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Commit fd8cfd30 authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
Browse files

arch: fix has_transparent_hugepage() 



I've just discovered that the useful-sounding has_transparent_hugepage()
is actually an architecture-dependent minefield: on some arches it only
builds if CONFIG_TRANSPARENT_HUGEPAGE=y, on others it's also there when
not, but on some of those (arm and arm64) it then gives the wrong
answer; and on mips alone it's marked __init, which would crash if
called later (but so far it has not been called later).

Straighten this out: make it available to all configs, with a sensible
default in asm-generic/pgtable.h, removing its definitions from those
arches (arc, arm, arm64, sparc, tile) which are served by the default,
adding #define has_transparent_hugepage has_transparent_hugepage to
those (mips, powerpc, s390, x86) which need to override the default at
runtime, and removing the __init from mips (but maybe that kind of code
should be avoided after init: set a static variable the first time it's
called).

Signed-off-by: default avatarHugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andres Lagar-Cavilla <andreslc@google.com>
Cc: Yang Shi <yang.shi@linaro.org>
Cc: Ning Qu <quning@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Acked-by: Vineet Gupta <vgupta@synopsys.com>		[arch/arc]
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>	[arch/s390]
Acked-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1d069b7d

arch/arc/include/asm/hugepage.h

+0 −2
Original line number Diff line number Diff line
@@ -61,8 +61,6 @@ static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr, 
extern void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr,

				 pmd_t *pmd);



#define has_transparent_hugepage() 1



/* Generic variants assume pgtable_t is struct page *, hence need for these */

#define __HAVE_ARCH_PGTABLE_DEPOSIT

extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,

arch/arm/include/asm/pgtable-3level.h

+0 −5
Original line number Diff line number Diff line
@@ -281,11 +281,6 @@ static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr, 
	flush_pmd_entry(pmdp);

}



static inline int has_transparent_hugepage(void)

{

	return 1;

}



#endif /* __ASSEMBLY__ */



#endif /* _ASM_PGTABLE_3LEVEL_H */

arch/arm64/include/asm/pgtable.h

+0 −5
Original line number Diff line number Diff line
@@ -314,11 +314,6 @@ static inline int pmd_protnone(pmd_t pmd) 


#define set_pmd_at(mm, addr, pmdp, pmd)	set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd))



static inline int has_transparent_hugepage(void)

{

	return 1;

}



#define __pgprot_modify(prot,mask,bits) \

	__pgprot((pgprot_val(prot) & ~(mask)) | (bits))

arch/mips/include/asm/pgtable.h

+1 −0
Original line number Diff line number Diff line
@@ -468,6 +468,7 @@ static inline int io_remap_pfn_range(struct vm_area_struct *vma, 


#ifdef CONFIG_TRANSPARENT_HUGEPAGE



#define has_transparent_hugepage has_transparent_hugepage

extern int has_transparent_hugepage(void);



static inline int pmd_trans_huge(pmd_t pmd)

arch/mips/mm/tlb-r4k.c

+11 −10
Original line number Diff line number Diff line
@@ -400,9 +400,11 @@ void add_wired_entry(unsigned long entrylo0, unsigned long entrylo1, 


#ifdef CONFIG_TRANSPARENT_HUGEPAGE



int __init has_transparent_hugepage(void)

int has_transparent_hugepage(void)

{

	unsigned int mask;

	static unsigned int mask = -1;



	if (mask == -1) {	/* first call comes during __init */

		unsigned long flags;



		local_irq_save(flags);
@@ -410,9 +412,8 @@ int __init has_transparent_hugepage(void) 
		back_to_back_c0_hazard();

		mask = read_c0_pagemask();

		write_c0_pagemask(PM_DEFAULT_MASK);



		local_irq_restore(flags);



	}

	return mask == PM_HUGE_MASK;

}