Messages in this thread | | | Date | Fri, 6 Oct 2023 13:01:07 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 3/3] sched/nohz: Remove weird error handling from find_new_ilb() |
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* Peter Zijlstra <peterz@infradead.org> wrote:
> On Fri, Oct 06, 2023 at 12:25:18PM +0200, Ingo Molnar wrote: > > find_new_ilb() returns nr_cpu_ids on failure - which is a weird > > choice in itself: not only is it a global variable, it is > > a +1 out of bounds CPU index... > > FWIW this is what all the cpumask bitops return when they've exhausted > the mask. Eg. no bits left set etc..
yeah, which then results in type-forcing uglies like:
kernel/events/core.c: if ((unsigned)cpu >= nr_cpu_ids) { kernel/events/core.c: if ((unsigned)cpu >= nr_cpu_ids) { kernel/smp.c: if ((unsigned)cpu >= nr_cpu_ids || !cpu_online(cpu)) {
:-/
So I don't think this is a particularly well thought-out interface.
Thanks,
Ingo
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