On Wed, Jan 16, 2019 at 07:57:03AM +0100, Michal Hocko wrote: > On Wed 16-01-19 11:51:32, Anshuman Khandual wrote: > > All architectures have been defining their own PGALLOC_GFP as (GFP_KERNEL | > > __GFP_ZERO) and using it for allocating page table pages. This causes some > > code duplication which can be easily avoided. GFP_KERNEL allocated and > > cleared out pages (__GFP_ZERO) are required for page tables on any given > > architecture. This creates a new generic GFP flag flag which can be used > > for any page table page allocation. Does not cause any functional change. > > > > GFP_PGTABLE is being added into include/asm-generic/pgtable.h which is the > > generic page tabe header just to prevent it's potential misuse as a general > > allocation flag if included in include/linux/gfp.h. > > I haven't reviewed the patch yet but I am wondering whether this is > really worth it without going all the way down to unify the common code > and remove much more code duplication. Or is this not possible for some > reason? Exactly what I suggested doing in response to v1. Also, the approach taken here is crazy. x86 has a feature that no other architecture has bothered to implement yet -- accounting page tables to the process. Yet instead of spreading that goodness to all other architectures, Anshuman has gone to more effort to avoid doing that.
