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Commit aa6f6a3d authored by Corrado Zoccolo's avatar Corrado Zoccolo Committed by Jens Axboe
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cfq-iosched: preparation to handle multiple service trees 



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: default avatarCorrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 5db5d642

block/cfq-iosched.c

+19 −11
Original line number Diff line number Diff line
@@ -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);

}