kernel/linux.git/drivers/base/power/qos.c, branch linux-4.16.y

PM / QoS: Fix device resume latency framework

2017-11-08T11:14:51+00:00

The special value of 0 for device resume latency PM QoS means "no restriction", but there are two problems with that. First, device resume latency PM QoS requests with 0 as the value are always put in front of requests with positive values in the priority lists used internally by the PM QoS framework, causing 0 to be chosen as an effective constraint value. However, that 0 is then interpreted as "no restriction" effectively overriding the other requests with specific restrictions which is incorrect. Second, the users of device resume latency PM QoS have no way to specify that *any* resume latency at all should be avoided, which is an artificial limitation in general. To address these issues, modify device resume latency PM QoS to use S32_MAX as the "no constraint" value and 0 as the "no latency at all" one and rework its users (the cpuidle menu governor, the genpd QoS governor and the runtime PM framework) to follow these changes. Also add a special "n/a" value to the corresponding user space I/F to allow user space to indicate that it cannot accept any resume latencies at all for the given device. Fixes: 85dc0b8a4019 (PM / QoS: Make it possible to expose PM QoS latency constraints) Link: https://bugzilla.kernel.org/show_bug.cgi?id=197323 Reported-by: Reinette Chatre Signed-off-by: Rafael J. Wysocki Tested-by: Reinette Chatre Tested-by: Geert Uytterhoeven Tested-by: Tero Kristo Reviewed-by: Ramesh Thomas

PM / QoS: Use the correct variable to check the QoS request type

2017-09-18T11:38:30+00:00

Use the actual function argument for the validation of the request type, instead of the type field in a fresh (supposedly zero-initialized) request structure. Signed-off-by: Jan H. Schönherr Signed-off-by: Rafael J. Wysocki

Merge branches 'pm-cpuidle', 'pm-cpufreq' and 'pm-sleep'

2017-03-02T23:43:11+00:00

* pm-cpuidle: intel_idle: stop exposing platform acronyms in sysfs cpuidle: menu: Avoid taking spinlock for accessing QoS values * pm-cpufreq: cpufreq: intel_pstate: Fix limits issue with operation mode switching cpufreq: qoriq: clean up unused code * pm-sleep: PM / hibernate: Define pr_fmt() and use pr_*() instead of printk() PM / hibernate: Untangle power_down()

cpuidle: menu: Avoid taking spinlock for accessing QoS values

2017-02-27T14:07:38+00:00

After commit 9908859acaa9 (cpuidle/menu: add per CPU PM QoS resume latency consideration) the cpuidle menu governor calls dev_pm_qos_read_value() on CPU devices to read the current resume latency QoS constraint values for them. That function takes a spinlock to prevent the device's power.qos pointer from becoming NULL during the access which is a problem for the RT patchset where spinlocks are converted into mutexes and the idle loop stops working. However, it is not even necessary for the menu governor to take that spinlock, because the power.qos pointer accessed under it cannot be modified during the access anyway. For this reason, introduce a "raw" routine for accessing device QoS resume latency constraints without locking and use it in the menu governor. Fixes: 9908859acaa9 (cpuidle/menu: add per CPU PM QoS resume latency consideration) Acked-by: Alex Shi Signed-off-by: Rafael J. Wysocki

PM / QoS: Remove global notifiers

2017-02-23T22:05:58+00:00

They were never used in the kernel, so get rid of them. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

PM / QoS: Fix memory leak on resume_latency.notifiers

2017-02-18T01:20:53+00:00

Since commit 2d984ad132a8 (PM / QoS: Introcuce latency tolerance device PM QoS type) we reassign "c" to point at qos->latency_tolerance before freeing c->notifiers, but the notifiers field of latency_tolerance is never used. Restore the original behaviour of freeing the notifiers pointer on qos->resume_latency, which is used, and fix the following kmemleak warning. unreferenced object 0xed9dba00 (size 64): comm "kworker/0:1", pid 36, jiffies 4294670128 (age 15202.983s) hex dump (first 32 bytes): 00 00 00 00 04 ba 9d ed 04 ba 9d ed 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [] kmemleak_alloc+0x74/0xb8 [] kmem_cache_alloc_trace+0x170/0x25c [] dev_pm_qos_constraints_allocate+0x3c/0xe4 [] __dev_pm_qos_add_request+0x84/0x1a0 [] dev_pm_qos_add_request+0x3c/0x54 [] usb_hub_create_port_device+0x110/0x2b8 [] hub_probe+0xadc/0xc80 [] usb_probe_interface+0x1b4/0x260 [] driver_probe_device+0x198/0x40c [] __device_attach_driver+0x8c/0x98 [] bus_for_each_drv+0x8c/0x9c [] __device_attach+0x98/0x138 [] device_initial_probe+0x14/0x18 [] bus_probe_device+0x30/0x88 [] device_add+0x430/0x554 [] usb_set_configuration+0x660/0x6fc Fixes: 2d984ad132a8 (PM / QoS: Introcuce latency tolerance device PM QoS type) Signed-off-by: John Keeping Signed-off-by: Rafael J. Wysocki

PM / QoS: Export dev_pm_qos_update_user_latency_tolerance

2016-11-30T21:34:24+00:00

nvme wants a module parameter that overrides the default latency tolerance. This makes it easy for nvme to reflect that default in sysfs. Signed-off-by: Andy Lutomirski Signed-off-by: Rafael J. Wysocki

PM / QoS: Fix writing 'auto' to pm_qos_latency_tolerance_us

2016-11-30T21:34:23+00:00

If it was already 'auto', then writing 'auto' again would incorrectly fail. Signed-off-by: Andy Lutomirski Signed-off-by: Rafael J. Wysocki

PM / QoS: Make it possible to expose device latency tolerance to userspace

2015-07-28T07:50:41+00:00

Typically when a device is created the bus core it belongs to (for example PCI) does not know if the device supports things like latency tolerance. This is left to the driver that binds to the device in question. However, at that time the device has already been created and there is no way to set its dev->power.set_latency_tolerance anymore. So follow what has been done for other PM QoS attributes as well and allow drivers to expose and hide latency tolerance from userspace, if the device supports it. Acked-by: Rafael J. Wysocki Signed-off-by: Mika Westerberg Signed-off-by: Andy Shevchenko Signed-off-by: Lee Jones

PM / QoS: Use lockdep asserts to find missing hold of power.lock

2015-01-23T21:31:08+00:00

Add lockdep asserts for holding the dev->power.lock to non-static functions which require this. They could be used outside of the file so asserts may help in detecting locking misuse. Signed-off-by: Krzysztof Kozlowski Signed-off-by: Rafael J. Wysocki