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| author | Frederic Weisbecker <fweisbec@gmail.com> | 2013-05-03 03:39:05 +0200 |
|---|---|---|
| committer | Frederic Weisbecker <fweisbec@gmail.com> | 2013-05-04 08:32:02 +0200 |
| commit | 265f22a975c1e4cc3a4d1f94a3ec53ffbb6f5b9f (patch) | |
| tree | c5b7ec6b64fc31e879e730d2edf8e836cfaf7e9b /include/linux/sched.h | |
| parent | 73c30828771acafb0a5e3a1c4cf75e6c5dc5f98a (diff) | |
| download | lwn-265f22a975c1e4cc3a4d1f94a3ec53ffbb6f5b9f.tar.gz lwn-265f22a975c1e4cc3a4d1f94a3ec53ffbb6f5b9f.zip | |
sched: Keep at least 1 tick per second for active dynticks tasks
The scheduler doesn't yet fully support environments
with a single task running without a periodic tick.
In order to ensure we still maintain the duties of scheduler_tick(),
keep at least 1 tick per second.
This makes sure that we keep the progression of various scheduler
accounting and background maintainance even with a very low granularity.
Examples include cpu load, sched average, CFS entity vruntime,
avenrun and events such as load balancing, amongst other details
handled in sched_class::task_tick().
This limitation will be removed in the future once we get
these individual items to work in full dynticks CPUs.
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include/linux/sched.h')
| -rw-r--r-- | include/linux/sched.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index ebf7095158a9..af008d7bad57 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1862,6 +1862,7 @@ static inline void wake_up_nohz_cpu(int cpu) { } #ifdef CONFIG_NO_HZ_FULL extern bool sched_can_stop_tick(void); +extern u64 scheduler_tick_max_deferment(void); #else static inline bool sched_can_stop_tick(void) { return false; } #endif |