| Date | Mon, 24 Jan 2022 09:06:39 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 48/54] kernel/time: replace cpumask_weight with cpumask_weight_eq where appropriate |
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On Sun, Jan 23, 2022 at 10:39:19AM -0800, Yury Norov wrote: > tick_cleanup_dead_cpu() calls cpumask_weight() to compare the weight > of cpumask with a given number. We can do it more efficiently with > cpumask_weight_eq() because conditional cpumask_weight may stop > traversing the cpumask earlier, as soon as condition is met.
But again, nobody gives a crap about performance here..
> Signed-off-by: Yury Norov <yury.norov@gmail.com> > --- > kernel/time/clockevents.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c > index 003ccf338d20..32d6629a55b2 100644 > --- a/kernel/time/clockevents.c > +++ b/kernel/time/clockevents.c > @@ -648,7 +648,7 @@ void tick_cleanup_dead_cpu(int cpu) > */ > list_for_each_entry_safe(dev, tmp, &clockevent_devices, list) { > if (cpumask_test_cpu(cpu, dev->cpumask) && > - cpumask_weight(dev->cpumask) == 1 && > + cpumask_weight_eq(dev->cpumask, 1) && > !tick_is_broadcast_device(dev)) { > BUG_ON(!clockevent_state_detached(dev)); > list_del(&dev->list); > -- > 2.30.2 >
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