* [PATCH 10/10] arch: fix has_transparent_hugepage()
2016-04-05 21:02 ` [PATCH 10/10] arch: fix has_transparent_hugepage() Hugh Dickins
@ 2016-04-05 21:02 ` Hugh Dickins
2016-04-05 23:25 ` David Miller
` (3 subsequent siblings)
4 siblings, 0 replies; 11+ messages in thread
From: Hugh Dickins @ 2016-04-05 21:02 UTC (permalink / raw)
To: Andrew Morton
Cc: Kirill A. Shutemov, Andrea Arcangeli, Andres Lagar-Cavilla,
Yang Shi, Ning Qu, Arnd Bergman, Ralf Baechle, Vineet Gupta,
Russell King, Will Deacon, Michael Ellerman, Aneesh Kumar K.V,
Martin Schwidefsky, Gerald Schaefer, David Miller, Chris Metcalf,
Ingo Molnar, linux-kernel, linux-arch, linux-mm
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>
---
arch/arc/include/asm/hugepage.h | 2 -
arch/arm/include/asm/pgtable-3level.h | 5 ----
arch/arm64/include/asm/pgtable.h | 5 ----
arch/mips/include/asm/pgtable.h | 1
arch/mips/mm/tlb-r4k.c | 21 ++++++++---------
arch/powerpc/include/asm/book3s/64/pgtable.h | 1
arch/powerpc/include/asm/pgtable.h | 1
arch/s390/include/asm/pgtable.h | 1
arch/sparc/include/asm/pgtable_64.h | 2 -
arch/tile/include/asm/pgtable.h | 1
arch/x86/include/asm/pgtable.h | 1
include/asm-generic/pgtable.h | 8 ++++++
12 files changed, 23 insertions(+), 26 deletions(-)
--- a/arch/arc/include/asm/hugepage.h
+++ b/arch/arc/include/asm/hugepage.h
@@ -61,8 +61,6 @@ static inline void set_pmd_at(struct mm_
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,
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -281,11 +281,6 @@ static inline void set_pmd_at(struct mm_
flush_pmd_entry(pmdp);
}
-static inline int has_transparent_hugepage(void)
-{
- return 1;
-}
-
#endif /* __ASSEMBLY__ */
#endif /* _ASM_PGTABLE_3LEVEL_H */
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -304,11 +304,6 @@ static inline pgprot_t mk_sect_prot(pgpr
#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))
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -468,6 +468,7 @@ static inline int io_remap_pfn_range(str
#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)
--- a/arch/mips/mm/tlb-r4k.c
+++ b/arch/mips/mm/tlb-r4k.c
@@ -399,19 +399,20 @@ void add_wired_entry(unsigned long entry
#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;
}
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -219,6 +219,7 @@ extern void set_pmd_at(struct mm_struct
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 */
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -65,7 +65,6 @@ extern int gup_hugepte(pte_t *ptep, unsi
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);
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1223,6 +1223,7 @@ static inline int pmd_trans_huge(pmd_t p
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;
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -681,8 +681,6 @@ static inline unsigned long pmd_trans_hu
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));
--- a/arch/tile/include/asm/pgtable.h
+++ b/arch/tile/include/asm/pgtable.h
@@ -487,7 +487,6 @@ static inline pmd_t pmd_modify(pmd_t pmd
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-#define has_transparent_hugepage() 1
#define pmd_trans_huge pmd_huge_page
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -181,6 +181,7 @@ static inline int pmd_trans_huge(pmd_t p
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 cpu_has_pse;
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -806,4 +806,12 @@ static inline int pmd_clear_huge(pmd_t *
#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 */
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH 10/10] arch: fix has_transparent_hugepage()
2016-04-05 21:02 ` [PATCH 10/10] arch: fix has_transparent_hugepage() Hugh Dickins
2016-04-05 21:02 ` Hugh Dickins
@ 2016-04-05 23:25 ` David Miller
2016-04-05 23:25 ` David Miller
2016-04-06 3:22 ` Vineet Gupta
` (2 subsequent siblings)
4 siblings, 1 reply; 11+ messages in thread
From: David Miller @ 2016-04-05 23:25 UTC (permalink / raw)
To: hughd
Cc: akpm, kirill.shutemov, aarcange, andreslc, yang.shi, quning, arnd,
ralf, vgupta, linux, will.deacon, mpe, aneesh.kumar, schwidefsky,
gerald.schaefer, cmetcalf, mingo, linux-kernel, linux-arch,
linux-mm
From: Hugh Dickins <hughd@google.com>
Date: Tue, 5 Apr 2016 14:02:49 -0700 (PDT)
> 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>
Acked-by: David S. Miller <davem@davemloft.net>
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^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH 10/10] arch: fix has_transparent_hugepage()
2016-04-05 23:25 ` David Miller
@ 2016-04-05 23:25 ` David Miller
0 siblings, 0 replies; 11+ messages in thread
From: David Miller @ 2016-04-05 23:25 UTC (permalink / raw)
To: hughd
Cc: akpm, kirill.shutemov, aarcange, andreslc, yang.shi, quning, arnd,
ralf, vgupta, linux, will.deacon, mpe, aneesh.kumar, schwidefsky,
gerald.schaefer, cmetcalf, mingo, linux-kernel, linux-arch,
linux-mm
From: Hugh Dickins <hughd@google.com>
Date: Tue, 5 Apr 2016 14:02:49 -0700 (PDT)
> 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>
Acked-by: David S. Miller <davem@davemloft.net>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH 10/10] arch: fix has_transparent_hugepage()
2016-04-05 21:02 ` [PATCH 10/10] arch: fix has_transparent_hugepage() Hugh Dickins
2016-04-05 21:02 ` Hugh Dickins
2016-04-05 23:25 ` David Miller
@ 2016-04-06 3:22 ` Vineet Gupta
2016-04-06 6:58 ` Ingo Molnar
2016-04-06 11:56 ` Gerald Schaefer
4 siblings, 0 replies; 11+ messages in thread
From: Vineet Gupta @ 2016-04-06 3:22 UTC (permalink / raw)
To: Hugh Dickins, Andrew Morton
Cc: Kirill A. Shutemov, Andrea Arcangeli, Andres Lagar-Cavilla,
Yang Shi, Ning Qu, Arnd Bergman, Ralf Baechle, Russell King,
Will Deacon, Michael Ellerman, Aneesh Kumar K.V,
Martin Schwidefsky, Gerald Schaefer, David Miller, Chris Metcalf,
Ingo Molnar, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, linux-mm@kvack.org
On Wednesday 06 April 2016 02:32 AM, Hugh Dickins wrote:
> 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>
Acked-by: Vineet Gupta <vgupta@synopsys.com> # for arch/arc bits
Thx,
-Vineet
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^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH 10/10] arch: fix has_transparent_hugepage()
2016-04-05 21:02 ` [PATCH 10/10] arch: fix has_transparent_hugepage() Hugh Dickins
` (2 preceding siblings ...)
2016-04-06 3:22 ` Vineet Gupta
@ 2016-04-06 6:58 ` Ingo Molnar
2016-04-06 6:58 ` Ingo Molnar
2016-04-06 12:29 ` Chris Metcalf
2016-04-06 11:56 ` Gerald Schaefer
4 siblings, 2 replies; 11+ messages in thread
From: Ingo Molnar @ 2016-04-06 6:58 UTC (permalink / raw)
To: Hugh Dickins
Cc: Andrew Morton, Kirill A. Shutemov, Andrea Arcangeli,
Andres Lagar-Cavilla, Yang Shi, Ning Qu, Arnd Bergman,
Ralf Baechle, Vineet Gupta, Russell King, Will Deacon,
Michael Ellerman, Aneesh Kumar K.V, Martin Schwidefsky,
Gerald Schaefer, David Miller, Chris Metcalf, linux-kernel,
linux-arch, linux-mm
* Hugh Dickins <hughd@google.com> wrote:
> --- a/arch/x86/include/asm/pgtable.h
> +++ b/arch/x86/include/asm/pgtable.h
> @@ -181,6 +181,7 @@ static inline int pmd_trans_huge(pmd_t p
> 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 cpu_has_pse;
Small nit, just writing:
#define has_transparent_hugepage
ought to be enough, right?
In any case:
Acked-by: Ingo Molnar <mingo@kernel.org>
Another nit, this:
> --- a/include/asm-generic/pgtable.h
> +++ b/include/asm-generic/pgtable.h
> @@ -806,4 +806,12 @@ static inline int pmd_clear_huge(pmd_t *
> #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
Looks a bit more structured as:
#ifndef has_transparent_hugepage
# ifdef CONFIG_TRANSPARENT_HUGEPAGE
# define has_transparent_hugepage() 1
# else
# define has_transparent_hugepage() 0
# endif
#endif
BYMMV.
Thanks,
Ingo
--
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^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH 10/10] arch: fix has_transparent_hugepage()
2016-04-06 6:58 ` Ingo Molnar
@ 2016-04-06 6:58 ` Ingo Molnar
2016-04-06 12:29 ` Chris Metcalf
1 sibling, 0 replies; 11+ messages in thread
From: Ingo Molnar @ 2016-04-06 6:58 UTC (permalink / raw)
To: Hugh Dickins
Cc: Andrew Morton, Kirill A. Shutemov, Andrea Arcangeli,
Andres Lagar-Cavilla, Yang Shi, Ning Qu, Arnd Bergman,
Ralf Baechle, Vineet Gupta, Russell King, Will Deacon,
Michael Ellerman, Aneesh Kumar K.V, Martin Schwidefsky,
Gerald Schaefer, David Miller, Chris Metcalf, linux-kernel,
linux-arch, linux-mm
* Hugh Dickins <hughd@google.com> wrote:
> --- a/arch/x86/include/asm/pgtable.h
> +++ b/arch/x86/include/asm/pgtable.h
> @@ -181,6 +181,7 @@ static inline int pmd_trans_huge(pmd_t p
> 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 cpu_has_pse;
Small nit, just writing:
#define has_transparent_hugepage
ought to be enough, right?
In any case:
Acked-by: Ingo Molnar <mingo@kernel.org>
Another nit, this:
> --- a/include/asm-generic/pgtable.h
> +++ b/include/asm-generic/pgtable.h
> @@ -806,4 +806,12 @@ static inline int pmd_clear_huge(pmd_t *
> #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
Looks a bit more structured as:
#ifndef has_transparent_hugepage
# ifdef CONFIG_TRANSPARENT_HUGEPAGE
# define has_transparent_hugepage() 1
# else
# define has_transparent_hugepage() 0
# endif
#endif
BYMMV.
Thanks,
Ingo
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH 10/10] arch: fix has_transparent_hugepage()
2016-04-06 6:58 ` Ingo Molnar
2016-04-06 6:58 ` Ingo Molnar
@ 2016-04-06 12:29 ` Chris Metcalf
2016-04-06 21:58 ` Ingo Molnar
1 sibling, 1 reply; 11+ messages in thread
From: Chris Metcalf @ 2016-04-06 12:29 UTC (permalink / raw)
To: Ingo Molnar, Hugh Dickins
Cc: Andrew Morton, Kirill A. Shutemov, Andrea Arcangeli,
Andres Lagar-Cavilla, Yang Shi, Ning Qu, Arnd Bergman,
Ralf Baechle, Vineet Gupta, Russell King, Will Deacon,
Michael Ellerman, Aneesh Kumar K.V, Martin Schwidefsky,
Gerald Schaefer, David Miller, linux-kernel, linux-arch, linux-mm
On 4/6/2016 2:58 AM, Ingo Molnar wrote:
> * Hugh Dickins <hughd@google.com> wrote:
>
>> --- a/arch/x86/include/asm/pgtable.h
>> +++ b/arch/x86/include/asm/pgtable.h
>> @@ -181,6 +181,7 @@ static inline int pmd_trans_huge(pmd_t p
>> 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 cpu_has_pse;
> Small nit, just writing:
>
> #define has_transparent_hugepage
>
> ought to be enough, right?
No, since then in hugepage_init() the has_transparent_hugepage() call site
would be left with just a stray pair of parentheses instead of a call.
--
Chris Metcalf, Mellanox Technologies
http://www.mellanox.com
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^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH 10/10] arch: fix has_transparent_hugepage()
2016-04-06 12:29 ` Chris Metcalf
@ 2016-04-06 21:58 ` Ingo Molnar
0 siblings, 0 replies; 11+ messages in thread
From: Ingo Molnar @ 2016-04-06 21:58 UTC (permalink / raw)
To: Chris Metcalf
Cc: Hugh Dickins, Andrew Morton, Kirill A. Shutemov, Andrea Arcangeli,
Andres Lagar-Cavilla, Yang Shi, Ning Qu, Arnd Bergman,
Ralf Baechle, Vineet Gupta, Russell King, Will Deacon,
Michael Ellerman, Aneesh Kumar K.V, Martin Schwidefsky,
Gerald Schaefer, David Miller, linux-kernel, linux-arch, linux-mm
* Chris Metcalf <cmetcalf@mellanox.com> wrote:
> On 4/6/2016 2:58 AM, Ingo Molnar wrote:
> >* Hugh Dickins <hughd@google.com> wrote:
> >
> >>--- a/arch/x86/include/asm/pgtable.h
> >>+++ b/arch/x86/include/asm/pgtable.h
> >>@@ -181,6 +181,7 @@ static inline int pmd_trans_huge(pmd_t p
> >> 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 cpu_has_pse;
> >Small nit, just writing:
> >
> > #define has_transparent_hugepage
> >
> >ought to be enough, right?
>
> No, since then in hugepage_init() the has_transparent_hugepage() call site
> would be left with just a stray pair of parentheses instead of a call.
Yes, indeed ...
Thanks,
Ingo
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH 10/10] arch: fix has_transparent_hugepage()
2016-04-05 21:02 ` [PATCH 10/10] arch: fix has_transparent_hugepage() Hugh Dickins
` (3 preceding siblings ...)
2016-04-06 6:58 ` Ingo Molnar
@ 2016-04-06 11:56 ` Gerald Schaefer
2016-04-06 11:56 ` Gerald Schaefer
4 siblings, 1 reply; 11+ messages in thread
From: Gerald Schaefer @ 2016-04-06 11:56 UTC (permalink / raw)
To: Hugh Dickins
Cc: Andrew Morton, Kirill A. Shutemov, Andrea Arcangeli,
Andres Lagar-Cavilla, Yang Shi, Ning Qu, Arnd Bergman,
Ralf Baechle, Vineet Gupta, Russell King, Will Deacon,
Michael Ellerman, Aneesh Kumar K.V, Martin Schwidefsky,
David Miller, Chris Metcalf, Ingo Molnar, linux-kernel,
linux-arch, linux-mm
On Tue, 5 Apr 2016 14:02:49 -0700 (PDT)
Hugh Dickins <hughd@google.com> wrote:
> 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>
> ---
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> # for arch/s390 bits
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^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH 10/10] arch: fix has_transparent_hugepage()
2016-04-06 11:56 ` Gerald Schaefer
@ 2016-04-06 11:56 ` Gerald Schaefer
0 siblings, 0 replies; 11+ messages in thread
From: Gerald Schaefer @ 2016-04-06 11:56 UTC (permalink / raw)
To: Hugh Dickins
Cc: Andrew Morton, Kirill A. Shutemov, Andrea Arcangeli,
Andres Lagar-Cavilla, Yang Shi, Ning Qu, Arnd Bergman,
Ralf Baechle, Vineet Gupta, Russell King, Will Deacon,
Michael Ellerman, Aneesh Kumar K.V, Martin Schwidefsky,
David Miller, Chris Metcalf, Ingo Molnar, linux-kernel,
linux-arch, linux-mm
On Tue, 5 Apr 2016 14:02:49 -0700 (PDT)
Hugh Dickins <hughd@google.com> wrote:
> 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>
> ---
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> # for arch/s390 bits
^ permalink raw reply [flat|nested] 11+ messages in thread