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>
92ca922f0a