The patch titled
rmap: fix walk during fork
has been added to the -mm tree. Its filename is
rmap-fix-walk-during-fork.patch
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------------------------------------------------------
Subject: rmap: fix walk during fork
From: Andrea Arcangeli <aarcange@xxxxxxxxxx>
The below bug in fork led to the rmap walk finding the parent huge-pmd
twice instead of just once, because the anon_vma_chain objects of the
child vma still point to the vma->vm_mm of the parent.
The patch fixes it by making the rmap walk accurate during fork. It's not
a big deal normally but it worth being accurate considering the cost is
the same.
Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Johannes Weiner <jweiner@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/fork.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN kernel/fork.c~rmap-fix-walk-during-fork kernel/fork.c
--- a/kernel/fork.c~rmap-fix-walk-during-fork
+++ a/kernel/fork.c
@@ -356,10 +356,10 @@ static int dup_mmap(struct mm_struct *mm
if (IS_ERR(pol))
goto fail_nomem_policy;
vma_set_policy(tmp, pol);
+ tmp->vm_mm = mm;
if (anon_vma_fork(tmp, mpnt))
goto fail_nomem_anon_vma_fork;
tmp->vm_flags &= ~VM_LOCKED;
- tmp->vm_mm = mm;
tmp->vm_next = tmp->vm_prev = NULL;
file = tmp->vm_file;
if (file) {
_
Patches currently in -mm which might be from aarcange@xxxxxxxxxx are
linux-next.patch
rmap-fix-walk-during-fork.patch
define-madv_hugepage.patch
vmscan-do-not-writeback-filesystem-pages-in-direct-reclaim.patch
vmscan-kick-flusher-threads-to-clean-pages-when-reclaim-is-encountering-dirty-pages.patch
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