Messages in this thread | | | Date | Tue, 8 Nov 2022 18:02:11 +0100 (CET) | From | Anna-Maria Behnsen <> | Subject | Re: [PATCH v4 14/16] timer: Implement the hierarchical pull model |
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On Tue, 8 Nov 2022, Frederic Weisbecker wrote:
> On Fri, Nov 04, 2022 at 03:57:35PM +0100, Anna-Maria Behnsen wrote: > > @@ -1859,6 +1863,36 @@ void forward_and_idle_timer_bases(unsigned long basej, u64 basem, > > */ > > is_idle = time_after(nextevt, basej + 1); > > > > + if (is_idle) { > > + u64 next_tmigr; > > + > > + next_tmigr = tmigr_cpu_deactivate(tevt->global); > > + > > + tevt->global = KTIME_MAX; > > + > > + /* > > + * If CPU is the last going idle in timer migration > > + * hierarchy, make sure CPU will wake up in time to handle > > + * remote timers. next_tmigr == KTIME_MAX if other CPUs are > > + * still active. > > + */ > > + if (next_tmigr < tevt->local) { > > + u64 tmp; > > + > > + /* If we missed a tick already, force 0 delta */ > > + if (next_tmigr < basem) > > + next_tmigr = basem; > > + > > + tmp = div_u64(next_tmigr - basem, TICK_NSEC); > > + > > + nextevt = basej + (unsigned long)tmp; > > + tevt->local = next_tmigr; > > + is_idle = time_after(nextevt, basej + 1); > > So after that, tevt->global shouldn't matter anymore for tick_nohz_next_event(), > right? If so then probably that line can go away (with a comment specifying why we can > ignore the global part)?: > > tevt.local = min_t(u64, tevt.local, tevt.global); >
tevt->global is set to KTIME_MAX anyway. So the whole tevt information is also no longer required in tick_nohz_next_event(). I need to rework the patch where this was introduced. Then the forward_and_idle_timer_bases() could still simply return the next timer and then there is no longer a point against using your idea with naming of the functions.
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