq, struct pt_regs *regs,
struct irqaction *action)
{
int status = 1; /* Force the "do bottom halves" bit */
int ret;
do {
if (!(action->flags & SA_INTERRUPT))
......@@ -90,8 +91,9 @@ handle_IRQ_event(unsigned int irq, struct pt_regs *regs,
else
local_irq_disable();
status |= action->flags;
action->handler(irq, action->dev_id, regs);
ret = action->handler(irq, action->dev_id, regs);
if (ret == IRQ_HANDLED)
status |= action->flags;
action = action->next;
} while (action);
if (status & SA_SAMPLE_RANDOM)
......
arch/arm/kernel/irq.c
View file @ 8cd809c5
......@@ -261,7 +261,7 @@ static int
__do_irq(unsigned int irq, struct irqaction *action, struct pt_regs *regs)
{
unsigned int status;
int retval = 0;
int ret, retval = 0;
spin_unlock(&irq_controller_lock);
......@@ -270,8 +270,10 @@ __do_irq(unsigned int irq, struct irqaction *action, struct pt_regs *regs)
status = 0;
do {
status |= action->flags;
retval |= action->handler(irq, action->dev_id, regs);
ret = action->handler(irq, action->dev_id, regs);
if (ret == IRQ_HANDLED)
status |= action->flags;
retval |= ret;
action = action->next;
} while (action);
......
arch/arm26/kernel/irq.c
View file @ 8cd809c5
......@@ -187,6 +187,7 @@ static void
__do_irq(unsigned int irq, struct irqaction *action, struct pt_regs *regs)
{
unsigned int status;
int ret;
spin_unlock(&irq_controller_lock);
if (!(action->flags & SA_INTERRUPT))
......@@ -194,8 +195,9 @@ __do_irq(unsigned int irq, struct irqaction *action, struct pt_regs *regs)
status = 0;
do {
status |= action->flags;
action->handler(irq, action->dev_id, regs);
ret = action->handler(irq, action->dev_id, regs);
if (ret == IRQ_HANDLED)
status |= action->flags;
action = action->next;
} while (action);
......
arch/cris/kernel/irq.c
View file @ 8cd809c5
......@@ -125,7 +125,7 @@ asmlinkage void do_IRQ(int irq, struct pt_regs * regs)
{
struct irqaction *action;
int do_random, cpu;
int retval = 0;
int ret, retval = 0;
cpu = smp_processor_id();
irq_enter();
......@@ -137,8 +137,10 @@ asmlinkage void do_IRQ(int irq, struct pt_regs * regs)
local_irq_enable();
do_random = 0;
do {
do_random |= action->flags;
retval |= action->handler(irq, action->dev_id, regs);
ret = action->handler(irq, action->dev_id, regs);
if (ret == IRQ_HANDLED)
do_random |= action->flags;
retval |= ret;
action = action->next;
} while (action);
......
arch/i386/kernel/irq.c
View file @ 8cd809c5
......@@ -220,14 +220,16 @@ asmlinkage int handle_IRQ_event(unsigned int irq,
struct pt_regs *regs, struct irqaction *action)
{
int status = 1; /* Force the "do bottom halves" bit */
int retval = 0;
int ret, retval = 0;
if (!(action->flags & SA_INTERRUPT))
local_irq_enable();
do {
status |= action->flags;
retval |= action->handler(irq, action->dev_id, regs);
ret = action->handler(irq, action->dev_id, regs);
if (ret == IRQ_HANDLED)
status |= action->flags;
retval |= ret;
action = action->next;
} while (action);
if (status & SA_SAMPLE_RANDOM)
......
arch/ia64/kernel/irq.c
View file @ 8cd809c5
......@@ -255,14 +255,16 @@ int handle_IRQ_event(unsigned int irq,
struct pt_regs *regs, struct irqaction *action)
{
int status = 1; /* Force the "do bottom halves" bit */
int retval = 0;
int ret, retval = 0;
if (!(action->flags & SA_INTERRUPT))
local_irq_enable();
do {
status |= action->flags;
retval |= action->handler(irq, action->dev_id, regs);
ret = action->handler(irq, action->dev_id, regs);
if (ret == IRQ_HANDLED)
status |= action->flags;
retval |= ret;
action = action->next;
} while (action);
if (status & SA_SAMPLE_RANDOM)
......
arch/mips/baget/irq.c
View file @ 8cd809c5
......@@ -180,7 +180,7 @@ int get_irq_list(char *buf)
static void do_IRQ(int irq, struct pt_regs * regs)
{
struct irqaction *action;
int do_random, cpu;
int ret, do_random, cpu;
cpu = smp_processor_id();
irq_enter();
......@@ -194,8 +194,9 @@ static void do_IRQ(int irq, struct pt_regs * regs)
action = *(irq + irq_action);
do_random = 0;
do {
do_random |= action->flags;
action->handler(irq, action->dev_id, regs);
ret = action->handler(irq, action->dev_id, regs);
if (ret == IRQ_HANDLED)
do_random |= action->flags;
action = action->next;
} while (action);
if (do_random & SA_SAMPLE_RANDOM)
......
arch/mips/kernel/irq.c
View file @ 8cd809c5
......@@ -144,14 +144,16 @@ inline void synchronize_irq(unsigned int irq)
int handle_IRQ_event(unsigned int irq, struct pt_regs * regs, struct irqaction * action)
{
int status = 1; /* Force the "do bottom halves" bit */
int retval = 0;
int ret, retval = 0;
if (!(action->flags & SA_INTERRUPT))
local_irq_enable();
do {
status |= action->flags;
retval |= action->handler(irq, action->dev_id, regs);
ret = action->handler(irq, action->dev_id, regs);
if (ret == IRQ_HANDLED)
status |= action->flags;
retval |= ret;
action = action->next;
} while (action);
if (status & SA_SAMPLE_RANDOM)
......
arch/ppc/kernel/irq.c
View file @ 8cd809c5
......@@ -414,13 +414,15 @@ static inline void
handle_irq_event(int irq, struct pt_regs *regs, struct irqaction *action)
{
int status = 0;
int ret;
if (!(action->flags & SA_INTERRUPT))
local_irq_enable();
do {
status |= action->flags;
action->handler(irq, action->dev_id, regs);
ret = action->handler(irq, action->dev_id, regs);
if (ret == IRQ_HANDLED)
status |= action->flags;
action = action->next;
} while (action);
if (status & SA_SAMPLE_RANDOM)
......
arch/ppc64/kernel/irq.c
View file @ 8cd809c5
......@@ -363,14 +363,16 @@ int show_interrupts(struct seq_file *p, void *v)
int handle_irq_event(int irq, struct pt_regs *regs, struct irqaction *action)
{
int status = 0;
int retval = 0;
int ret, retval = 0;
if (!(action->flags & SA_INTERRUPT))
local_irq_enable();
do {
status |= action->flags;
retval |= action->handler(irq, action->dev_id, regs);
ret = action->handler(irq, action->dev_id, regs);
if (ret == IRQ_HANDLED)
status |= action->flags;
retval |= ret;
action = action->next;
} while (action);
if (status & SA_SAMPLE_RANDOM)
......
arch/sh/kernel/irq.c
View file @ 8cd809c5
......@@ -137,14 +137,16 @@ int show_interrupts(struct seq_file *p, void *v)
int handle_IRQ_event(unsigned int irq, struct pt_regs * regs, struct irqaction * action)
{
int status = 1; /* Force the "do bottom halves" bit */
int retval = 0;
int ret, retval = 0;
if (!(action->flags & SA_INTERRUPT))
local_irq_enable();
do {
status |= action->flags;
retval |= action->handler(irq, action->dev_id, regs);
ret = action->handler(irq, action->dev_id, regs);
if (ret == IRQ_HANDLED)
status |= action->flags;
retval |= ret;
action = action->next;
} while (action);
......
arch/sh64/kernel/irq.c
View file @ 8cd809c5
......@@ -148,6 +148,7 @@ asmlinkage void do_NMI(unsigned long vector_num, struct pt_regs * regs)
int handle_IRQ_event(unsigned int irq, struct pt_regs * regs, struct irqaction * action)
{
int status;
int ret;
status = 1; /* Force the "do bottom halves" bit */
......@@ -155,8 +156,9 @@ int handle_IRQ_event(unsigned int irq, struct pt_regs * regs, struct irqaction *
local_irq_enable();
do {
status |= action->flags;
action->handler(irq, action->dev_id, regs);
ret = action->handler(irq, action->dev_id, regs);
if (ret == IRQ_HANDLED)
status |= action->flags;
action = action->next;
} while (action);
if (status & SA_SAMPLE_RANDOM)
......
arch/um/kernel/irq.c
View file @ 8cd809c5
......@@ -147,13 +147,15 @@ int handle_IRQ_event(unsigned int irq, struct pt_regs * regs,
struct irqaction * action)
{
int status = 1; /* Force the "do bottom halves" bit */
int ret;
if (!(action->flags & SA_INTERRUPT))
local_irq_enable();
do {
status |= action->flags;
action->handler(irq, action->dev_id, regs);
ret = action->handler(irq, action->dev_id, regs);
if (ret == IRQ_HANDLED)
status |= action->flags;
action = action->next;
} while (action);
if (status & SA_SAMPLE_RANDOM)
......
arch/v850/kernel/irq.c
View file @ 8cd809c5
......@@ -141,13 +141,15 @@ int show_interrupts(struct seq_file *p, void *v)
int handle_IRQ_event(unsigned int irq, struct pt_regs * regs, struct irqaction * action)
{
int status = 1; /* Force the "do bottom halves" bit */
int ret;
if (!(action->flags & SA_INTERRUPT))
local_irq_enable();
do {
status |= action->flags;
action->handler(irq, action->dev_id, regs);
ret = action->handler(irq, action->dev_id, regs);
if (ret == IRQ_HANDLED)
status |= action->flags;
action = action->next;
} while (action);
if (status & SA_SAMPLE_RANDOM)
......
arch/x86_64/kernel/irq.c
View file @ 8cd809c5
......@@ -213,13 +213,15 @@ inline void synchronize_irq(unsigned int irq)
int handle_IRQ_event(unsigned int irq, struct pt_regs * regs, struct irqaction * action)
{
int status = 1; /* Force the "do bottom halves" bit */
int ret;
if (!(action->flags & SA_INTERRUPT))
local_irq_enable();
do {
status |= action->flags;
action->handler(irq, action->dev_id, regs);
ret = action->handler(irq, action->dev_id, regs);
if (ret == IRQ_HANDLED)
status |= action->flags;
action = action->next;
} while (action);
if (status & SA_SAMPLE_RANDOM)
......
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