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: Hugh 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: David 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: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Hugh Dickins 2016-05-19 17:13:00 -07:00 committed by Linus Torvalds
parent 1d069b7dd5
commit fd8cfd3000
12 changed files with 23 additions and 26 deletions

View File

@ -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,

View File

@ -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 */

View File

@ -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))

View File

@ -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)

View File

@ -400,19 +400,20 @@ 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;
unsigned long flags;
static unsigned int mask = -1;
local_irq_save(flags);
write_c0_pagemask(PM_HUGE_MASK);
back_to_back_c0_hazard();
mask = read_c0_pagemask();
write_c0_pagemask(PM_DEFAULT_MASK);
local_irq_restore(flags);
if (mask == -1) { /* first call comes during __init */
unsigned long flags;
local_irq_save(flags);
write_c0_pagemask(PM_HUGE_MASK);
back_to_back_c0_hazard();
mask = read_c0_pagemask();
write_c0_pagemask(PM_DEFAULT_MASK);
local_irq_restore(flags);
}
return mask == PM_HUGE_MASK;
}

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@ -219,6 +219,7 @@ extern void set_pmd_at(struct mm_struct *mm, unsigned long addr,
pmd_t *pmdp, pmd_t pmd);
extern void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr,
pmd_t *pmd);
#define has_transparent_hugepage has_transparent_hugepage
extern int has_transparent_hugepage(void);
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

View File

@ -65,7 +65,6 @@ extern int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
struct page **pages, int *nr);
#ifndef CONFIG_TRANSPARENT_HUGEPAGE
#define pmd_large(pmd) 0
#define has_transparent_hugepage() 0
#endif
pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
bool *is_thp, unsigned *shift);

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@ -1223,6 +1223,7 @@ static inline int pmd_trans_huge(pmd_t pmd)
return pmd_val(pmd) & _SEGMENT_ENTRY_LARGE;
}
#define has_transparent_hugepage has_transparent_hugepage
static inline int has_transparent_hugepage(void)
{
return MACHINE_HAS_HPAGE ? 1 : 0;

View File

@ -681,8 +681,6 @@ static inline unsigned long pmd_trans_huge(pmd_t pmd)
return pte_val(pte) & _PAGE_PMD_HUGE;
}
#define has_transparent_hugepage() 1
static inline pmd_t pmd_mkold(pmd_t pmd)
{
pte_t pte = __pte(pmd_val(pmd));

View File

@ -487,7 +487,6 @@ static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#define has_transparent_hugepage() 1
#define pmd_trans_huge pmd_huge_page
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

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@ -181,6 +181,7 @@ static inline int pmd_trans_huge(pmd_t pmd)
return (pmd_val(pmd) & (_PAGE_PSE|_PAGE_DEVMAP)) == _PAGE_PSE;
}
#define has_transparent_hugepage has_transparent_hugepage
static inline int has_transparent_hugepage(void)
{
return boot_cpu_has(X86_FEATURE_PSE);

View File

@ -806,4 +806,12 @@ static inline int pmd_clear_huge(pmd_t *pmd)
#define io_remap_pfn_range remap_pfn_range
#endif
#ifndef has_transparent_hugepage
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#define has_transparent_hugepage() 1
#else
#define has_transparent_hugepage() 0
#endif
#endif
#endif /* _ASM_GENERIC_PGTABLE_H */