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author | 2015-02-17 14:17:51 -0800 | |
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committer | 2015-02-17 14:17:51 -0800 | |
commit | 99fa0ad92c4fd8b529c89b3640b42323984be761 (patch) | |
tree | ba4ef84ab54c2c5636521c1b1ae4e9056d46c75c /kernel/sched | |
parent | Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmo... (diff) | |
parent | ACPI / idle: Implement ->enter_freeze callback routine (diff) | |
download | linux-99fa0ad92c4fd8b529c89b3640b42323984be761.tar.gz linux-99fa0ad92c4fd8b529c89b3640b42323984be761.tar.bz2 linux-99fa0ad92c4fd8b529c89b3640b42323984be761.zip |
Merge tag 'suspend-to-idle-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull suspend-to-idle updates from Rafael Wysocki:
"Suspend-to-idle timer quiescing support for v3.20-rc1
Until now suspend-to-idle has not been able to save much more energy
than runtime PM because of timer interrupts that periodically bring
CPUs out of idle while they are waiting for a wakeup interrupt. Of
course, the timer interrupts are not wakeup ones, so the handling of
them can be deferred until a real wakeup interrupt happens, but at the
same time we don't want to mass-expire timers at that point.
The solution is to suspend the entire timekeeping when the last CPU is
entering an idle state and resume it when the first CPU goes out of
idle. That has to be done with care, though, so as to avoid accessing
suspended clocksources etc. end we need extra support from idle
drivers for that.
This series of commits adds support for quiescing timers during
suspend-to-idle and adds the requisite callbacks to intel_idle and the
ACPI cpuidle driver"
* tag 'suspend-to-idle-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI / idle: Implement ->enter_freeze callback routine
intel_idle: Add ->enter_freeze callbacks
PM / sleep: Make it possible to quiesce timers during suspend-to-idle
timekeeping: Make it safe to use the fast timekeeper while suspended
timekeeping: Pass readout base to update_fast_timekeeper()
PM / sleep: Re-implement suspend-to-idle handling
Diffstat (limited to 'kernel/sched')
-rw-r--r-- | kernel/sched/idle.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index aaf1c1d5cf5d..94b2d7b88a27 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -7,6 +7,7 @@ #include <linux/tick.h> #include <linux/mm.h> #include <linux/stackprotector.h> +#include <linux/suspend.h> #include <asm/tlb.h> @@ -105,6 +106,21 @@ static void cpuidle_idle_call(void) rcu_idle_enter(); /* + * Suspend-to-idle ("freeze") is a system state in which all user space + * has been frozen, all I/O devices have been suspended and the only + * activity happens here and in iterrupts (if any). In that case bypass + * the cpuidle governor and go stratight for the deepest idle state + * available. Possibly also suspend the local tick and the entire + * timekeeping to prevent timer interrupts from kicking us out of idle + * until a proper wakeup interrupt happens. + */ + if (idle_should_freeze()) { + cpuidle_enter_freeze(); + local_irq_enable(); + goto exit_idle; + } + + /* * Ask the cpuidle framework to choose a convenient idle state. * Fall back to the default arch idle method on errors. */ |