[PATCH 10/16] blkcg: use q and plid instead of opaque void * for blkio_group association
From: Tejun Heo
Date: Mon Jan 23 2012 - 18:12:05 EST
From: Tejun Heo <tejun@xxxxxxxxxx>
blkgio_group is association between a block cgroup and a queue for a
given policy. Using opaque void * for association makes things
confusing and hinders factoring of common code. Use request_queue *
and, if necessary, policy id instead.
This will help block cgroup API cleanup.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
---
block/blk-cgroup.c | 32 +++++++++++++++-----------------
block/blk-cgroup.h | 22 ++++++++++++----------
block/blk-throttle.c | 50 +++++++++++++++++++++++---------------------------
block/cfq-iosched.c | 30 ++++++++++++++++--------------
block/cfq.h | 7 ++++---
5 files changed, 70 insertions(+), 71 deletions(-)
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index ff34543..d90e9e8 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -129,7 +129,7 @@ blkio_update_group_weight(struct blkio_group *blkg, unsigned int weight)
if (blkiop->plid != blkg->plid)
continue;
if (blkiop->ops.blkio_update_group_weight_fn)
- blkiop->ops.blkio_update_group_weight_fn(blkg->key,
+ blkiop->ops.blkio_update_group_weight_fn(blkg->q,
blkg, weight);
}
}
@@ -147,12 +147,12 @@ static inline void blkio_update_group_bps(struct blkio_group *blkg, u64 bps,
if (fileid == BLKIO_THROTL_read_bps_device
&& blkiop->ops.blkio_update_group_read_bps_fn)
- blkiop->ops.blkio_update_group_read_bps_fn(blkg->key,
+ blkiop->ops.blkio_update_group_read_bps_fn(blkg->q,
blkg, bps);
if (fileid == BLKIO_THROTL_write_bps_device
&& blkiop->ops.blkio_update_group_write_bps_fn)
- blkiop->ops.blkio_update_group_write_bps_fn(blkg->key,
+ blkiop->ops.blkio_update_group_write_bps_fn(blkg->q,
blkg, bps);
}
}
@@ -170,12 +170,12 @@ static inline void blkio_update_group_iops(struct blkio_group *blkg,
if (fileid == BLKIO_THROTL_read_iops_device
&& blkiop->ops.blkio_update_group_read_iops_fn)
- blkiop->ops.blkio_update_group_read_iops_fn(blkg->key,
+ blkiop->ops.blkio_update_group_read_iops_fn(blkg->q,
blkg, iops);
if (fileid == BLKIO_THROTL_write_iops_device
&& blkiop->ops.blkio_update_group_write_iops_fn)
- blkiop->ops.blkio_update_group_write_iops_fn(blkg->key,
+ blkiop->ops.blkio_update_group_write_iops_fn(blkg->q,
blkg,iops);
}
}
@@ -478,14 +478,14 @@ int blkio_alloc_blkg_stats(struct blkio_group *blkg)
EXPORT_SYMBOL_GPL(blkio_alloc_blkg_stats);
void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
- struct blkio_group *blkg, void *key, dev_t dev,
+ struct blkio_group *blkg, struct request_queue *q, dev_t dev,
enum blkio_policy_id plid)
{
unsigned long flags;
spin_lock_irqsave(&blkcg->lock, flags);
spin_lock_init(&blkg->stats_lock);
- rcu_assign_pointer(blkg->key, key);
+ rcu_assign_pointer(blkg->q, q);
blkg->blkcg_id = css_id(&blkcg->css);
hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
blkg->plid = plid;
@@ -531,18 +531,16 @@ int blkiocg_del_blkio_group(struct blkio_group *blkg)
EXPORT_SYMBOL_GPL(blkiocg_del_blkio_group);
/* called under rcu_read_lock(). */
-struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key)
+struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
+ struct request_queue *q,
+ enum blkio_policy_id plid)
{
struct blkio_group *blkg;
struct hlist_node *n;
- void *__key;
- hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {
- __key = blkg->key;
- if (__key == key)
+ hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node)
+ if (blkg->q == q && blkg->plid == plid)
return blkg;
- }
-
return NULL;
}
EXPORT_SYMBOL_GPL(blkiocg_lookup_group);
@@ -1551,7 +1549,7 @@ static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup)
struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
unsigned long flags;
struct blkio_group *blkg;
- void *key;
+ struct request_queue *q;
struct blkio_policy_type *blkiop;
struct blkio_policy_node *pn, *pntmp;
@@ -1566,7 +1564,7 @@ static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup)
blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group,
blkcg_node);
- key = rcu_dereference(blkg->key);
+ q = rcu_dereference(blkg->q);
__blkiocg_del_blkio_group(blkg);
spin_unlock_irqrestore(&blkcg->lock, flags);
@@ -1580,7 +1578,7 @@ static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup)
list_for_each_entry(blkiop, &blkio_list, list) {
if (blkiop->plid != blkg->plid)
continue;
- blkiop->ops.blkio_unlink_group_fn(key, blkg);
+ blkiop->ops.blkio_unlink_group_fn(q, blkg);
}
spin_unlock(&blkio_list_lock);
} while (1);
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index bd7427b..a19b265 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -153,8 +153,8 @@ struct blkio_group_stats_cpu {
};
struct blkio_group {
- /* An rcu protected unique identifier for the group */
- void *key;
+ /* Pointer to the associated request_queue, RCU protected */
+ struct request_queue __rcu *q;
struct hlist_node blkcg_node;
unsigned short blkcg_id;
/* Store cgroup path */
@@ -202,17 +202,18 @@ extern unsigned int blkcg_get_read_iops(struct blkio_cgroup *blkcg,
extern unsigned int blkcg_get_write_iops(struct blkio_cgroup *blkcg,
dev_t dev);
-typedef void (blkio_unlink_group_fn) (void *key, struct blkio_group *blkg);
+typedef void (blkio_unlink_group_fn)(struct request_queue *q,
+ struct blkio_group *blkg);
typedef bool (blkio_clear_queue_fn)(struct request_queue *q);
-typedef void (blkio_update_group_weight_fn) (void *key,
+typedef void (blkio_update_group_weight_fn)(struct request_queue *q,
struct blkio_group *blkg, unsigned int weight);
-typedef void (blkio_update_group_read_bps_fn) (void * key,
+typedef void (blkio_update_group_read_bps_fn)(struct request_queue *q,
struct blkio_group *blkg, u64 read_bps);
-typedef void (blkio_update_group_write_bps_fn) (void *key,
+typedef void (blkio_update_group_write_bps_fn)(struct request_queue *q,
struct blkio_group *blkg, u64 write_bps);
-typedef void (blkio_update_group_read_iops_fn) (void *key,
+typedef void (blkio_update_group_read_iops_fn)(struct request_queue *q,
struct blkio_group *blkg, unsigned int read_iops);
-typedef void (blkio_update_group_write_iops_fn) (void *key,
+typedef void (blkio_update_group_write_iops_fn)(struct request_queue *q,
struct blkio_group *blkg, unsigned int write_iops);
struct blkio_policy_ops {
@@ -306,12 +307,13 @@ extern struct blkio_cgroup blkio_root_cgroup;
extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
extern struct blkio_cgroup *task_blkio_cgroup(struct task_struct *tsk);
extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
- struct blkio_group *blkg, void *key, dev_t dev,
+ struct blkio_group *blkg, struct request_queue *q, dev_t dev,
enum blkio_policy_id plid);
extern int blkio_alloc_blkg_stats(struct blkio_group *blkg);
extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
- void *key);
+ struct request_queue *q,
+ enum blkio_policy_id plid);
void blkiocg_update_timeslice_used(struct blkio_group *blkg,
unsigned long time,
unsigned long unaccounted_time);
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index c252df9..6613de7 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -252,7 +252,7 @@ static void throtl_init_add_tg_lists(struct throtl_data *td,
__throtl_tg_fill_dev_details(td, tg);
/* Add group onto cgroup list */
- blkiocg_add_blkio_group(blkcg, &tg->blkg, (void *)td,
+ blkiocg_add_blkio_group(blkcg, &tg->blkg, td->queue,
tg->blkg.dev, BLKIO_POLICY_THROTL);
tg->bps[READ] = blkcg_get_read_bps(blkcg, tg->blkg.dev);
@@ -288,7 +288,6 @@ static struct
throtl_grp *throtl_find_tg(struct throtl_data *td, struct blkio_cgroup *blkcg)
{
struct throtl_grp *tg = NULL;
- void *key = td;
/*
* This is the common case when there are no blkio cgroups.
@@ -297,7 +296,8 @@ throtl_grp *throtl_find_tg(struct throtl_data *td, struct blkio_cgroup *blkcg)
if (blkcg == &blkio_root_cgroup)
tg = td->root_tg;
else
- tg = tg_of_blkg(blkiocg_lookup_group(blkcg, key));
+ tg = tg_of_blkg(blkiocg_lookup_group(blkcg, td->queue,
+ BLKIO_POLICY_THROTL));
__throtl_tg_fill_dev_details(td, tg);
return tg;
@@ -1012,22 +1012,22 @@ static bool throtl_release_tgs(struct throtl_data *td, bool release_root)
* no new IO will come in this group. So get rid of this group as soon as
* any pending IO in the group is finished.
*
- * This function is called under rcu_read_lock(). key is the rcu protected
- * pointer. That means "key" is a valid throtl_data pointer as long as we are
- * rcu read lock.
+ * This function is called under rcu_read_lock(). @q is the rcu protected
+ * pointer. That means @q is a valid request_queue pointer as long as we
+ * are rcu read lock.
*
- * "key" was fetched from blkio_group under blkio_cgroup->lock. That means
+ * @q was fetched from blkio_group under blkio_cgroup->lock. That means
* it should not be NULL as even if queue was going away, cgroup deltion
* path got to it first.
*/
-void throtl_unlink_blkio_group(void *key, struct blkio_group *blkg)
+void throtl_unlink_blkio_group(struct request_queue *q,
+ struct blkio_group *blkg)
{
unsigned long flags;
- struct throtl_data *td = key;
- spin_lock_irqsave(td->queue->queue_lock, flags);
- throtl_destroy_tg(td, tg_of_blkg(blkg));
- spin_unlock_irqrestore(td->queue->queue_lock, flags);
+ spin_lock_irqsave(q->queue_lock, flags);
+ throtl_destroy_tg(q->td, tg_of_blkg(blkg));
+ spin_unlock_irqrestore(q->queue_lock, flags);
}
static bool throtl_clear_queue(struct request_queue *q)
@@ -1054,52 +1054,48 @@ static void throtl_update_blkio_group_common(struct throtl_data *td,
}
/*
- * For all update functions, key should be a valid pointer because these
+ * For all update functions, @q should be a valid pointer because these
* update functions are called under blkcg_lock, that means, blkg is
- * valid and in turn key is valid. queue exit path can not race because
+ * valid and in turn @q is valid. queue exit path can not race because
* of blkcg_lock
*
* Can not take queue lock in update functions as queue lock under blkcg_lock
* is not allowed. Under other paths we take blkcg_lock under queue_lock.
*/
-static void throtl_update_blkio_group_read_bps(void *key,
+static void throtl_update_blkio_group_read_bps(struct request_queue *q,
struct blkio_group *blkg, u64 read_bps)
{
- struct throtl_data *td = key;
struct throtl_grp *tg = tg_of_blkg(blkg);
tg->bps[READ] = read_bps;
- throtl_update_blkio_group_common(td, tg);
+ throtl_update_blkio_group_common(q->td, tg);
}
-static void throtl_update_blkio_group_write_bps(void *key,
+static void throtl_update_blkio_group_write_bps(struct request_queue *q,
struct blkio_group *blkg, u64 write_bps)
{
- struct throtl_data *td = key;
struct throtl_grp *tg = tg_of_blkg(blkg);
tg->bps[WRITE] = write_bps;
- throtl_update_blkio_group_common(td, tg);
+ throtl_update_blkio_group_common(q->td, tg);
}
-static void throtl_update_blkio_group_read_iops(void *key,
+static void throtl_update_blkio_group_read_iops(struct request_queue *q,
struct blkio_group *blkg, unsigned int read_iops)
{
- struct throtl_data *td = key;
struct throtl_grp *tg = tg_of_blkg(blkg);
tg->iops[READ] = read_iops;
- throtl_update_blkio_group_common(td, tg);
+ throtl_update_blkio_group_common(q->td, tg);
}
-static void throtl_update_blkio_group_write_iops(void *key,
+static void throtl_update_blkio_group_write_iops(struct request_queue *q,
struct blkio_group *blkg, unsigned int write_iops)
{
- struct throtl_data *td = key;
struct throtl_grp *tg = tg_of_blkg(blkg);
tg->iops[WRITE] = write_iops;
- throtl_update_blkio_group_common(td, tg);
+ throtl_update_blkio_group_common(q->td, tg);
}
static void throtl_shutdown_wq(struct request_queue *q)
@@ -1306,7 +1302,7 @@ void blk_throtl_exit(struct request_queue *q)
spin_unlock_irq(q->queue_lock);
/*
- * Wait for tg->blkg->key accessors to exit their grace periods.
+ * Wait for tg->blkg->q accessors to exit their grace periods.
* Do this wait only if there are other undestroyed groups out
* there (other than root group). This can happen if cgroup deletion
* path claimed the responsibility of cleaning up a group before
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index fcdb0e2..f063557 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1020,7 +1020,8 @@ static inline struct cfq_group *cfqg_of_blkg(struct blkio_group *blkg)
return NULL;
}
-static void cfq_update_blkio_group_weight(void *key, struct blkio_group *blkg,
+static void cfq_update_blkio_group_weight(struct request_queue *q,
+ struct blkio_group *blkg,
unsigned int weight)
{
struct cfq_group *cfqg = cfqg_of_blkg(blkg);
@@ -1043,10 +1044,10 @@ static void cfq_init_add_cfqg_lists(struct cfq_data *cfqd,
if (bdi->dev) {
sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg,
- (void *)cfqd, MKDEV(major, minor));
+ cfqd->queue, MKDEV(major, minor));
} else
cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg,
- (void *)cfqd, 0);
+ cfqd->queue, 0);
cfqd->nr_blkcg_linked_grps++;
cfqg->weight = blkcg_get_weight(blkcg, cfqg->blkg.dev);
@@ -1097,7 +1098,6 @@ static struct cfq_group *
cfq_find_cfqg(struct cfq_data *cfqd, struct blkio_cgroup *blkcg)
{
struct cfq_group *cfqg = NULL;
- void *key = cfqd;
struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info;
unsigned int major, minor;
@@ -1108,7 +1108,8 @@ cfq_find_cfqg(struct cfq_data *cfqd, struct blkio_cgroup *blkcg)
if (blkcg == &blkio_root_cgroup)
cfqg = &cfqd->root_group;
else
- cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key));
+ cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, cfqd->queue,
+ BLKIO_POLICY_PROP));
if (cfqg && !cfqg->blkg.dev && bdi->dev && dev_name(bdi->dev)) {
sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
@@ -1247,21 +1248,22 @@ static bool cfq_release_cfq_groups(struct cfq_data *cfqd)
* any pending IO in the group is finished.
*
* This function is called under rcu_read_lock(). key is the rcu protected
- * pointer. That means "key" is a valid cfq_data pointer as long as we are rcu
- * read lock.
+ * pointer. That means @q is a valid request_queue pointer as long as we
+ * are rcu read lock.
*
- * "key" was fetched from blkio_group under blkio_cgroup->lock. That means
+ * @q was fetched from blkio_group under blkio_cgroup->lock. That means
* it should not be NULL as even if elevator was exiting, cgroup deltion
* path got to it first.
*/
-static void cfq_unlink_blkio_group(void *key, struct blkio_group *blkg)
+static void cfq_unlink_blkio_group(struct request_queue *q,
+ struct blkio_group *blkg)
{
- unsigned long flags;
- struct cfq_data *cfqd = key;
+ struct cfq_data *cfqd = q->elevator->elevator_data;
+ unsigned long flags;
- spin_lock_irqsave(cfqd->queue->queue_lock, flags);
+ spin_lock_irqsave(q->queue_lock, flags);
cfq_destroy_cfqg(cfqd, cfqg_of_blkg(blkg));
- spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
+ spin_unlock_irqrestore(q->queue_lock, flags);
}
static struct elevator_type iosched_cfq;
@@ -3725,7 +3727,7 @@ static int cfq_init_queue(struct request_queue *q)
rcu_read_lock();
cfq_blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg,
- (void *)cfqd, 0);
+ cfqd->queue, 0);
rcu_read_unlock();
cfqd->nr_blkcg_linked_grps++;
diff --git a/block/cfq.h b/block/cfq.h
index 2a15592..343b78a 100644
--- a/block/cfq.h
+++ b/block/cfq.h
@@ -68,8 +68,9 @@ static inline void cfq_blkiocg_update_completion_stats(struct blkio_group *blkg,
}
static inline void cfq_blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
- struct blkio_group *blkg, void *key, dev_t dev) {
- blkiocg_add_blkio_group(blkcg, blkg, key, dev, BLKIO_POLICY_PROP);
+ struct blkio_group *blkg, struct request_queue *q, dev_t dev)
+{
+ blkiocg_add_blkio_group(blkcg, blkg, q, dev, BLKIO_POLICY_PROP);
}
static inline int cfq_blkiocg_del_blkio_group(struct blkio_group *blkg)
@@ -105,7 +106,7 @@ static inline void cfq_blkiocg_update_dispatch_stats(struct blkio_group *blkg,
static inline void cfq_blkiocg_update_completion_stats(struct blkio_group *blkg, uint64_t start_time, uint64_t io_start_time, bool direction, bool sync) {}
static inline void cfq_blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
- struct blkio_group *blkg, void *key, dev_t dev) {}
+ struct blkio_group *blkg, struct request_queue *q, dev_t dev) {}
static inline int cfq_blkiocg_del_blkio_group(struct blkio_group *blkg)
{
return 0;
--
1.7.7.3
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