Merge branch 'pm-qos' into pm-cpuidle

James Bottomley <jejb@mulgrave.(none)>

James Bottomley <jejb@titanic.il.steeleye.com>

James E Wilson <wilson@specifix.com>

James Hogan <jhogan@kernel.org> <james.hogan@imgtec.com>

James Hogan <jhogan@kernel.org> <james@albanarts.com>

James Ketrenos <jketreno@io.(none)>

Javi Merino <javi.merino@kernel.org> <javi.merino@arm.com>

<javier@osg.samsung.com> <javier.martinez@collabora.co.uk>

		device, after it has been suspended at run time, from a resume

		request to the moment the device will be ready to process I/O,

		in microseconds.  If it is equal to 0, however, this means that

		the PM QoS resume latency may be arbitrary.

		the PM QoS resume latency may be arbitrary and the special value

		"n/a" means that user space cannot accept any resume latency at

		all for the given device.

		Not all drivers support this attribute.  If it isn't supported,

		it is not present.

		This attribute has no effect on system-wide suspend/resume and

		hibernation.

What:		/sys/devices/.../power/pm_qos_remote_wakeup

Date:		September 2012

Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>

Description:

		The /sys/devices/.../power/pm_qos_remote_wakeup attribute

		is used for manipulating the PM QoS "remote wakeup required"

		flag.  If set, this flag indicates to the kernel that the

		device is a source of user events that have to be signaled from

		its low-power states.

		Not all drivers support this attribute.  If it isn't supported,

		it is not present.

		This attribute has no effect on system-wide suspend/resume and

		hibernation.

What;		/sys/power/pm_trace_dev_match

Date:		October 2010

Contact:	James Hogan <james@albanarts.com>

Contact:	James Hogan <jhogan@kernel.org>

Description:

		The /sys/power/pm_trace_dev_match file contains the name of the

		device associated with the last PM event point saved in the RTC

Although MT wq wasted a lot of resource, the level of concurrency

provided was unsatisfactory.  The limitation was common to both ST and

MT wq albeit less severe on MT.  Each wq maintained its own separate

worker pool.  A MT wq could provide only one execution context per CPU

while a ST wq one for the whole system.  Work items had to compete for

worker pool.  An MT wq could provide only one execution context per CPU

while an ST wq one for the whole system.  Work items had to compete for

those very limited execution contexts leading to various problems

including proneness to deadlocks around the single execution context.

``alloc_workqueue()`` allocates a wq.  The original

``create_*workqueue()`` functions are deprecated and scheduled for

removal.  ``alloc_workqueue()`` takes three arguments - @``name``,

removal.  ``alloc_workqueue()`` takes three arguments - ``@name``,

``@flags`` and ``@max_active``.  ``@name`` is the name of the wq and

also used as the name of the rescuer thread if there is one.

  served by worker threads with elevated nice level.

  Note that normal and highpri worker-pools don't interact with

  each other.  Each maintain its separate pool of workers and

  each other.  Each maintains its separate pool of workers and

  implements concurrency management among its workers.

``WQ_CPU_INTENSIVE``

time thus achieving the same ordering property as ST wq.

In the current implementation the above configuration only guarantees

ST behavior within a given NUMA node. Instead alloc_ordered_queue should

be used to achieve system wide ST behavior.

ST behavior within a given NUMA node. Instead ``alloc_ordered_queue()`` should

be used to achieve system-wide ST behavior.

Example Execution Scenarios

index.txt	-	File index, Mailing list and Links (this document)

intel-pstate.txt -	Intel pstate cpufreq driver specific file.

pcc-cpufreq.txt -	PCC cpufreq driver specific file.