Commit 92ca922f authored by Hong zhi guo's avatar Hong zhi guo Committed by Linus Torvalds

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

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: default avatarHong Zhiguo <>
Cc: Nick Piggin <>
Cc: Johannes Weiner <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent c2cddf99
......@@ -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);
if (list_is_last(&first->list, &vmap_area_list))
goto found;
first = list_entry(first->,
struct vmap_area, list);
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