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tick: Sched: Restructure code 

Get rid of one indentation level. Preparatory patch for a major
rework. No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Link: http://lkml.kernel.org/r/20150414203502.101563235@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner 2015-04-14 21:08:56 +00:00
parent 0ff53d0964
commit 157d29e101
1 changed files with 93 additions and 102 deletions
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55
kernel/time/tick-sched.c
View File

@ -611,28 +611,26 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,
}
}
/*
* Do not stop the tick, if we are only one off (or less)
* or if the cpu is required for RCU:
*/
if (!ts->tick_stopped && delta_jiffies <= 1)
if ((long)delta_jiffies <= 1) {
if (!ts->tick_stopped)
goto out;
/* Schedule the tick, if we are at least one jiffie off */
if ((long)delta_jiffies >= 1) {
if (delta_jiffies == 0) {
/* Tick is stopped, but required now. Enforce it */
tick_nohz_restart(ts, now);
goto out;
}
}
/*
* If this cpu is the one which updates jiffies, then
* give up the assignment and let it be taken by the
* cpu which runs the tick timer next, which might be
* this cpu as well. If we don't drop this here the
* jiffies might be stale and do_timer() never
* invoked. Keep track of the fact that it was the one
* which had the do_timer() duty last. If this cpu is
* the one which had the do_timer() duty last, we
* limit the sleep time to the timekeeping
* max_deferement value which we retrieved
* above. Otherwise we can sleep as long as we want.
* If this cpu is the one which updates jiffies, then give up
* the assignment and let it be taken by the cpu which runs
* the tick timer next, which might be this cpu as well. If we
* don't drop this here the jiffies might be stale and
* do_timer() never invoked. Keep track of the fact that it
* was the one which had the do_timer() duty last. If this cpu
* is the one which had the do_timer() duty last, we limit the
* sleep time to the timekeeping max_deferement value which we
* retrieved above. Otherwise we can sleep as long as we want.
*/
if (cpu == tick_do_timer_cpu) {
tick_do_timer_cpu = TICK_DO_TIMER_NONE;
@ -645,18 +643,16 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,
}
#ifdef CONFIG_NO_HZ_FULL
if (!ts->inidle) {
time_delta = min(time_delta,
scheduler_tick_max_deferment());
}
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
* that there is no timer pending or at least extremely
* far into the future (12 days for HZ=1000). In this
* case we set the expiry to the end of time.
* timer. delta_jiffies >= NEXT_TIMER_MAX_DELTA signals that
* there is no timer pending or at least extremely far into
* the future (12 days for HZ=1000). In this case we set the
* expiry to the end of time.
*/
if (likely(delta_jiffies < NEXT_TIMER_MAX_DELTA)) {
/*
@ -712,11 +708,6 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,
HRTIMER_MODE_ABS_PINNED);
else
tick_program_event(expires, 1);
} else {
/* Tick is stopped, but required now. Enforce it */
tick_nohz_restart(ts, now);
}
out:
ts->next_jiffies = next_jiffies;
ts->last_jiffies = last_jiffies;