Re: [PATCH V3 2/3] mm/hugetlb: Define a generic fallback for is_hugepage_only_range()

[Anshuman Khandual]

On 05/09/2020 03:52 AM, Mike Kravetz wrote:
> On 5/7/20 8:07 PM, Anshuman Khandual wrote:
>> There are multiple similar definitions for is_hugepage_only_range() on
>> various platforms. Lets just add it's generic fallback definition for
>> platforms that do not override. This help reduce code duplication.
>>
>> Cc: Russell King <linux@xxxxxxxxxxxxxxx>
>> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
>> Cc: Will Deacon <will@xxxxxxxxxx>
>> Cc: Tony Luck <tony.luck@xxxxxxxxx>
>> Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
>> Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
>> Cc: "James E.J. Bottomley" <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
>> Cc: Helge Deller <deller@xxxxxx>
>> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
>> Cc: Paul Mackerras <paulus@xxxxxxxxx>
>> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
>> Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
>> Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
>> Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
>> Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
>> Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx>
>> Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
>> Cc: Rich Felker <dalias@xxxxxxxx>
>> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
>> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
>> Cc: Borislav Petkov <bp@xxxxxxxxx>
>> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
>> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
>> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
>> Cc: x86@xxxxxxxxxx
>> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
>> Cc: linux-ia64@xxxxxxxxxxxxxxx
>> Cc: linux-mips@xxxxxxxxxxxxxxx
>> Cc: linux-parisc@xxxxxxxxxxxxxxx
>> Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
>> Cc: linux-riscv@xxxxxxxxxxxxxxxxxxx
>> Cc: linux-s390@xxxxxxxxxxxxxxx
>> Cc: linux-sh@xxxxxxxxxxxxxxx
>> Cc: sparclinux@xxxxxxxxxxxxxxx
>> Cc: linux-mm@xxxxxxxxx
>> Cc: linux-arch@xxxxxxxxxxxxxxx
>> Cc: linux-kernel@xxxxxxxxxxxxxxx
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
>> ---
>>  arch/arm/include/asm/hugetlb.h     | 6 ------
>>  arch/arm64/include/asm/hugetlb.h   | 6 ------
>>  arch/ia64/include/asm/hugetlb.h    | 1 +
>>  arch/mips/include/asm/hugetlb.h    | 7 -------
>>  arch/parisc/include/asm/hugetlb.h  | 6 ------
>>  arch/powerpc/include/asm/hugetlb.h | 1 +
>>  arch/riscv/include/asm/hugetlb.h   | 6 ------
>>  arch/s390/include/asm/hugetlb.h    | 7 -------
>>  arch/sh/include/asm/hugetlb.h      | 6 ------
>>  arch/sparc/include/asm/hugetlb.h   | 6 ------
>>  arch/x86/include/asm/hugetlb.h     | 6 ------
>>  include/linux/hugetlb.h            | 9 +++++++++
>>  12 files changed, 11 insertions(+), 56 deletions(-)
>>
> <snip>
>> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
>> index 43a1cef8f0f1..c01c0c6f7fd4 100644
>> --- a/include/linux/hugetlb.h
>> +++ b/include/linux/hugetlb.h
>> @@ -591,6 +591,15 @@ static inline unsigned int blocks_per_huge_page(struct hstate *h)
>>  
>>  #include <asm/hugetlb.h>
>>  
>> +#ifndef is_hugepage_only_range
>> +static inline int is_hugepage_only_range(struct mm_struct *mm,
>> +					unsigned long addr, unsigned long len)
>> +{
>> +	return 0;
>> +}
>> +#define is_hugepage_only_range is_hugepage_only_range
>> +#endif
>> +
>>  #ifndef arch_make_huge_pte
>>  static inline pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
>>  				       struct page *page, int writable)
>>
> 
> Did you try building without CONFIG_HUGETLB_PAGE defined?  I'm guessing

Yes I did for multiple platforms (s390, arm64, ia64, x86, powerpc etc).

> that you need a stub for is_hugepage_only_range().  Or, perhaps add this
> to asm-generic/hugetlb.h?
> 
There is already a stub (include/linux/hugetlb.h) when !CONFIG_HUGETLB_PAGE.