Messages in this thread Patch in this message | | | Date | Fri, 20 Jan 2023 23:25:40 +0100 | From | Frederic Weisbecker <> | Subject | Re: [PATCH] tick/nohz: Fix cpu_is_hotpluggable() by checking with nohz subsystem |
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On Thu, Jan 19, 2023 at 08:44:35PM +0000, Joel Fernandes (Google) wrote: > -static int tick_nohz_cpu_down(unsigned int cpu) > +static int tick_nohz_cpu_hotplug_ret(unsigned int cpu) > { > /* > * The tick_do_timer_cpu CPU handles housekeeping duty (unbound > @@ -522,6 +522,16 @@ static int tick_nohz_cpu_down(unsigned int cpu) > return 0; > } > > +static int tick_nohz_cpu_down(unsigned int cpu) > +{ > + return tick_nohz_cpu_hotplug_ret(cpu); > +} > + > +bool tick_nohz_cpu_hotpluggable(unsigned int cpu) > +{ > + return tick_nohz_cpu_hotplug_ret(cpu) == 0;
This is still calling the hotplug function for the CPU in order to know if the CPU is hotpluggable...
Why not:
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index ba2ac1469d47..a46506f7ec6d 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -532,7 +532,7 @@ void __init tick_nohz_full_setup(cpumask_var_t cpumask) tick_nohz_full_running = true; } -static int tick_nohz_cpu_down(unsigned int cpu) +bool tick_nohz_cpu_hotpluggable(unsigned int cpu) { /* * The tick_do_timer_cpu CPU handles housekeeping duty (unbound @@ -540,8 +540,13 @@ static int tick_nohz_cpu_down(unsigned int cpu) * CPUs. It must remain online when nohz full is enabled. */ if (tick_nohz_full_running && tick_do_timer_cpu == cpu) - return -EBUSY; - return 0; + return false; + return true; +} + +static int tick_nohz_cpu_down(unsigned int cpu) +{ + return tick_nohz_cpu_hotpluggable(cpu) ? 0 : -EBUSY; } void __init tick_nohz_init(void)
> void __init tick_nohz_init(void) > { > int cpu, ret; > -- > 2.39.0.246.g2a6d74b583-goog >
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