PM: QoS: Update file information comments (fe52de36) · Commits · 戴 / test

include/linux/pm_qos.h

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		/* SPDX-License-Identifier: GPL-2.0 */
		#ifndef _LINUX_PM_QOS_H
		#define _LINUX_PM_QOS_H
		/* interface for the pm_qos_power infrastructure of the linux kernel.
		/*
		* Definitions related to Power Management Quality of Service (PM QoS).
		*
		* Copyright (C) 2020 Intel Corporation
		*
		* Authors:
		* Mark Gross <mgross@linux.intel.com>
		* Rafael J. Wysocki <rafael.j.wysocki@intel.com>
		*/

		#ifndef _LINUX_PM_QOS_H
		#define _LINUX_PM_QOS_H

		#include <linux/plist.h>
		#include <linux/notifier.h>
		#include <linux/device.h>

kernel/power/qos.c

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		// SPDX-License-Identifier: GPL-2.0-only
		/*
		* This module exposes the interface to kernel space for specifying
		* QoS dependencies. It provides infrastructure for registration of:
		* Power Management Quality of Service (PM QoS) support base.
		*
		* Dependents on a QoS value : register requests
		* Watchers of QoS value : get notified when target QoS value changes
		* Copyright (C) 2020 Intel Corporation
		*
		* This QoS design is best effort based. Dependents register their QoS needs.
		* Watchers register to keep track of the current QoS needs of the system.
		*
		* There are 3 basic classes of QoS parameter: latency, timeout, throughput
		* each have defined units:
		* latency: usec
		* timeout: usec <-- currently not used.
		* throughput: kbs (kilo byte / sec)
		*
		* There are lists of pm_qos_objects each one wrapping requests, notifiers
		* Authors:
		* Mark Gross <mgross@linux.intel.com>
		* Rafael J. Wysocki <rafael.j.wysocki@intel.com>
		*
		* User mode requests on a QOS parameter register themselves to the
		* subsystem by opening the device node /dev/... and writing there request to
		* the node. As long as the process holds a file handle open to the node the
		* client continues to be accounted for. Upon file release the usermode
		* request is removed and a new qos target is computed. This way when the
		* request that the application has is cleaned up when closes the file
		* pointer or exits the pm_qos_object will get an opportunity to clean up.
		* Provided here is an interface for specifying PM QoS dependencies. It allows
		* entities depending on QoS constraints to register their requests which are
		* aggregated as appropriate to produce effective constraints (target values)
		* that can be monitored by entities needing to respect them, either by polling
		* or through a built-in notification mechanism.
		*
		* Mark Gross <mgross@linux.intel.com>
		* In addition to the basic functionality, more specific interfaces for managing
		* global CPU latency QoS requests and frequency QoS requests are provided.
		*/

		/#define DEBUG/

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