From c214f124161d446b340597e7c968e0a2dc149142 Mon Sep 17 00:00:00 2001 From: Lukasz Luba Date: Tue, 9 Nov 2021 19:57:10 +0000 Subject: arch_topology: Introduce thermal pressure update function The thermal pressure is a mechanism which is used for providing information about reduced CPU performance to the scheduler. Usually code has to convert the value from frequency units into capacity units, which are understandable by the scheduler. Create a common conversion code which can be just used via a handy API. Internally, the topology_update_thermal_pressure() operates on frequency in MHz and max CPU frequency is taken from 'freq_factor' (per-cpu). Signed-off-by: Lukasz Luba Reviewed-by: Thara Gopinath Signed-off-by: Viresh Kumar --- drivers/base/arch_topology.c | 43 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 42 insertions(+), 1 deletion(-) (limited to 'drivers/base') diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index ff16a36a908b..a3ae0b4eea09 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -22,6 +22,7 @@ static DEFINE_PER_CPU(struct scale_freq_data __rcu *, sft_data); static struct cpumask scale_freq_counters_mask; static bool scale_freq_invariant; +static DEFINE_PER_CPU(u32, freq_factor) = 1; static bool supports_scale_freq_counters(const struct cpumask *cpus) { @@ -165,6 +166,47 @@ void topology_set_thermal_pressure(const struct cpumask *cpus, } EXPORT_SYMBOL_GPL(topology_set_thermal_pressure); +/** + * topology_update_thermal_pressure() - Update thermal pressure for CPUs + * @cpus : The related CPUs for which capacity has been reduced + * @capped_freq : The maximum allowed frequency that CPUs can run at + * + * Update the value of thermal pressure for all @cpus in the mask. The + * cpumask should include all (online+offline) affected CPUs, to avoid + * operating on stale data when hot-plug is used for some CPUs. The + * @capped_freq reflects the currently allowed max CPUs frequency due to + * thermal capping. It might be also a boost frequency value, which is bigger + * than the internal 'freq_factor' max frequency. In such case the pressure + * value should simply be removed, since this is an indication that there is + * no thermal throttling. The @capped_freq must be provided in kHz. + */ +void topology_update_thermal_pressure(const struct cpumask *cpus, + unsigned long capped_freq) +{ + unsigned long max_capacity, capacity; + u32 max_freq; + int cpu; + + cpu = cpumask_first(cpus); + max_capacity = arch_scale_cpu_capacity(cpu); + max_freq = per_cpu(freq_factor, cpu); + + /* Convert to MHz scale which is used in 'freq_factor' */ + capped_freq /= 1000; + + /* + * Handle properly the boost frequencies, which should simply clean + * the thermal pressure value. + */ + if (max_freq <= capped_freq) + capacity = max_capacity; + else + capacity = mult_frac(max_capacity, capped_freq, max_freq); + + arch_set_thermal_pressure(cpus, max_capacity - capacity); +} +EXPORT_SYMBOL_GPL(topology_update_thermal_pressure); + static ssize_t cpu_capacity_show(struct device *dev, struct device_attribute *attr, char *buf) @@ -217,7 +259,6 @@ static void update_topology_flags_workfn(struct work_struct *work) update_topology = 0; } -static DEFINE_PER_CPU(u32, freq_factor) = 1; static u32 *raw_capacity; static int free_raw_capacity(void) -- cgit v1.2.3-59-g8ed1b From 7e97b3dc2556743dd02612c92a8de7026e8d7dc9 Mon Sep 17 00:00:00 2001 From: Lukasz Luba Date: Tue, 9 Nov 2021 19:57:14 +0000 Subject: arch_topology: Remove unused topology_set_thermal_pressure() and related There is no need of this function (and related) since code has been converted to use the new arch_update_thermal_pressure() API. The old code can be removed. Signed-off-by: Lukasz Luba Signed-off-by: Viresh Kumar --- arch/arm/include/asm/topology.h | 1 - arch/arm64/include/asm/topology.h | 1 - drivers/base/arch_topology.c | 17 +++++------------ include/linux/arch_topology.h | 3 --- include/linux/sched/topology.h | 7 ------- init/Kconfig | 2 +- 6 files changed, 6 insertions(+), 25 deletions(-) (limited to 'drivers/base') diff --git a/arch/arm/include/asm/topology.h b/arch/arm/include/asm/topology.h index f1eafacc9a30..c7d2510e5a78 100644 --- a/arch/arm/include/asm/topology.h +++ b/arch/arm/include/asm/topology.h @@ -23,7 +23,6 @@ /* Replace task scheduler's default thermal pressure API */ #define arch_scale_thermal_pressure topology_get_thermal_pressure -#define arch_set_thermal_pressure topology_set_thermal_pressure #define arch_update_thermal_pressure topology_update_thermal_pressure #else diff --git a/arch/arm64/include/asm/topology.h b/arch/arm64/include/asm/topology.h index 7a421cbc99ed..f386b90a79c8 100644 --- a/arch/arm64/include/asm/topology.h +++ b/arch/arm64/include/asm/topology.h @@ -32,7 +32,6 @@ void update_freq_counters_refs(void); /* Replace task scheduler's default thermal pressure API */ #define arch_scale_thermal_pressure topology_get_thermal_pressure -#define arch_set_thermal_pressure topology_set_thermal_pressure #define arch_update_thermal_pressure topology_update_thermal_pressure #include diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index a3ae0b4eea09..976154140f0b 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -156,16 +156,6 @@ void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity) DEFINE_PER_CPU(unsigned long, thermal_pressure); -void topology_set_thermal_pressure(const struct cpumask *cpus, - unsigned long th_pressure) -{ - int cpu; - - for_each_cpu(cpu, cpus) - WRITE_ONCE(per_cpu(thermal_pressure, cpu), th_pressure); -} -EXPORT_SYMBOL_GPL(topology_set_thermal_pressure); - /** * topology_update_thermal_pressure() - Update thermal pressure for CPUs * @cpus : The related CPUs for which capacity has been reduced @@ -183,7 +173,7 @@ EXPORT_SYMBOL_GPL(topology_set_thermal_pressure); void topology_update_thermal_pressure(const struct cpumask *cpus, unsigned long capped_freq) { - unsigned long max_capacity, capacity; + unsigned long max_capacity, capacity, th_pressure; u32 max_freq; int cpu; @@ -203,7 +193,10 @@ void topology_update_thermal_pressure(const struct cpumask *cpus, else capacity = mult_frac(max_capacity, capped_freq, max_freq); - arch_set_thermal_pressure(cpus, max_capacity - capacity); + th_pressure = max_capacity - capacity; + + for_each_cpu(cpu, cpus) + WRITE_ONCE(per_cpu(thermal_pressure, cpu), th_pressure); } EXPORT_SYMBOL_GPL(topology_update_thermal_pressure); diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h index ace1e5dcf773..cce6136b300a 100644 --- a/include/linux/arch_topology.h +++ b/include/linux/arch_topology.h @@ -56,9 +56,6 @@ static inline unsigned long topology_get_thermal_pressure(int cpu) return per_cpu(thermal_pressure, cpu); } -void topology_set_thermal_pressure(const struct cpumask *cpus, - unsigned long th_pressure); - void topology_update_thermal_pressure(const struct cpumask *cpus, unsigned long capped_freq); diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h index 6e89a8e43aa7..8054641c0a7b 100644 --- a/include/linux/sched/topology.h +++ b/include/linux/sched/topology.h @@ -266,13 +266,6 @@ unsigned long arch_scale_thermal_pressure(int cpu) } #endif -#ifndef arch_set_thermal_pressure -static __always_inline -void arch_set_thermal_pressure(const struct cpumask *cpus, - unsigned long th_pressure) -{ } -#endif - #ifndef arch_update_thermal_pressure static __always_inline void arch_update_thermal_pressure(const struct cpumask *cpus, diff --git a/init/Kconfig b/init/Kconfig index 036b750e8d8a..086fd11348e0 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -550,7 +550,7 @@ config SCHED_THERMAL_PRESSURE i.e. put less load on throttled CPUs than on non/less throttled ones. This requires the architecture to implement - arch_set_thermal_pressure() and arch_scale_thermal_pressure(). + arch_update_thermal_pressure() and arch_scale_thermal_pressure(). config BSD_PROCESS_ACCT bool "BSD Process Accounting" -- cgit v1.2.3-59-g8ed1b