cfq-iosched: reduce bit operations in cfq_choose_req()

Reduce the number of bit operations in cfq_choose_req() on average
(and worst) cases.

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 00763e5..7ffcedd 100644 (file)
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -667,15 +667,11 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2,
        if (rq2 == NULL)
                return rq1;
 
-       if (rq_is_sync(rq1) && !rq_is_sync(rq2))
-               return rq1;
-       else if (rq_is_sync(rq2) && !rq_is_sync(rq1))
-               return rq2;
-       if ((rq1->cmd_flags & REQ_META) && !(rq2->cmd_flags & REQ_META))
-               return rq1;
-       else if ((rq2->cmd_flags & REQ_META) &&
-                !(rq1->cmd_flags & REQ_META))
-               return rq2;
+       if (rq_is_sync(rq1) != rq_is_sync(rq2))
+               return rq_is_sync(rq1) ? rq1 : rq2;
+
+       if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_META)
+               return rq1->cmd_flags & REQ_META ? rq1 : rq2;
 
        s1 = blk_rq_pos(rq1);
        s2 = blk_rq_pos(rq2);