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cpuidle: Documentation: Clean up PM QoS description

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Clean up the language in one paragraph in the PM QoS description in
Documentation/admin-guide/pm/cpuidle.rst.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Rafael J. Wysocki 2020-02-05 02:08:31 +01:00
parent 4dcb78ee57
commit f06572ef47
1 changed files with 4 additions and 4 deletions
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Documentation/admin-guide/pm/cpuidle.rst
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@ -632,16 +632,16 @@ class priority list and destroyed. If that happens, the priority list mechanism
will be used, again, to determine the new effective value for the whole list
and that value will become the new real constraint.
In turn, for each CPU there is only one resume latency PM QoS request
associated with the :file:`power/pm_qos_resume_latency_us` file under
In turn, for each CPU there is one resume latency PM QoS request associated with
the :file:`power/pm_qos_resume_latency_us` file under
:file:`/sys/devices/system/cpu/cpu<N>/` in ``sysfs`` and writing to it causes
this single PM QoS request to be updated regardless of which user space
process does that. In other words, this PM QoS request is shared by the entire
user space, so access to the file associated with it needs to be arbitrated
to avoid confusion. [Arguably, the only legitimate use of this mechanism in
practice is to pin a process to the CPU in question and let it use the
``sysfs`` interface to control the resume latency constraint for it.] It
still only is a request, however. It is a member of a priority list used to
``sysfs`` interface to control the resume latency constraint for it.] It is
still only a request, however. It is an entry in a priority list used to
determine the effective value to be set as the resume latency constraint for the
CPU in question every time the list of requests is updated this way or another
(there may be other requests coming from kernel code in that list).