From 62027aea23fcd14478abdddd3b74a4e0f5fb2984 Mon Sep 17 00:00:00 2001 From: Len Brown Date: Fri, 1 Apr 2011 18:13:10 -0400 Subject: cpuidle: create bootparam "cpuidle.off=1" useful for disabling cpuidle to fall back to architecture-default idle loop cpuidle drivers and governors will fail to register. on x86 they'll say so: intel_idle: intel_idle yielding to (null) ACPI: acpi_idle yielding to (null) Signed-off-by: Len Brown --- drivers/cpuidle/cpuidle.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'drivers/cpuidle/cpuidle.c') diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index bf5092455a8..faae2c357ba 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -28,6 +28,12 @@ LIST_HEAD(cpuidle_detected_devices); static void (*pm_idle_old)(void); static int enabled_devices; +static int off __read_mostly; + +int cpuidle_disabled(void) +{ + return off; +} #if defined(CONFIG_ARCH_HAS_CPU_IDLE_WAIT) static void cpuidle_kick_cpus(void) @@ -427,6 +433,9 @@ static int __init cpuidle_init(void) { int ret; + if (cpuidle_disabled()) + return -ENODEV; + pm_idle_old = pm_idle; ret = cpuidle_add_class_sysfs(&cpu_sysdev_class); @@ -438,4 +447,5 @@ static int __init cpuidle_init(void) return 0; } +module_param(off, int, 0444); core_initcall(cpuidle_init); -- cgit v1.2.3-70-g09d2 From d91ee5863b71e8c90eaf6035bff3078a85e2e7b5 Mon Sep 17 00:00:00 2001 From: Len Brown Date: Fri, 1 Apr 2011 18:28:35 -0400 Subject: cpuidle: replace xen access to x86 pm_idle and default_idle When a Xen Dom0 kernel boots on a hypervisor, it gets access to the raw-hardware ACPI tables. While it parses the idle tables for the hypervisor's beneift, it uses HLT for its own idle. Rather than have xen scribble on pm_idle and access default_idle, have it simply disable_cpuidle() so acpi_idle will not load and architecture default HLT will be used. cc: xen-devel@lists.xensource.com Tested-by: Konrad Rzeszutek Wilk Acked-by: H. Peter Anvin Signed-off-by: Len Brown --- arch/x86/xen/setup.c | 3 ++- drivers/cpuidle/cpuidle.c | 4 ++++ include/linux/cpuidle.h | 2 ++ 3 files changed, 8 insertions(+), 1 deletion(-) (limited to 'drivers/cpuidle/cpuidle.c') diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index 60aeeb56948..a9627e2e329 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -9,6 +9,7 @@ #include #include #include +#include #include #include @@ -426,7 +427,7 @@ void __init xen_arch_setup(void) #ifdef CONFIG_X86_32 boot_cpu_data.hlt_works_ok = 1; #endif - pm_idle = default_idle; + disable_cpuidle(); boot_option_idle_override = IDLE_HALT; fiddle_vdso(); diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index faae2c357ba..041df0b056b 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -34,6 +34,10 @@ int cpuidle_disabled(void) { return off; } +void disable_cpuidle(void) +{ + off = 1; +} #if defined(CONFIG_ARCH_HAS_CPU_IDLE_WAIT) static void cpuidle_kick_cpus(void) diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index 36719ead50e..b89f67da919 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -122,6 +122,7 @@ struct cpuidle_driver { }; #ifdef CONFIG_CPU_IDLE +extern void disable_cpuidle(void); extern int cpuidle_register_driver(struct cpuidle_driver *drv); struct cpuidle_driver *cpuidle_get_driver(void); @@ -135,6 +136,7 @@ extern int cpuidle_enable_device(struct cpuidle_device *dev); extern void cpuidle_disable_device(struct cpuidle_device *dev); #else +static inline void disable_cpuidle(void) { } static inline int cpuidle_register_driver(struct cpuidle_driver *drv) {return -ENODEV; } -- cgit v1.2.3-70-g09d2 From a0bfa1373859e9d11dc92561a8667588803e42d8 Mon Sep 17 00:00:00 2001 From: Len Brown Date: Fri, 1 Apr 2011 19:34:59 -0400 Subject: cpuidle: stop depending on pm_idle cpuidle users should call cpuidle_call_idle() directly rather than via (pm_idle)() function pointer. Architecture may choose to continue using (pm_idle)(), but cpuidle need not depend on it: my_arch_cpu_idle() ... if(cpuidle_call_idle()) pm_idle(); cc: Kevin Hilman cc: Paul Mundt cc: x86@kernel.org Acked-by: H. Peter Anvin Signed-off-by: Len Brown --- arch/arm/kernel/process.c | 4 +++- arch/sh/kernel/idle.c | 6 ++++-- arch/x86/kernel/process_32.c | 4 +++- arch/x86/kernel/process_64.c | 4 +++- drivers/cpuidle/cpuidle.c | 38 ++++++++++++++++++-------------------- include/linux/cpuidle.h | 2 ++ 6 files changed, 33 insertions(+), 25 deletions(-) (limited to 'drivers/cpuidle/cpuidle.c') diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 5e1e5419722..d7ee0d4c072 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -30,6 +30,7 @@ #include #include #include +#include #include #include @@ -196,7 +197,8 @@ void cpu_idle(void) cpu_relax(); } else { stop_critical_timings(); - pm_idle(); + if (cpuidle_call_idle()) + pm_idle(); start_critical_timings(); /* * This will eventually be removed - pm_idle diff --git a/arch/sh/kernel/idle.c b/arch/sh/kernel/idle.c index 425d604e3a2..9c7099ebfe1 100644 --- a/arch/sh/kernel/idle.c +++ b/arch/sh/kernel/idle.c @@ -16,12 +16,13 @@ #include #include #include +#include #include #include #include #include -void (*pm_idle)(void) = NULL; +static void (*pm_idle)(void); static int hlt_counter; @@ -100,7 +101,8 @@ void cpu_idle(void) local_irq_disable(); /* Don't trace irqs off for idle */ stop_critical_timings(); - pm_idle(); + if (cpuidle_call_idle()) + pm_idle(); /* * Sanity check to ensure that pm_idle() returns * with IRQs enabled diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index a3d0dc59067..7a3b65107a2 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -38,6 +38,7 @@ #include #include #include +#include #include #include @@ -109,7 +110,8 @@ void cpu_idle(void) local_irq_disable(); /* Don't trace irqs off for idle */ stop_critical_timings(); - pm_idle(); + if (cpuidle_idle_call()) + pm_idle(); start_critical_timings(); } tick_nohz_restart_sched_tick(); diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index ca6f7ab8df3..f693e44e1bf 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -37,6 +37,7 @@ #include #include #include +#include #include #include @@ -136,7 +137,8 @@ void cpu_idle(void) enter_idle(); /* Don't trace irqs off for idle */ stop_critical_timings(); - pm_idle(); + if (cpuidle_idle_call()) + pm_idle(); start_critical_timings(); /* In many cases the interrupt that ended idle diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 041df0b056b..d4c54237288 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -25,10 +25,10 @@ DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices); DEFINE_MUTEX(cpuidle_lock); LIST_HEAD(cpuidle_detected_devices); -static void (*pm_idle_old)(void); static int enabled_devices; static int off __read_mostly; +static int initialized __read_mostly; int cpuidle_disabled(void) { @@ -56,25 +56,23 @@ static int __cpuidle_register_device(struct cpuidle_device *dev); * cpuidle_idle_call - the main idle loop * * NOTE: no locks or semaphores should be used here + * return non-zero on failure */ -static void cpuidle_idle_call(void) +int cpuidle_idle_call(void) { struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); struct cpuidle_state *target_state; int next_state; + if (off) + return -ENODEV; + + if (!initialized) + return -ENODEV; + /* check if the device is ready */ - if (!dev || !dev->enabled) { - if (pm_idle_old) - pm_idle_old(); - else -#if defined(CONFIG_ARCH_HAS_DEFAULT_IDLE) - default_idle(); -#else - local_irq_enable(); -#endif - return; - } + if (!dev || !dev->enabled) + return -EBUSY; #if 0 /* shows regressions, re-enable for 2.6.29 */ @@ -99,7 +97,7 @@ static void cpuidle_idle_call(void) next_state = cpuidle_curr_governor->select(dev); if (need_resched()) { local_irq_enable(); - return; + return 0; } target_state = &dev->states[next_state]; @@ -124,6 +122,8 @@ static void cpuidle_idle_call(void) /* give the governor an opportunity to reflect on the outcome */ if (cpuidle_curr_governor->reflect) cpuidle_curr_governor->reflect(dev); + + return 0; } /** @@ -131,10 +131,10 @@ static void cpuidle_idle_call(void) */ void cpuidle_install_idle_handler(void) { - if (enabled_devices && (pm_idle != cpuidle_idle_call)) { + if (enabled_devices) { /* Make sure all changes finished before we switch to new idle */ smp_wmb(); - pm_idle = cpuidle_idle_call; + initialized = 1; } } @@ -143,8 +143,8 @@ void cpuidle_install_idle_handler(void) */ void cpuidle_uninstall_idle_handler(void) { - if (enabled_devices && pm_idle_old && (pm_idle != pm_idle_old)) { - pm_idle = pm_idle_old; + if (enabled_devices) { + initialized = 0; cpuidle_kick_cpus(); } } @@ -440,8 +440,6 @@ static int __init cpuidle_init(void) if (cpuidle_disabled()) return -ENODEV; - pm_idle_old = pm_idle; - ret = cpuidle_add_class_sysfs(&cpu_sysdev_class); if (ret) return ret; diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index b89f67da919..b51629e15cf 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -123,6 +123,7 @@ struct cpuidle_driver { #ifdef CONFIG_CPU_IDLE extern void disable_cpuidle(void); +extern int cpuidle_idle_call(void); extern int cpuidle_register_driver(struct cpuidle_driver *drv); struct cpuidle_driver *cpuidle_get_driver(void); @@ -137,6 +138,7 @@ extern void cpuidle_disable_device(struct cpuidle_device *dev); #else static inline void disable_cpuidle(void) { } +static inline int cpuidle_idle_call(void) { return -ENODEV; } static inline int cpuidle_register_driver(struct cpuidle_driver *drv) {return -ENODEV; } -- cgit v1.2.3-70-g09d2