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authorAndrea Arcangeli <aarcange@redhat.com>2011-01-13 15:47:15 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-13 17:32:47 -0800
commit14d1a55cd26f1860f837f37ae42520c7c13b1347 (patch)
treeb80634a6a2a5f306fd1c3fc408993dd9fc98202b /mm/memory.c
parent05b258e99725112c4febeab4fad23ea2c8908a3a (diff)
thp: add debug checks for mapcount related invariants
Add debug checks for invariants that if broken could lead to mapcount vs page_mapcount debug checks to trigger later in split_huge_page. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 12ee1ea237f..31250faff39 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -804,6 +804,7 @@ static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src
next = pmd_addr_end(addr, end);
if (pmd_trans_huge(*src_pmd)) {
int err;
+ VM_BUG_ON(next-addr != HPAGE_PMD_SIZE);
err = copy_huge_pmd(dst_mm, src_mm,
dst_pmd, src_pmd, addr, vma);
if (err == -ENOMEM)
@@ -1015,9 +1016,10 @@ static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
do {
next = pmd_addr_end(addr, end);
if (pmd_trans_huge(*pmd)) {
- if (next-addr != HPAGE_PMD_SIZE)
+ if (next-addr != HPAGE_PMD_SIZE) {
+ VM_BUG_ON(!rwsem_is_locked(&tlb->mm->mmap_sem));
split_huge_page_pmd(vma->vm_mm, pmd);
- else if (zap_huge_pmd(tlb, vma, pmd)) {
+ } else if (zap_huge_pmd(tlb, vma, pmd)) {
(*zap_work)--;
continue;
}