kernel/linux.git/drivers/cpuidle/sysfs.c, branch v5.6.17

Merge branch 'intel_idle+acpi'

2020-01-22T23:35:50+00:00

Merge changes updating the ACPI processor driver in order to export acpi_processor_evaluate_cst() to the code outside of it and adding ACPI support to the intel_idle driver based on that. * intel_idle+acpi: Documentation: admin-guide: PM: Add intel_idle document intel_idle: Use ACPI _CST on server systems intel_idle: Add module parameter to prevent ACPI _CST from being used intel_idle: Allow ACPI _CST to be used for selected known processors cpuidle: Allow idle states to be disabled by default intel_idle: Use ACPI _CST for processor models without C-state tables intel_idle: Refactor intel_idle_cpuidle_driver_init() ACPI: processor: Export acpi_processor_evaluate_cst() ACPI: processor: Make ACPI_PROCESSOR_CSTATE depend on ACPI_PROCESSOR ACPI: processor: Clean up acpi_processor_evaluate_cst() ACPI: processor: Introduce acpi_processor_evaluate_cst() ACPI: processor: Export function to claim _CST control

cpuidle: sysfs: fix warnings when compiling with W=1

2020-01-22T23:31:31+00:00

Fix kernel documentation comments to remove warnings when compiling with W=1. Signed-off-by: Benjamin Gaignard Signed-off-by: Rafael J. Wysocki

cpuidle: Allow idle states to be disabled by default

2019-12-27T10:02:08+00:00

In certain situations it may be useful to prevent some idle states from being used by default while allowing user space to enable them later on. For this purpose, introduce a new state flag, CPUIDLE_FLAG_OFF, to mark idle states that should be disabled by default, make the core set CPUIDLE_STATE_DISABLED_BY_USER for those states at the initialization time and add a new state attribute in sysfs, "default_status", to inform user space of the initial status of the given idle state ("disabled" if CPUIDLE_FLAG_OFF is set for it, "enabled" otherwise). Signed-off-by: Rafael J. Wysocki

cpuidle: Use nanoseconds as the unit of time

2019-11-11T20:56:07+00:00

Currently, the cpuidle subsystem uses microseconds as the unit of time which (among other things) causes the idle loop to incur some integer division overhead for no clear benefit. In order to allow cpuidle to measure time in nanoseconds, add two new fields, exit_latency_ns and target_residency_ns, to represent the exit latency and target residency of an idle state in nanoseconds, respectively, to struct cpuidle_state and initialize them with the help of the corresponding values in microseconds provided by drivers. Additionally, change cpuidle_governor_latency_req() to return the idle state exit latency constraint in nanoseconds. Also meeasure idle state residency (last_residency_ns in struct cpuidle_device and time_ns in struct cpuidle_driver) in nanoseconds and update the cpuidle core and governors accordingly. However, the menu governor still computes typical intervals in microseconds to avoid integer overflows. Signed-off-by: Rafael J. Wysocki Acked-by: Peter Zijlstra (Intel) Acked-by: Doug Smythies Tested-by: Doug Smythies

cpuidle: Consolidate disabled state checks

2019-11-06T12:19:56+00:00

There are two reasons why CPU idle states may be disabled: either because the driver has disabled them or because they have been disabled by user space via sysfs. In the former case, the state's "disabled" flag is set once during the initialization of the driver and it is never cleared later (it is read-only effectively). In the latter case, the "disable" field of the given state's cpuidle_state_usage struct is set and it may be changed via sysfs. Thus checking whether or not an idle state has been disabled involves reading these two flags every time. In order to avoid the additional check of the state's "disabled" flag (which is effectively read-only anyway), use the value of it at the init time to set a (new) flag in the "disable" field of that state's cpuidle_state_usage structure and use the sysfs interface to manipulate another (new) flag in it. This way the state is disabled whenever the "disable" field of its cpuidle_state_usage structure is nonzero, whatever the reason, and it is the only place to look into to check whether or not the state has been disabled. Signed-off-by: Rafael J. Wysocki Acked-by: Daniel Lezcano Acked-by: Peter Zijlstra (Intel)

cpuidle: add poll_limit_ns to cpuidle_device structure

2019-07-30T15:27:37+00:00

Add a poll_limit_ns variable to cpuidle_device structure. Calculate and configure it in the new cpuidle_poll_time function, in case its zero. Individual governors are allowed to override this value. Signed-off-by: Marcelo Tosatti Signed-off-by: Rafael J. Wysocki

cpuidle: Add 'above' and 'below' idle state metrics

2018-12-12T22:22:18+00:00

Add two new metrics for CPU idle states, "above" and "below", to count the number of times the given state had been asked for (or entered from the kernel's perspective), but the observed idle duration turned out to be too short or too long for it (respectively). These metrics help to estimate the quality of the CPU idle governor in use. Signed-off-by: Rafael J. Wysocki

PM: cpuidle/suspend: Add s2idle usage and time state attributes

2018-03-29T11:06:08+00:00

Add a new attribute group called "s2idle" under the sysfs directory of each cpuidle state that supports the ->enter_s2idle callback and put two new attributes, "usage" and "time", into that group to represent the number of times the given state was requested for suspend-to-idle and the total time spent in suspend-to-idle after requesting that state, respectively. That will allow diagnostic information related to suspend-to-idle to be collected without enabling advanced debug features and analyzing dmesg output. Signed-off-by: Rafael J. Wysocki

cpuidle: Validate cpu_dev in cpuidle_add_sysfs()

2017-03-21T21:26:37+00:00

If a given cpu is not in cpu_present and cpu hotplug is disabled, arch can skip setting up the cpu_dev. Arch cpuidle driver should pass correct cpu mask for registration, but failing to do so by the driver causes error to propagate and crash like this: [ 30.076045] Unable to handle kernel paging request for data at address 0x00000048 [ 30.076100] Faulting instruction address: 0xc0000000007b2f30 cpu 0x4d: Vector: 300 (Data Access) at [c000003feb18b670] pc: c0000000007b2f30: kobject_get+0x20/0x70 lr: c0000000007b3c94: kobject_add_internal+0x54/0x3f0 sp: c000003feb18b8f0 msr: 9000000000009033 dar: 48 dsisr: 40000000 current = 0xc000003fd2ed8300 paca = 0xc00000000fbab500 softe: 0 irq_happened: 0x01 pid = 1, comm = swapper/0 Linux version 4.11.0-rc2-svaidy+ (sv@sagarika) (gcc version 6.2.0 20161005 (Ubuntu 6.2.0-5ubuntu12) ) #10 SMP Sun Mar 19 00:08:09 IST 2017 enter ? for help [c000003feb18b960] c0000000007b3c94 kobject_add_internal+0x54/0x3f0 [c000003feb18b9f0] c0000000007b43a4 kobject_init_and_add+0x64/0xa0 [c000003feb18ba70] c000000000e284f4 cpuidle_add_sysfs+0xb4/0x130 [c000003feb18baf0] c000000000e26038 cpuidle_register_device+0x118/0x1c0 [c000003feb18bb30] c000000000e26c48 cpuidle_register+0x78/0x120 [c000003feb18bbc0] c00000000168fd9c powernv_processor_idle_init+0x110/0x1c4 [c000003feb18bc40] c00000000000cff8 do_one_initcall+0x68/0x1d0 [c000003feb18bd00] c0000000016242f4 kernel_init_freeable+0x280/0x360 [c000003feb18bdc0] c00000000000d864 kernel_init+0x24/0x160 [c000003feb18be30] c00000000000b4e8 ret_from_kernel_thread+0x5c/0x74 Validating cpu_dev fixes the crash and reports correct error message like: [ 30.163506] Failed to register cpuidle device for cpu136 [ 30.173329] Registration of powernv driver failed. Signed-off-by: Vaidyanathan Srinivasan [ rjw: Comment massage ] Signed-off-by: Rafael J. Wysocki

cpuidle: fix improper return value on error

2016-12-06T01:24:14+00:00

In function cpuidle_add_state_sysfs(), variable ret takes the return value. Its value should be negative on errors. Because ret is reset in the loop, its value will be 0 during the second and after repeat of the loop. If kzalloc() returns a NULL pointer then, it will return 0. It may be better to explicitly assign "-ENOMEM" when the call to kzalloc() fails. Link: https://bugzilla.kernel.org/show_bug.cgi?id=188901 Signed-off-by: Pan Bian Signed-off-by: Rafael J. Wysocki