Messages in this thread | | | Date | Thu, 9 Mar 2023 17:30:12 +0100 | From | Frederic Weisbecker <> | Subject | Re: [PATCH v5 11/18] timer: Split out "get next timer interrupt" functionality |
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Le Wed, Mar 01, 2023 at 03:17:37PM +0100, Anna-Maria Behnsen a écrit : > The functionallity for getting the next timer interrupt in > get_next_timer_interrupt() is splitted into a separate function > fetch_next_timer_interrupt() to be usable by other callsides. > > This is preparatory work for the conversion of the NOHZ timer > placement to a pull at expiry time model. No functional change. > > Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de> [...] > diff --git a/kernel/time/timer.c b/kernel/time/timer.c > index ff41d978cb22..dfc744545159 100644 > --- a/kernel/time/timer.c > +++ b/kernel/time/timer.c > @@ -2040,31 +2071,9 @@ u64 get_next_timer_interrupt(unsigned long basej, u64 basem) > if (time_before(nextevt, basej)) > nextevt = basej; > tevt.local = basem + (u64)(nextevt - basej) * TICK_NSEC; > - goto unlock; > + tevt.global = KTIME_MAX; > } > > - /* > - * If the bases are marked idle, i.e. the next event on both the > - * local and the global queue are farther away than a tick, > - * evaluate both bases. No need to check whether one of the bases > - * has an already expired timer as this is caught by the !is_idle > - * condition above. > - */ > - if (base_local->timers_pending) > - tevt.local = basem + (u64)(nextevt_local - basej) * TICK_NSEC; > - > - /* > - * If the local queue expires first, then the global event can be > - * ignored. The CPU wakes up before that. If the global queue is > - * empty, nothing to do either. > - */ > - if (!local_first && base_global->timers_pending) > - tevt.global = basem + (u64)(nextevt_global - basej) * TICK_NSEC; > - > -unlock: > - raw_spin_unlock(&base_global->lock); > - raw_spin_unlock(&base_local->lock); > - > tevt.local = min_t(u64, tevt.local, tevt.global);
So if you leave that last line, it means that the CPU will eventually and unconditionally wake up for the next global timer if it's before the next local timer. Am I understanding this right and, if so, is that intended?
Thanks.
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