kernel/linux.git/drivers/cpuidle, branch linux-4.20.y

cpuidle: big.LITTLE: fix refcount leak

2019-02-12T19:02:17+00:00

[ Upstream commit 9456823c842f346c74265fcd98d008d87a7eb6f5 ] of_find_node_by_path() acquires a reference to the node returned by it and that reference needs to be dropped by its caller. bl_idle_init() doesn't do that, so fix it. Signed-off-by: Yangtao Li Acked-by: Daniel Lezcano Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

powerpc/pseries/cpuidle: Fix preempt warning

2019-01-26T08:20:44+00:00

[ Upstream commit 2b038cbc5fcf12a7ee1cc9bfd5da1e46dacdee87 ] When booting a pseries kernel with PREEMPT enabled, it dumps the following warning: BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1 caller is pseries_processor_idle_init+0x5c/0x22c CPU: 13 PID: 1 Comm: swapper/0 Not tainted 4.20.0-rc3-00090-g12201a0128bc-dirty #828 Call Trace: [c000000429437ab0] [c0000000009c8878] dump_stack+0xec/0x164 (unreliable) [c000000429437b00] [c0000000005f2f24] check_preemption_disabled+0x154/0x160 [c000000429437b90] [c000000000cab8e8] pseries_processor_idle_init+0x5c/0x22c [c000000429437c10] [c000000000010ed4] do_one_initcall+0x64/0x300 [c000000429437ce0] [c000000000c54500] kernel_init_freeable+0x3f0/0x500 [c000000429437db0] [c0000000000112dc] kernel_init+0x2c/0x160 [c000000429437e20] [c00000000000c1d0] ret_from_kernel_thread+0x5c/0x6c This happens because the code calls get_lppaca() which calls get_paca() and it checks if preemption is disabled through check_preemption_disabled(). Preemption should be disabled because the per CPU variable may make no sense if there is a preemption (and a CPU switch) after it reads the per CPU data and when it is used. In this device driver specifically, it is not a problem, because this code just needs to have access to one lppaca struct, and it does not matter if it is the current per CPU lppaca struct or not (i.e. when there is a preemption and a CPU migration). That said, the most appropriate fix seems to be related to avoiding the debug_smp_processor_id() call at get_paca(), instead of calling preempt_disable() before get_paca(). Signed-off-by: Breno Leitao Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin

ARM: cpuidle: Convert to use cpuidle_register|unregister()

2018-11-08T17:53:00+00:00

The only reason that remains, to why the ARM cpuidle driver calls cpuidle_register_driver(), is to avoid printing an error message in case another driver already have been registered for the CPU. This seems a bit silly, but more importantly, if that is a common scenario, perhaps we should change cpuidle_register() accordingly instead. In either case, let's consolidate the code, by converting to use cpuidle_register|unregister(), which also avoids the unnecessary allocation of the struct cpuidle_device. Signed-off-by: Ulf Hansson Reviewed-by: Lorenzo Pieralisi Reviewed-by: Daniel Lezcano Signed-off-by: Rafael J. Wysocki

ARM: cpuidle: Don't register the driver when back-end init returns -ENXIO

2018-11-08T17:52:02+00:00

There's no point to register the cpuidle driver for the current CPU, when the initialization of the arch specific back-end data fails by returning -ENXIO. Instead, let's re-order the sequence to its original flow, by first trying to initialize the back-end part and then act accordingly on the returned error code. Additionally, let's print the error message, no matter of what error code that was returned. Fixes: a0d46a3dfdc3 (ARM: cpuidle: Register per cpuidle device) Signed-off-by: Ulf Hansson Reviewed-by: Daniel Lezcano Cc: 4.19+ # v4.19+ Signed-off-by: Rafael J. Wysocki

Merge tag 'pm-4.20-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

2018-10-30T16:08:07+00:00

Pull more power management updates from Rafael Wysocki: "These remove a questionable heuristic from the menu cpuidle governor, fix a recent build regression in the intel_pstate driver, clean up ARM big-Little support in cpufreq and fix up hung task watchdog's interaction with system-wide power management transitions. Specifics: - Fix build regression in the intel_pstate driver that doesn't build without CONFIG_ACPI after recent changes (Dominik Brodowski). - One of the heuristics in the menu cpuidle governor is based on a function returning 0 most of the time, so drop it and clean up the scheduler code related to it (Daniel Lezcano). - Prevent the arm_big_little cpufreq driver from being used on ARM64 which is not suitable for it and drop the arm_big_little_dt driver that is not used any more (Sudeep Holla). - Prevent the hung task watchdog from triggering during resume from system-wide sleep states by disabling it before freezing tasks and enabling it again after they have been thawed (Vitaly Kuznetsov)" * tag 'pm-4.20-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: kernel: hung_task.c: disable on suspend cpufreq: remove unused arm_big_little_dt driver cpufreq: drop ARM_BIG_LITTLE_CPUFREQ support for ARM64 cpufreq: intel_pstate: Fix compilation for !CONFIG_ACPI cpuidle: menu: Remove get_loadavg() from the performance multiplier sched: Factor out nr_iowait and nr_iowait_cpu

sched: loadavg: consolidate LOAD_INT, LOAD_FRAC, CALC_LOAD

2018-10-26T23:26:32+00:00

There are several definitions of those functions/macros in places that mess with fixed-point load averages. Provide an official version. [akpm@linux-foundation.org: fix missed conversion in block/blk-iolatency.c] Link: http://lkml.kernel.org/r/20180828172258.3185-5-hannes@cmpxchg.org Signed-off-by: Johannes Weiner Acked-by: Peter Zijlstra (Intel) Tested-by: Suren Baghdasaryan Tested-by: Daniel Drake Cc: Christopher Lameter Cc: Ingo Molnar Cc: Johannes Weiner Cc: Mike Galbraith Cc: Peter Enderborg Cc: Randy Dunlap Cc: Shakeel Butt Cc: Tejun Heo Cc: Vinayak Menon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

cpuidle: menu: Remove get_loadavg() from the performance multiplier

2018-10-25T14:49:27+00:00

The function get_loadavg() returns almost always zero. To be more precise, statistically speaking for a total of 1023379 times passing in the function, the load is equal to zero 1020728 times, greater than 100, 610 times, the remaining is between 0 and 5. In 2011, the get_loadavg() was removed from the Android tree because of the above [1]. At this time, the load was: unsigned long this_cpu_load(void) { struct rq *this = this_rq(); return this->cpu_load[0]; } In 2014, the code was changed by commit 372ba8cb46b2 (cpuidle: menu: Lookup CPU runqueues less) and the load is: void get_iowait_load(unsigned long *nr_waiters, unsigned long *load) { struct rq *rq = this_rq(); *nr_waiters = atomic_read(&rq->nr_iowait); *load = rq->load.weight; } with the same result. Both measurements show using the load in this code path does no matter anymore. Removing it. [1] https://android.googlesource.com/kernel/common/+/4dedd9f124703207895777ac6e91dacde0f7cc17 Signed-off-by: Daniel Lezcano Acked-by: Mel Gorman Acked-by: Peter Zijlstra (Intel) Signed-off-by: Rafael J. Wysocki

cpuidle: menu: Avoid computations when result will be discarded

2018-10-18T07:34:13+00:00

If the minimum interval taken into account in the average computation loop in get_typical_interval() is less than the expected idle duration determined so far, the resultant average cannot be greater than that value as well and the entire return result of the function is going to be discarded anyway going forward. In that case, it is a waste of time to carry out the remaining computations in get_typical_interval(), so avoid that by returning early if the minimum interval is not below the expected idle duration. No intentional changes of behavior. Signed-off-by: Rafael J. Wysocki

cpuidle: menu: Drop redundant comparison

2018-10-18T07:34:13+00:00

Since the correction factor cannot be greater than RESOLUTION * DECAY, the result of the predicted_us computation in menu_select() cannot be greater than data->next_timer_us, so it is not necessary to compare the "typical interval" value coming from get_typical_interval() with data->next_timer_us separately. It is sufficient to copmare predicted_us with the return value of get_typical_interval() directly, so do that and drop the now redundant expected_interval variable. No intentional changes of behavior. Signed-off-by: Rafael J. Wysocki

cpuidle: menu: Simplify checks related to the polling state

2018-10-12T08:46:37+00:00

After some recent menu governor changes, the promotion of the "polling" state to a physical one is mostly controlled by the latency limit (resulting from the "interactivity" factor) and not by the time to the closest timer event, so it should be sufficient to check the exit latency of that state for this purpose (of course, its target residency still needs to be within the next timer event range for energy-efficiency). Also, the physical state the "polling" one is promoted to need not be the next one in principle (in case the next state is disabled, for example). For these reasons, simplify the checks made to decide whether or not to promote the "polling" state to a physical one and update the target idle duration when it is promoted in case the residency of the new state turns out to be above the tick boundary (in which case there is no reason to stop the tick). Tested-by: Doug Smythies Signed-off-by: Rafael J. Wysocki