Re: [PATCH] Fix shared interrupt handling of SA_INTERRUPT and SA_SAMPLE_RANDOM
From: Takashi Iwai
Date: Thu Aug 26 2004 - 08:16:43 EST
At Wed, 25 Aug 2004 13:41:12 -0700,
Andrew Morton wrote:
>
> Takashi Iwai <tiwai@xxxxxxx> wrote:
> >
> > Anyway, suppressing the unnecessary call of add_interrupt_randomness()
> > should be still valid. The reduced patch is below.
(snip)
>
> Shouldn't that be `if (ret == IRQ_HANDLED)'?
Yes, it's more strict.
> Probably I'll need to pass this to lots of other architecture maintainers
> to make the same change. Please write a nice changelog so they understand
> what your patch does.
Here I patched more architectures. Please pass to arch maintainers if
you thinks it's ok.
Takashi
==
[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: Takashi Iwai <tiwai@xxxxxxx>
--- linux-2.6.8.1/arch/sh/kernel/irq.c-dist 2004-08-26 14:20:41.536919578 +0200
+++ linux-2.6.8.1/arch/sh/kernel/irq.c 2004-08-26 14:21:00.638579701 +0200
@@ -137,14 +137,16 @@ unlock:
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);
--- linux-2.6.8.1/arch/um/kernel/irq.c-dist 2004-08-26 14:22:40.692851759 +0200
+++ linux-2.6.8.1/arch/um/kernel/irq.c 2004-08-26 14:23:03.695627509 +0200
@@ -155,13 +155,15 @@ int handle_IRQ_event(unsigned int irq, s
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)
--- linux-2.6.8.1/arch/arm/kernel/irq.c-dist 2004-08-26 12:52:34.666247196 +0200
+++ linux-2.6.8.1/arch/arm/kernel/irq.c 2004-08-26 12:53:31.595279800 +0200
@@ -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 irqact
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);
--- linux-2.6.8.1/arch/ppc/kernel/irq.c-dist 2004-08-26 14:19:28.275567074 +0200
+++ linux-2.6.8.1/arch/ppc/kernel/irq.c 2004-08-26 14:19:50.988405487 +0200
@@ -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)
--- linux-2.6.8.1/arch/i386/kernel/irq.c-dist 2004-08-25 13:13:05.000000000 +0200
+++ linux-2.6.8.1/arch/i386/kernel/irq.c 2004-08-26 12:48:25.203108557 +0200
@@ -220,14 +220,16 @@ asmlinkage int handle_IRQ_event(unsigned
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)
--- linux-2.6.8.1/arch/cris/kernel/irq.c-dist 2004-08-26 14:14:40.384855612 +0200
+++ linux-2.6.8.1/arch/cris/kernel/irq.c 2004-08-26 14:15:14.701072531 +0200
@@ -125,7 +125,7 @@ asmlinkage void do_IRQ(int irq, struct p
{
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 p
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);
--- linux-2.6.8.1/arch/ia64/kernel/irq.c-dist 2004-08-26 12:50:25.147796632 +0200
+++ linux-2.6.8.1/arch/ia64/kernel/irq.c 2004-08-26 12:51:06.708311749 +0200
@@ -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)
--- linux-2.6.8.1/arch/mips/baget/irq.c-dist 2004-08-26 14:17:55.830532962 +0200
+++ linux-2.6.8.1/arch/mips/baget/irq.c 2004-08-26 14:18:34.502764418 +0200
@@ -180,7 +180,7 @@ skip:
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_re
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)
--- linux-2.6.8.1/arch/mips/kernel/irq.c-dist 2004-08-26 14:18:41.770116666 +0200
+++ linux-2.6.8.1/arch/mips/kernel/irq.c 2004-08-26 14:19:08.196125140 +0200
@@ -144,14 +144,16 @@ inline void synchronize_irq(unsigned int
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)
--- linux-2.6.8.1/arch/v850/kernel/irq.c-dist 2004-08-26 14:23:14.792107468 +0200
+++ linux-2.6.8.1/arch/v850/kernel/irq.c 2004-08-26 14:23:34.635601155 +0200
@@ -141,13 +141,15 @@ skip:
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)
--- linux-2.6.8.1/arch/sh64/kernel/irq.c-dist 2004-08-26 14:21:14.716381411 +0200
+++ linux-2.6.8.1/arch/sh64/kernel/irq.c 2004-08-26 14:21:36.941332490 +0200
@@ -148,6 +148,7 @@ asmlinkage void do_NMI(unsigned long vec
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, s
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)
--- linux-2.6.8.1/arch/alpha/kernel/irq.c-dist 2004-08-26 12:51:34.133057570 +0200
+++ linux-2.6.8.1/arch/alpha/kernel/irq.c 2004-08-26 12:52:02.341618752 +0200
@@ -83,6 +83,7 @@ handle_IRQ_event(unsigned int irq, struc
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, struc
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)
--- linux-2.6.8.1/arch/arm26/kernel/irq.c-dist 2004-08-26 14:13:44.808461520 +0200
+++ linux-2.6.8.1/arch/arm26/kernel/irq.c 2004-08-26 14:14:08.377115505 +0200
@@ -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 irqact
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);
--- linux-2.6.8.1/arch/ppc64/kernel/irq.c-dist 2004-08-26 14:20:00.603220604 +0200
+++ linux-2.6.8.1/arch/ppc64/kernel/irq.c 2004-08-26 14:20:24.840713164 +0200
@@ -362,14 +362,16 @@ skip:
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)
--- linux-2.6.8.1/arch/x86_64/kernel/irq.c-dist 2004-08-26 12:48:38.518091949 +0200
+++ linux-2.6.8.1/arch/x86_64/kernel/irq.c 2004-08-26 12:51:19.752337402 +0200
@@ -213,13 +213,15 @@ inline void synchronize_irq(unsigned int
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)
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/