On Tue, 4 Apr 2023 at 14:32, Kal Cutter Conley <kal.conley@xxxxxxxxxxx> wrote: > > > > > > > > Is not the max 64K as you test against XDP_UMEM_MAX_CHUNK_SIZE in > > > > > > > xdp_umem_reg()? > > > > > > > > > > > > The absolute max is 64K. In the case of HPAGE_SIZE < 64K, then it > > > > > > would be HPAGE_SIZE. > > > > > > > > > > Is there such a case when HPAGE_SIZE would be less than 64K? If not, > > > > > then just write 64K. > > > > > > > > Yes. While most platforms have HPAGE_SIZE defined to a compile-time > > > > constant >= 64K (very often 2M) there are platforms (at least ia64 and > > > > powerpc) where the hugepage size is configured at boot. Specifically, > > > > in the case of Itanium (ia64), the hugepage size may be configured at > > > > boot to any valid page size > PAGE_SIZE (e.g. 8K). See: > > > > https://elixir.bootlin.com/linux/latest/source/arch/ia64/mm/hugetlbpage.c#L159 > > > > > > So for all practical purposes it is max 64K. Let us just write that then. > > > > What about when CONFIG_HUGETLB_PAGE is not defined? Should we keep it > > set to PAGE_SIZE in that case, or would you like it to be a fixed > > constant == 64K always? > > Sorry. Now it's not clear to me if you are suggesting the > documentation be changed or the code or both? The documentation.
