vmalloc: walk vmap_areas by sorted list instead of rb_next()
authorHong zhi guo <honkiko@gmail.com>
Tue, 31 Jul 2012 23:41:35 +0000 (16:41 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 1 Aug 2012 01:42:39 +0000 (18:42 -0700)
commit92ca922f0a19145f2dcc99d84fe656fa55b52c2e
tree3d7e616ce15d79d44c1c21f16958978a211fc738
parentc2cddf991974a00aa7b40a21e829bc034b8199b6
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>
mm/vmalloc.c