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author | David Gibson <david@gibson.dropbear.id.au> | 2006-03-22 11:08:57 +0300 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-22 18:54:03 +0300 |
commit | 9da61aef0fd5b17dd4bf4baf33db12c470def774 (patch) | |
tree | cb4bb0b63c36a0b303ceadc0cec0fae00c49ecf3 /include/linux/hugetlb.h | |
parent | 27a85ef1b81300cfff06b4c8037e9914dfb09acc (diff) | |
download | linux-9da61aef0fd5b17dd4bf4baf33db12c470def774.tar.xz |
[PATCH] hugepage: Fix hugepage logic in free_pgtables()
free_pgtables() has special logic to call hugetlb_free_pgd_range() instead
of the normal free_pgd_range() on hugepage VMAs. However, the test it uses
to do so is incorrect: it calls is_hugepage_only_range on a hugepage sized
range at the start of the vma. is_hugepage_only_range() will return true
if the given range has any intersection with a hugepage address region, and
in this case the given region need not be hugepage aligned. So, for
example, this test can return true if called on, say, a 4k VMA immediately
preceding a (nicely aligned) hugepage VMA.
At present we get away with this because the powerpc version of
hugetlb_free_pgd_range() is just a call to free_pgd_range(). On ia64 (the
only other arch with a non-trivial is_hugepage_only_range()) we get away
with it for a different reason; the hugepage area is not contiguous with
the rest of the user address space, and VMAs are not permitted in between,
so the test can't return a false positive there.
Nonetheless this should be fixed. We do that in the patch below by
replacing the is_hugepage_only_range() test with an explicit test of the
VMA using is_vm_hugetlb_page().
This in turn changes behaviour for platforms where is_hugepage_only_range()
returns false always (everything except powerpc and ia64). We address this
by ensuring that hugetlb_free_pgd_range() is defined to be identical to
free_pgd_range() (instead of a no-op) on everything except ia64. Even so,
it will prevent some otherwise possible coalescing of calls down to
free_pgd_range(). Since this only happens for hugepage VMAs, removing this
small optimization seems unlikely to cause any trouble.
This patch causes no regressions on the libhugetlbfs testsuite - ppc64
POWER5 (8-way), ppc64 G5 (2-way) and i386 Pentium M (UP).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux/hugetlb.h')
-rw-r--r-- | include/linux/hugetlb.h | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 5d84c368ffe4..e465fbf1ef5f 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -43,8 +43,10 @@ void hugetlb_change_protection(struct vm_area_struct *vma, #ifndef ARCH_HAS_HUGEPAGE_ONLY_RANGE #define is_hugepage_only_range(mm, addr, len) 0 -#define hugetlb_free_pgd_range(tlb, addr, end, floor, ceiling) \ - do { } while (0) +#endif + +#ifndef ARCH_HAS_HUGETLB_FREE_PGD_RANGE +#define hugetlb_free_pgd_range free_pgd_range #endif #ifndef ARCH_HAS_PREPARE_HUGEPAGE_RANGE @@ -93,8 +95,7 @@ static inline unsigned long hugetlb_total_pages(void) #define prepare_hugepage_range(addr, len) (-EINVAL) #define pmd_huge(x) 0 #define is_hugepage_only_range(mm, addr, len) 0 -#define hugetlb_free_pgd_range(tlb, addr, end, floor, ceiling) \ - do { } while (0) +#define hugetlb_free_pgd_range(tlb, addr, end, floor, ceiling) ({BUG(); 0; }) #define hugetlb_fault(mm, vma, addr, write) ({ BUG(); 0; }) #define hugetlb_change_protection(vma, address, end, newprot) |