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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 /kernel/time/tick-sched.c | |
| parent | rcu: Fix full dynticks' dependency on wide RCU nocb mode (diff) | |
| download | linux-265f22a975c1e4cc3a4d1f94a3ec53ffbb6f5b9f.tar.xz linux-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 'kernel/time/tick-sched.c')
| -rw-r--r-- | kernel/time/tick-sched.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 1c9f53b2ddb7..07929c633570 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -600,6 +600,13 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts, time_delta = KTIME_MAX; } +#ifdef CONFIG_NO_HZ_FULL + if (!ts->inidle) { + time_delta = min(time_delta, + scheduler_tick_max_deferment()); + } +#endif + /* * calculate the expiry time for the next timer wheel * timer. delta_jiffies >= NEXT_TIMER_MAX_DELTA signals |