path: root/init
diff options
authorLinus Torvalds <torvalds@linux-foundation.org>2019-07-08 16:39:53 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-08 16:39:53 -0700
commitdad1c12ed831a7a89cc01e5582cd0b81a4be7f19 (patch)
tree7a84799d3108bd9d3f1d4b530afd3ff9300db982 /init
parent090bc5a2a91499c1fd64b78d125daa6ca5531d38 (diff)
parentaf24bde8df2029f067dc46aff0393c8f18ff6e2f (diff)
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar: - Remove the unused per rq load array and all its infrastructure, by Dietmar Eggemann. - Add utilization clamping support by Patrick Bellasi. This is a refinement of the energy aware scheduling framework with support for boosting of interactive and capping of background workloads: to make sure critical GUI threads get maximum frequency ASAP, and to make sure background processing doesn't unnecessarily move to cpufreq governor to higher frequencies and less energy efficient CPU modes. - Add the bare minimum of tracepoints required for LISA EAS regression testing, by Qais Yousef - which allows automated testing of various power management features, including energy aware scheduling. - Restructure the former tsk_nr_cpus_allowed() facility that the -rt kernel used to modify the scheduler's CPU affinity logic such as migrate_disable() - introduce the task->cpus_ptr value instead of taking the address of &task->cpus_allowed directly - by Sebastian Andrzej Siewior. - Misc optimizations, fixes, cleanups and small enhancements - see the Git log for details. * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits) sched/uclamp: Add uclamp support to energy_compute() sched/uclamp: Add uclamp_util_with() sched/cpufreq, sched/uclamp: Add clamps for FAIR and RT tasks sched/uclamp: Set default clamps for RT tasks sched/uclamp: Reset uclamp values on RESET_ON_FORK sched/uclamp: Extend sched_setattr() to support utilization clamping sched/core: Allow sched_setattr() to use the current policy sched/uclamp: Add system default clamps sched/uclamp: Enforce last task's UCLAMP_MAX sched/uclamp: Add bucket local max tracking sched/uclamp: Add CPU's clamp buckets refcounting sched/fair: Rename weighted_cpuload() to cpu_runnable_load() sched/debug: Export the newly added tracepoints sched/debug: Add sched_overutilized tracepoint sched/debug: Add new tracepoint to track PELT at se level sched/debug: Add new tracepoints to track PELT at rq level sched/debug: Add a new sched_trace_*() helper functions sched/autogroup: Make autogroup_path() always available sched/wait: Deduplicate code with do-while sched/topology: Remove unused 'sd' parameter from arch_scale_cpu_capacity() ...
Diffstat (limited to 'init')
2 files changed, 55 insertions, 1 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 0e2344389501..c88289c18d59 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -677,6 +677,59 @@ config HAVE_UNSTABLE_SCHED_CLOCK
+menu "Scheduler features"
+ bool "Enable utilization clamping for RT/FAIR tasks"
+ help
+ This feature enables the scheduler to track the clamped utilization
+ of each CPU based on RUNNABLE tasks scheduled on that CPU.
+ With this option, the user can specify the min and max CPU
+ utilization allowed for RUNNABLE tasks. The max utilization defines
+ the maximum frequency a task should use while the min utilization
+ defines the minimum frequency it should use.
+ Both min and max utilization clamp values are hints to the scheduler,
+ aiming at improving its frequency selection policy, but they do not
+ enforce or grant any specific bandwidth for tasks.
+ If in doubt, say N.
+ int "Number of supported utilization clamp buckets"
+ range 5 20
+ default 5
+ depends on UCLAMP_TASK
+ help
+ Defines the number of clamp buckets to use. The range of each bucket
+ number of clamp buckets the finer their granularity and the higher
+ the precision of clamping aggregation and tracking at run-time.
+ For example, with the minimum configuration value we will have 5
+ clamp buckets tracking 20% utilization each. A 25% boosted tasks will
+ be refcounted in the [20..39]% bucket and will set the bucket clamp
+ effective value to 25%.
+ If a second 30% boosted task should be co-scheduled on the same CPU,
+ that task will be refcounted in the same bucket of the first task and
+ it will boost the bucket clamp effective value to 30%.
+ The clamp effective value of a bucket is reset to its nominal value
+ (20% in the example above) when there are no more tasks refcounted in
+ that bucket.
+ An additional boost/capping margin can be added to some tasks. In the
+ example above the 25% task will be boosted to 30% until it exits the
+ CPU. If that should be considered not acceptable on certain systems,
+ it's always possible to reduce the margin by increasing the number of
+ clamp buckets to trade off used memory for run-time tracking
+ precision.
+ If in doubt, use the default value.
# For architectures that want to enable the support for NUMA-affine scheduler
# balancing logic:
diff --git a/init/init_task.c b/init/init_task.c
index afa6ad795355..7ab773b9b3cd 100644
--- a/init/init_task.c
+++ b/init/init_task.c
@@ -72,7 +72,8 @@ struct task_struct init_task
.static_prio = MAX_PRIO - 20,
.normal_prio = MAX_PRIO - 20,
.policy = SCHED_NORMAL,
- .cpus_allowed = CPU_MASK_ALL,
+ .cpus_ptr = &init_task.cpus_mask,
+ .cpus_mask = CPU_MASK_ALL,
.nr_cpus_allowed= NR_CPUS,
.mm = NULL,
.active_mm = &init_mm,

Privacy Policy