Messages in this thread | | | Date | Wed, 4 Oct 2023 11:43:30 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v4] sched/core: Use zero length to reset cpumasks in sched_setaffinity() |
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On Wed, Oct 04, 2023 at 11:23:41AM +0200, Ingo Molnar wrote:
> > if (user_mask) { > > - cpumask_copy(user_mask, in_mask); > > + /* > > + * All-set user cpumask resets affinity and drops the explicit > > + * user mask. > > + */ > > + cpumask_and(user_mask, in_mask, cpu_possible_mask); > > + if (cpumask_equal(user_mask, cpu_possible_mask)) { > > + kfree(user_mask); > > + user_mask = NULL; > > + } > > Question: is there any observable behavioral difference between current > (old) all-set cpumask calls and the patched (new) one?
Very little I think -- the main difference is that we no longer carry the ->user_cpus_ptr mask around, and that saves a little masking.
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