Commit Graph

106 Commits

Author SHA1 Message Date
Srivatsa S. Bhat cf31cd1a0c ACPI idle, CPU hotplug: Fix NULL pointer dereference during hotplug
On a KVM guest, when a CPU is taken offline and brought back online, we hit
the following NULL pointer dereference:

[   45.400843] Unregister pv shared memory for cpu 1
[   45.412331] smpboot: CPU 1 is now offline
[   45.529894] SMP alternatives: lockdep: fixing up alternatives
[   45.533472] smpboot: Booting Node 0 Processor 1 APIC 0x1
[   45.411526] kvm-clock: cpu 1, msr 0:7d14601, secondary cpu clock
[   45.571370] KVM setup async PF for cpu 1
[   45.572331] kvm-stealtime: cpu 1, msr 7d0e040
[   45.575031] BUG: unable to handle kernel NULL pointer dereference at           (null)
[   45.576017] IP: [<ffffffff81519f98>] cpuidle_disable_device+0x18/0x80
[   45.576017] PGD 5dfb067 PUD 5da8067 PMD 0
[   45.576017] Oops: 0000 [#1] SMP
[   45.576017] Modules linked in:
[   45.576017] CPU 0
[   45.576017] Pid: 607, comm: stress_cpu_hotp Not tainted 3.6.0-padata-tp-debug #3 Bochs Bochs
[   45.576017] RIP: 0010:[<ffffffff81519f98>]  [<ffffffff81519f98>] cpuidle_disable_device+0x18/0x80
[   45.576017] RSP: 0018:ffff880005d93ce8  EFLAGS: 00010286
[   45.576017] RAX: ffff880005d93fd8 RBX: 0000000000000000 RCX: 0000000000000006
[   45.576017] RDX: 0000000000000006 RSI: 2222222222222222 RDI: 0000000000000000
[   45.576017] RBP: ffff880005d93cf8 R08: 2222222222222222 R09: 2222222222222222
[   45.576017] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[   45.576017] R13: 0000000000000000 R14: ffffffff81c8cca0 R15: 0000000000000001
[   45.576017] FS:  00007f91936ae700(0000) GS:ffff880007c00000(0000) knlGS:0000000000000000
[   45.576017] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[   45.576017] CR2: 0000000000000000 CR3: 0000000005db3000 CR4: 00000000000006f0
[   45.576017] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   45.576017] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[   45.576017] Process stress_cpu_hotp (pid: 607, threadinfo ffff880005d92000, task ffff8800066bbf40)
[   45.576017] Stack:
[   45.576017]  ffff880007a96400 0000000000000000 ffff880005d93d28 ffffffff813ac689
[   45.576017]  ffff880007a96400 ffff880007a96400 0000000000000002 ffffffff81cd8d01
[   45.576017]  ffff880005d93d58 ffffffff813aa498 0000000000000001 00000000ffffffdd
[   45.576017] Call Trace:
[   45.576017]  [<ffffffff813ac689>] acpi_processor_hotplug+0x55/0x97
[   45.576017]  [<ffffffff813aa498>] acpi_cpu_soft_notify+0x93/0xce
[   45.576017]  [<ffffffff816ae47d>] notifier_call_chain+0x5d/0x110
[   45.576017]  [<ffffffff8109730e>] __raw_notifier_call_chain+0xe/0x10
[   45.576017]  [<ffffffff81069050>] __cpu_notify+0x20/0x40
[   45.576017]  [<ffffffff81069085>] cpu_notify+0x15/0x20
[   45.576017]  [<ffffffff816978f1>] _cpu_up+0xee/0x137
[   45.576017]  [<ffffffff81697983>] cpu_up+0x49/0x59
[   45.576017]  [<ffffffff8168758d>] store_online+0x9d/0xe0
[   45.576017]  [<ffffffff8140a9f8>] dev_attr_store+0x18/0x30
[   45.576017]  [<ffffffff812322c0>] sysfs_write_file+0xe0/0x150
[   45.576017]  [<ffffffff811b389c>] vfs_write+0xac/0x180
[   45.576017]  [<ffffffff811b3be2>] sys_write+0x52/0xa0
[   45.576017]  [<ffffffff816b31e9>] system_call_fastpath+0x16/0x1b
[   45.576017] Code: 48 c7 c7 40 e5 ca 81 e8 07 d0 18 00 5d c3 0f 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 48 83 ec 10 48 89 5d f0 4c 89 65 f8 48 89 fb <f6> 07 02 75 13 48 8b 5d f0 4c 8b 65 f8 c9 c3 66 0f 1f 84 00 00
[   45.576017] RIP  [<ffffffff81519f98>] cpuidle_disable_device+0x18/0x80
[   45.576017]  RSP <ffff880005d93ce8>
[   45.576017] CR2: 0000000000000000
[   45.656079] ---[ end trace 433d6c9ac0b02cef ]---

Analysis:
Commit 3d339dc (cpuidle / ACPI : move cpuidle_device field out of the
acpi_processor_power structure()) made the allocation of the dev structure
(struct cpuidle) of a CPU dynamic, whereas previously it was statically
allocated. And this dynamic allocation occurs in acpi_processor_power_init()
if pr->flags.power evaluates to non-zero.

On KVM guests, pr->flags.power evaluates to zero, hence dev is never
allocated. This causes the NULL pointer (dev) dereference in
cpuidle_disable_device() during a subsequent CPU online operation. Fix this
by ensuring that dev is non-NULL before dereferencing.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-10-08 22:52:54 -04:00
Daniel Lezcano ed953472d1 cpuidle: rename function name "__cpuidle_register_driver", v2
The function __cpuidle_register_driver name is confusing because it
suggests, conforming to the coding style of the kernel, it registers
the driver without taking a lock. Actually, it just fill the different
power field states with a decresing value if the power has not been
specified.

Clarify the purpose of the function by changing its name and
move the condition out of this function.

This patch fix nothing and does not change the behavior of the
function. It is just for the sake of clarity.

IHMO, reading in the code:

+       if (!drv->power_specified)
+               set_power_states(drv);

is much more explicit than:

-       __cpuidle_register_driver(drv);

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-09-22 00:38:32 +02:00
Daniel Lezcano a77de28662 cpuidle: remove some empty lines
This mindless patch is just about removing some trailing
carriage returns.

[rjw: Changed the subject.]

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-09-19 21:59:42 +02:00
Rafael J. Wysocki 66804c13f7 PM / cpuidle: Make ladder governor use the "disabled" state flag
For the mechanism introduced by commit cbc9ef0 (PM / Domains: Add
preliminary support for cpuidle, v2) to work with the ladder
governor, that governor should respect the "disabled" state flag
added by that commit.  Change the ladder governor accordingly.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-09-04 01:35:45 +02:00
Carsten Emde 62d6ae880e Honor state disabling in the cpuidle ladder governor
There are two cpuidle governors ladder and menu. While the ladder
governor is always available, if CONFIG_CPU_IDLE is selected, the
menu governor additionally requires CONFIG_NO_HZ.

A particular C state can be disabled by writing to the sysfs file
/sys/devices/system/cpu/cpuN/cpuidle/stateN/disable, but this mechanism
is only implemented in the menu governor. Thus, in a system where
CONFIG_NO_HZ is not selected, the ladder governor becomes default and
always will walk through all sleep states - irrespective of whether the
C state was disabled via sysfs or not. The only way to select a specific
C state was to write the related latency to /dev/cpu_dma_latency and
keep the file open as long as this setting was required - not very
practical and not suitable for setting a single core in an SMP system.

With this patch, the ladder governor only will promote to the next
C state, if it has not been disabled, and it will demote, if the
current C state was disabled.

Note that the patch does not make the setting of the sysfs variable
"disable" coherent, i.e. if one is disabling a light state, then all
deeper states are disabled as well, but the "disable" variable does not
reflect it. Likewise, if one enables a deep state but a lighter state
still is disabled, then this has no effect. A related section has been
added to the documentation.

Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-09-04 01:35:44 +02:00
Jon Medhurst (Tixy) 5fbbb90dfd cpuidle: Prevent null pointer dereference in cpuidle_coupled_cpu_notify
When a kernel is built to support multiple hardware types it's possible
that CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED is set but the hardware the
kernel is run on doesn't support cpuidle and therefore doesn't load a
driver for it. In this case, when the system is shut down,
cpuidle_coupled_cpu_notify() gets called with cpuidle_devices set to
NULL. There are quite possibly other circumstances where this
situation can also occur and we should check for it.

Signed-off-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-08-17 19:37:08 +02:00
Colin Cross 63c6ba4352 cpuidle: coupled: fix sleeping while atomic in cpu notifier
The cpu hotplug notifier gets called in both atomic and non-atomic
contexts, it is not always safe to lock a mutex.  Filter out all events
except the six necessary ones, which are all sleepable, before taking
the mutex.

Signed-off-by: Colin Cross <ccross@android.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-08-17 19:37:01 +02:00
Linus Torvalds 476525004a Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux
Pull ACPI & power management update from Len Brown:
 "Re-write of the turbostat tool.
     lower overhead was necessary for measuring very large system when
     they are very idle.

  IVB support in intel_idle
     It's what I run on my IVB, others should be able to also:-)

  ACPICA core update
     We have found some bugs due to divergence between Linux and the
     upstream ACPICA base.  Most of these patches are to reduce that
     divergence to reduce the risk of future bugs.

  Some cpuidle updates, mostly for non-Intel
     More will be coming, as they depend on this part.

  Some thermal management changes needed by non-ACPI systems.

  Some _OST (OS Status Indication) updates for hot ACPI hot-plug."

* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux: (51 commits)
  Thermal: Documentation update
  Thermal: Add Hysteresis attributes
  Thermal: Make Thermal trip points writeable
  ACPI/AC: prevent OOPS on some boxes due to missing check power_supply_register() return value check
  tools/power: turbostat: fix large c1% issue
  tools/power: turbostat v2 - re-write for efficiency
  ACPICA: Update to version 20120711
  ACPICA: AcpiSrc: Fix some translation issues for Linux conversion
  ACPICA: Update header files copyrights to 2012
  ACPICA: Add new ACPI table load/unload external interfaces
  ACPICA: Split file: tbxface.c -> tbxfload.c
  ACPICA: Add PCC address space to space ID decode function
  ACPICA: Fix some comment fields
  ACPICA: Table manager: deploy new firmware error/warning interfaces
  ACPICA: Add new interfaces for BIOS(firmware) errors and warnings
  ACPICA: Split exception code utilities to a new file, utexcep.c
  ACPI: acpi_pad: tune round_robin_time
  ACPICA: Update to version 20120620
  ACPICA: Add support for implicit notify on multiple devices
  ACPICA: Update comments; no functional change
  ...
2012-07-26 14:28:55 -07:00
Len Brown ec033d0a02 Merge branches 'acpi_pad', 'acpica', 'apei-bugzilla-43282', 'battery', 'cpuidle-coupled', 'cpuidle-tweaks', 'intel_idle-ivb', 'ost', 'red-hat-bz-772730', 'thermal', 'thermal-spear' and 'turbostat-v2' into release 2012-07-26 00:03:58 -04:00
Rafael J. Wysocki 7791bd230c Merge branch 'pm-domains'
* pm-domains:
  PM / Domains: Fix build warning for CONFIG_PM_RUNTIME unset
  PM / Domains: Replace plain integer with NULL pointer in domain.c file
  PM / Domains: Add missing static storage class specifier in domain.c file
  PM / Domains: Allow device callbacks to be added at any time
  PM / Domains: Add device domain data reference counter
  PM / Domains: Add preliminary support for cpuidle, v2
  PM / Domains: Do not stop devices after restoring their states
  PM / Domains: Use subsystem runtime suspend/resume callbacks by default
2012-07-19 00:03:17 +02:00
Preeti U Murthy 8651f97bd9 PM / cpuidle: System resume hang fix with cpuidle
On certain bios, resume hangs if cpus are allowed to enter idle states
during suspend [1].

This was fixed in apci idle driver [2].But intel_idle driver does not
have this fix. Thus instead of replicating the fix in both the idle
drivers, or in more platform specific idle drivers if needed, the
more general cpuidle infrastructure could handle this.

A suspend callback in cpuidle_driver could handle this fix. But
a cpuidle_driver provides only basic functionalities like platform idle
state detection capability and mechanisms to support entry and exit
into CPU idle states. All other cpuidle functions are found in the
cpuidle generic infrastructure for good reason that all cpuidle
drivers, irrepective of their platforms will support these functions.

One option therefore would be to register a suspend callback in cpuidle
which handles this fix. This could be called through a PM_SUSPEND_PREPARE
notifier. But this is too generic a notfier for a driver to handle.

Also, ideally the job of cpuidle is not to handle side effects of suspend.
It should expose the interfaces which "handle cpuidle 'during' suspend"
or any other operation, which the subsystems call during that respective
operation.

The fix demands that during suspend, no cpus should be allowed to enter
deep C-states. The interface cpuidle_uninstall_idle_handler() in cpuidle
ensures that. Not just that it also kicks all the cpus which are already
in idle out of their idle states which was being done during cpu hotplug
through a CPU_DYING_FROZEN callbacks.

Now the question arises about when during suspend should
cpuidle_uninstall_idle_handler() be called. Since we are dealing with
drivers it seems best to call this function during dpm_suspend().
Delaying the call till dpm_suspend_noirq() does no harm, as long as it is
before cpu_hotplug_begin() to avoid race conditions with cpu hotpulg
operations. In dpm_suspend_noirq(), it would be wise to place this call
before suspend_device_irqs() to avoid ugly interactions with the same.

Ananlogously, during resume.

References:
[1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/674075.
[2] http://marc.info/?l=linux-pm&m=133958534231884&w=2

Reported-and-tested-by: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-07-10 21:34:49 +02:00
Rafael J. Wysocki cbc9ef0287 PM / Domains: Add preliminary support for cpuidle, v2
On some systems there are CPU cores located in the same power
domains as I/O devices.  Then, power can only be removed from the
domain if all I/O devices in it are not in use and the CPU core
is idle.  Add preliminary support for that to the generic PM domains
framework.

First, the platform is expected to provide a cpuidle driver with one
extra state designated for use with the generic PM domains code.
This state should be initially disabled and its exit_latency value
should be set to whatever time is needed to bring up the CPU core
itself after restoring power to it, not including the domain's
power on latency.  Its .enter() callback should point to a procedure
that will remove power from the domain containing the CPU core at
the end of the CPU power transition.

The remaining characteristics of the extra cpuidle state, referred to
as the "domain" cpuidle state below, (e.g. power usage, target
residency) should be populated in accordance with the properties of
the hardware.

Next, the platform should execute genpd_attach_cpuidle() on the PM
domain containing the CPU core.  That will cause the generic PM
domains framework to treat that domain in a special way such that:

 * When all devices in the domain have been suspended and it is about
   to be turned off, the states of the devices will be saved, but
   power will not be removed from the domain.  Instead, the "domain"
   cpuidle state will be enabled so that power can be removed from
   the domain when the CPU core is idle and the state has been chosen
   as the target by the cpuidle governor.

 * When the first I/O device in the domain is resumed and
   __pm_genpd_poweron(() is called for the first time after
   power has been removed from the domain, the "domain" cpuidle
   state will be disabled to avoid subsequent surprise power removals
   via cpuidle.

The effective exit_latency value of the "domain" cpuidle state
depends on the time needed to bring up the CPU core itself after
restoring power to it as well as on the power on latency of the
domain containing the CPU core.  Thus the "domain" cpuidle state's
exit_latency has to be recomputed every time the domain's power on
latency is updated, which may happen every time power is restored
to the domain, if the measured power on latency is greater than
the latency stored in the corresponding generic_pm_domain structure.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Kevin Hilman <khilman@ti.com>
2012-07-03 19:07:42 +02:00
Rafael J. Wysocki 6e797a0788 PM / cpuidle: Add driver reference counter
Add a reference counter for the cpuidle driver, so that it can't
be unregistered when it is in use.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-07-03 19:06:25 +02:00
ShuoX Liu dc7fd275ae cpuidle: move field disable from per-driver to per-cpu
Andrew J.Schorr raises a question.  When he changes the disable setting on
a single CPU, it affects all the other CPUs.  Basically, currently, the
disable field is per-driver instead of per-cpu.  All the C states of the
same driver are shared by all CPU in the same machine.

The patch changes the `disable' field to per-cpu, so we could set this
separately for each cpu.

Signed-off-by: ShuoX Liu <shuox.liu@intel.com>
Reported-by: Andrew J.Schorr <aschorr@telemetry-investments.com>
Reviewed-by: Yanmin Zhang <yanmin_zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-07-03 19:05:31 +02:00
Colin Cross 20ff51a36b cpuidle: coupled: add parallel barrier function
Adds cpuidle_coupled_parallel_barrier, which can be used by coupled
cpuidle state enter functions to handle resynchronization after
determining if any cpu needs to abort.  The normal use case will
be:

static bool abort_flag;
static atomic_t abort_barrier;

int arch_cpuidle_enter(struct cpuidle_device *dev, ...)
{
	if (arch_turn_off_irq_controller()) {
	   	/* returns an error if an irq is pending and would be lost
		   if idle continued and turned off power */
		abort_flag = true;
	}

	cpuidle_coupled_parallel_barrier(dev, &abort_barrier);

	if (abort_flag) {
	   	/* One of the cpus didn't turn off it's irq controller */
	   	arch_turn_on_irq_controller();
		return -EINTR;
	}

	/* continue with idle */
	...
}

This will cause all cpus to abort idle together if one of them needs
to abort.

Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-06-02 00:49:36 -04:00
Colin Cross 4126c0197b cpuidle: add support for states that affect multiple cpus
On some ARM SMP SoCs (OMAP4460, Tegra 2, and probably more), the
cpus cannot be independently powered down, either due to
sequencing restrictions (on Tegra 2, cpu 0 must be the last to
power down), or due to HW bugs (on OMAP4460, a cpu powering up
will corrupt the gic state unless the other cpu runs a work
around).  Each cpu has a power state that it can enter without
coordinating with the other cpu (usually Wait For Interrupt, or
WFI), and one or more "coupled" power states that affect blocks
shared between the cpus (L2 cache, interrupt controller, and
sometimes the whole SoC).  Entering a coupled power state must
be tightly controlled on both cpus.

The easiest solution to implementing coupled cpu power states is
to hotplug all but one cpu whenever possible, usually using a
cpufreq governor that looks at cpu load to determine when to
enable the secondary cpus.  This causes problems, as hotplug is an
expensive operation, so the number of hotplug transitions must be
minimized, leading to very slow response to loads, often on the
order of seconds.

This file implements an alternative solution, where each cpu will
wait in the WFI state until all cpus are ready to enter a coupled
state, at which point the coupled state function will be called
on all cpus at approximately the same time.

Once all cpus are ready to enter idle, they are woken by an smp
cross call.  At this point, there is a chance that one of the
cpus will find work to do, and choose not to enter idle.  A
final pass is needed to guarantee that all cpus will call the
power state enter function at the same time.  During this pass,
each cpu will increment the ready counter, and continue once the
ready counter matches the number of online coupled cpus.  If any
cpu exits idle, the other cpus will decrement their counter and
retry.

To use coupled cpuidle states, a cpuidle driver must:

   Set struct cpuidle_device.coupled_cpus to the mask of all
   coupled cpus, usually the same as cpu_possible_mask if all cpus
   are part of the same cluster.  The coupled_cpus mask must be
   set in the struct cpuidle_device for each cpu.

   Set struct cpuidle_device.safe_state to a state that is not a
   coupled state.  This is usually WFI.

   Set CPUIDLE_FLAG_COUPLED in struct cpuidle_state.flags for each
   state that affects multiple cpus.

   Provide a struct cpuidle_state.enter function for each state
   that affects multiple cpus.  This function is guaranteed to be
   called on all cpus at approximately the same time.  The driver
   should ensure that the cpus all abort together if any cpu tries
   to abort once the function is called.

update1:

cpuidle: coupled: fix count of online cpus

online_count was never incremented on boot, and was also counting
cpus that were not part of the coupled set.  Fix both issues by
introducting a new function that counts online coupled cpus, and
call it from register as well as the hotplug notifier.

update2:

cpuidle: coupled: fix decrementing ready count

cpuidle_coupled_set_not_ready sometimes refuses to decrement the
ready count in order to prevent a race condition.  This makes it
unsuitable for use when finished with idle.  Add a new function
cpuidle_coupled_set_done that decrements both the ready count and
waiting count, and call it after idle is complete.

Cc: Amit Kucheria <amit.kucheria@linaro.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Trinabh Gupta <g.trinabh@gmail.com>
Cc: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Colin Cross <ccross@android.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-06-02 00:49:09 -04:00
Colin Cross 3af272ab75 cpuidle: fix error handling in __cpuidle_register_device
Fix the error handling in __cpuidle_register_device to include
the missing list_del.  Move it to a label, which will simplify
the error handling when coupled states are added.

Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Colin Cross <ccross@android.com>
Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-06-02 00:48:49 -04:00
Colin Cross 56cfbf74a1 cpuidle: refactor out cpuidle_enter_state
Split the code to enter a state and update the stats into a helper
function, cpuidle_enter_state, and export it.  This function will
be called by the coupled state code to handle entering the safe
state and the final coupled state.

Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Colin Cross <ccross@android.com>
Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-06-02 00:48:31 -04:00
Srivatsa S. Bhat 1b0a0e9a15 cpuidle: add checks to avoid NULL pointer dereference
The existing check for dev == NULL in __cpuidle_register_device() is
rendered useless because dev is dereferenced before the check itself.
Moreover, correctly speaking, it is the job of the callers of this
function, i.e., cpuidle_register_device() & cpuidle_enable_device() (which
also happen to be exported functions) to ensure that
__cpuidle_register_device() is called with a non-NULL dev.

So add the necessary dev == NULL checks in the two callers and remove the
(useless) check from __cpuidle_register_device().

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-06-01 16:07:23 -04:00
Sergey Senozhatsky 0aeb9cac6f cpuidle: remove unused hrtimer_peek_ahead_timers() call
commit 9a6558371b
  Author: Arjan van de Ven <arjan@linux.intel.com>
  Date:   Sun Nov 9 12:45:10 2008 -0800

     regression: disable timer peek-ahead for 2.6.28

     It's showing up as regressions; disabling it very likely just papers
     over an underlying issue, but time is running out for 2.6.28, lets get
     back to this for 2.6.29

 Many years has passed since 2008, so it seems ok to remove whole `#if 0' block.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Trinabh Gupta <g.trinabh@gmail.com>
Cc: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-06-01 16:06:48 -04:00
Thomas Gleixner 4a1625133d cpuidle: Use kick_all_cpus_sync()
kick_all_cpus_sync() is the core implementation of cpu_idle_wait()
which is copied all over the arch code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120507175652.119842173@linutronix.de
2012-05-08 12:35:06 +02:00
Len Brown eeaab2d8af Merge branches 'idle-fix' and 'misc' into release 2012-04-06 21:48:59 -04:00
Toshi Kani ee01e66337 cpuidle: Fix panic in CPU off-lining with no idle driver
Fix a NULL pointer dereference panic in cpuidle_play_dead() during
CPU off-lining when no cpuidle driver is registered.  A cpuidle
driver may be registered at boot-time based on CPU type.  This patch
allows an off-lined CPU to enter HLT-based idle in this condition.

Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Cc: Boris Ostrovsky <boris.ostrovsky@amd.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Tested-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-04-06 15:01:25 -04:00
Linus Torvalds a335750b9a Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux
Pull ACPI & Power Management changes from Len Brown:
 - ACPI 5.0 after-ripples, ACPICA/Linux divergence cleanup
 - cpuidle evolving, more ARM use
 - thermal sub-system evolving, ditto
 - assorted other PM bits

Fix up conflicts in various cpuidle implementations due to ARM cpuidle
cleanups (ARM at91 self-refresh and cpu idle code rewritten into
"standby" in asm conflicting with the consolidation of cpuidle time
keeping), trivial SH include file context conflict and RCU tracing fixes
in generic code.

* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux: (77 commits)
  ACPI throttling: fix endian bug in acpi_read_throttling_status()
  Disable MCP limit exceeded messages from Intel IPS driver
  ACPI video: Don't start video device until its associated input device has been allocated
  ACPI video: Harden video bus adding.
  ACPI: Add support for exposing BGRT data
  ACPI: export acpi_kobj
  ACPI: Fix logic for removing mappings in 'acpi_unmap'
  CPER failed to handle generic error records with multiple sections
  ACPI: Clean redundant codes in scan.c
  ACPI: Fix unprotected smp_processor_id() in acpi_processor_cst_has_changed()
  ACPI: consistently use should_use_kmap()
  PNPACPI: Fix device ref leaking in acpi_pnp_match
  ACPI: Fix use-after-free in acpi_map_lsapic
  ACPI: processor_driver: add missing kfree
  ACPI, APEI: Fix incorrect APEI register bit width check and usage
  Update documentation for parameter *notrigger* in einj.txt
  ACPI, APEI, EINJ, new parameter to control trigger action
  ACPI, APEI, EINJ, limit the range of einj_param
  ACPI, APEI, Fix ERST header length check
  cpuidle: power_usage should be declared signed integer
  ...
2012-03-30 16:45:39 -07:00
Boris Ostrovsky 02401c06b7 cpuidle: power_usage should be declared signed integer
power_usage is always assigned a negative value and should be declared
a signed integer

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@amd.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-03-30 03:23:30 -04:00
Boris Ostrovsky 1a022e3f1b idle, x86: Allow off-lined CPU to enter deeper C states
Currently when a CPU is off-lined it enters either MWAIT-based idle or,
if MWAIT is not desired or supported, HLT-based idle (which places the
processor in C1 state). This patch allows processors without MWAIT
support to stay in states deeper than C1.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@amd.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-03-30 03:23:01 -04:00
Daniel Lezcano fc850f39ea cpuidle: use the driver's state_count as default
If the state_count is not initialized for the device use
the driver's state count as the default. That will prevent
to add it manually in the cpuidle driver initialization
routine and will save us from duplicate line of code.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-03-30 01:55:04 -04:00
ShuoX Liu 3a53396b03 cpuidle: add a sysfs entry to disable specific C state for debug purpose.
Some C states of new CPU might be not good.  One reason is BIOS might
configure them incorrectly.  To help developers root cause it quickly, the
patch adds a new sysfs entry, so developers could disable specific C state
manually.

In addition, C state might have much impact on performance tuning, as it
takes much time to enter/exit C states, which might delay interrupt
processing.  With the new debug option, developers could check if a deep C
state could impact performance and how much impact it could cause.

Also add this option in Documentation/cpuidle/sysfs.txt.

[akpm@linux-foundation.org: check kstrtol return value]
Signed-off-by: ShuoX Liu <shuox.liu@intel.com>
Reviewed-by: Yanmin Zhang <yanmin_zhang@intel.com>
Reviewed-and-Tested-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-03-30 01:52:58 -04:00
Robert Lee e1689795a7 cpuidle: Add common time keeping and irq enabling
Make necessary changes to implement time keeping and irq enabling
in the core cpuidle code.  This will allow the removal of these
functionalities from various platform cpuidle implementations whose
timekeeping and irq enabling follows the form in this common code.

Signed-off-by: Robert Lee <rob.lee@linaro.org>
Tested-by: Jean Pihet <j-pihet@ti.com>
Tested-by: Amit Daniel <amit.kachhap@linaro.org>
Tested-by: Robert Lee <rob.lee@linaro.org>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-03-21 01:59:40 -04:00
Ingo Molnar 737f24bda7 Merge branch 'perf/urgent' into perf/core
Conflicts:
	tools/perf/builtin-record.c
	tools/perf/builtin-top.c
	tools/perf/perf.h
	tools/perf/util/top.h

Merge reason: resolve these cherry-picking conflicts.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-05 09:20:08 +01:00
Benjamin Herrenschmidt aa491ad3d4 cpuidle: Default y on powerpc pSeries
We moved all our pSeries idle loops to the cpu idle framework
so we really want it to come up by default.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-22 16:48:51 +11:00
Steven Rostedt 76027ea863 cpuidle/tracing: Denote the tracepoints as being in rcu_idle_exit() section
As the tracepoints in the cpuidle code are called when rcu_idle_exit() is in
effect, the _rcuidle() version must be used, otherwise the rcu_read_lock()s
that protect the tracepoint will not be honored.

Cc: Len Brown <len.brown@intel.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-02-13 09:14:46 -05:00
Kay Sievers 8a25a2fd12 cpu: convert 'cpu' and 'machinecheck' sysdev_class to a regular subsystem
This moves the 'cpu sysdev_class' over to a regular 'cpu' subsystem
and converts the devices to regular devices. The sysdev drivers are
implemented as subsystem interfaces now.

After all sysdev classes are ported to regular driver core entities, the
sysdev implementation will be entirely removed from the kernel.

Userspace relies on events and generic sysfs subsystem infrastructure
from sysdev devices, which are made available with this conversion.

Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Borislav Petkov <bp@amd64.org>
Cc: Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
Cc: Len Brown <lenb@kernel.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-12-21 14:29:42 -08:00
Linus Torvalds 3c00303206 Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux:
  cpuidle: Single/Global registration of idle states
  cpuidle: Split cpuidle_state structure and move per-cpu statistics fields
  cpuidle: Remove CPUIDLE_FLAG_IGNORE and dev->prepare()
  cpuidle: Move dev->last_residency update to driver enter routine; remove dev->last_state
  ACPI: Fix CONFIG_ACPI_DOCK=n compiler warning
  ACPI: Export FADT pm_profile integer value to userspace
  thermal: Prevent polling from happening during system suspend
  ACPI: Drop ACPI_NO_HARDWARE_INIT
  ACPI atomicio: Convert width in bits to bytes in __acpi_ioremap_fast()
  PNPACPI: Simplify disabled resource registration
  ACPI: Fix possible recursive locking in hwregs.c
  ACPI: use kstrdup()
  mrst pmu: update comment
  tools/power turbostat: less verbose debugging
2011-11-07 10:13:52 -08:00
Deepthi Dharwar 46bcfad7a8 cpuidle: Single/Global registration of idle states
This patch makes the cpuidle_states structure global (single copy)
instead of per-cpu. The statistics needed on per-cpu basis
by the governor are kept per-cpu. This simplifies the cpuidle
subsystem as state registration is done by single cpu only.
Having single copy of cpuidle_states saves memory. Rare case
of asymmetric C-states can be handled within the cpuidle driver
and architectures such as POWER do not have asymmetric C-states.

Having single/global registration of all the idle states,
dynamic C-state transitions on x86 are handled by
the boot cpu. Here, the boot cpu  would disable all the devices,
re-populate the states and later enable all the devices,
irrespective of the cpu that would receive the notification first.

Reference:
https://lkml.org/lkml/2011/4/25/83

Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Trinabh Gupta <g.trinabh@gmail.com>
Tested-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2011-11-06 21:13:58 -05:00
Deepthi Dharwar 4202735e8a cpuidle: Split cpuidle_state structure and move per-cpu statistics fields
This is the first step towards global registration of cpuidle
states. The statistics used primarily by the governor are per-cpu
and have to be split from rest of the fields inside cpuidle_state,
which would be made global i.e. single copy. The driver_data field
is also per-cpu and moved.

Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Trinabh Gupta <g.trinabh@gmail.com>
Tested-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2011-11-06 21:13:49 -05:00
Deepthi Dharwar b25edc42bf cpuidle: Remove CPUIDLE_FLAG_IGNORE and dev->prepare()
The cpuidle_device->prepare() mechanism causes updates to the
cpuidle_state[].flags, setting and clearing CPUIDLE_FLAG_IGNORE
to tell the governor not to chose a state on a per-cpu basis at
run-time. State demotion is now handled by the driver and it returns
the actual state entered. Hence, this mechanism is not required.
Also this removes per-cpu flags from cpuidle_state enabling
it to be made global.

Reference:
https://lkml.org/lkml/2011/3/25/52

Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm>
Signed-off-by: Trinabh Gupta <g.trinabh@gmail.com>
Tested-by: Jean Pihet <j-pihet@ti.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2011-11-06 21:13:43 -05:00
Deepthi Dharwar e978aa7d7d cpuidle: Move dev->last_residency update to driver enter routine; remove dev->last_state
Cpuidle governor only suggests the state to enter using the
governor->select() interface, but allows the low level driver to
override the recommended state. The actual entered state
may be different because of software or hardware demotion. Software
demotion is done by the back-end cpuidle driver and can be accounted
correctly. Current cpuidle code uses last_state field to capture the
actual state entered and based on that updates the statistics for the
state entered.

Ideally the driver enter routine should update the counters,
and it should return the state actually entered rather than the time
spent there. The generic cpuidle code should simply handle where
the counters live in the sysfs namespace, not updating the counters.

Reference:
https://lkml.org/lkml/2011/3/25/52

Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Trinabh Gupta <g.trinabh@gmail.com>
Tested-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2011-11-06 21:13:30 -05:00
Paul Gortmaker 70e522a028 cpuidle: ladder.c needs module.h and not just moduleparam.h
This file has module_init/exit and MODULE_LICENSE, and so it
needs the full module.h header.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:31:31 -04:00
Paul Gortmaker 884b17e109 cpuidle: Add module.h to drivers/cpuidle files as required.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:31:30 -04:00
Jean Pihet e8db0be124 PM QoS: Move and rename the implementation files
The PM QoS implementation files are better named
kernel/power/qos.c and include/linux/pm_qos.h.

The PM QoS support is compiled under the CONFIG_PM option.

Signed-off-by: Jean Pihet <j-pihet@ti.com>
Acked-by: markgross <markgross@thegnar.org>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-08-25 15:35:03 +02:00
Len Brown a0bfa13738 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 <khilman@deeprootsystems.com>
cc: Paul Mundt <lethal@linux-sh.org>
cc: x86@kernel.org
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2011-08-03 19:06:37 -04:00
Len Brown d91ee5863b 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 <konrad.wilk@oracle.com>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2011-08-03 19:06:36 -04:00
Len Brown 62027aea23 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 <len.brown@intel.com>
2011-08-03 19:06:36 -04:00
Linus Torvalds f310642123 Merge branch 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6
* 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6:
  x86 idle: deprecate mwait_idle() and "idle=mwait" cmdline param
  x86 idle: deprecate "no-hlt" cmdline param
  x86 idle APM: deprecate CONFIG_APM_CPU_IDLE
  x86 idle floppy: deprecate disable_hlt()
  x86 idle: EXPORT_SYMBOL(default_idle, pm_idle) only when APM demands it
  x86 idle: clarify AMD erratum 400 workaround
  idle governor: Avoid lock acquisition to read pm_qos before entering idle
  cpuidle: menu: fixed wrapping timers at 4.294 seconds
2011-05-29 11:18:09 -07:00
Tero Kristo 7467571f44 cpuidle: menu: fixed wrapping timers at 4.294 seconds
Cpuidle menu governor is using u32 as a temporary datatype for storing
nanosecond values which wrap around at 4.294 seconds. This causes errors
in predicted sleep times resulting in higher than should be C state
selection and increased power consumption. This also breaks cpuidle
state residency statistics.

cc: stable@kernel.org # .32.x through .39.x
Signed-off-by: Tero Kristo <tero.kristo@nokia.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2011-05-29 00:35:47 -04:00
Jiri Kosina 0a9d59a246 Merge branch 'master' into for-next 2011-02-15 10:24:31 +01:00
Jesper Juhl 42b16b3fbb Kill off warning: ‘inline’ is not at beginning of declaration
Fix a bunch of
	warning: ‘inline’ is not at beginning of declaration
messages when building a 'make allyesconfig' kernel with -Wextra.

These warnings are trivial to kill, yet rather annoying when building with
-Wextra.
The more we can cut down on pointless crap like this the better (IMHO).

A previous patch to do this for a 'allnoconfig' build has already been
merged. This just takes the cleanup a little further.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-01-19 15:43:08 +01:00
Len Brown 43952886f0 Merge branch 'cpuidle-perf-events' into idle-test 2011-01-12 18:06:19 -05:00
Len Brown 56dbed129d Merge branch 'linus' into idle-test 2011-01-12 18:06:06 -05:00