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authorAndrea Arcangeli <aarcange@redhat.com>2011-01-13 15:47:08 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-13 17:32:45 -0800
commit94fcc585fb85ad7b059c70872489b50044d401f3 (patch)
tree67efce3803149bec77df1f50a06f384deae02ba6 /mm/mmap.c
parentbc835011afbea3957217ee716093d791fb2fe44f (diff)
thp: avoid breaking huge pmd invariants in case of vma_adjust failures
An huge pmd can only be mapped if the corresponding 2M virtual range is fully contained in the vma. At times the VM calls split_vma twice, if the first split_vma succeeds and the second fail, the first split_vma remains in effect and it's not rolled back. For split_vma or vma_adjust to fail an allocation failure is needed so it's a very unlikely event (the out of memory killer would normally fire before any allocation failure is visible to kernel and userland and if an out of memory condition happens it's unlikely to happen exactly here). Nevertheless it's safer to ensure that no huge pmd can be left around if the vma is adjusted in a way that can't fit hugepages anymore at the new vm_start/vm_end address. 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/mmap.c')
-rw-r--r--mm/mmap.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 753f44d17047..73cc648873d6 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -589,6 +589,8 @@ again: remove_next = 1 + (end > next->vm_end);
}
}
+ vma_adjust_trans_huge(vma, start, end, adjust_next);
+
/*
* When changing only vma->vm_end, we don't really need anon_vma
* lock. This is a fairly rare case by itself, but the anon_vma