diff options
author | David Gibson <david@gibson.dropbear.id.au> | 2006-03-22 03:08:57 -0500 |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-22 10:54:03 -0500 |
commit | 9da61aef0fd5b17dd4bf4baf33db12c470def774 (patch) | |
tree | cb4bb0b63c36a0b303ceadc0cec0fae00c49ecf3 /mm | |
parent | 27a85ef1b81300cfff06b4c8037e9914dfb09acc (diff) |
[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 'mm')
-rw-r--r-- | mm/memory.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/mm/memory.c b/mm/memory.c index 71bc664efed5..f6e3be9cbf5a 100644 --- a/mm/memory.c +++ b/mm/memory.c | |||
@@ -277,7 +277,7 @@ void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma, | |||
277 | anon_vma_unlink(vma); | 277 | anon_vma_unlink(vma); |
278 | unlink_file_vma(vma); | 278 | unlink_file_vma(vma); |
279 | 279 | ||
280 | if (is_hugepage_only_range(vma->vm_mm, addr, HPAGE_SIZE)) { | 280 | if (is_vm_hugetlb_page(vma)) { |
281 | hugetlb_free_pgd_range(tlb, addr, vma->vm_end, | 281 | hugetlb_free_pgd_range(tlb, addr, vma->vm_end, |
282 | floor, next? next->vm_start: ceiling); | 282 | floor, next? next->vm_start: ceiling); |
283 | } else { | 283 | } else { |
@@ -285,8 +285,7 @@ void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma, | |||
285 | * Optimization: gather nearby vmas into one call down | 285 | * Optimization: gather nearby vmas into one call down |
286 | */ | 286 | */ |
287 | while (next && next->vm_start <= vma->vm_end + PMD_SIZE | 287 | while (next && next->vm_start <= vma->vm_end + PMD_SIZE |
288 | && !is_hugepage_only_range(vma->vm_mm, next->vm_start, | 288 | && !is_vm_hugetlb_page(vma)) { |
289 | HPAGE_SIZE)) { | ||
290 | vma = next; | 289 | vma = next; |
291 | next = vma->vm_next; | 290 | next = vma->vm_next; |
292 | anon_vma_unlink(vma); | 291 | anon_vma_unlink(vma); |