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author | Thomas Gleixner <tglx@linutronix.de> | 2013-03-21 22:49:35 +0100 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2013-04-08 17:39:23 +0200 |
commit | d166991234347215dc23fc9dc15a63a83a1a54e1 (patch) | |
tree | 5ca0351d7271b7591ab2a73bcad127cf8944ad63 /kernel/cpu/idle.c | |
parent | idle: Provide a generic entry point for the idle code (diff) | |
download | linux-d166991234347215dc23fc9dc15a63a83a1a54e1.tar.xz linux-d166991234347215dc23fc9dc15a63a83a1a54e1.zip |
idle: Implement generic idle function
All idle functions in arch/* are more or less the same, plus minus a
few bugs and extra instrumentation, tickless support and other
optional items.
Implement a generic idle function which resembles the functionality
found in arch/. Provide weak arch_cpu_idle_* functions which can be
overridden by the architecture code if needed.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130321215233.646635455@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/cpu/idle.c')
-rw-r--r-- | kernel/cpu/idle.c | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/kernel/cpu/idle.c b/kernel/cpu/idle.c index 1908f00e0e98..54c320383934 100644 --- a/kernel/cpu/idle.c +++ b/kernel/cpu/idle.c @@ -3,8 +3,113 @@ */ #include <linux/sched.h> #include <linux/cpu.h> +#include <linux/tick.h> +#include <linux/mm.h> +#include <asm/tlb.h> + +#include <trace/events/power.h> + +#ifndef CONFIG_GENERIC_IDLE_LOOP void cpu_startup_entry(enum cpuhp_state state) { cpu_idle(); } +#else + +static int __read_mostly cpu_idle_force_poll; + +void cpu_idle_poll_ctrl(bool enable) +{ + if (enable) { + cpu_idle_force_poll++; + } else { + cpu_idle_force_poll--; + WARN_ON_ONCE(cpu_idle_force_poll < 0); + } +} + +#ifdef CONFIG_GENERIC_IDLE_POLL_SETUP +static int __init cpu_idle_poll_setup(char *__unused) +{ + cpu_idle_force_poll = 1; + return 1; +} +__setup("nohlt", cpu_idle_poll_setup); + +static int __init cpu_idle_nopoll_setup(char *__unused) +{ + cpu_idle_force_poll = 0; + return 1; +} +__setup("hlt", cpu_idle_nopoll_setup); +#endif + +static inline int cpu_idle_poll(void) +{ + trace_cpu_idle_rcuidle(0, smp_processor_id()); + local_irq_enable(); + while (!need_resched()) + cpu_relax(); + trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id()); + return 1; +} + +/* Weak implementations for optional arch specific functions */ +void __weak arch_cpu_idle_prepare(void) { } +void __weak arch_cpu_idle_enter(void) { } +void __weak arch_cpu_idle_exit(void) { } +void __weak arch_cpu_idle_dead(void) { } +void __weak arch_cpu_idle(void) +{ + cpu_idle_force_poll = 1; +} + +/* + * Generic idle loop implementation + */ +static void cpu_idle_loop(void) +{ + while (1) { + tick_nohz_idle_enter(); + + while (!need_resched()) { + check_pgt_cache(); + rmb(); + + if (cpu_is_offline(smp_processor_id())) + arch_cpu_idle_dead(); + + local_irq_disable(); + arch_cpu_idle_enter(); + + if (cpu_idle_force_poll) { + cpu_idle_poll(); + } else { + current_clr_polling(); + if (!need_resched()) { + stop_critical_timings(); + rcu_idle_enter(); + arch_cpu_idle(); + WARN_ON_ONCE(irqs_disabled()); + rcu_idle_exit(); + start_critical_timings(); + } else { + local_irq_enable(); + } + current_set_polling(); + } + arch_cpu_idle_exit(); + } + tick_nohz_idle_exit(); + schedule_preempt_disabled(); + } +} + +void cpu_startup_entry(enum cpuhp_state state) +{ + current_set_polling(); + arch_cpu_idle_prepare(); + cpu_idle_loop(); +} +#endif |