From: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Find the anon_vma to lock from the page rather than from the vma, after recent
anon_vma changes that allows a vma to belong to more than a single anon_vma.
Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
---
mm/huge_memory.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -761,13 +761,14 @@ static void __split_huge_page(struct pag
struct anon_vma *anon_vma)
{
int mapcount, mapcount2;
- struct vm_area_struct *vma;
+ struct anon_vma_chain *avc;
BUG_ON(!PageHead(page));
BUG_ON(PageTail(page));
mapcount = 0;
- list_for_each_entry(vma, &anon_vma->head, anon_vma_node) {
+ list_for_each_entry(avc, &anon_vma->head, same_anon_vma) {
+ struct vm_area_struct *vma = avc->vma;
unsigned long addr = vma_address(page, vma);
if (addr == -EFAULT)
continue;
@@ -778,7 +779,8 @@ static void __split_huge_page(struct pag
__split_huge_page_refcount(page);
mapcount2 = 0;
- list_for_each_entry(vma, &anon_vma->head, anon_vma_node) {
+ list_for_each_entry(avc, &anon_vma->head, same_anon_vma) {
+ struct vm_area_struct *vma = avc->vma;
unsigned long addr = vma_address(page, vma);
if (addr == -EFAULT)
continue;
@@ -791,29 +793,29 @@ static void __split_huge_page(struct pag
void __split_huge_page_vma(struct vm_area_struct *vma, pmd_t *pmd)
{
struct page *page;
- struct anon_vma *anon_vma;
struct mm_struct *mm;
BUG_ON(vma->vm_flags & VM_HUGETLB);
mm = vma->vm_mm;
- anon_vma = vma->anon_vma;
-
- spin_lock(&anon_vma->lock);
- BUG_ON(pmd_trans_splitting(*pmd));
spin_lock(&mm->page_table_lock);
if (unlikely(!pmd_trans_huge(*pmd))) {
spin_unlock(&mm->page_table_lock);
- spin_unlock(&anon_vma->lock);
return;
}
page = pmd_page(*pmd);
+ VM_BUG_ON(!page_count(page));
+ get_page(page);
spin_unlock(&mm->page_table_lock);
- __split_huge_page(page, anon_vma);
+ /*
+ * The vma->anon_vma->lock is the wrong lock if the page is shared,
+ * the anon_vma->lock pointed by page->mapping is the right one.
+ */
+ split_huge_page(page);
- spin_unlock(&anon_vma->lock);
+ put_page(page);
BUG_ON(pmd_trans_huge(*pmd));
}
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxxx For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>