[PATCH 2/2] mm, vmalloc: use well-defined find_last_bit() func

Joonsoo Kim
2013-08-02T01:57:23Z

Our intention in here is to find last_bit within the region to flush.
There is well-defined function, find_last_bit() for this purpose and
it's performance may be slightly better than current implementation.
So change it.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index d23c432..93d3182 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1016,15 +1016,16 @@ void vm_unmap_aliases(void)

rcu_read_lock();
list_for_each_entry_rcu(vb, &vbq->free, free_list) {
- int i;
+ int i, j;

spin_lock(&vb->lock);
i = find_first_bit(vb->dirty_map, VMAP_BBMAP_BITS);
- while (i < VMAP_BBMAP_BITS) {
+ if (i < VMAP_BBMAP_BITS) {
unsigned long s, e;
- int j;
- j = find_next_zero_bit(vb->dirty_map,
- VMAP_BBMAP_BITS, i);
+
+ j = find_last_bit(vb->dirty_map,
+ VMAP_BBMAP_BITS);
+ j = j + 1; /* need exclusive index */

s = vb->va->va_start + (i << PAGE_SHIFT);
e = vb->va->va_start + (j << PAGE_SHIFT);
@@ -1034,10 +1035,6 @@ void vm_unmap_aliases(void)
start = s;
if (e > end)
end = e;
-
- i = j;
- i = find_next_bit(vb->dirty_map,
- VMAP_BBMAP_BITS, i);
}
spin_unlock(&vb->lock);
}
--
1.7.9.5