linux-toradex.git/drivers/base/cpu.c, branch v4.11-rc1

CPU / PM: expose pm_qos_resume_latency for CPUs

2017-01-30T10:05:29+00:00

The cpu-dma PM QoS constraint impacts all the cpus in the system. There
is no way to let the user to choose a PM QoS constraint per cpu.

The following patch exposes to the userspace a per cpu based sysfs file
in order to let the userspace to change the value of the PM QoS latency
constraint.

This change is inoperative in its form and the cpuidle governors have to
take into account the per cpu latency constraint in addition to the
global cpu-dma latency constraint in order to operate properly.

BTW
The pm_qos_resume_latency usage defined in
Documentation/ABI/testing/sysfs-devices-power
The /sys/devices/.../power/pm_qos_resume_latency_us attribute
contains the PM QoS resume latency limit for the given device,
which is the maximum allowed time it can take to resume the
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.

Signed-off-by: Alex Shi 
Signed-off-by: Rafael J. Wysocki

cpu: clean up register_cpu func

2016-08-31T13:19:55+00:00

This patch could reduce one branch in this function. Also
make the code more readble.

Signed-off-by: Alex Shi 
Acked-by: Daniel Lezcano 
To: linux-kernel@vger.kernel.org
To: Greg Kroah-Hartman 
Cc: linux-pm@vger.kernel.org
Cc: Ulf Hansson 
Cc: Daniel Lezcano 
Signed-off-by: Greg Kroah-Hartman

drivers/base/cpu.c: use __cpu_*_mask directly

2016-01-21T01:09:18+00:00

The only user of the lvalue-ness of the cpu_*_mask variables is in
drivers/base/cpu.c, and that is mostly a work-around for the fact that not
even const variables can be used in static initialization.  Now that the
underlying struct cpumasks are exposed we can take their address.

Signed-off-by: Rasmus Villemoes 
Acked-by: Rusty Russell 
Acked-by: Greg Kroah-Hartman 
Cc: Michael Ellerman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cpu: Remove bogus __ref annotation of cpu_subsys_online()

2015-08-05T22:18:26+00:00

In commit 0db0628d9012 ("kernel: delete __cpuinit usage from all core
kernel files") cpu_up() lost its __cpuinit annotation, vanishing the
need for cpu_subsys_online() to have a __ref annotation. Just drop it
to be able to catch real section mismatches in the future.

Signed-off-by: Mathias Krause 
Cc: Paul Gortmaker 
Signed-off-by: Greg Kroah-Hartman

show nohz_full cpus in sysfs

2015-05-20T07:15:09+00:00

Currently there is no way to query which CPUs are in nohz_full
mode from userspace.

Export the CPU list running in nohz_full mode in sysfs,
specifically in the file /sys/devices/system/cpu/nohz_full

This can be used by system management tools like libvirt,
openstack, and others to ensure proper task placement.

Signed-off-by: Rik van Riel 
Acked-by: Mike Galbraith 
Acked-by: Chris Metcalf 
Signed-off-by: Greg Kroah-Hartman

show isolated cpus in sysfs

2015-05-20T07:15:06+00:00

After system bootup, there is no totally reliable way to see
which CPUs are isolated, because the kernel may modify the
CPUs specified on the isolcpus= kernel command line option.

Export the CPU list that actually got isolated in sysfs,
specifically in the file /sys/devices/system/cpu/isolated

This can be used by system management tools like libvirt,
openstack, and others to ensure proper placement of tasks.

Suggested-by: Li Zefan 
Signed-off-by: Rik van Riel 
Acked-by: Mike Galbraith 
Acked-by: Chris Metcalf 
Signed-off-by: Greg Kroah-Hartman

drivers/base: use %*pb[l] to print bitmaps including cpumasks and nodemasks

2015-02-14T05:21:38+00:00

printk and friends can now format bitmaps using '%*pb[l]'.  cpumask
and nodemask also provide cpumask_pr_args() and nodemask_pr_args()
respectively which can be used to generate the two printf arguments
necessary to format the specified cpu/nodemask.

* Line termination only requires one extra space at the end of the
  buffer.  Use PAGE_SIZE - 1 instead of PAGE_SIZE - 2 when formatting.

Signed-off-by: Tejun Heo 
Acked-by: Greg Kroah-Hartman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

drivers: base: add cpu_device_create to support per-cpu devices

2014-11-07T19:45:00+00:00

This patch adds a new function to create per-cpu devices.
This helps in:
1. reusing the device infrastructure to create any cpu related
   attributes and corresponding sysfs instead of creating and
   dealing with raw kobjects directly
2. retaining the legacy path(/sys/devices/system/cpu/..) to support
   existing sysfs ABI
3. avoiding to create links in the bus directory pointing to the
   device as there would be per-cpu instance of these devices with
   the same name since dev->bus is not populated to cpu_sysbus on
   purpose

Signed-off-by: Sudeep Holla 
Tested-by: Stephen Boyd 
Cc: Greg Kroah-Hartman 
Cc: David Herrmann 
Cc: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman

cpumask: factor out show_cpumap into separate helper function

2014-11-07T19:45:00+00:00

Many sysfs *_show function use cpu{list,mask}_scnprintf to copy cpumap
to the buffer aligned to PAGE_SIZE, append '\n' and '\0' to return null
terminated buffer with newline.

This patch creates a new helper function cpumap_print_to_pagebuf in
cpumask.h using newly added bitmap_print_to_pagebuf and consolidates
most of those sysfs functions using the new helper function.

Signed-off-by: Sudeep Holla 
Suggested-by: Stephen Boyd 
Tested-by: Stephen Boyd 
Acked-by: "Rafael J. Wysocki" 
Acked-by: Bjorn Helgaas 
Acked-by: Peter Zijlstra (Intel) 
Cc: Greg Kroah-Hartman 
Cc: x86@kernel.org
Cc: linux-acpi@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

x86: align x86 arch with generic CPU modalias handling

2014-02-18T20:45:38+00:00

The x86 CPU feature modalias handling existed before it was reimplemented
generically. This patch aligns the x86 handling so that it
(a) reuses some more code that is now generic;
(b) uses the generic format for the modalias module metadata entry, i.e., it
    now uses 'cpu:type:x86,venVVVVfamFFFFmodMMMM:feature:,XXXX,YYYY' instead of
    the 'x86cpu:vendor:VVVV:family:FFFF:model:MMMM:feature:,XXXX,YYYY' that was
    used before.

Signed-off-by: Ard Biesheuvel 
Acked-by: H. Peter Anvin 
Signed-off-by: Greg Kroah-Hartman