hugetlb: restrict hugepage_migration_support() to x86_64
Currently hugepage migration is available for all archs which support
pmd-level hugepage, but testing is done only for x86_64 and there're
bugs for other archs. So to avoid breaking such archs, this patch
limits the availability strictly to x86_64 until developers of other
archs get interested in enabling this feature.
Simply disabling hugepage migration on non-x86_64 archs is not enough to
fix the reported problem where sys_move_pages() hits the BUG_ON() in
follow_page(FOLL_GET), so let's fix this by checking if hugepage
migration is supported in vma_migratable().
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Miller <davem@davemloft.net>
Cc: <stable@vger.kernel.org> [3.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/arm/mm/hugetlbpage.c b/arch/arm/mm/hugetlbpage.c
index 54ee616..66781bf3 100644
--- a/arch/arm/mm/hugetlbpage.c
+++ b/arch/arm/mm/hugetlbpage.c
@@ -56,8 +56,3 @@
{
return pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT);
}
-
-int pmd_huge_support(void)
-{
- return 1;
-}
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 31eb959..023747b 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -58,11 +58,6 @@
#endif
}
-int pmd_huge_support(void)
-{
- return 1;
-}
-
static __init int setup_hugepagesz(char *opt)
{
unsigned long ps = memparse(opt, &opt);
diff --git a/arch/ia64/mm/hugetlbpage.c b/arch/ia64/mm/hugetlbpage.c
index 68232db..76069c1 100644
--- a/arch/ia64/mm/hugetlbpage.c
+++ b/arch/ia64/mm/hugetlbpage.c
@@ -114,11 +114,6 @@
return 0;
}
-int pmd_huge_support(void)
-{
- return 0;
-}
-
struct page *
follow_huge_pmd(struct mm_struct *mm, unsigned long address, pmd_t *pmd, int write)
{
diff --git a/arch/metag/mm/hugetlbpage.c b/arch/metag/mm/hugetlbpage.c
index 0424315..3c52fa6 100644
--- a/arch/metag/mm/hugetlbpage.c
+++ b/arch/metag/mm/hugetlbpage.c
@@ -110,11 +110,6 @@
return 0;
}
-int pmd_huge_support(void)
-{
- return 1;
-}
-
struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
pmd_t *pmd, int write)
{
diff --git a/arch/mips/mm/hugetlbpage.c b/arch/mips/mm/hugetlbpage.c
index 77e0ae0..4ec8ee1 100644
--- a/arch/mips/mm/hugetlbpage.c
+++ b/arch/mips/mm/hugetlbpage.c
@@ -84,11 +84,6 @@
return (pud_val(pud) & _PAGE_HUGE) != 0;
}
-int pmd_huge_support(void)
-{
- return 1;
-}
-
struct page *
follow_huge_pmd(struct mm_struct *mm, unsigned long address,
pmd_t *pmd, int write)
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index eb92365..7e70ae9 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -86,11 +86,6 @@
*/
return ((pgd_val(pgd) & 0x3) != 0x0);
}
-
-int pmd_huge_support(void)
-{
- return 1;
-}
#else
int pmd_huge(pmd_t pmd)
{
@@ -106,11 +101,6 @@
{
return 0;
}
-
-int pmd_huge_support(void)
-{
- return 0;
-}
#endif
pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c
index 0727a55d..0ff66a7 100644
--- a/arch/s390/mm/hugetlbpage.c
+++ b/arch/s390/mm/hugetlbpage.c
@@ -220,11 +220,6 @@
return 0;
}
-int pmd_huge_support(void)
-{
- return 1;
-}
-
struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
pmd_t *pmdp, int write)
{
diff --git a/arch/sh/mm/hugetlbpage.c b/arch/sh/mm/hugetlbpage.c
index 0d676a4..d776234 100644
--- a/arch/sh/mm/hugetlbpage.c
+++ b/arch/sh/mm/hugetlbpage.c
@@ -83,11 +83,6 @@
return 0;
}
-int pmd_huge_support(void)
-{
- return 0;
-}
-
struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
pmd_t *pmd, int write)
{
diff --git a/arch/sparc/mm/hugetlbpage.c b/arch/sparc/mm/hugetlbpage.c
index 9bd9ce8..d329537 100644
--- a/arch/sparc/mm/hugetlbpage.c
+++ b/arch/sparc/mm/hugetlbpage.c
@@ -231,11 +231,6 @@
return 0;
}
-int pmd_huge_support(void)
-{
- return 0;
-}
-
struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
pmd_t *pmd, int write)
{
diff --git a/arch/tile/mm/hugetlbpage.c b/arch/tile/mm/hugetlbpage.c
index 0cb3bba..e514899 100644
--- a/arch/tile/mm/hugetlbpage.c
+++ b/arch/tile/mm/hugetlbpage.c
@@ -166,11 +166,6 @@
return !!(pud_val(pud) & _PAGE_HUGE_PAGE);
}
-int pmd_huge_support(void)
-{
- return 1;
-}
-
struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
pmd_t *pmd, int write)
{
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 7d5feb5..e41b258 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1873,6 +1873,10 @@
def_bool y
depends on X86_64 || X86_PAE
+config ARCH_ENABLE_HUGEPAGE_MIGRATION
+ def_bool y
+ depends on X86_64 && HUGETLB_PAGE && MIGRATION
+
menu "Power management and ACPI options"
config ARCH_HIBERNATION_HEADER
diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c
index 8c9f647..8b977eb 100644
--- a/arch/x86/mm/hugetlbpage.c
+++ b/arch/x86/mm/hugetlbpage.c
@@ -58,11 +58,6 @@
{
return NULL;
}
-
-int pmd_huge_support(void)
-{
- return 0;
-}
#else
struct page *
@@ -80,11 +75,6 @@
{
return !!(pud_val(pud) & _PAGE_PSE);
}
-
-int pmd_huge_support(void)
-{
- return 1;
-}
#endif
#ifdef CONFIG_HUGETLB_PAGE
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index b65166d..d0bad1a 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -392,15 +392,13 @@
extern void dissolve_free_huge_pages(unsigned long start_pfn,
unsigned long end_pfn);
-int pmd_huge_support(void);
-/*
- * Currently hugepage migration is enabled only for pmd-based hugepage.
- * This function will be updated when hugepage migration is more widely
- * supported.
- */
static inline int hugepage_migration_support(struct hstate *h)
{
- return pmd_huge_support() && (huge_page_shift(h) == PMD_SHIFT);
+#ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION
+ return huge_page_shift(h) == PMD_SHIFT;
+#else
+ return 0;
+#endif
}
static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
@@ -450,7 +448,6 @@
return page->index;
}
#define dissolve_free_huge_pages(s, e) do {} while (0)
-#define pmd_huge_support() 0
#define hugepage_migration_support(h) 0
static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index 3c1b968..f230a97 100644
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -175,6 +175,12 @@
{
if (vma->vm_flags & (VM_IO | VM_PFNMAP))
return 0;
+
+#ifndef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION
+ if (vma->vm_flags & VM_HUGETLB)
+ return 0;
+#endif
+
/*
* Migration allocates pages in the highest zone. If we cannot
* do so then migration (at least from node to node) is not
diff --git a/mm/Kconfig b/mm/Kconfig
index 28cec51..75ac479 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -267,6 +267,9 @@
pages as migration can relocate pages to satisfy a huge page
allocation instead of reclaiming.
+config ARCH_ENABLE_HUGEPAGE_MIGRATION
+ boolean
+
config PHYS_ADDR_T_64BIT
def_bool 64BIT || ARCH_PHYS_ADDR_T_64BIT