diff options
Diffstat (limited to 'kernel/power')
| -rw-r--r-- | kernel/power/qos.c | 34 |
1 files changed, 12 insertions, 22 deletions
diff --git a/kernel/power/qos.c b/kernel/power/qos.c index 7374c76f409a..ef73573db43d 100644 --- a/kernel/power/qos.c +++ b/kernel/power/qos.c @@ -1,31 +1,21 @@ // 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. + * Authors: + * Mark Gross <mgross@linux.intel.com> + * Rafael J. Wysocki <rafael.j.wysocki@intel.com> * - * 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) + * 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. * - * There are lists of pm_qos_objects each one wrapping requests, notifiers - * - * 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. - * - * 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*/ |