Re: [PATCH v2 1/2] mm/hugetlb: Cleanup ARCH_HAS_GIGANTIC_PAGE

[Aneesh Kumar K.V]

On Tuesday 16 May 2017 03:52 PM, Anshuman Khandual wrote:
> On 05/16/2017 02:47 PM, Aneesh Kumar K.V wrote:
> > This moves the #ifdef in C code to a Kconfig dependency. Also we move the
> > gigantic_page_supported() function to be arch specific. This gives arch to
> > conditionally enable runtime allocation of gigantic huge page. Architectures
> > like ppc64 supports different gigantic huge page size (16G and 1G) based on the
> > translation mode selected. This provides an opportunity for ppc64 to enable
> > runtime allocation only w.r.t 1G hugepage.
>
> Right.
>
> > No functional change in this patch.
> >
> > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
> > ---
> >  arch/arm64/Kconfig               | 2 +-
> >  arch/arm64/include/asm/hugetlb.h | 4 ++++
> >  arch/s390/Kconfig                | 2 +-
> >  arch/s390/include/asm/hugetlb.h  | 3 +++
> >  arch/x86/Kconfig                 | 2 +-
> >  mm/hugetlb.c                     | 7 ++-----
> >  6 files changed, 12 insertions(+), 8 deletions(-)
> >
> > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > index 3741859765cf..1f8c1f73aada 100644
> > --- a/arch/arm64/Kconfig
> > +++ b/arch/arm64/Kconfig
> > @@ -11,7 +11,7 @@ config ARM64
> >  	select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
> >  	select ARCH_HAS_ELF_RANDOMIZE
> >  	select ARCH_HAS_GCOV_PROFILE_ALL
> > -	select ARCH_HAS_GIGANTIC_PAGE
> > +	select ARCH_HAS_GIGANTIC_PAGE if MEMORY_ISOLATION && COMPACTION && CMA
> >  	select ARCH_HAS_KCOV
> >  	select ARCH_HAS_SET_MEMORY
> >  	select ARCH_HAS_SG_CHAIN
> > diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/hugetlb.h
> > index bbc1e35aa601..793bd73b0d07 100644
> > --- a/arch/arm64/include/asm/hugetlb.h
> > +++ b/arch/arm64/include/asm/hugetlb.h
> > @@ -83,4 +83,8 @@ extern void huge_ptep_set_wrprotect(struct mm_struct *mm,
> >  extern void huge_ptep_clear_flush(struct vm_area_struct *vma,
> >  				  unsigned long addr, pte_t *ptep);
> >
> > +#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
> > +static inline bool gigantic_page_supported(void) { return true; }
> > +#endif
> > +
> >  #endif /* __ASM_HUGETLB_H */
> > diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> > index a2dcef0aacc7..a41bbf420dda 100644
> > --- a/arch/s390/Kconfig
> > +++ b/arch/s390/Kconfig
> > @@ -67,7 +67,7 @@ config S390
> >  	select ARCH_HAS_DEVMEM_IS_ALLOWED
> >  	select ARCH_HAS_ELF_RANDOMIZE
> >  	select ARCH_HAS_GCOV_PROFILE_ALL
> > -	select ARCH_HAS_GIGANTIC_PAGE
> > +	select ARCH_HAS_GIGANTIC_PAGE if MEMORY_ISOLATION && COMPACTION && CMA
> >  	select ARCH_HAS_KCOV
> >  	select ARCH_HAS_SET_MEMORY
> >  	select ARCH_HAS_SG_CHAIN
> > diff --git a/arch/s390/include/asm/hugetlb.h b/arch/s390/include/asm/hugetlb.h
> > index cd546a245c68..89057b2cc8fe 100644
> > --- a/arch/s390/include/asm/hugetlb.h
> > +++ b/arch/s390/include/asm/hugetlb.h
> > @@ -112,4 +112,7 @@ static inline pte_t huge_pte_modify(pte_t pte, pgprot_t newprot)
> >  	return pte_modify(pte, newprot);
> >  }
> >
> > +#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
> > +static inline bool gigantic_page_supported(void) { return true; }
> > +#endif
> >  #endif /* _ASM_S390_HUGETLB_H */
> > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> > index cc98d5a294ee..30a6328136ac 100644
> > --- a/arch/x86/Kconfig
> > +++ b/arch/x86/Kconfig
> > @@ -22,7 +22,7 @@ config X86_64
> >  	def_bool y
> >  	depends on 64BIT
> >  	# Options that are inherently 64-bit kernel only:
> > -	select ARCH_HAS_GIGANTIC_PAGE
> > +	select ARCH_HAS_GIGANTIC_PAGE if MEMORY_ISOLATION && COMPACTION && CMA
> >  	select ARCH_SUPPORTS_INT128
> >  	select ARCH_USE_CMPXCHG_LOCKREF
> >  	select HAVE_ARCH_SOFT_DIRTY
>
> Should not we define gigantic_page_supported() function for X86 as well
> like the other two archs above ?

yes. Will update the patch.

-aneesh