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SubjectRe: [PATCH] RISC-V: Issue a local tlb flush if possible.
On Tue, Aug 13, 2019 at 12:15:15AM +0000, Atish Patra wrote:
> I thought if it recieves an empty cpumask, then it should at least do a
> local flush is the expected behavior. Are you saying that we should
> just skip all and return ?

How could we ever receive an empty cpu mask? I think it could only
be empty without the current cpu. At least that is my reading of
the callers and a few other implementations.

> > if (!cpumask || cpumask_test_cpu(cpu, cpumask) {
> > if ((start == 0 && size == -1) || size > PAGE_SIZE)
> > local_flush_tlb_all();
> > else if (size == PAGE_SIZE)
> > local_flush_tlb_page(start);
> > cpumask_clear_cpu(cpuid, cpumask);
>
> This will modify the original cpumask which is not correct. clear part
> has to be done on hmask to avoid a copy.

Indeed. But looking at the x86 tlbflush implementation it seems like we
could use cpumask_any_but() to avoid having to modify the passed in
cpumask.

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