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authorHong zhi guo <honkiko@gmail.com>2012-07-31 16:41:35 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-31 18:42:39 -0700
commit92ca922f0a19145f2dcc99d84fe656fa55b52c2e (patch)
tree3d7e616ce15d79d44c1c21f16958978a211fc738 /mm/vmalloc.c
parentc2cddf991974a00aa7b40a21e829bc034b8199b6 (diff)
downloadlinux-92ca922f0a19145f2dcc99d84fe656fa55b52c2e.tar.gz
vmalloc: walk vmap_areas by sorted list instead of rb_next()
There's a walk by repeating rb_next to find a suitable hole.  Could be
simply replaced by walk on the sorted vmap_area_list.  More simpler and
efficient.

Mutation of the list and tree only happens in pair within
__insert_vmap_area and __free_vmap_area, under protection of
vmap_area_lock.  The patch code is also under vmap_area_lock, so the list
walk is safe, and consistent with the tree walk.

Tested on SMP by repeating batch of vmalloc anf vfree for random sizes and
rounds for hours.

Signed-off-by: Hong Zhiguo <honkiko@gmail.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmalloc.c')
-rw-r--r--mm/vmalloc.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index e03f4c7307a5..7e25ee3ce6e5 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -413,11 +413,11 @@ nocache:
 		if (addr + size - 1 < addr)
 			goto overflow;
 
-		n = rb_next(&first->rb_node);
-		if (n)
-			first = rb_entry(n, struct vmap_area, rb_node);
-		else
+		if (list_is_last(&first->list, &vmap_area_list))
 			goto found;
+
+		first = list_entry(first->list.next,
+				struct vmap_area, list);
 	}
 
 found: