Re: [PATCH v7 6/6] arm64: mm: Optimize linear_map_split_to_ptes()

On Fri, Aug 29, 2025 at 12:52:47PM +0100, Ryan Roberts wrote:

When splitting kernel leaf mappings, either via
split_kernel_leaf_mapping_locked() or linear_map_split_to_ptes(),
previously a leaf mapping was always split to the next size down. e.g.
pud -> contpmd -> pmd -> contpte -> pte. But for
linear_map_split_to_ptes() we can avoid the contpmd and contpte states
because we know we want to split all the way down to ptes.

This avoids visiting all the ptes in a table if it was created by
splitting a pmd, which is noticible on systems with a lot of memory.

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>