Re: [PATCH 2/6] KVM: selftests: Stash the host page size in a global in the guest_memfd test

Ackerley Tng
2025-09-30T06:52:20Z

Sean Christopherson <seanjc@google.com> writes:

> On Mon, Sep 29, 2025, Ackerley Tng wrote:
>> Sean Christopherson <seanjc@google.com> writes:
>>
>> > Use a global variable to track the host page size in the guest_memfd test
>> > so that the information doesn't need to be constantly passed around. The
>> > state is purely a reflection of the underlying system, i.e. can't be set
>> > by the test and is constant for a given invocation of the test, and thus
>> > explicitly passing the host page size to individual testcases adds no
>> > value, e.g. doesn't allow testing different combinations.
>> >
>>
>> I was going to pass in page_size to each of these test cases to test
>> HugeTLB support, that's how page_size crept into the parameters of these
>> functions.
>>
>> Could we do a getpagesize() within the gmem_test() macro that you
>> introduced instead?
>
> We could, and I actually had it that way to start. But I found that burying the
> effective setting of page_size made it harder to see that it's a runtime constant,
> versus something that can be configured by the test.

I guess I could also just update the global static variable page_size
for HugeTLB tests since we won't be running tests with different page
sizes in parallel. Maybe that's better, actually.