On 09/19/2018 02:02 PM, Keith Busch wrote: > Pinning user pages out of nvdimm dax memory is significantly slower > compared to system ram. Analysis points to software overhead incurred > from a radix tree lookup. This patch series fixes that by removing the > relatively costly dev_pagemap lookup that was repeated for each page, > significantly increasing gup time.
Could you also remind us why DAX pages are such special snowflakes and *require* radix tree lookups in the first place?
