Files
android_kernel_xiaomi_sm8450/include/linux/sched/topology.h
Thara Gopinath de785069ec ANDROID: sched: Per-Sched-domain over utilization
The current implementation of overutilization, aborts energy aware
scheduling if any cpu in the system is over-utilized. This patch introduces
over utilization flag per sched domain level instead of a single flag
system wide. Load balancing is done at the sched domain where any
of the cpu is over utilized. If energy aware scheduling is
enabled and no cpu in a sched domain is overuttilized,
load balancing is skipped for that sched domain and energy aware
scheduling continues at that level.

The implementation takes advantage of the shared sched_domain structure
that is common across all the sched domains at a level. The new flag
introduced is placed in this structure so that all the sched domains the
same level share the flag. In case of an overutilized cpu, the flag gets
set at level1 sched_domain. The flag at the parent sched_domain level gets
set in either of the two following scenarios.
 1. There is a misfit task in one of the cpu's in this sched_domain.
 2. The total utilization of the domain is greater than the domain capacity

The flag is cleared if no cpu in a sched domain is overutilized.

This implementation still can have corner scenarios with respect to
misfit tasks. For example consider a sched group with n cpus and
n+1 70%utilized tasks. Ideally this is a case for load balance to happen
in a parent sched domain. But neither the total group utilization is
high enough for the load balance to be triggered in the parent domain nor
there is a cpu with a single overutilized task so that aload balance is
triggered in a parent domain. But again this could be a purely academic
sceanrio, as during task wake up these tasks will be placed
more appropriately.

Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
Change-Id: I3f327cff4080096a3e58208dd72c9b7f7913cdb2
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
Git-commit: addef37808728c719d8c095a75bcf81befdacdaf
Git-repo: https://android.googlesource.com/kernel/common/
[clingutla@codeaurora.org: Resolved trivial merge conflicts]
Signed-off-by: Lingutla Chandrasekhar <clingutla@codeaurora.org>
[satyap@codeaurora.org: port to 5.x and resolve trivial merge conflicts]
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>
2019-12-10 12:50:35 -08:00

238 lines
6.4 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_SCHED_TOPOLOGY_H
#define _LINUX_SCHED_TOPOLOGY_H
#include <linux/topology.h>
#include <linux/sched/idle.h>
/*
* sched-domains (multiprocessor balancing) declarations:
*/
#ifdef CONFIG_SMP
#define SD_LOAD_BALANCE 0x0001 /* Do load balancing on this domain. */
#define SD_BALANCE_NEWIDLE 0x0002 /* Balance when about to become idle */
#define SD_BALANCE_EXEC 0x0004 /* Balance on exec */
#define SD_BALANCE_FORK 0x0008 /* Balance on fork, clone */
#define SD_BALANCE_WAKE 0x0010 /* Balance on wakeup */
#define SD_WAKE_AFFINE 0x0020 /* Wake task to waking CPU */
#define SD_ASYM_CPUCAPACITY 0x0040 /* Domain members have different CPU capacities */
#define SD_SHARE_CPUCAPACITY 0x0080 /* Domain members share CPU capacity */
#define SD_SHARE_POWERDOMAIN 0x0100 /* Domain members share power domain */
#define SD_SHARE_PKG_RESOURCES 0x0200 /* Domain members share CPU pkg resources */
#define SD_SERIALIZE 0x0400 /* Only a single load balancing instance */
#define SD_ASYM_PACKING 0x0800 /* Place busy groups earlier in the domain */
#define SD_PREFER_SIBLING 0x1000 /* Prefer to place tasks in a sibling domain */
#define SD_OVERLAP 0x2000 /* sched_domains of this level overlap */
#define SD_NUMA 0x4000 /* cross-node balancing */
#ifdef CONFIG_SCHED_SMT
static inline int cpu_smt_flags(void)
{
return SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES;
}
#endif
#ifdef CONFIG_SCHED_MC
static inline int cpu_core_flags(void)
{
return SD_SHARE_PKG_RESOURCES;
}
#endif
#ifdef CONFIG_NUMA
static inline int cpu_numa_flags(void)
{
return SD_NUMA;
}
#endif
extern int arch_asym_cpu_priority(int cpu);
struct sched_domain_attr {
int relax_domain_level;
};
#define SD_ATTR_INIT (struct sched_domain_attr) { \
.relax_domain_level = -1, \
}
extern int sched_domain_level_max;
struct sched_group;
struct sched_domain_shared {
atomic_t ref;
atomic_t nr_busy_cpus;
int has_idle_cores;
#ifdef CONFIG_SCHED_WALT
bool overutilized;
#endif
};
struct sched_domain {
/* These fields must be setup */
struct sched_domain __rcu *parent; /* top domain must be null terminated */
struct sched_domain __rcu *child; /* bottom domain must be null terminated */
struct sched_group *groups; /* the balancing groups of the domain */
unsigned long min_interval; /* Minimum balance interval ms */
unsigned long max_interval; /* Maximum balance interval ms */
unsigned int busy_factor; /* less balancing by factor if busy */
unsigned int imbalance_pct; /* No balance until over watermark */
unsigned int cache_nice_tries; /* Leave cache hot tasks for # tries */
int nohz_idle; /* NOHZ IDLE status */
int flags; /* See SD_* */
int level;
/* Runtime fields. */
unsigned long last_balance; /* init to jiffies. units in jiffies */
unsigned int balance_interval; /* initialise to 1. units in ms. */
unsigned int nr_balance_failed; /* initialise to 0 */
/* idle_balance() stats */
u64 max_newidle_lb_cost;
unsigned long next_decay_max_lb_cost;
u64 avg_scan_cost; /* select_idle_sibling */
#ifdef CONFIG_SCHEDSTATS
/* load_balance() stats */
unsigned int lb_count[CPU_MAX_IDLE_TYPES];
unsigned int lb_failed[CPU_MAX_IDLE_TYPES];
unsigned int lb_balanced[CPU_MAX_IDLE_TYPES];
unsigned int lb_imbalance[CPU_MAX_IDLE_TYPES];
unsigned int lb_gained[CPU_MAX_IDLE_TYPES];
unsigned int lb_hot_gained[CPU_MAX_IDLE_TYPES];
unsigned int lb_nobusyg[CPU_MAX_IDLE_TYPES];
unsigned int lb_nobusyq[CPU_MAX_IDLE_TYPES];
/* Active load balancing */
unsigned int alb_count;
unsigned int alb_failed;
unsigned int alb_pushed;
/* SD_BALANCE_EXEC stats */
unsigned int sbe_count;
unsigned int sbe_balanced;
unsigned int sbe_pushed;
/* SD_BALANCE_FORK stats */
unsigned int sbf_count;
unsigned int sbf_balanced;
unsigned int sbf_pushed;
/* try_to_wake_up() stats */
unsigned int ttwu_wake_remote;
unsigned int ttwu_move_affine;
unsigned int ttwu_move_balance;
#endif
#ifdef CONFIG_SCHED_DEBUG
char *name;
#endif
union {
void *private; /* used during construction */
struct rcu_head rcu; /* used during destruction */
};
struct sched_domain_shared *shared;
unsigned int span_weight;
/*
* Span of all CPUs in this domain.
*
* NOTE: this field is variable length. (Allocated dynamically
* by attaching extra space to the end of the structure,
* depending on how many CPUs the kernel has booted up with)
*/
unsigned long span[0];
};
static inline struct cpumask *sched_domain_span(struct sched_domain *sd)
{
return to_cpumask(sd->span);
}
extern void partition_sched_domains_locked(int ndoms_new,
cpumask_var_t doms_new[],
struct sched_domain_attr *dattr_new);
extern void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
struct sched_domain_attr *dattr_new);
/* Allocate an array of sched domains, for partition_sched_domains(). */
cpumask_var_t *alloc_sched_domains(unsigned int ndoms);
void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms);
bool cpus_share_cache(int this_cpu, int that_cpu);
typedef const struct cpumask *(*sched_domain_mask_f)(int cpu);
typedef int (*sched_domain_flags_f)(void);
#define SDTL_OVERLAP 0x01
struct sd_data {
struct sched_domain *__percpu *sd;
struct sched_domain_shared *__percpu *sds;
struct sched_group *__percpu *sg;
struct sched_group_capacity *__percpu *sgc;
};
struct sched_domain_topology_level {
sched_domain_mask_f mask;
sched_domain_flags_f sd_flags;
int flags;
int numa_level;
struct sd_data data;
#ifdef CONFIG_SCHED_DEBUG
char *name;
#endif
};
extern void set_sched_topology(struct sched_domain_topology_level *tl);
#ifdef CONFIG_SCHED_DEBUG
# define SD_INIT_NAME(type) .name = #type
#else
# define SD_INIT_NAME(type)
#endif
#else /* CONFIG_SMP */
struct sched_domain_attr;
static inline void
partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[],
struct sched_domain_attr *dattr_new)
{
}
static inline void
partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
struct sched_domain_attr *dattr_new)
{
}
static inline bool cpus_share_cache(int this_cpu, int that_cpu)
{
return true;
}
#endif /* !CONFIG_SMP */
#ifndef arch_scale_cpu_capacity
static __always_inline
unsigned long arch_scale_cpu_capacity(int cpu)
{
return SCHED_CAPACITY_SCALE;
}
#endif
static inline int task_node(const struct task_struct *p)
{
return cpu_to_node(task_cpu(p));
}
#endif /* _LINUX_SCHED_TOPOLOGY_H */