![Valentin Schneider](/assets/img/avatar_default.png)
Rather that hide their purpose in some dark, damp corner of Documentation/, add some documentation to the default implementations. Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200731192016.7484-2-valentin.schneider@arm.com
258 lines
6.8 KiB
C
258 lines
6.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_SCHED_TOPOLOGY_H
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#define _LINUX_SCHED_TOPOLOGY_H
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#include <linux/topology.h>
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#include <linux/sched/idle.h>
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/*
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* sched-domains (multiprocessor balancing) declarations:
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*/
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#ifdef CONFIG_SMP
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#define SD_BALANCE_NEWIDLE 0x0001 /* Balance when about to become idle */
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#define SD_BALANCE_EXEC 0x0002 /* Balance on exec */
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#define SD_BALANCE_FORK 0x0004 /* Balance on fork, clone */
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#define SD_BALANCE_WAKE 0x0008 /* Balance on wakeup */
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#define SD_WAKE_AFFINE 0x0010 /* Wake task to waking CPU */
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#define SD_ASYM_CPUCAPACITY 0x0020 /* Domain members have different CPU capacities */
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#define SD_SHARE_CPUCAPACITY 0x0040 /* Domain members share CPU capacity */
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#define SD_SHARE_POWERDOMAIN 0x0080 /* Domain members share power domain */
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#define SD_SHARE_PKG_RESOURCES 0x0100 /* Domain members share CPU pkg resources */
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#define SD_SERIALIZE 0x0200 /* Only a single load balancing instance */
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#define SD_ASYM_PACKING 0x0400 /* Place busy groups earlier in the domain */
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#define SD_PREFER_SIBLING 0x0800 /* Prefer to place tasks in a sibling domain */
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#define SD_OVERLAP 0x1000 /* sched_domains of this level overlap */
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#define SD_NUMA 0x2000 /* cross-node balancing */
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#ifdef CONFIG_SCHED_SMT
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static inline int cpu_smt_flags(void)
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{
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return SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES;
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}
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#endif
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#ifdef CONFIG_SCHED_MC
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static inline int cpu_core_flags(void)
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{
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return SD_SHARE_PKG_RESOURCES;
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}
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#endif
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#ifdef CONFIG_NUMA
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static inline int cpu_numa_flags(void)
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{
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return SD_NUMA;
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}
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#endif
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extern int arch_asym_cpu_priority(int cpu);
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struct sched_domain_attr {
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int relax_domain_level;
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};
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#define SD_ATTR_INIT (struct sched_domain_attr) { \
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.relax_domain_level = -1, \
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}
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extern int sched_domain_level_max;
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struct sched_group;
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struct sched_domain_shared {
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atomic_t ref;
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atomic_t nr_busy_cpus;
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int has_idle_cores;
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};
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struct sched_domain {
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/* These fields must be setup */
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struct sched_domain __rcu *parent; /* top domain must be null terminated */
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struct sched_domain __rcu *child; /* bottom domain must be null terminated */
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struct sched_group *groups; /* the balancing groups of the domain */
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unsigned long min_interval; /* Minimum balance interval ms */
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unsigned long max_interval; /* Maximum balance interval ms */
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unsigned int busy_factor; /* less balancing by factor if busy */
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unsigned int imbalance_pct; /* No balance until over watermark */
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unsigned int cache_nice_tries; /* Leave cache hot tasks for # tries */
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int nohz_idle; /* NOHZ IDLE status */
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int flags; /* See SD_* */
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int level;
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/* Runtime fields. */
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unsigned long last_balance; /* init to jiffies. units in jiffies */
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unsigned int balance_interval; /* initialise to 1. units in ms. */
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unsigned int nr_balance_failed; /* initialise to 0 */
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/* idle_balance() stats */
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u64 max_newidle_lb_cost;
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unsigned long next_decay_max_lb_cost;
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u64 avg_scan_cost; /* select_idle_sibling */
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#ifdef CONFIG_SCHEDSTATS
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/* load_balance() stats */
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unsigned int lb_count[CPU_MAX_IDLE_TYPES];
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unsigned int lb_failed[CPU_MAX_IDLE_TYPES];
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unsigned int lb_balanced[CPU_MAX_IDLE_TYPES];
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unsigned int lb_imbalance[CPU_MAX_IDLE_TYPES];
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unsigned int lb_gained[CPU_MAX_IDLE_TYPES];
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unsigned int lb_hot_gained[CPU_MAX_IDLE_TYPES];
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unsigned int lb_nobusyg[CPU_MAX_IDLE_TYPES];
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unsigned int lb_nobusyq[CPU_MAX_IDLE_TYPES];
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/* Active load balancing */
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unsigned int alb_count;
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unsigned int alb_failed;
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unsigned int alb_pushed;
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/* SD_BALANCE_EXEC stats */
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unsigned int sbe_count;
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unsigned int sbe_balanced;
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unsigned int sbe_pushed;
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/* SD_BALANCE_FORK stats */
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unsigned int sbf_count;
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unsigned int sbf_balanced;
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unsigned int sbf_pushed;
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/* try_to_wake_up() stats */
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unsigned int ttwu_wake_remote;
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unsigned int ttwu_move_affine;
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unsigned int ttwu_move_balance;
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#endif
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#ifdef CONFIG_SCHED_DEBUG
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char *name;
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#endif
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union {
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void *private; /* used during construction */
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struct rcu_head rcu; /* used during destruction */
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};
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struct sched_domain_shared *shared;
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unsigned int span_weight;
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/*
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* Span of all CPUs in this domain.
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*
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* NOTE: this field is variable length. (Allocated dynamically
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* by attaching extra space to the end of the structure,
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* depending on how many CPUs the kernel has booted up with)
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*/
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unsigned long span[];
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};
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static inline struct cpumask *sched_domain_span(struct sched_domain *sd)
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{
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return to_cpumask(sd->span);
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}
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extern void partition_sched_domains_locked(int ndoms_new,
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cpumask_var_t doms_new[],
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struct sched_domain_attr *dattr_new);
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extern void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
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struct sched_domain_attr *dattr_new);
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/* Allocate an array of sched domains, for partition_sched_domains(). */
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cpumask_var_t *alloc_sched_domains(unsigned int ndoms);
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void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms);
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bool cpus_share_cache(int this_cpu, int that_cpu);
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typedef const struct cpumask *(*sched_domain_mask_f)(int cpu);
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typedef int (*sched_domain_flags_f)(void);
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#define SDTL_OVERLAP 0x01
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struct sd_data {
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struct sched_domain *__percpu *sd;
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struct sched_domain_shared *__percpu *sds;
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struct sched_group *__percpu *sg;
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struct sched_group_capacity *__percpu *sgc;
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};
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struct sched_domain_topology_level {
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sched_domain_mask_f mask;
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sched_domain_flags_f sd_flags;
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int flags;
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int numa_level;
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struct sd_data data;
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#ifdef CONFIG_SCHED_DEBUG
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char *name;
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#endif
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};
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extern void set_sched_topology(struct sched_domain_topology_level *tl);
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#ifdef CONFIG_SCHED_DEBUG
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# define SD_INIT_NAME(type) .name = #type
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#else
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# define SD_INIT_NAME(type)
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#endif
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#else /* CONFIG_SMP */
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struct sched_domain_attr;
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static inline void
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partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[],
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struct sched_domain_attr *dattr_new)
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{
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}
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static inline void
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partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
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struct sched_domain_attr *dattr_new)
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{
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}
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static inline bool cpus_share_cache(int this_cpu, int that_cpu)
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{
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return true;
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}
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#endif /* !CONFIG_SMP */
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#ifndef arch_scale_cpu_capacity
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/**
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* arch_scale_cpu_capacity - get the capacity scale factor of a given CPU.
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* @cpu: the CPU in question.
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*
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* Return: the CPU scale factor normalized against SCHED_CAPACITY_SCALE, i.e.
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*
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* max_perf(cpu)
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* ----------------------------- * SCHED_CAPACITY_SCALE
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* max(max_perf(c) : c \in CPUs)
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*/
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static __always_inline
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unsigned long arch_scale_cpu_capacity(int cpu)
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{
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return SCHED_CAPACITY_SCALE;
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}
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#endif
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#ifndef arch_scale_thermal_pressure
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static __always_inline
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unsigned long arch_scale_thermal_pressure(int cpu)
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{
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return 0;
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}
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#endif
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#ifndef arch_set_thermal_pressure
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static __always_inline
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void arch_set_thermal_pressure(const struct cpumask *cpus,
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unsigned long th_pressure)
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{ }
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#endif
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static inline int task_node(const struct task_struct *p)
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{
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return cpu_to_node(task_cpu(p));
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}
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#endif /* _LINUX_SCHED_TOPOLOGY_H */
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