On 20/04/16 00:59, Aneesh Kumar K.V wrote: > Michael Ellerman <[email protected]> writes: > >> On Fri, 2016-19-02 at 05:38:47 UTC, Rashmica Gupta wrote: >>> Currently on PPC64 changing kernel pagesize from 4K to 64K leaves >>> FORCE_MAX_ZONEORDER set to 13 - which produces a compile error. >>> >> ... >>> So, update the range of FORCE_MAX_ZONEORDER from 9-64 to 8-9 for 64K pages >>> and from 13-64 to 9-13 for 4K pages. >>> >>> Signed-off-by: Rashmica Gupta <[email protected]> >>> Reviewed-by: Balbir Singh <[email protected]> >> >> Applied to powerpc next, thanks. >> >> https://git.kernel.org/powerpc/c/a7ee539584acf4a565b7439cea >> > > HPAGE_PMD_ORDER is not something we should check w.r.t 4k linux page > size. We do have the below constraint w.r.t hugetlb pages > > static inline bool hstate_is_gigantic(struct hstate *h) > { > return huge_page_order(h) >= MAX_ORDER; > } > > That require MAX_ORDER to be greater than 12. >
The build will fail for MAX_ZONEORDER beyond the specified limits. MAX_ORDER > 12 for what page size? My understanding is this 1. gigantic refers to the fact the regular allocators cannot allocate this page 2. Use alloc_contig_range() with CONFIG_CMA for gigantic pages I could be wrong > Did we test hugetlbfs 4k config with this patch ? Will it work if we > start marking hugepage as gigantic page ? Nope.. I did not Thanks for the review! Balbir Singh _______________________________________________ Linuxppc-dev mailing list [email protected] https://lists.ozlabs.org/listinfo/linuxppc-dev
