Commit 3d3c2379 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe

block, cfq: move icq cache management to block core

Let elevators set ->icq_size and ->icq_align in elevator_type and
elv_register() and elv_unregister() respectively create and destroy
kmem_cache for icq.

* elv_register() now can return failure.  All callers updated.

* icq caches are automatically named "ELVNAME_io_cq".

* cfq_slab_setup/kill() are collapsed into cfq_init/exit().

* While at it, minor indentation change for iosched_cfq.elevator_name
  for consistency.

This will help moving icq management to block core.  This doesn't
introduce any functional change.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 47fdd4ca
......@@ -3914,34 +3914,6 @@ static void *cfq_init_queue(struct request_queue *q)
return cfqd;
}
static void cfq_slab_kill(void)
{
/*
* Caller already ensured that pending RCU callbacks are completed,
* so we should have no busy allocations at this point.
*/
if (cfq_pool)
kmem_cache_destroy(cfq_pool);
if (cfq_icq_pool)
kmem_cache_destroy(cfq_icq_pool);
}
static int __init cfq_slab_setup(void)
{
cfq_pool = KMEM_CACHE(cfq_queue, 0);
if (!cfq_pool)
goto fail;
cfq_icq_pool = KMEM_CACHE(cfq_io_cq, 0);
if (!cfq_icq_pool)
goto fail;
return 0;
fail:
cfq_slab_kill();
return -ENOMEM;
}
/*
* sysfs parts below -->
*/
......@@ -4053,8 +4025,10 @@ static struct elevator_type iosched_cfq = {
.elevator_init_fn = cfq_init_queue,
.elevator_exit_fn = cfq_exit_queue,
},
.icq_size = sizeof(struct cfq_io_cq),
.icq_align = __alignof__(struct cfq_io_cq),
.elevator_attrs = cfq_attrs,
.elevator_name = "cfq",
.elevator_name = "cfq",
.elevator_owner = THIS_MODULE,
};
......@@ -4072,6 +4046,8 @@ static struct blkio_policy_type blkio_policy_cfq;
static int __init cfq_init(void)
{
int ret;
/*
* could be 0 on HZ < 1000 setups
*/
......@@ -4086,10 +4062,17 @@ static int __init cfq_init(void)
#else
cfq_group_idle = 0;
#endif
if (cfq_slab_setup())
cfq_pool = KMEM_CACHE(cfq_queue, 0);
if (!cfq_pool)
return -ENOMEM;
elv_register(&iosched_cfq);
ret = elv_register(&iosched_cfq);
if (ret) {
kmem_cache_destroy(cfq_pool);
return ret;
}
cfq_icq_pool = iosched_cfq.icq_cache;
blkio_policy_register(&blkio_policy_cfq);
return 0;
......@@ -4099,8 +4082,7 @@ static void __exit cfq_exit(void)
{
blkio_policy_unregister(&blkio_policy_cfq);
elv_unregister(&iosched_cfq);
rcu_barrier(); /* make sure all cic RCU frees are complete */
cfq_slab_kill();
kmem_cache_destroy(cfq_pool);
}
module_init(cfq_init);
......
......@@ -448,9 +448,7 @@ static struct elevator_type iosched_deadline = {
static int __init deadline_init(void)
{
elv_register(&iosched_deadline);
return 0;
return elv_register(&iosched_deadline);
}
static void __exit deadline_exit(void)
......
......@@ -886,15 +886,36 @@ void elv_unregister_queue(struct request_queue *q)
}
EXPORT_SYMBOL(elv_unregister_queue);
void elv_register(struct elevator_type *e)
int elv_register(struct elevator_type *e)
{
char *def = "";
/* create icq_cache if requested */
if (e->icq_size) {
if (WARN_ON(e->icq_size < sizeof(struct io_cq)) ||
WARN_ON(e->icq_align < __alignof__(struct io_cq)))
return -EINVAL;
snprintf(e->icq_cache_name, sizeof(e->icq_cache_name),
"%s_io_cq", e->elevator_name);
e->icq_cache = kmem_cache_create(e->icq_cache_name, e->icq_size,
e->icq_align, 0, NULL);
if (!e->icq_cache)
return -ENOMEM;
}
/* register, don't allow duplicate names */
spin_lock(&elv_list_lock);
BUG_ON(elevator_find(e->elevator_name));
if (elevator_find(e->elevator_name)) {
spin_unlock(&elv_list_lock);
if (e->icq_cache)
kmem_cache_destroy(e->icq_cache);
return -EBUSY;
}
list_add_tail(&e->list, &elv_list);
spin_unlock(&elv_list_lock);
/* print pretty message */
if (!strcmp(e->elevator_name, chosen_elevator) ||
(!*chosen_elevator &&
!strcmp(e->elevator_name, CONFIG_DEFAULT_IOSCHED)))
......@@ -902,14 +923,26 @@ void elv_register(struct elevator_type *e)
printk(KERN_INFO "io scheduler %s registered%s\n", e->elevator_name,
def);
return 0;
}
EXPORT_SYMBOL_GPL(elv_register);
void elv_unregister(struct elevator_type *e)
{
/* unregister */
spin_lock(&elv_list_lock);
list_del_init(&e->list);
spin_unlock(&elv_list_lock);
/*
* Destroy icq_cache if it exists. icq's are RCU managed. Make
* sure all RCU operations are complete before proceeding.
*/
if (e->icq_cache) {
rcu_barrier();
kmem_cache_destroy(e->icq_cache);
e->icq_cache = NULL;
}
}
EXPORT_SYMBOL_GPL(elv_unregister);
......
......@@ -94,9 +94,7 @@ static struct elevator_type elevator_noop = {
static int __init noop_init(void)
{
elv_register(&elevator_noop);
return 0;
return elv_register(&elevator_noop);
}
static void __exit noop_exit(void)
......
......@@ -78,10 +78,19 @@ struct elv_fs_entry {
*/
struct elevator_type
{
/* managed by elevator core */
struct kmem_cache *icq_cache;
/* fields provided by elevator implementation */
struct elevator_ops ops;
size_t icq_size;
size_t icq_align;
struct elv_fs_entry *elevator_attrs;
char elevator_name[ELV_NAME_MAX];
struct module *elevator_owner;
/* managed by elevator core */
char icq_cache_name[ELV_NAME_MAX + 5]; /* elvname + "_io_cq" */
struct list_head list;
};
......@@ -127,7 +136,7 @@ extern void elv_drain_elevator(struct request_queue *);
/*
* io scheduler registration
*/
extern void elv_register(struct elevator_type *);
extern int elv_register(struct elevator_type *);
extern void elv_unregister(struct elevator_type *);
/*
......
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