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cfq-iosched: preparation to handle multiple service trees

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We embed a pointer to the service tree in each queue, to handle multiple
service trees easily.
Service trees are enriched with a counter.
cfq_add_rq_rb is invoked after putting the rq in the fifo, to ensure
that all fields in rq are properly initialized.

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Corrado Zoccolo 2009-10-26 22:44:33 +01:00 committed by Jens Axboe
parent 5db5d64277
commit aa6f6a3de1
1 changed files with 19 additions and 11 deletions
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30
block/cfq-iosched.c
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@ -75,8 +75,9 @@ static DEFINE_SPINLOCK(ioc_gone_lock);
struct cfq_rb_root {
struct rb_root rb;
struct rb_node *left;
unsigned count;
};
#define CFQ_RB_ROOT (struct cfq_rb_root) { RB_ROOT, NULL, }
#define CFQ_RB_ROOT (struct cfq_rb_root) { RB_ROOT, NULL, 0, }
/*
* Per process-grouping structure
@ -128,6 +129,7 @@ struct cfq_queue {
pid_t pid;
struct cfq_rb_root *service_tree;
struct cfq_queue *new_cfqq;
};
@ -503,6 +505,7 @@ static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root)
if (root->left == n)
root->left = NULL;
rb_erase_init(n, &root->rb);
--root->count;
}
/*
@ -553,11 +556,12 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct rb_node **p, *parent;
struct cfq_queue *__cfqq;
unsigned long rb_key;
struct cfq_rb_root *service_tree = &cfqd->service_tree;
int left;
if (cfq_class_idle(cfqq)) {
rb_key = CFQ_IDLE_DELAY;
parent = rb_last(&cfqd->service_tree.rb);
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;
@ -575,7 +579,7 @@ 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(&cfqd->service_tree);
__cfqq = cfq_rb_first(service_tree);
rb_key += __cfqq ? __cfqq->rb_key : jiffies;
}
@ -586,12 +590,14 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
if (rb_key == cfqq->rb_key)
return;
cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree);
cfqq->service_tree = NULL;
}
left = 1;
parent = NULL;
p = &cfqd->service_tree.rb.rb_node;
cfqq->service_tree = service_tree;
p = &service_tree->rb.rb_node;
while (*p) {
struct rb_node **n;
@ -623,11 +629,12 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
}
if (left)
cfqd->service_tree.left = &cfqq->rb_node;
service_tree->left = &cfqq->rb_node;
cfqq->rb_key = rb_key;
rb_link_node(&cfqq->rb_node, parent, p);
rb_insert_color(&cfqq->rb_node, &cfqd->service_tree.rb);
rb_insert_color(&cfqq->rb_node, &service_tree->rb);
service_tree->count++;
}
static struct cfq_queue *
@ -730,8 +737,10 @@ static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
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, &cfqd->service_tree);
if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree);
cfqq->service_tree = NULL;
}
if (cfqq->p_root) {
rb_erase(&cfqq->p_node, cfqq->p_root);
cfqq->p_root = NULL;
@ -2292,10 +2301,9 @@ static void cfq_insert_request(struct request_queue *q, struct request *rq)
cfq_log_cfqq(cfqd, cfqq, "insert_request");
cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc);
cfq_add_rq_rb(rq);
rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]);
list_add_tail(&rq->queuelist, &cfqq->fifo);
cfq_add_rq_rb(rq);
cfq_rq_enqueued(cfqd, cfqq, rq);
}