Btrfs: optimize set extent bit
The Btrfs set_extent_bit call currently searches the rbtree
every time it needs to find more extent_state objects to fill
the requested operation.
This adds a simple test with rb_next to see if the next object
in the tree was adjacent to the one we just found. If so,
we skip the search and just use the next object.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 6826018..7e5c5a0 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -694,8 +694,8 @@
BUG_ON(err == -EEXIST);
goto out;
}
-
state = rb_entry(node, struct extent_state, rb_node);
+hit_next:
last_start = state->start;
last_end = state->end;
@@ -706,6 +706,7 @@
* Just lock what we found and keep going
*/
if (state->start == start && state->end <= end) {
+ struct rb_node *next_node;
set = state->state & bits;
if (set && exclusive) {
*failed_start = state->start;
@@ -716,7 +717,17 @@
merge_state(tree, state);
if (last_end == (u64)-1)
goto out;
+
start = last_end + 1;
+ if (start < end && prealloc && !need_resched()) {
+ next_node = rb_next(node);
+ if (next_node) {
+ state = rb_entry(next_node, struct extent_state,
+ rb_node);
+ if (state->start == start)
+ goto hit_next;
+ }
+ }
goto search_again;
}
@@ -852,7 +863,7 @@
gfp_t mask)
{
return set_extent_bit(tree, start, end,
- EXTENT_DELALLOC | EXTENT_DIRTY,
+ EXTENT_DELALLOC | EXTENT_DIRTY | EXTENT_UPTODATE,
0, NULL, mask);
}