kernel/drivers/cpufreq/intel_pstate.c, branch linux-5.1.y

cpufreq/intel_pstate: Load only on Intel hardware

2019-04-01T21:39:23Z

This driver is Intel-only so loading on anything which is not Intel is pointless. Prevent it from doing so. While at it, correct the "not supported" print statement to say CPU "model" which is what that test does. Fixes: 076b862c7e44 (cpufreq: intel_pstate: Add reasons for failure and debug messages) Suggested-by: Erwan Velu Signed-off-by: Borislav Petkov Reviewed-by: Thomas Renninger Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Also use CPPC nominal_perf for base_frequency

2019-03-25T22:57:21Z

The ACPI specification states that if the "Guaranteed Performance Register" is not implemented, the OSPM assumes guaranteed performance to always be equal to nominal performance. So for invalid or unimplemented guaranteed performance register, use nominal performance as guaranteed performance. This change will fall back to nominal_perf when guranteed_perf is invalid. If nominal_perf is also invalid or not present, fall back to the existing implementation, which is to read from HWP Capabilities MSR. Fixes: 86d333a8cc7f ("cpufreq: intel_pstate: Add base_frequency attribute") Suggested-by: Rafael J. Wysocki Signed-off-by: Srinivas Pandruvada Cc: 4.20+ # 4.20+ Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Fix up iowait_boost computation

2019-03-12T08:47:30Z

After commit b8bd1581aa61 ("cpufreq: intel_pstate: Rework iowait boosting to be less aggressive") the handling of the case when the SCHED_CPUFREQ_IOWAIT flag is set again after a few iterations of intel_pstate_update_util() is a bit inconsistent, because the new value of cpu->iowait_boost may be lower than ONE_EIGHTH_FP if it was set before, but has not dropped down to zero just yet. Fix that up by ensuring that the new value of cpu->iowait_boost will always be at least ONE_EIGHTH_FP then. Fixes: b8bd1581aa61 ("cpufreq: intel_pstate: Rework iowait boosting to be less aggressive") Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Rework iowait boosting to be less aggressive

2019-02-18T10:34:32Z

The current iowait boosting mechanism in intel_pstate_update_util() is quite aggressive, as it goes to the maximum P-state right away, and may cause excessive amounts of energy to be used, which is not desirable and arguably isn't necessary too. Follow commit a5a0809bc58e ("cpufreq: schedutil: Make iowait boost more energy efficient") that reworked the analogous iowait boost mechanism in the schedutil governor and make the iowait boosting in intel_pstate_update_util() work along the same lines. Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Eliminate intel_pstate_get_base_pstate()

2019-02-18T10:34:32Z

There is only one caller of intel_pstate_get_base_pstate() and it is more straightforward to carry out the computation directly in the caller, so do that and drop intel_pstate_get_base_pstate(). No intentional changes of behavior. Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Avoid redundant initialization of local vars

2019-02-18T10:34:32Z

After commit 1a4fe38add8b ("cpufreq: intel_pstate: Remove max/min fractions to limit performance") the initial value of the pstate local variable in intel_pstate_max_within_limits() and the initial value of the max_pstate local variable in intel_pstate_prepare_request() are both immediately discarded, so initialize both these variables to their target values upfront. No intentional changes of behavior. Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Add reasons for failure and debug messages

2019-02-13T11:32:10Z

The init code path has several exceptions where the driver can decide not to load. As CONFIG_X86_INTEL_PSTATE is generally set to Y, the return code is not reachable. The initialization code is neither verbose of the reason why it did choose to prematurely exit, so it is difficult for a user to determine, on a given platform, why the driver didn't load properly. This patch is about reporting to the user the reason/context of why the driver failed to load. That is a precious hint when debugging a platform. Signed-off-by: Erwan Velu [ rjw: Subject & changelog, minor fixups ] Signed-off-by: Rafael J. Wysocki

cpufreq: Use struct kobj_attribute instead of struct global_attr

2019-01-29T10:44:30Z

The cpufreq_global_kobject is created using kobject_create_and_add() helper, which assigns the kobj_type as dynamic_kobj_ktype and show/store routines are set to kobj_attr_show() and kobj_attr_store(). These routines pass struct kobj_attribute as an argument to the show/store callbacks. But all the cpufreq files created using the cpufreq_global_kobject expect the argument to be of type struct attribute. Things work fine currently as no one accesses the "attr" argument. We may not see issues even if the argument is used, as struct kobj_attribute has struct attribute as its first element and so they will both get same address. But this is logically incorrect and we should rather use struct kobj_attribute instead of struct global_attr in the cpufreq core and drivers and the show/store callbacks should take struct kobj_attribute as argument instead. This bug is caught using CFI CLANG builds in android kernel which catches mismatch in function prototypes for such callbacks. Reported-by: Donghee Han Reported-by: Sangkyu Kim Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-12-26T21:07:19Z

Pull RCU updates from Ingo Molnar: "The biggest RCU changes in this cycle were: - Convert RCU's BUG_ON() and similar calls to WARN_ON() and similar. - Replace calls of RCU-bh and RCU-sched update-side functions to their vanilla RCU counterparts. This series is a step towards complete removal of the RCU-bh and RCU-sched update-side functions. ( Note that some of these conversions are going upstream via their respective maintainers. ) - Documentation updates, including a number of flavor-consolidation updates from Joel Fernandes. - Miscellaneous fixes. - Automate generation of the initrd filesystem used for rcutorture testing. - Convert spin_is_locked() assertions to instead use lockdep. ( Note that some of these conversions are going upstream via their respective maintainers. ) - SRCU updates, especially including a fix from Dennis Krein for a bag-on-head-class bug. - RCU torture-test updates" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (112 commits) rcutorture: Don't do busted forward-progress testing rcutorture: Use 100ms buckets for forward-progress callback histograms rcutorture: Recover from OOM during forward-progress tests rcutorture: Print forward-progress test age upon failure rcutorture: Print time since GP end upon forward-progress failure rcutorture: Print histogram of CB invocation at OOM time rcutorture: Print GP age upon forward-progress failure rcu: Print per-CPU callback counts for forward-progress failures rcu: Account for nocb-CPU callback counts in RCU CPU stall warnings rcutorture: Dump grace-period diagnostics upon forward-progress OOM rcutorture: Prepare for asynchronous access to rcu_fwd_startat torture: Remove unnecessary "ret" variables rcutorture: Affinity forward-progress test to avoid housekeeping CPUs rcutorture: Break up too-long rcu_torture_fwd_prog() function rcutorture: Remove cbflood facility torture: Bring any extra CPUs online during kernel startup rcutorture: Add call_rcu() flooding forward-progress tests rcutorture/formal: Replace synchronize_sched() with synchronize_rcu() tools/kernel.h: Replace synchronize_sched() with synchronize_rcu() net/decnet: Replace rcu_barrier_bh() with rcu_barrier() ...

cpufreq: intel_pstate: Force HWP min perf before offline

2018-11-29T21:31:58Z

Force HWP Request MAX = HWP Request MIN = HWP Capability MIN and EPP to 0xFF. In this way the performance limits on the offlined CPU will not influence performance limits on its sibling CPU, which is still online. If the sibling CPU is calling for higher performance, it will impact the max core performance. Here core performance will follow higher of the performance requests from each sibling. Reported-and-tested-by: Chen Yu Signed-off-by: Srinivas Pandruvada Signed-off-by: Rafael J. Wysocki