[V2] powerpc/Kconfig: Update config option based on page size.
bsingharora at gmail.com
Wed Apr 20 09:09:38 AEST 2016
On 20/04/16 00:59, Aneesh Kumar K.V wrote:
> Michael Ellerman <mpe at ellerman.id.au> 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 <rashmicy at gmail.com>
>>> Reviewed-by: Balbir Singh <bsingharora at gmail.com>
>> Applied to powerpc next, thanks.
> 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
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!
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