Messages in this thread Patch in this message | | | From | Vivek Goyal <> | Subject | [PATCH 03/21] blkio: Implement macro to traverse each idle tree in group | Date | Sun, 29 Nov 2009 21:59:10 -0500 |
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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> --- block/cfq-iosched.c | 35 +++++++++++++++++++++-------------- 1 files changed, 21 insertions(+), 14 deletions(-)
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 3baa3f4..c73ff44 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -303,6 +303,15 @@ CFQ_CFQQ_FNS(deep); #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 < 3; i++) \ + for (j = 0, st = i < 2 ? &cfqg->service_trees[i][j] : \ + &cfqg->service_tree_idle; \ + (i < 2 && j < 3) || (i == 2 && j < 1); \ + j++, st = i < 2 ? &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 +574,10 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, */ 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); @@ -1592,18 +1605,14 @@ static int cfq_forced_dispatch(struct cfq_data *cfqd) 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); @@ -2974,6 +2983,7 @@ static void *cfq_init_queue(struct request_queue *q) 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) @@ -2981,11 +2991,8 @@ static void *cfq_init_queue(struct request_queue *q) /* 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 -- 1.6.2.5
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