Revert "[PATCH] i386: add idle notifier"
This reverts commit 2ff2d3d74705d34ab71b21f54634fcf50d57bdd5.
Uwe Bugla reports that he cannot mount a floppy drive any more, and Jiri
Slaby bisected it down to this commit.
Benjamin LaHaise also points out that this is a big hot-path, and that
interrupt delivery while idle is very common and should not go through
all these expensive gyrations.
Fix up conflicts in arch/i386/kernel/apic.c and arch/i386/kernel/irq.c
due to other unrelated irq changes.
Cc: Stephane Eranian <eranian@hpl.hp.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Uwe Bugla <uwe.bugla@gmx.de>
Cc: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
index 9655c23..7a2c9cb 100644
--- a/arch/i386/kernel/apic.c
+++ b/arch/i386/kernel/apic.c
@@ -38,7 +38,6 @@
#include <asm/hpet.h>
#include <asm/i8253.h>
#include <asm/nmi.h>
-#include <asm/idle.h>
#include <mach_apic.h>
#include <mach_apicdef.h>
@@ -561,7 +560,6 @@
* Besides, if we don't timer interrupts ignore the global
* interrupt lock, which is the WrongThing (tm) to do.
*/
- exit_idle();
irq_enter();
local_apic_timer_interrupt();
irq_exit();
@@ -1221,7 +1219,6 @@
{
unsigned long v;
- exit_idle();
irq_enter();
/*
* Check if this really is a spurious interrupt and ACK it
@@ -1245,7 +1242,6 @@
{
unsigned long v, v1;
- exit_idle();
irq_enter();
/* First tickle the hardware, only then report what went on. -- REW */
v = apic_read(APIC_ESR);
diff --git a/arch/i386/kernel/cpu/mcheck/p4.c b/arch/i386/kernel/cpu/mcheck/p4.c
index 8359c19..504434a 100644
--- a/arch/i386/kernel/cpu/mcheck/p4.c
+++ b/arch/i386/kernel/cpu/mcheck/p4.c
@@ -12,7 +12,6 @@
#include <asm/system.h>
#include <asm/msr.h>
#include <asm/apic.h>
-#include <asm/idle.h>
#include <asm/therm_throt.h>
@@ -60,7 +59,6 @@
fastcall void smp_thermal_interrupt(struct pt_regs *regs)
{
- exit_idle();
irq_enter();
vendor_thermal_interrupt(regs);
irq_exit();
diff --git a/arch/i386/kernel/irq.c b/arch/i386/kernel/irq.c
index 0f2ca590..8db8d51 100644
--- a/arch/i386/kernel/irq.c
+++ b/arch/i386/kernel/irq.c
@@ -18,8 +18,6 @@
#include <linux/cpu.h>
#include <linux/delay.h>
-#include <asm/idle.h>
-
#include <asm/apic.h>
#include <asm/uaccess.h>
@@ -77,7 +75,6 @@
union irq_ctx *curctx, *irqctx;
u32 *isp;
#endif
- exit_idle();
if (unlikely((unsigned)irq >= NR_IRQS)) {
printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
index bea304d..393a67d 100644
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -49,7 +49,6 @@
#include <asm/i387.h>
#include <asm/desc.h>
#include <asm/vm86.h>
-#include <asm/idle.h>
#ifdef CONFIG_MATH_EMULATION
#include <asm/math_emu.h>
#endif
@@ -82,42 +81,6 @@
EXPORT_SYMBOL(pm_idle);
static DEFINE_PER_CPU(unsigned int, cpu_idle_state);
-static ATOMIC_NOTIFIER_HEAD(idle_notifier);
-
-void idle_notifier_register(struct notifier_block *n)
-{
- atomic_notifier_chain_register(&idle_notifier, n);
-}
-
-void idle_notifier_unregister(struct notifier_block *n)
-{
- atomic_notifier_chain_unregister(&idle_notifier, n);
-}
-
-static DEFINE_PER_CPU(volatile unsigned long, idle_state);
-
-void enter_idle(void)
-{
- /* needs to be atomic w.r.t. interrupts, not against other CPUs */
- __set_bit(0, &__get_cpu_var(idle_state));
- atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);
-}
-
-static void __exit_idle(void)
-{
- /* needs to be atomic w.r.t. interrupts, not against other CPUs */
- if (__test_and_clear_bit(0, &__get_cpu_var(idle_state)) == 0)
- return;
- atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
-}
-
-void exit_idle(void)
-{
- if (current->pid)
- return;
- __exit_idle();
-}
-
void disable_hlt(void)
{
hlt_counter++;
@@ -168,7 +131,6 @@
*/
static void poll_idle (void)
{
- local_irq_enable();
cpu_relax();
}
@@ -229,16 +191,7 @@
play_dead();
__get_cpu_var(irq_stat).idle_timestamp = jiffies;
-
- /*
- * Idle routines should keep interrupts disabled
- * from here on, until they go to idle.
- * Otherwise, idle callbacks can misfire.
- */
- local_irq_disable();
- enter_idle();
idle();
- __exit_idle();
}
tick_nohz_restart_sched_tick();
preempt_enable_no_resched();
@@ -293,11 +246,7 @@
__monitor((void *)¤t_thread_info()->flags, 0, 0);
smp_mb();
if (!need_resched())
- __sti_mwait(eax, ecx);
- else
- local_irq_enable();
- } else {
- local_irq_enable();
+ __mwait(eax, ecx);
}
}
diff --git a/arch/i386/kernel/smp.c b/arch/i386/kernel/smp.c
index 9bd9637..0e89778 100644
--- a/arch/i386/kernel/smp.c
+++ b/arch/i386/kernel/smp.c
@@ -23,7 +23,6 @@
#include <asm/mtrr.h>
#include <asm/tlbflush.h>
-#include <asm/idle.h>
#include <mach_apic.h>
/*
@@ -624,7 +623,6 @@
/*
* At this point the info structure may be out of scope unless wait==1
*/
- exit_idle();
irq_enter();
(*func)(info);
irq_exit();
diff --git a/include/asm-i386/idle.h b/include/asm-i386/idle.h
deleted file mode 100644
index 87ab939..0000000
--- a/include/asm-i386/idle.h
+++ /dev/null
@@ -1,14 +0,0 @@
-#ifndef _ASM_I386_IDLE_H
-#define _ASM_I386_IDLE_H 1
-
-#define IDLE_START 1
-#define IDLE_END 2
-
-struct notifier_block;
-void idle_notifier_register(struct notifier_block *n);
-void idle_notifier_unregister(struct notifier_block *n);
-
-void exit_idle(void);
-void enter_idle(void);
-
-#endif
diff --git a/include/asm-i386/processor.h b/include/asm-i386/processor.h
index edfbe46..11bf899 100644
--- a/include/asm-i386/processor.h
+++ b/include/asm-i386/processor.h
@@ -257,14 +257,6 @@
: :"a" (eax), "c" (ecx));
}
-static inline void __sti_mwait(unsigned long eax, unsigned long ecx)
-{
- /* "mwait %eax,%ecx;" */
- asm volatile(
- "sti; .byte 0x0f,0x01,0xc9;"
- : :"a" (eax), "c" (ecx));
-}
-
extern void mwait_idle_with_hints(unsigned long eax, unsigned long ecx);
/* from system description table in BIOS. Mostly for MCA use, but
