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e8f14172c6
Tasks without a user-defined clamp value are considered not clamped
and by default their utilization can have any value in the
[0..SCHED_CAPACITY_SCALE] range.
Tasks with a user-defined clamp value are allowed to request any value
in that range, and the required clamp is unconditionally enforced.
However, a "System Management Software" could be interested in limiting
the range of clamp values allowed for all tasks.
Add a privileged interface to define a system default configuration via:
/proc/sys/kernel/sched_uclamp_util_{min,max}
which works as an unconditional clamp range restriction for all tasks.
With the default configuration, the full SCHED_CAPACITY_SCALE range of
values is allowed for each clamp index. Otherwise, the task-specific
clamp is capped by the corresponding system default value.
Do that by tracking, for each task, the "effective" clamp value and
bucket the task has been refcounted in at enqueue time. This
allows to lazy aggregate "requested" and "system default" values at
enqueue time and simplifies refcounting updates at dequeue time.
The cached bucket ids are used to avoid (relatively) more expensive
integer divisions every time a task is enqueued.
An active flag is used to report when the "effective" value is valid and
thus the task is actually refcounted in the corresponding rq's bucket.
Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alessio Balsini <balsini@android.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Perret <quentin.perret@arm.com>
Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com>
Cc: Steve Muckle <smuckle@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Todd Kjos <tkjos@google.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lkml.kernel.org/r/20190621084217.8167-5-patrick.bellasi@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
104 lines
3.1 KiB
C
104 lines
3.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_SCHED_SYSCTL_H
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#define _LINUX_SCHED_SYSCTL_H
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#include <linux/types.h>
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struct ctl_table;
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#ifdef CONFIG_DETECT_HUNG_TASK
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extern int sysctl_hung_task_check_count;
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extern unsigned int sysctl_hung_task_panic;
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extern unsigned long sysctl_hung_task_timeout_secs;
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extern unsigned long sysctl_hung_task_check_interval_secs;
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extern int sysctl_hung_task_warnings;
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extern int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
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void __user *buffer,
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size_t *lenp, loff_t *ppos);
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#else
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/* Avoid need for ifdefs elsewhere in the code */
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enum { sysctl_hung_task_timeout_secs = 0 };
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#endif
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extern unsigned int sysctl_sched_latency;
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extern unsigned int sysctl_sched_min_granularity;
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extern unsigned int sysctl_sched_wakeup_granularity;
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extern unsigned int sysctl_sched_child_runs_first;
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enum sched_tunable_scaling {
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SCHED_TUNABLESCALING_NONE,
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SCHED_TUNABLESCALING_LOG,
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SCHED_TUNABLESCALING_LINEAR,
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SCHED_TUNABLESCALING_END,
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};
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extern enum sched_tunable_scaling sysctl_sched_tunable_scaling;
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extern unsigned int sysctl_numa_balancing_scan_delay;
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extern unsigned int sysctl_numa_balancing_scan_period_min;
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extern unsigned int sysctl_numa_balancing_scan_period_max;
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extern unsigned int sysctl_numa_balancing_scan_size;
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#ifdef CONFIG_SCHED_DEBUG
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extern __read_mostly unsigned int sysctl_sched_migration_cost;
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extern __read_mostly unsigned int sysctl_sched_nr_migrate;
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int sched_proc_update_handler(struct ctl_table *table, int write,
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void __user *buffer, size_t *length,
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loff_t *ppos);
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#endif
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/*
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* control realtime throttling:
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*
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* /proc/sys/kernel/sched_rt_period_us
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* /proc/sys/kernel/sched_rt_runtime_us
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*/
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extern unsigned int sysctl_sched_rt_period;
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extern int sysctl_sched_rt_runtime;
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#ifdef CONFIG_UCLAMP_TASK
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extern unsigned int sysctl_sched_uclamp_util_min;
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extern unsigned int sysctl_sched_uclamp_util_max;
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#endif
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#ifdef CONFIG_CFS_BANDWIDTH
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extern unsigned int sysctl_sched_cfs_bandwidth_slice;
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#endif
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#ifdef CONFIG_SCHED_AUTOGROUP
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extern unsigned int sysctl_sched_autogroup_enabled;
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#endif
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extern int sysctl_sched_rr_timeslice;
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extern int sched_rr_timeslice;
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extern int sched_rr_handler(struct ctl_table *table, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos);
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extern int sched_rt_handler(struct ctl_table *table, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos);
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#ifdef CONFIG_UCLAMP_TASK
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extern int sysctl_sched_uclamp_handler(struct ctl_table *table, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos);
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#endif
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extern int sysctl_numa_balancing(struct ctl_table *table, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos);
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extern int sysctl_schedstats(struct ctl_table *table, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos);
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#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
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extern unsigned int sysctl_sched_energy_aware;
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extern int sched_energy_aware_handler(struct ctl_table *table, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos);
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#endif
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#endif /* _LINUX_SCHED_SYSCTL_H */
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