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Commit ea3d5226 authored by Linus Torvalds's avatar Linus Torvalds
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Revert "[PATCH] i386: add idle notifier" 



This reverts commit 2ff2d3d7.

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: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9654640d

arch/i386/kernel/apic.c

+0 −4
Original line number Diff line number Diff line
@@ -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 @@ void fastcall smp_apic_timer_interrupt(struct pt_regs *regs) 
	 * 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 @@ void smp_spurious_interrupt(struct pt_regs *regs) 
{

	unsigned long v;



	exit_idle();

	irq_enter();

	/*

	 * Check if this really is a spurious interrupt and ACK it
@@ -1245,7 +1242,6 @@ void smp_error_interrupt(struct pt_regs *regs) 
{

	unsigned long v, v1;



	exit_idle();

	irq_enter();

	/* First tickle the hardware, only then report what went on. -- REW */

	v = apic_read(APIC_ESR);

arch/i386/kernel/cpu/mcheck/p4.c

+0 −2
Original line number Diff line number Diff line
@@ -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 @@ static void (*vendor_thermal_interrupt)(struct pt_regs *regs) = unexpected_therm 


fastcall void smp_thermal_interrupt(struct pt_regs *regs)

{

	exit_idle();

	irq_enter();

	vendor_thermal_interrupt(regs);

	irq_exit();

arch/i386/kernel/irq.c

+0 −3
Original line number Diff line number Diff line
@@ -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 @@ fastcall unsigned int do_IRQ(struct pt_regs *regs) 
	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",

arch/i386/kernel/process.c

+1 −52
Original line number Diff line number Diff line
@@ -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 @@ void (*pm_idle)(void); 
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 @@ EXPORT_SYMBOL(default_idle); 
 */

static void poll_idle (void)

{

	local_irq_enable();

	cpu_relax();

}
@@ -229,16 +191,7 @@ void cpu_idle(void) 
				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 @@ void mwait_idle_with_hints(unsigned long eax, unsigned long ecx) 
		__monitor((void *)&current_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);

	}

}

arch/i386/kernel/smp.c

+0 −2
Original line number Diff line number Diff line
@@ -23,7 +23,6 @@ 


#include <asm/mtrr.h>

#include <asm/tlbflush.h>

#include <asm/idle.h>

#include <mach_apic.h>



/*
@@ -624,7 +623,6 @@ fastcall void smp_call_function_interrupt(struct pt_regs *regs) 
	/*

	 * At this point the info structure may be out of scope unless wait==1

	 */

	exit_idle();

	irq_enter();

	(*func)(info);

	irq_exit();