On Wed, Aug 07, 2019 at 10:30:04AM -0700, Rob Clark wrote: > So, we do end up using GFP_HIGHUSER, which appears to get passed thru > when shmem gets to the point of actually allocating pages.. not sure > if that just ends up being a hint, or if it guarantees that we don't > get something in the linear map. > > (Bear with me while I "page" this all back in.. last time I dug thru > the shmem code was probably pre-armv8, or at least before I had any > armv8 hw)
GFP_HIGHUSER basically just means that this is an allocation that could dip into highmem, in which case it would not have a kernel mapping. This can happen on arm + LPAE, but not on arm64.
