From: Linus Torvalds Date: Mon, 26 Feb 2007 17:21:46 +0000 (-0800) Subject: Revert "[PATCH] i386: add idle notifier" X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=ea3d5226f52ef30f52aa0a04f47f5919c7facacf;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git 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 Cc: Andi Kleen Cc: Andrew Morton Cc: Uwe Bugla Cc: Jiri Slaby Signed-off-by: Linus Torvalds --- diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c index 9655c233e6f1..7a2c9cbdb511 100644 --- a/arch/i386/kernel/apic.c +++ b/arch/i386/kernel/apic.c @@ -38,7 +38,6 @@ #include #include #include -#include #include #include @@ -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); diff --git a/arch/i386/kernel/cpu/mcheck/p4.c b/arch/i386/kernel/cpu/mcheck/p4.c index 8359c19d3a23..504434a46011 100644 --- a/arch/i386/kernel/cpu/mcheck/p4.c +++ b/arch/i386/kernel/cpu/mcheck/p4.c @@ -12,7 +12,6 @@ #include #include #include -#include #include @@ -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(); diff --git a/arch/i386/kernel/irq.c b/arch/i386/kernel/irq.c index 0f2ca590bf23..8db8d514c9c0 100644 --- a/arch/i386/kernel/irq.c +++ b/arch/i386/kernel/irq.c @@ -18,8 +18,6 @@ #include #include -#include - #include #include @@ -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", diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c index bea304d48cdb..393a67d5d943 100644 --- a/arch/i386/kernel/process.c +++ b/arch/i386/kernel/process.c @@ -49,7 +49,6 @@ #include #include #include -#include #ifdef CONFIG_MATH_EMULATION #include #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 *)¤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 9bd9637ae692..0e8977871b1f 100644 --- a/arch/i386/kernel/smp.c +++ b/arch/i386/kernel/smp.c @@ -23,7 +23,6 @@ #include #include -#include #include /* @@ -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(); diff --git a/include/asm-i386/idle.h b/include/asm-i386/idle.h deleted file mode 100644 index 87ab93911199..000000000000 --- 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 edfbe46a5e13..11bf899de8aa 100644 --- a/include/asm-i386/processor.h +++ b/include/asm-i386/processor.h @@ -257,14 +257,6 @@ static inline void __mwait(unsigned long eax, unsigned long ecx) : :"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