[libc] Perform bitfield zero initialization wave-parallel (#143607)

Summary:
We need to set the bitfield memory to zero because the system does not
guarantee zeroed out memory. Even if fresh pages are zero, the system
allows re-use so we would need a `kfd` level API to skip this step.

Because we can't this patch updates the logic to perform the zero
initialization wave-parallel. This reduces the amount of time it takes
to allocate a fresh by up to a tenth.

This has the unfortunate side effect that the control flow is more
convoluted and we waste some extra registers, but it's worth it to
reduce the slab allocation latency.

0 files changed, 0 insertions, 0 deletions