Re: [PATCH 1/8 v2] cfq-iosched: Introduce cfq_entity for CFQ queue
From: Vivek Goyal
Date: Mon Dec 13 2010 - 10:44:38 EST
On Mon, Dec 13, 2010 at 09:44:24AM +0800, Gui Jianfeng wrote:
> Introduce cfq_entity for CFQ queue
>
> Signed-off-by: Gui Jianfeng <guijianfeng@xxxxxxxxxxxxxx>
> ---
> block/cfq-iosched.c | 125 +++++++++++++++++++++++++++++++++-----------------
> 1 files changed, 82 insertions(+), 43 deletions(-)
>
> diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
> index 5d0349d..9b07a24 100644
> --- a/block/cfq-iosched.c
> +++ b/block/cfq-iosched.c
> @@ -91,20 +91,31 @@ struct cfq_rb_root {
> #define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT, .left = NULL, \
> .count = 0, .min_vdisktime = 0, }
>
> +
> +/*
> + * This's the CFQ queue schedule entity which is scheduled on service tree.
> + */
> +struct cfq_entity {
> + /* service tree */
> + struct cfq_rb_root *service_tree;
> + /* service_tree member */
> + struct rb_node rb_node;
> + /* service_tree key, represent the position on the tree */
> + unsigned long rb_key;
> +};
> +
> /*
> * Per process-grouping structure
> */
> struct cfq_queue {
> + /* The schedule entity */
> + struct cfq_entity cfqe;
> /* reference count */
> atomic_t ref;
> /* various state flags, see below */
> unsigned int flags;
> /* parent cfq_data */
> struct cfq_data *cfqd;
> - /* service_tree member */
> - struct rb_node rb_node;
> - /* service_tree key */
> - unsigned long rb_key;
> /* prio tree member */
> struct rb_node p_node;
> /* prio tree root we belong to, if any */
> @@ -143,7 +154,6 @@ struct cfq_queue {
> u32 seek_history;
> sector_t last_request_pos;
>
> - struct cfq_rb_root *service_tree;
> struct cfq_queue *new_cfqq;
> struct cfq_group *cfqg;
> struct cfq_group *orig_cfqg;
> @@ -302,6 +312,15 @@ struct cfq_data {
> struct rcu_head rcu;
> };
>
> +static inline struct cfq_queue *
> +cfqq_of_entity(struct cfq_entity *cfqe)
> +{
> + if (cfqe)
> + return container_of(cfqe, struct cfq_queue,
> + cfqe);
> + return NULL;
> +}
> +
> static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd);
>
> static struct cfq_rb_root *service_tree_for(struct cfq_group *cfqg,
> @@ -743,7 +762,7 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2,
> /*
> * The below is leftmost cache rbtree addon
> */
> -static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root)
> +static struct cfq_entity *cfq_rb_first(struct cfq_rb_root *root)
> {
> /* Service tree is empty */
> if (!root->count)
> @@ -753,7 +772,7 @@ static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root)
> root->left = rb_first(&root->rb);
>
> if (root->left)
> - return rb_entry(root->left, struct cfq_queue, rb_node);
> + return rb_entry(root->left, struct cfq_entity, rb_node);
>
> return NULL;
> }
> @@ -1170,21 +1189,24 @@ static inline void cfq_put_cfqg(struct cfq_group *cfqg) {}
> static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
> bool add_front)
> {
> + struct cfq_entity *cfqe;
> struct rb_node **p, *parent;
> - struct cfq_queue *__cfqq;
> + struct cfq_entity *__cfqe;
> unsigned long rb_key;
> struct cfq_rb_root *service_tree;
> int left;
> int new_cfqq = 1;
> int group_changed = 0;
>
> + cfqe = &cfqq->cfqe;
> +
> #ifdef CONFIG_CFQ_GROUP_IOSCHED
> if (!cfqd->cfq_group_isolation
> && cfqq_type(cfqq) == SYNC_NOIDLE_WORKLOAD
> && cfqq->cfqg && cfqq->cfqg != &cfqd->root_group) {
> /* Move this cfq to root group */
> cfq_log_cfqq(cfqd, cfqq, "moving to root group");
> - if (!RB_EMPTY_NODE(&cfqq->rb_node))
> + if (!RB_EMPTY_NODE(&cfqe->rb_node))
> cfq_group_service_tree_del(cfqd, cfqq->cfqg);
> cfqq->orig_cfqg = cfqq->cfqg;
> cfqq->cfqg = &cfqd->root_group;
> @@ -1194,7 +1216,7 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
> && cfqq_type(cfqq) == SYNC_WORKLOAD && cfqq->orig_cfqg) {
> /* cfqq is sequential now needs to go to its original group */
> BUG_ON(cfqq->cfqg != &cfqd->root_group);
> - if (!RB_EMPTY_NODE(&cfqq->rb_node))
> + if (!RB_EMPTY_NODE(&cfqe->rb_node))
> cfq_group_service_tree_del(cfqd, cfqq->cfqg);
> cfq_put_cfqg(cfqq->cfqg);
> cfqq->cfqg = cfqq->orig_cfqg;
> @@ -1209,9 +1231,11 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
> if (cfq_class_idle(cfqq)) {
> rb_key = CFQ_IDLE_DELAY;
> parent = rb_last(&service_tree->rb);
> - if (parent && parent != &cfqq->rb_node) {
> - __cfqq = rb_entry(parent, struct cfq_queue, rb_node);
> - rb_key += __cfqq->rb_key;
> + if (parent && parent != &cfqe->rb_node) {
> + __cfqe = rb_entry(parent,
> + struct cfq_entity,
> + rb_node);
Above can fit into a single line or at max two lines?
> + rb_key += __cfqe->rb_key;
> } else
> rb_key += jiffies;
> } else if (!add_front) {
> @@ -1226,37 +1250,39 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
> cfqq->slice_resid = 0;
> } else {
> rb_key = -HZ;
> - __cfqq = cfq_rb_first(service_tree);
> - rb_key += __cfqq ? __cfqq->rb_key : jiffies;
> + __cfqe = cfq_rb_first(service_tree);
> + rb_key += __cfqe ? __cfqe->rb_key : jiffies;
> }
>
> - if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
> + if (!RB_EMPTY_NODE(&cfqe->rb_node)) {
> new_cfqq = 0;
> /*
> * same position, nothing more to do
> */
> - if (rb_key == cfqq->rb_key &&
> - cfqq->service_tree == service_tree)
> + if (rb_key == cfqe->rb_key &&
> + cfqe->service_tree == service_tree)
> return;
>
> - cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree);
> - cfqq->service_tree = NULL;
> + cfq_rb_erase(&cfqe->rb_node,
> + cfqe->service_tree);
Above can fit on single line?
> + cfqe->service_tree = NULL;
> }
>
> left = 1;
> parent = NULL;
> - cfqq->service_tree = service_tree;
> + cfqe->service_tree = service_tree;
> p = &service_tree->rb.rb_node;
> while (*p) {
> struct rb_node **n;
>
> parent = *p;
> - __cfqq = rb_entry(parent, struct cfq_queue, rb_node);
> + __cfqe = rb_entry(parent, struct cfq_entity,
> + rb_node);
Single line.
>
> /*
> * sort by key, that represents service time.
> */
> - if (time_before(rb_key, __cfqq->rb_key))
> + if (time_before(rb_key, __cfqe->rb_key))
> n = &(*p)->rb_left;
> else {
> n = &(*p)->rb_right;
> @@ -1267,11 +1293,11 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
> }
>
> if (left)
> - service_tree->left = &cfqq->rb_node;
> + service_tree->left = &cfqe->rb_node;
>
> - cfqq->rb_key = rb_key;
> - rb_link_node(&cfqq->rb_node, parent, p);
> - rb_insert_color(&cfqq->rb_node, &service_tree->rb);
> + cfqe->rb_key = rb_key;
> + rb_link_node(&cfqe->rb_node, parent, p);
> + rb_insert_color(&cfqe->rb_node, &service_tree->rb);
> service_tree->count++;
> if ((add_front || !new_cfqq) && !group_changed)
> return;
> @@ -1373,13 +1399,17 @@ static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
> */
> static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
> {
> + struct cfq_entity *cfqe;
> cfq_log_cfqq(cfqd, cfqq, "del_from_rr");
> BUG_ON(!cfq_cfqq_on_rr(cfqq));
> cfq_clear_cfqq_on_rr(cfqq);
>
> - if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
> - cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree);
> - cfqq->service_tree = NULL;
> + cfqe = &cfqq->cfqe;
> +
> + if (!RB_EMPTY_NODE(&cfqe->rb_node)) {
> + cfq_rb_erase(&cfqe->rb_node,
> + cfqe->service_tree);
Single line above.
> + cfqe->service_tree = NULL;
> }
> if (cfqq->p_root) {
> rb_erase(&cfqq->p_node, cfqq->p_root);
> @@ -1707,13 +1737,13 @@ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
> return NULL;
> if (RB_EMPTY_ROOT(&service_tree->rb))
> return NULL;
> - return cfq_rb_first(service_tree);
> + return cfqq_of_entity(cfq_rb_first(service_tree));
> }
>
> static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd)
> {
> struct cfq_group *cfqg;
> - struct cfq_queue *cfqq;
> + struct cfq_entity *cfqe;
> int i, j;
> struct cfq_rb_root *st;
>
> @@ -1724,9 +1754,11 @@ static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd)
> if (!cfqg)
> return NULL;
>
> - for_each_cfqg_st(cfqg, i, j, st)
> - if ((cfqq = cfq_rb_first(st)) != NULL)
> - return cfqq;
> + for_each_cfqg_st(cfqg, i, j, st) {
> + cfqe = cfq_rb_first(st);
> + if (cfqe != NULL)
> + return cfqq_of_entity(cfqe);
> + }
> return NULL;
> }
>
> @@ -1863,9 +1895,12 @@ static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd,
>
> static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq)
> {
> + struct cfq_entity *cfqe;
> enum wl_prio_t prio = cfqq_prio(cfqq);
> - struct cfq_rb_root *service_tree = cfqq->service_tree;
> + struct cfq_rb_root *service_tree;
>
> + cfqe = &cfqq->cfqe;
> + service_tree = cfqe->service_tree;
> BUG_ON(!service_tree);
> BUG_ON(!service_tree->count);
>
> @@ -2075,7 +2110,7 @@ static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq)
> static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd,
> struct cfq_group *cfqg, enum wl_prio_t prio)
> {
> - struct cfq_queue *queue;
> + struct cfq_entity *cfqe;
> int i;
> bool key_valid = false;
> unsigned long lowest_key = 0;
> @@ -2083,10 +2118,11 @@ static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd,
>
> for (i = 0; i <= SYNC_WORKLOAD; ++i) {
> /* select the one with lowest rb_key */
> - queue = cfq_rb_first(service_tree_for(cfqg, prio, i));
> - if (queue &&
> - (!key_valid || time_before(queue->rb_key, lowest_key))) {
> - lowest_key = queue->rb_key;
> + cfqe = cfq_rb_first(service_tree_for(cfqg, prio, i));
> + if (cfqe &&
> + (!key_valid ||
> + time_before(cfqe->rb_key, lowest_key))) {
Merge two lines into one above.
> + lowest_key = cfqe->rb_key;
> cur_best = i;
> key_valid = true;
> }
> @@ -2834,7 +2870,10 @@ static void cfq_ioc_set_ioprio(struct io_context *ioc)
> static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
> pid_t pid, bool is_sync)
> {
> - RB_CLEAR_NODE(&cfqq->rb_node);
> + struct cfq_entity *cfqe;
> +
> + cfqe = &cfqq->cfqe;
> + RB_CLEAR_NODE(&cfqe->rb_node);
> RB_CLEAR_NODE(&cfqq->p_node);
> INIT_LIST_HEAD(&cfqq->fifo);
>
> @@ -3243,7 +3282,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
> /* Allow preemption only if we are idling on sync-noidle tree */
> if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD &&
> cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD &&
> - new_cfqq->service_tree->count == 2 &&
> + new_cfqq->cfqe.service_tree->count == 2 &&
> RB_EMPTY_ROOT(&cfqq->sort_list))
> return true;
>
Apart from above minor nits, this patch looks good to me.
Acked-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
Vivek
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/