blkio: Implement macro to traverse each service tree in group
o Implement a macro to traverse each service tree in the group. This avoids
usage of double for loop and special condition for idle tree 4 times.
o Macro is little twisted because of special handling of idle class service
tree.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index a4d1726..fab2be0 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -140,9 +140,9 @@
* IDLE is handled separately, so it has negative index
*/
enum wl_prio_t {
- IDLE_WORKLOAD = -1,
BE_WORKLOAD = 0,
- RT_WORKLOAD = 1
+ RT_WORKLOAD = 1,
+ IDLE_WORKLOAD = 2,
};
/*
@@ -303,6 +303,17 @@
#define cfq_log(cfqd, fmt, args...) \
blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args)
+/* Traverses through cfq group service trees */
+#define for_each_cfqg_st(cfqg, i, j, st) \
+ for (i = 0; i <= IDLE_WORKLOAD; i++) \
+ for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\
+ : &cfqg->service_tree_idle; \
+ (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \
+ (i == IDLE_WORKLOAD && j == 0); \
+ j++, st = i < IDLE_WORKLOAD ? \
+ &cfqg->service_trees[i][j]: NULL) \
+
+
static inline enum wl_prio_t cfqq_prio(struct cfq_queue *cfqq)
{
if (cfq_class_idle(cfqq))
@@ -565,6 +576,10 @@
*/
static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root)
{
+ /* Service tree is empty */
+ if (!root->count)
+ return NULL;
+
if (!root->left)
root->left = rb_first(&root->rb);
@@ -1587,18 +1602,14 @@
int dispatched = 0;
int i, j;
struct cfq_group *cfqg = &cfqd->root_group;
+ struct cfq_rb_root *st;
- for (i = 0; i < 2; ++i)
- for (j = 0; j < 3; ++j)
- while ((cfqq = cfq_rb_first(&cfqg->service_trees[i][j]))
- != NULL)
- dispatched += __cfq_forced_dispatch_cfqq(cfqq);
-
- while ((cfqq = cfq_rb_first(&cfqg->service_tree_idle)) != NULL)
- dispatched += __cfq_forced_dispatch_cfqq(cfqq);
+ for_each_cfqg_st(cfqg, i, j, st) {
+ while ((cfqq = cfq_rb_first(st)) != NULL)
+ dispatched += __cfq_forced_dispatch_cfqq(cfqq);
+ }
cfq_slice_expired(cfqd, 0);
-
BUG_ON(cfqd->busy_queues);
cfq_log(cfqd, "forced_dispatch=%d", dispatched);
@@ -2969,6 +2980,7 @@
struct cfq_data *cfqd;
int i, j;
struct cfq_group *cfqg;
+ struct cfq_rb_root *st;
cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node);
if (!cfqd)
@@ -2976,11 +2988,8 @@
/* Init root group */
cfqg = &cfqd->root_group;
-
- for (i = 0; i < 2; ++i)
- for (j = 0; j < 3; ++j)
- cfqg->service_trees[i][j] = CFQ_RB_ROOT;
- cfqg->service_tree_idle = CFQ_RB_ROOT;
+ for_each_cfqg_st(cfqg, i, j, st)
+ *st = CFQ_RB_ROOT;
/*
* Not strictly needed (since RB_ROOT just clears the node and we
