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Message-Id: <1300375860-14596-1-git-send-email-teravest@google.com>
Date: Thu, 17 Mar 2011 08:31:00 -0700
From: Justin TerAvest <teravest@...gle.com>
To: jaxboe@...ionio.com, vgoyal@...hat.com, adurbin@...gle.com
Cc: ctalbott@...gle.com, linux-kernel@...r.kernel.org,
Justin TerAvest <teravest@...gle.com>
Subject: [PATCH] cfq-iosched: add symmetric reference wrappers
Can you sanity check this before I send it out?
The cfq_group and cfq_queue objects did not have symmetric
wrapper functions and many of the reference taking was
open coded. For clarity add the following wrappers:
cfq_group:
- cfq_get_group_ref()
- cfq_put_group_ref()
cfq_queue:
- cfq_get_queue_ref()
- cfq_put_queue_ref()
The use of '_ref' was done not to collide with existing
function names.
Signed-off-by: Justin TerAvest <teravest@...gle.com>
---
block/cfq-iosched.c | 95 +++++++++++++++++++++++++++++---------------------
1 files changed, 55 insertions(+), 40 deletions(-)
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 89e0d1c..e3136d7 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -301,6 +301,11 @@ struct cfq_data {
struct rcu_head rcu;
};
+static void cfq_get_group_ref(struct cfq_group *cfqg);
+static void cfq_put_group_ref(struct cfq_group *cfqg);
+static void cfq_get_queue_ref(struct cfq_queue *cfqq);
+static void cfq_put_queue_ref(struct cfq_queue *cfqq);
+
static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd);
static struct cfq_rb_root *service_tree_for(struct cfq_group *cfqg,
@@ -1019,7 +1024,7 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create)
* elevator which will be dropped by either elevator exit
* or cgroup deletion path depending on who is exiting first.
*/
- cfqg->ref = 1;
+ cfq_get_group_ref(cfqg);
/*
* Add group onto cgroup list. It might happen that bdi->dev is
@@ -1062,24 +1067,12 @@ static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create)
return cfqg;
}
-static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg)
+static void cfq_get_group_ref(struct cfq_group *cfqg)
{
cfqg->ref++;
- return cfqg;
}
-static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg)
-{
- /* Currently, all async queues are mapped to root group */
- if (!cfq_cfqq_sync(cfqq))
- cfqg = &cfqq->cfqd->root_group;
-
- cfqq->cfqg = cfqg;
- /* cfqq reference on cfqg */
- cfqq->cfqg->ref++;
-}
-
-static void cfq_put_cfqg(struct cfq_group *cfqg)
+static void cfq_put_group_ref(struct cfq_group *cfqg)
{
struct cfq_rb_root *st;
int i, j;
@@ -1093,6 +1086,17 @@ static void cfq_put_cfqg(struct cfq_group *cfqg)
kfree(cfqg);
}
+static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg)
+{
+ /* Currently, all async queues are mapped to root group */
+ if (!cfq_cfqq_sync(cfqq))
+ cfqg = &cfqq->cfqd->root_group;
+
+ cfqq->cfqg = cfqg;
+ /* cfqq reference on cfqg */
+ cfq_get_group_ref(cfqq->cfqg);
+}
+
static void cfq_destroy_cfqg(struct cfq_data *cfqd, struct cfq_group *cfqg)
{
/* Something wrong if we are trying to remove same group twice */
@@ -1104,7 +1108,7 @@ static void cfq_destroy_cfqg(struct cfq_data *cfqd, struct cfq_group *cfqg)
* Put the reference taken at the time of creation so that when all
* queues are gone, group can be destroyed.
*/
- cfq_put_cfqg(cfqg);
+ cfq_put_group_ref(cfqg);
}
static void cfq_release_cfq_groups(struct cfq_data *cfqd)
@@ -1148,14 +1152,18 @@ void cfq_unlink_blkio_group(void *key, struct blkio_group *blkg)
}
#else /* GROUP_IOSCHED */
-static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create)
+
+static void cfq_get_group_ref(struct cfq_group *cfqg)
{
- return &cfqd->root_group;
}
-static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg)
+static void cfq_put_group_ref(struct cfq_group *cfqg)
{
- return cfqg;
+}
+
+static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create)
+{
+ return &cfqd->root_group;
}
static inline void
@@ -1164,7 +1172,6 @@ cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) {
}
static void cfq_release_cfq_groups(struct cfq_data *cfqd) {}
-static inline void cfq_put_cfqg(struct cfq_group *cfqg) {}
#endif /* GROUP_IOSCHED */
@@ -2524,6 +2531,11 @@ static int cfq_dispatch_requests(struct request_queue *q, int force)
return 1;
}
+static void cfq_get_queue_ref(struct cfq_queue *cfqq)
+{
+ cfqq->ref++;
+}
+
/*
* task holds one reference to the queue, dropped when task exits. each rq
* in-flight on this queue also holds a reference, dropped when rq is freed.
@@ -2531,7 +2543,7 @@ static int cfq_dispatch_requests(struct request_queue *q, int force)
* Each cfq queue took a reference on the parent group. Drop it now.
* queue lock must be held here.
*/
-static void cfq_put_queue(struct cfq_queue *cfqq)
+static void cfq_put_queue_ref(struct cfq_queue *cfqq)
{
struct cfq_data *cfqd = cfqq->cfqd;
struct cfq_group *cfqg;
@@ -2554,7 +2566,7 @@ static void cfq_put_queue(struct cfq_queue *cfqq)
BUG_ON(cfq_cfqq_on_rr(cfqq));
kmem_cache_free(cfq_pool, cfqq);
- cfq_put_cfqg(cfqg);
+ cfq_put_group_ref(cfqg);
}
/*
@@ -2659,7 +2671,7 @@ static void cfq_put_cooperator(struct cfq_queue *cfqq)
break;
}
next = __cfqq->new_cfqq;
- cfq_put_queue(__cfqq);
+ cfq_put_queue_ref(__cfqq);
__cfqq = next;
}
}
@@ -2673,7 +2685,7 @@ static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
cfq_put_cooperator(cfqq);
- cfq_put_queue(cfqq);
+ cfq_put_queue_ref(cfqq);
}
static void __cfq_exit_single_io_context(struct cfq_data *cfqd,
@@ -2815,7 +2827,7 @@ static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic)
GFP_ATOMIC);
if (new_cfqq) {
cic->cfqq[BLK_RW_ASYNC] = new_cfqq;
- cfq_put_queue(cfqq);
+ cfq_put_queue_ref(cfqq);
}
}
@@ -2874,7 +2886,7 @@ static void changed_cgroup(struct io_context *ioc, struct cfq_io_context *cic)
*/
cfq_log_cfqq(cfqd, sync_cfqq, "changed cgroup");
cic_set_cfqq(cic, NULL, 1);
- cfq_put_queue(sync_cfqq);
+ cfq_put_queue_ref(sync_cfqq);
}
spin_unlock_irqrestore(q->queue_lock, flags);
@@ -2975,11 +2987,11 @@ cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc,
* pin the queue now that it's allocated, scheduler exit will prune it
*/
if (!is_sync && !(*async_cfqq)) {
- cfqq->ref++;
+ cfq_get_queue_ref(cfqq);
*async_cfqq = cfqq;
}
- cfqq->ref++;
+ cfq_get_queue_ref(cfqq);
return cfqq;
}
@@ -3604,10 +3616,10 @@ static void cfq_put_request(struct request *rq)
rq->elevator_private[1] = NULL;
/* Put down rq reference on cfqg */
- cfq_put_cfqg(RQ_CFQG(rq));
+ cfq_put_group_ref(RQ_CFQG(rq));
rq->elevator_private[2] = NULL;
- cfq_put_queue(cfqq);
+ cfq_put_queue_ref(cfqq);
}
}
@@ -3618,7 +3630,7 @@ cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic,
cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq);
cic_set_cfqq(cic, cfqq->new_cfqq, 1);
cfq_mark_cfqq_coop(cfqq->new_cfqq);
- cfq_put_queue(cfqq);
+ cfq_put_queue_ref(cfqq);
return cic_to_cfqq(cic, 1);
}
@@ -3640,7 +3652,7 @@ split_cfqq(struct cfq_io_context *cic, struct cfq_queue *cfqq)
cfq_put_cooperator(cfqq);
- cfq_put_queue(cfqq);
+ cfq_put_queue_ref(cfqq);
return NULL;
}
/*
@@ -3693,10 +3705,12 @@ new_queue:
cfqq->allocated[rw]++;
- cfqq->ref++;
+ cfq_get_queue_ref(cfqq);
rq->elevator_private[0] = cic;
rq->elevator_private[1] = cfqq;
- rq->elevator_private[2] = cfq_ref_get_cfqg(cfqq->cfqg);
+
+ cfq_get_group_ref(cfqq->cfqg);
+ rq->elevator_private[2] = cfqq->cfqg;
spin_unlock_irqrestore(q->queue_lock, flags);
return 0;
@@ -3789,13 +3803,13 @@ static void cfq_put_async_queues(struct cfq_data *cfqd)
for (i = 0; i < IOPRIO_BE_NR; i++) {
if (cfqd->async_cfqq[0][i])
- cfq_put_queue(cfqd->async_cfqq[0][i]);
+ cfq_put_queue_ref(cfqd->async_cfqq[0][i]);
if (cfqd->async_cfqq[1][i])
- cfq_put_queue(cfqd->async_cfqq[1][i]);
+ cfq_put_queue_ref(cfqd->async_cfqq[1][i]);
}
if (cfqd->async_idle_cfqq)
- cfq_put_queue(cfqd->async_idle_cfqq);
+ cfq_put_queue_ref(cfqd->async_idle_cfqq);
}
static void cfq_cfqd_free(struct rcu_head *head)
@@ -3893,9 +3907,10 @@ static void *cfq_init_queue(struct request_queue *q)
#ifdef CONFIG_CFQ_GROUP_IOSCHED
/*
* Take a reference to root group which we never drop. This is just
- * to make sure that cfq_put_cfqg() does not try to kfree root group
+ * to make sure that cfq_put_group_ref() does not try to kfree
+ * root group
*/
- cfqg->ref = 1;
+ cfq_get_group_ref(cfqg);
rcu_read_lock();
cfq_blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg,
(void *)cfqd, 0);
--
1.7.3.1
--
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