blk-throttle: Define readable macros instead of static variables

The 'throtl_grp_quantum' and 'throtl_quantum' are both read-only
variables, thus better to use readable macros instead of static
variables, which can also save some spaces for .bss area.

Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 06e73ed..ca9002d 100644 (file)
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -15,10 +15,10 @@
 #include "blk-cgroup-rwstat.h"
 
 /* Max dispatch from a group in 1 round */
-static int throtl_grp_quantum = 8;
+#define THROTL_GRP_QUANTUM 8
 
 /* Total max dispatch from all groups in one round */
-static int throtl_quantum = 32;
+#define THROTL_QUANTUM 32
 
 /* Throttling is performed over a slice and after that slice is renewed */
 #define DFL_THROTL_SLICE_HD (HZ / 10)
@@ -1175,8 +1175,8 @@ static int throtl_dispatch_tg(struct throtl_grp *tg)
 {
        struct throtl_service_queue *sq = &tg->service_queue;
        unsigned int nr_reads = 0, nr_writes = 0;
-       unsigned int max_nr_reads = throtl_grp_quantum*3/4;
-       unsigned int max_nr_writes = throtl_grp_quantum - max_nr_reads;
+       unsigned int max_nr_reads = THROTL_GRP_QUANTUM * 3 / 4;
+       unsigned int max_nr_writes = THROTL_GRP_QUANTUM - max_nr_reads;
        struct bio *bio;
 
        /* Try to dispatch 75% READS and 25% WRITES */
@@ -1226,7 +1226,7 @@ static int throtl_select_dispatch(struct throtl_service_queue *parent_sq)
                if (sq->nr_queued[0] || sq->nr_queued[1])
                        tg_update_disptime(tg);
 
-               if (nr_disp >= throtl_quantum)
+               if (nr_disp >= THROTL_QUANTUM)
                        break;
        }