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Commit 498d3aa2 authored by Jens Axboe's avatar Jens Axboe Committed by Jens Axboe
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[PATCH] cfq-iosched: style cleanups and comments

parent 67060e37
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+50 −16
Original line number Diff line number Diff line
@@ -222,7 +222,7 @@ CFQ_CFQQ_FNS(slice_new);

static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short);
static void cfq_dispatch_insert(request_queue_t *, struct request *);
static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask);
static struct cfq_queue *cfq_get_queue(struct cfq_data *, unsigned int, struct task_struct *, gfp_t);

/*
 * scheduler run of queue, if there are requests pending and no one in the
@@ -389,6 +389,9 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2)
	}
}

/*
 * The below is leftmost cache rbtree addon
 */
static struct rb_node *cfq_rb_first(struct cfq_rb_root *root)
{
	if (!root->left)
@@ -442,13 +445,18 @@ static unsigned long cfq_slice_offset(struct cfq_data *cfqd,
	return ((cfqd->busy_queues - 1) * cfq_prio_slice(cfqd, 1, 0));
}

/*
 * The cfqd->service_tree holds all pending cfq_queue's that have
 * requests waiting to be processed. It is sorted in the order that
 * we will service the queues.
 */
static void cfq_service_tree_add(struct cfq_data *cfqd,
				    struct cfq_queue *cfqq)
{
	struct rb_node **p = &cfqd->service_tree.rb.rb_node;
	struct rb_node *parent = NULL;
	unsigned long rb_key;
	int left = 1;
	int left;

	rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies;
	rb_key += cfqq->slice_resid;
@@ -464,6 +472,7 @@ static void cfq_service_tree_add(struct cfq_data *cfqd,
		cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
	}

	left = 1;
	while (*p) {
		struct cfq_queue *__cfqq;
		struct rb_node **n;
@@ -503,17 +512,16 @@ static void cfq_service_tree_add(struct cfq_data *cfqd,
	rb_insert_color(&cfqq->rb_node, &cfqd->service_tree.rb);
}

/*
 * Update cfqq's position in the service tree.
 */
static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
{
	struct cfq_data *cfqd = cfqq->cfqd;

	/*
	 * Resorting requires the cfqq to be on the RR list already.
	 */
	if (!cfq_cfqq_on_rr(cfqq))
		return;

	cfq_service_tree_add(cfqd, cfqq);
	if (cfq_cfqq_on_rr(cfqq))
		cfq_service_tree_add(cfqq->cfqd, cfqq);
}

/*
@@ -530,6 +538,10 @@ cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
	cfq_resort_rr_list(cfqq, 0);
}

/*
 * Called when the cfqq no longer has requests pending, remove it from
 * the service tree.
 */
static inline void
cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
@@ -654,8 +666,7 @@ static void cfq_remove_request(struct request *rq)
	}
}

static int
cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
static int cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
{
	struct cfq_data *cfqd = q->elevator->elevator_data;
	struct request *__rq;
@@ -781,6 +792,10 @@ static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted,
		__cfq_slice_expired(cfqd, cfqq, preempted, timed_out);
}

/*
 * Get next queue for service. Unless we have a queue preemption,
 * we'll simply select the first cfqq in the service tree.
 */
static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
{
	struct cfq_queue *cfqq = NULL;
@@ -792,10 +807,11 @@ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
		cfqq = list_entry_cfqq(cfqd->cur_rr.next);
	} else if (!RB_EMPTY_ROOT(&cfqd->service_tree.rb)) {
		struct rb_node *n = cfq_rb_first(&cfqd->service_tree);
		unsigned long end;

		cfqq = rb_entry(n, struct cfq_queue, rb_node);
		if (cfq_class_idle(cfqq)) {
			unsigned long end;

			/*
			 * if we have idle queues and no rt or be queues had
			 * pending requests, either allow immediate service if
@@ -813,6 +829,9 @@ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
	return cfqq;
}

/*
 * Get and set a new active queue for service.
 */
static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
{
	struct cfq_queue *cfqq;
@@ -898,6 +917,9 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
	mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
}

/*
 * Move request from internal lists to the request queue dispatch list.
 */
static void cfq_dispatch_insert(request_queue_t *q, struct request *rq)
{
	struct cfq_queue *cfqq = RQ_CFQQ(rq);
@@ -944,7 +966,8 @@ cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
}

/*
 * get next queue for service
 * Select a queue for service. If we have a current active queue,
 * check whether to continue servicing it, or retrieve and set a new one.
 */
static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
{
@@ -985,6 +1008,10 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
	return cfqq;
}

/*
 * Dispatch some requests from cfqq, moving them to the request queue
 * dispatch list.
 */
static int
__cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
			int max_dispatch)
@@ -1059,6 +1086,10 @@ static int cfq_forced_dispatch_cfqqs(struct list_head *list)
	return dispatched;
}

/*
 * Drain our current requests. Used for barriers and when switching
 * io schedulers on-the-fly.
 */
static int cfq_forced_dispatch(struct cfq_data *cfqd)
{
	int dispatched = 0;
@@ -1224,10 +1255,6 @@ static void __cfq_exit_single_io_context(struct cfq_data *cfqd,
	}
}


/*
 * Called with interrupts disabled
 */
static void cfq_exit_single_io_context(struct cfq_io_context *cic)
{
	struct cfq_data *cfqd = cic->key;
@@ -1241,6 +1268,10 @@ static void cfq_exit_single_io_context(struct cfq_io_context *cic)
	}
}

/*
 * The process that ioc belongs to has exited, we need to clean up
 * and put the internal structures we have that belongs to that process.
 */
static void cfq_exit_io_context(struct io_context *ioc)
{
	struct cfq_io_context *__cic;
@@ -1427,6 +1458,9 @@ cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk,
	return cfqq;
}

/*
 * We drop cfq io contexts lazily, so we may find a dead one.
 */
static void
cfq_drop_dead_cic(struct io_context *ioc, struct cfq_io_context *cic)
{