linux/kernel/sched/idle.c
Linus Torvalds 7725131982 ACPI and power management updates for 3.17-rc1
- ACPICA update to upstream version 20140724.  That includes
    ACPI 5.1 material (support for the _CCA and _DSD predefined names,
    changes related to the DMAR and PCCT tables and ARM support among
    other things) and cleanups related to using ACPICA's header files.
    A major part of it is related to acpidump and the core code used
    by that utility.  Changes from Bob Moore, David E Box, Lv Zheng,
    Sascha Wildner, Tomasz Nowicki, Hanjun Guo.
 
  - Radix trees for memory bitmaps used by the hibernation core from
    Joerg Roedel.
 
  - Support for waking up the system from suspend-to-idle (also known
    as the "freeze" sleep state) using ACPI-based PCI wakeup signaling
    (Rafael J Wysocki).
 
  - Fixes for issues related to ACPI button events (Rafael J Wysocki).
 
  - New device ID for an ACPI-enumerated device included into the
    Wildcat Point PCH from Jie Yang.
 
  - ACPI video updates related to backlight handling from Hans de Goede
    and Linus Torvalds.
 
  - Preliminary changes needed to support ACPI on ARM from Hanjun Guo
    and Graeme Gregory.
 
  - ACPI PNP core cleanups from Arjun Sreedharan and Zhang Rui.
 
  - Cleanups related to ACPI_COMPANION() and ACPI_HANDLE() macros
    (Rafael J Wysocki).
 
  - ACPI-based device hotplug cleanups from Wei Yongjun and
    Rafael J Wysocki.
 
  - Cleanups and improvements related to system suspend from
    Lan Tianyu, Randy Dunlap and Rafael J Wysocki.
 
  - ACPI battery cleanup from Wei Yongjun.
 
  - cpufreq core fixes from Viresh Kumar.
 
  - Elimination of a deadband effect from the cpufreq ondemand
    governor and intel_pstate driver cleanups from Stratos Karafotis.
 
  - 350MHz CPU support for the powernow-k6 cpufreq driver from
    Mikulas Patocka.
 
  - Fix for the imx6 cpufreq driver from Anson Huang.
 
  - cpuidle core and governor cleanups from Daniel Lezcano,
    Sandeep Tripathy and Mohammad Merajul Islam Molla.
 
  - Build fix for the big_little cpuidle driver from Sachin Kamat.
 
  - Configuration fix for the Operation Performance Points (OPP)
    framework from Mark Brown.
 
  - APM cleanup from Jean Delvare.
 
  - cpupower utility fixes and cleanups from Peter Senna Tschudin,
    Andrey Utkin, Himangi Saraogi, Rickard Strandqvist, Thomas Renninger.
 
 /
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Merge tag 'pm+acpi-3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI and power management updates from Rafael Wysocki:
 "Again, ACPICA leads the pack (47 commits), followed by cpufreq (18
  commits) and system suspend/hibernation (9 commits).

  From the new code perspective, the ACPICA update brings ACPI 5.1 to
  the table, including a new device configuration object called _DSD
  (Device Specific Data) that will hopefully help us to operate device
  properties like Device Trees do (at least to some extent) and changes
  related to supporting ACPI on ARM.

  Apart from that we have hibernation changes making it use radix trees
  to store memory bitmaps which should speed up some operations carried
  out by it quite significantly.  We also have some power management
  changes related to suspend-to-idle (the "freeze" sleep state) support
  and more preliminary changes needed to support ACPI on ARM (outside of
  ACPICA).

  The rest is fixes and cleanups pretty much everywhere.

  Specifics:

   - ACPICA update to upstream version 20140724.  That includes ACPI 5.1
     material (support for the _CCA and _DSD predefined names, changes
     related to the DMAR and PCCT tables and ARM support among other
     things) and cleanups related to using ACPICA's header files.  A
     major part of it is related to acpidump and the core code used by
     that utility.  Changes from Bob Moore, David E Box, Lv Zheng,
     Sascha Wildner, Tomasz Nowicki, Hanjun Guo.

   - Radix trees for memory bitmaps used by the hibernation core from
     Joerg Roedel.

   - Support for waking up the system from suspend-to-idle (also known
     as the "freeze" sleep state) using ACPI-based PCI wakeup signaling
     (Rafael J Wysocki).

   - Fixes for issues related to ACPI button events (Rafael J Wysocki).

   - New device ID for an ACPI-enumerated device included into the
     Wildcat Point PCH from Jie Yang.

   - ACPI video updates related to backlight handling from Hans de Goede
     and Linus Torvalds.

   - Preliminary changes needed to support ACPI on ARM from Hanjun Guo
     and Graeme Gregory.

   - ACPI PNP core cleanups from Arjun Sreedharan and Zhang Rui.

   - Cleanups related to ACPI_COMPANION() and ACPI_HANDLE() macros
     (Rafael J Wysocki).

   - ACPI-based device hotplug cleanups from Wei Yongjun and Rafael J
     Wysocki.

   - Cleanups and improvements related to system suspend from Lan
     Tianyu, Randy Dunlap and Rafael J Wysocki.

   - ACPI battery cleanup from Wei Yongjun.

   - cpufreq core fixes from Viresh Kumar.

   - Elimination of a deadband effect from the cpufreq ondemand governor
     and intel_pstate driver cleanups from Stratos Karafotis.

   - 350MHz CPU support for the powernow-k6 cpufreq driver from Mikulas
     Patocka.

   - Fix for the imx6 cpufreq driver from Anson Huang.

   - cpuidle core and governor cleanups from Daniel Lezcano, Sandeep
     Tripathy and Mohammad Merajul Islam Molla.

   - Build fix for the big_little cpuidle driver from Sachin Kamat.

   - Configuration fix for the Operation Performance Points (OPP)
     framework from Mark Brown.

   - APM cleanup from Jean Delvare.

   - cpupower utility fixes and cleanups from Peter Senna Tschudin,
     Andrey Utkin, Himangi Saraogi, Rickard Strandqvist, Thomas
     Renninger"

* tag 'pm+acpi-3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (118 commits)
  ACPI / LPSS: add LPSS device for Wildcat Point PCH
  ACPI / PNP: Replace faulty is_hex_digit() by isxdigit()
  ACPICA: Update version to 20140724.
  ACPICA: ACPI 5.1: Update for PCCT table changes.
  ACPICA/ARM: ACPI 5.1: Update for GTDT table changes.
  ACPICA/ARM: ACPI 5.1: Update for MADT changes.
  ACPICA/ARM: ACPI 5.1: Update for FADT changes.
  ACPICA: ACPI 5.1: Support for the _CCA predifined name.
  ACPICA: ACPI 5.1: New notify value for System Affinity Update.
  ACPICA: ACPI 5.1: Support for the _DSD predefined name.
  ACPICA: Debug object: Add current value of Timer() to debug line prefix.
  ACPICA: acpihelp: Add UUID support, restructure some existing files.
  ACPICA: Utilities: Fix local printf issue.
  ACPICA: Tables: Update for DMAR table changes.
  ACPICA: Remove some extraneous printf arguments.
  ACPICA: Update for comments/formatting. No functional changes.
  ACPICA: Disassembler: Add support for the ToUUID opererator (macro).
  ACPICA: Remove a redundant cast to acpi_size for ACPI_OFFSET() macro.
  ACPICA: Work around an ancient GCC bug.
  ACPI / processor: Make it possible to get local x2apic id via _MAT
  ...
2014-08-06 20:34:19 -07:00

270 lines
6.4 KiB
C

/*
* Generic entry point for the idle threads
*/
#include <linux/sched.h>
#include <linux/cpu.h>
#include <linux/cpuidle.h>
#include <linux/tick.h>
#include <linux/mm.h>
#include <linux/stackprotector.h>
#include <asm/tlb.h>
#include <trace/events/power.h>
#include "sched.h"
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)
{
rcu_idle_enter();
trace_cpu_idle_rcuidle(0, smp_processor_id());
local_irq_enable();
while (!tif_need_resched())
cpu_relax();
trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
rcu_idle_exit();
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;
local_irq_enable();
}
/**
* cpuidle_idle_call - the main idle function
*
* NOTE: no locks or semaphores should be used here
*
* On archs that support TIF_POLLING_NRFLAG, is called with polling
* set, and it returns with polling set. If it ever stops polling, it
* must clear the polling bit.
*/
static void cpuidle_idle_call(void)
{
struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
int next_state, entered_state;
unsigned int broadcast;
/*
* Check if the idle task must be rescheduled. If it is the
* case, exit the function after re-enabling the local irq.
*/
if (need_resched()) {
local_irq_enable();
return;
}
/*
* During the idle period, stop measuring the disabled irqs
* critical sections latencies
*/
stop_critical_timings();
/*
* Tell the RCU framework we are entering an idle section,
* so no more rcu read side critical sections and one more
* step to the grace period
*/
rcu_idle_enter();
/*
* Ask the cpuidle framework to choose a convenient idle state.
* Fall back to the default arch idle method on errors.
*/
next_state = cpuidle_select(drv, dev);
if (next_state < 0) {
use_default:
/*
* We can't use the cpuidle framework, let's use the default
* idle routine.
*/
if (current_clr_polling_and_test())
local_irq_enable();
else
arch_cpu_idle();
goto exit_idle;
}
/*
* The idle task must be scheduled, it is pointless to
* go to idle, just update no idle residency and get
* out of this function
*/
if (current_clr_polling_and_test()) {
dev->last_residency = 0;
entered_state = next_state;
local_irq_enable();
goto exit_idle;
}
broadcast = drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP;
/*
* Tell the time framework to switch to a broadcast timer
* because our local timer will be shutdown. If a local timer
* is used from another cpu as a broadcast timer, this call may
* fail if it is not available
*/
if (broadcast &&
clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu))
goto use_default;
/*
* Enter the idle state previously returned by the governor decision.
* This function will block until an interrupt occurs and will take
* care of re-enabling the local interrupts
*/
entered_state = cpuidle_enter(drv, dev, next_state);
if (broadcast)
clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &dev->cpu);
/*
* Give the governor an opportunity to reflect on the outcome
*/
cpuidle_reflect(dev, entered_state);
exit_idle:
__current_set_polling();
/*
* It is up to the idle functions to reenable local interrupts
*/
if (WARN_ON_ONCE(irqs_disabled()))
local_irq_enable();
rcu_idle_exit();
start_critical_timings();
}
/*
* Generic idle loop implementation
*
* Called with polling cleared.
*/
static void cpu_idle_loop(void)
{
while (1) {
/*
* If the arch has a polling bit, we maintain an invariant:
*
* Our polling bit is clear if we're not scheduled (i.e. if
* rq->curr != rq->idle). This means that, if rq->idle has
* the polling bit set, then setting need_resched is
* guaranteed to cause the cpu to reschedule.
*/
__current_set_polling();
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();
/*
* In poll mode we reenable interrupts and spin.
*
* Also if we detected in the wakeup from idle
* path that the tick broadcast device expired
* for us, we don't want to go deep idle as we
* know that the IPI is going to arrive right
* away
*/
if (cpu_idle_force_poll || tick_check_broadcast_expired())
cpu_idle_poll();
else
cpuidle_idle_call();
arch_cpu_idle_exit();
}
/*
* Since we fell out of the loop above, we know
* TIF_NEED_RESCHED must be set, propagate it into
* PREEMPT_NEED_RESCHED.
*
* This is required because for polling idle loops we will
* not have had an IPI to fold the state for us.
*/
preempt_set_need_resched();
tick_nohz_idle_exit();
__current_clr_polling();
/*
* We promise to call sched_ttwu_pending and reschedule
* if need_resched is set while polling is set. That
* means that clearing polling needs to be visible
* before doing these things.
*/
smp_mb__after_atomic();
sched_ttwu_pending();
schedule_preempt_disabled();
}
}
void cpu_startup_entry(enum cpuhp_state state)
{
/*
* This #ifdef needs to die, but it's too late in the cycle to
* make this generic (arm and sh have never invoked the canary
* init for the non boot cpus!). Will be fixed in 3.11
*/
#ifdef CONFIG_X86
/*
* If we're the non-boot CPU, nothing set the stack canary up
* for us. The boot CPU already has it initialized but no harm
* in doing it again. This is a good place for updating it, as
* we wont ever return from this function (so the invalid
* canaries already on the stack wont ever trigger).
*/
boot_init_stack_canary();
#endif
arch_cpu_idle_prepare();
cpu_idle_loop();
}