Commit c177c81e authored Jun 04, 2014 by Naoya Horiguchi Committed by Linus Torvalds Jun 04, 2014

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>

parent 7f39dda9

arch/arm/mm/hugetlbpage.c

+0 −5

Original line number	Diff line number	Diff line
		@@ -56,8 +56,3 @@ int pmd_huge(pmd_t pmd)
		{
		return pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT);
		}

		int pmd_huge_support(void)
		{
		return 1;
		}

arch/arm64/mm/hugetlbpage.c

+0 −5

Original line number	Diff line number	Diff line
		@@ -58,11 +58,6 @@ int pud_huge(pud_t pud)
		#endif
		}

		int pmd_huge_support(void)
		{
		return 1;
		}

		static __init int setup_hugepagesz(char *opt)
		{
		unsigned long ps = memparse(opt, &opt);

arch/ia64/mm/hugetlbpage.c

+0 −5

Original line number	Diff line number	Diff line
		@@ -114,11 +114,6 @@ int pud_huge(pud_t pud)
		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)
		{

arch/metag/mm/hugetlbpage.c

+0 −5

Original line number	Diff line number	Diff line
		@@ -110,11 +110,6 @@ int pud_huge(pud_t pud)
		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)
		{

arch/mips/mm/hugetlbpage.c

+0 −5

Original line number	Diff line number	Diff line
		@@ -84,11 +84,6 @@ int pud_huge(pud_t pud)
		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)