diff options
| author |   Rik van Riel <riel@redhat.com> | 2010-08-09 17:18:39 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2010-08-09 20:44:55 -0700 |
| commit | 5c341ee1dfc8fe69d66b1c8b19e463c6d7201ae1 (patch) | |
| tree | 41f05611f8b1d7562c2193ade8c089408f262a6b /include | |
| parent | mm: change direct call of spin_lock(anon_vma->lock) to inline function (diff) | |
| download | linux-dev-5c341ee1dfc8fe69d66b1c8b19e463c6d7201ae1.tar.xz linux-dev-5c341ee1dfc8fe69d66b1c8b19e463c6d7201ae1.zip | |
mm: track the root (oldest) anon_vma
Track the root (oldest) anon_vma in each anon_vma tree. Because we only
take the lock on the root anon_vma, we cannot use the lock on higher-up
anon_vmas to lock anything. This makes it impossible to do an indirect
lookup of the root anon_vma, since the data structures could go away from
under us.
However, a direct pointer is safe because the root anon_vma is always the
last one that gets freed on munmap or exit, by virtue of the same_vma list
order and unlink_anon_vmas walking the list forward.
[akpm@linux-foundation.org: fix typo]
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: Larry Woodman <lwoodman@redhat.com>
Acked-by: Larry Woodman <lwoodman@redhat.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/rmap.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 5f981be61416..41fa6ddc6214 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -26,6 +26,7 @@ */ struct anon_vma { spinlock_t lock; /* Serialize access to vma list */ + struct anon_vma *root; /* Root of this anon_vma tree */ #if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION) /* |