In dma_cachectl(), when flushing line by line, only invoke pmap_extract() once per page and cache the result.
In dma_cachectl(), when flushing line by line, only invoke pmap_extract()
once per page and cache the result.

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars