Commit Graph

10 Commits

Author SHA1 Message Date
Linus Torvalds
467a9e1633 CPU hotplug notifiers registration fixes for 3.15-rc1
The purpose of this single series of commits from Srivatsa S Bhat (with
 a small piece from Gautham R Shenoy) touching multiple subsystems that use
 CPU hotplug notifiers is to provide a way to register them that will not
 lead to deadlocks with CPU online/offline operations as described in the
 changelog of commit 93ae4f978c (CPU hotplug: Provide lockless versions
 of callback registration functions).
 
 The first three commits in the series introduce the API and document it
 and the rest simply goes through the users of CPU hotplug notifiers and
 converts them to using the new method.
 
 /
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2.0.22 (GNU/Linux)
 
 iQIcBAABCAAGBQJTQow2AAoJEILEb/54YlRxW4QQAJlYRDUzwFJzJzYhltQYuVR+
 4D74XMtvXgoJfg3cwdSWvMKKpJZnA9BVN0f7Hcx9wYmgdexYUuHeZJmMNyc3S2+g
 KjKBIsugvgmZhHbbLd6TJ6GBbhGT5JLt9VmSfL9zIkveInU1YHFUUqL/mxdHm4J0
 BSGKjk2rN3waRJgmY+xfliFLtQjDKFwJpMuvrgtoUyfas3f4sIV43UNbqdvA/weJ
 rzedxXOlKH/id4b56lj/4iIzcoL3mwvJJ7r6n0CEMsKv87z09kqR0O+69Tsq/cgs
 j17CsvoJOmZGk3QTeKVMQWBsvk6aPoDu3zK83gLbQMt+qjOpSTbJLz/3HZw4/TrW
 ss4nuZne1DLMGS+6hoxYbTP+6Ni//Kn+l/LrHc5jb7m1X3lMO4W2aV3IROtIE1rv
 lEP1IG01NU4u9YwkVj1dyhrkSp8tLPul4SrUK8W+oNweOC5crjJV7vJbIPJgmYiM
 IZN55wln0yVRtR4TX+rmvN0PixsInE8MeaVCmReApyF9pdzul/StxlBze5BKLSJD
 cqo1kNPpsmdxoDucqUpQ/gSvy+IOl2qnlisB5PpV93sk7De6TFDYrGHxjYIW7jMf
 StXwdCDDQhzd2Q8Kfpp895A1dbIl8rKtwA6bTU2eX+BfMVFzuMdT44cvosx1+UdQ
 sWl//rg76nb13dFjvF+q
 =SW7Q
 -----END PGP SIGNATURE-----

Merge tag 'cpu-hotplug-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull CPU hotplug notifiers registration fixes from Rafael Wysocki:
 "The purpose of this single series of commits from Srivatsa S Bhat
  (with a small piece from Gautham R Shenoy) touching multiple
  subsystems that use CPU hotplug notifiers is to provide a way to
  register them that will not lead to deadlocks with CPU online/offline
  operations as described in the changelog of commit 93ae4f978c ("CPU
  hotplug: Provide lockless versions of callback registration
  functions").

  The first three commits in the series introduce the API and document
  it and the rest simply goes through the users of CPU hotplug notifiers
  and converts them to using the new method"

* tag 'cpu-hotplug-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (52 commits)
  net/iucv/iucv.c: Fix CPU hotplug callback registration
  net/core/flow.c: Fix CPU hotplug callback registration
  mm, zswap: Fix CPU hotplug callback registration
  mm, vmstat: Fix CPU hotplug callback registration
  profile: Fix CPU hotplug callback registration
  trace, ring-buffer: Fix CPU hotplug callback registration
  xen, balloon: Fix CPU hotplug callback registration
  hwmon, via-cputemp: Fix CPU hotplug callback registration
  hwmon, coretemp: Fix CPU hotplug callback registration
  thermal, x86-pkg-temp: Fix CPU hotplug callback registration
  octeon, watchdog: Fix CPU hotplug callback registration
  oprofile, nmi-timer: Fix CPU hotplug callback registration
  intel-idle: Fix CPU hotplug callback registration
  clocksource, dummy-timer: Fix CPU hotplug callback registration
  drivers/base/topology.c: Fix CPU hotplug callback registration
  acpi-cpufreq: Fix CPU hotplug callback registration
  zsmalloc: Fix CPU hotplug callback registration
  scsi, fcoe: Fix CPU hotplug callback registration
  scsi, bnx2fc: Fix CPU hotplug callback registration
  scsi, bnx2i: Fix CPU hotplug callback registration
  ...
2014-04-07 14:55:46 -07:00
Srivatsa S. Bhat
009f225ef0 powercap, intel-rapl: Fix CPU hotplug callback registration
Subsystems that want to register CPU hotplug callbacks, as well as perform
initialization for the CPUs that are already online, often do it as shown
below:

	get_online_cpus();

	for_each_online_cpu(cpu)
		init_cpu(cpu);

	register_cpu_notifier(&foobar_cpu_notifier);

	put_online_cpus();

This is wrong, since it is prone to ABBA deadlocks involving the
cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently
with CPU hotplug operations).

Instead, the correct and race-free way of performing the callback
registration is:

	cpu_notifier_register_begin();

	for_each_online_cpu(cpu)
		init_cpu(cpu);

	/* Note the use of the double underscored version of the API */
	__register_cpu_notifier(&foobar_cpu_notifier);

	cpu_notifier_register_done();

Fix the intel-rapl code in the powercap driver by using this latter form
of callback registration. But retain the calls to get/put_online_cpus(),
since they also protect the function rapl_cleanup_data(). By nesting
get/put_online_cpus() *inside* cpu_notifier_register_begin/done(), we avoid
the ABBA deadlock possibility mentioned above.

Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Tested-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-03-20 13:43:44 +01:00
Jacob Pan
d6b2e6d09a powercap / intel_rapl: spell out SoC names
Spell out names for supported SoCs.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-02-14 00:49:34 +01:00
Jacob Pan
7b8747725d powercap / intel_rapl: relax sanity check on energy counters
Some RAPL domains may not be active at the time driver is being
loaded. Checking energy counter increment may be too strict and
time consuming. So relax the sanity check on energy counters of
these domains.

Otherwise, they may be ignored and become unavailable to the
powercap framework.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-02-14 00:49:33 +01:00
Jacob Pan
ed93b71492 powercap / RAPL: add support for ValleyView Soc
This patch adds support for RAPL on Intel ValleyView based SoC
platforms, such as Baytrail.

Besides adding CPU ID, special energy unit encoding is handled
for ValleyView.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-12-22 01:27:51 +01:00
Srinivas Pandruvada
95677a9a38 PowerCap: Fix mode for energy counter
As per the documentation of powercap sysfs, energy_uj field is read only,
if it can't be reset. Currently it always allows write but will fail,
if there is no reset callback.
Changing mode field, to read only if there is no reset callback.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Reported-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-12-05 02:05:48 +01:00
Srinivas Pandruvada
08ff4cbe10 PowerCap: Fix build error with option -Werror=format-security
Fix compile error with gcc option: -Werror=format-security for
dev_set_name(&control_type->dev, name).

Changed to dev_set_name(&control_type->dev, "%s", name).

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-11-05 02:36:57 +01:00
Thierry Reding
9e3410b764 PowerCap: Convert class code to use dev_groups
The newly added power capping framework uses the obsolete .dev_attrs
field of struct class. However this field will be removed in 3.13, so
convert the code to use the .dev_groups field instead.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-25 23:16:31 +02:00
Jacob Pan
2d281d8196 PowerCap: Introduce Intel RAPL power capping driver
The Intel Running Average Power Limit (RAPL) technology provides platform
software with the ability to monitor, control, and get notifications on
power usage.

This feature is present in all Sandy Bridge and later Intel processors.
Newer models allow more fine grained controls to be applied.  In RAPL,
power control is divided into domains, which include package, DRAM
controller, CPU core (Power Plane 0), graphics uncore (power plane 1), etc.

The purpose of this driver is to expose the RAPL settings to userspace.
Overall, RAPL fits in the new powercap class driver in that platform
level power capping controls are exposed via this generic interface.

This driver is based on an earlier patch from Zhang Rui.

However, while the previous work was mainly focused on thermal monitoring
the focus here is on the usability from user space perspective.

References: https://lkml.org/lkml/2011/5/26/93
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-18 13:29:52 +02:00
Srinivas Pandruvada
75d2364ea0 PowerCap: Add class driver
The power capping framework providing a consistent interface between the
kernel and user space that allows power capping drivers to expose their
settings to user space in a uniform way.
The overall design of the framework is described in the documentation
added by the previous patch in this series.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-17 00:36:06 +02:00