/*
- * linux/drivers/block/as-iosched.c
- *
* Anticipatory & deadline i/o scheduler.
*
* Copyright (C) 2002 Jens Axboe <axboe@suse.de>
static kmem_cache_t *arq_pool;
+static atomic_t ioc_count = ATOMIC_INIT(0);
+static struct completion *ioc_gone;
+
+static void as_move_to_dispatch(struct as_data *ad, struct as_rq *arq);
+static void as_antic_stop(struct as_data *ad);
+
/*
* IO Context helper functions
*/
static void free_as_io_context(struct as_io_context *aic)
{
kfree(aic);
+ if (atomic_dec_and_test(&ioc_count) && ioc_gone)
+ complete(ioc_gone);
+}
+
+static void as_trim(struct io_context *ioc)
+{
+ if (ioc->aic)
+ free_as_io_context(ioc->aic);
+ ioc->aic = NULL;
}
/* Called when the task exits */
ret->seek_total = 0;
ret->seek_samples = 0;
ret->seek_mean = 0;
+ atomic_inc(&ioc_count);
}
return ret;
* existing request against the same sector), which can happen when using
* direct IO, then return the alias.
*/
-static struct as_rq *as_add_arq_rb(struct as_data *ad, struct as_rq *arq)
+static struct as_rq *__as_add_arq_rb(struct as_data *ad, struct as_rq *arq)
{
struct rb_node **p = &ARQ_RB_ROOT(ad, arq)->rb_node;
struct rb_node *parent = NULL;
return NULL;
}
+static void as_add_arq_rb(struct as_data *ad, struct as_rq *arq)
+{
+ struct as_rq *alias;
+
+ while ((unlikely(alias = __as_add_arq_rb(ad, arq)))) {
+ as_move_to_dispatch(ad, alias);
+ as_antic_stop(ad);
+ }
+}
+
static inline void as_del_arq_rb(struct as_data *ad, struct as_rq *arq)
{
if (!ON_RB(&arq->rb_node)) {
/*
* take it off the sort and fifo list, add to dispatch queue
*/
- while (!list_empty(&rq->queuelist)) {
- struct request *__rq = list_entry_rq(rq->queuelist.next);
- struct as_rq *__arq = RQ_DATA(__rq);
-
- list_del(&__rq->queuelist);
-
- elv_dispatch_add_tail(ad->q, __rq);
-
- if (__arq->io_context && __arq->io_context->aic)
- atomic_inc(&__arq->io_context->aic->nr_dispatched);
-
- WARN_ON(__arq->state != AS_RQ_QUEUED);
- __arq->state = AS_RQ_DISPATCHED;
-
- ad->nr_dispatched++;
- }
-
as_remove_queued_request(ad->q, rq);
WARN_ON(arq->state != AS_RQ_QUEUED);
return 1;
}
-/*
- * Add arq to a list behind alias
- */
-static inline void
-as_add_aliased_request(struct as_data *ad, struct as_rq *arq,
- struct as_rq *alias)
-{
- struct request *req = arq->request;
- struct list_head *insert = alias->request->queuelist.prev;
-
- /*
- * Transfer list of aliases
- */
- while (!list_empty(&req->queuelist)) {
- struct request *__rq = list_entry_rq(req->queuelist.next);
- struct as_rq *__arq = RQ_DATA(__rq);
-
- list_move_tail(&__rq->queuelist, &alias->request->queuelist);
-
- WARN_ON(__arq->state != AS_RQ_QUEUED);
- }
-
- /*
- * Another request with the same start sector on the rbtree.
- * Link this request to that sector. They are untangled in
- * as_move_to_dispatch
- */
- list_add(&arq->request->queuelist, insert);
-
- /*
- * Don't want to have to handle merges.
- */
- as_del_arq_hash(arq);
- arq->request->flags |= REQ_NOMERGE;
-}
-
/*
* add arq to rbtree and fifo
*/
{
struct as_data *ad = q->elevator->elevator_data;
struct as_rq *arq = RQ_DATA(rq);
- struct as_rq *alias;
int data_dir;
- if (arq->state != AS_RQ_PRESCHED) {
- printk("arq->state: %d\n", arq->state);
- WARN_ON(1);
- }
arq->state = AS_RQ_NEW;
if (rq_data_dir(arq->request) == READ
atomic_inc(&arq->io_context->aic->nr_queued);
}
- alias = as_add_arq_rb(ad, arq);
- if (!alias) {
- /*
- * set expire time (only used for reads) and add to fifo list
- */
- arq->expires = jiffies + ad->fifo_expire[data_dir];
- list_add_tail(&arq->fifo, &ad->fifo_list[data_dir]);
-
- if (rq_mergeable(arq->request))
- as_add_arq_hash(ad, arq);
- as_update_arq(ad, arq); /* keep state machine up to date */
+ as_add_arq_rb(ad, arq);
+ if (rq_mergeable(arq->request))
+ as_add_arq_hash(ad, arq);
- } else {
- as_add_aliased_request(ad, arq, alias);
-
- /*
- * have we been anticipating this request?
- * or does it come from the same process as the one we are
- * anticipating for?
- */
- if (ad->antic_status == ANTIC_WAIT_REQ
- || ad->antic_status == ANTIC_WAIT_NEXT) {
- if (as_can_break_anticipation(ad, arq))
- as_antic_stop(ad);
- }
- }
+ /*
+ * set expire time (only used for reads) and add to fifo list
+ */
+ arq->expires = jiffies + ad->fifo_expire[data_dir];
+ list_add_tail(&arq->fifo, &ad->fifo_list[data_dir]);
+ as_update_arq(ad, arq); /* keep state machine up to date */
arq->state = AS_RQ_QUEUED;
}
* if the merge was a front merge, we need to reposition request
*/
if (rq_rb_key(req) != arq->rb_key) {
- struct as_rq *alias, *next_arq = NULL;
-
- if (ad->next_arq[arq->is_sync] == arq)
- next_arq = as_find_next_arq(ad, arq);
-
- /*
- * Note! We should really be moving any old aliased requests
- * off this request and try to insert them into the rbtree. We
- * currently don't bother. Ditto the next function.
- */
as_del_arq_rb(ad, arq);
- if ((alias = as_add_arq_rb(ad, arq))) {
- list_del_init(&arq->fifo);
- as_add_aliased_request(ad, arq, alias);
- if (next_arq)
- ad->next_arq[arq->is_sync] = next_arq;
- }
+ as_add_arq_rb(ad, arq);
/*
* Note! At this stage of this and the next function, our next
* request may not be optimal - eg the request may have "grown"
as_add_arq_hash(ad, arq);
if (rq_rb_key(req) != arq->rb_key) {
- struct as_rq *alias, *next_arq = NULL;
-
- if (ad->next_arq[arq->is_sync] == arq)
- next_arq = as_find_next_arq(ad, arq);
-
as_del_arq_rb(ad, arq);
- if ((alias = as_add_arq_rb(ad, arq))) {
- list_del_init(&arq->fifo);
- as_add_aliased_request(ad, arq, alias);
- if (next_arq)
- ad->next_arq[arq->is_sync] = next_arq;
- }
+ as_add_arq_rb(ad, arq);
}
/*
}
}
- /*
- * Transfer list of aliases
- */
- while (!list_empty(&next->queuelist)) {
- struct request *__rq = list_entry_rq(next->queuelist.next);
- struct as_rq *__arq = RQ_DATA(__rq);
-
- list_move_tail(&__rq->queuelist, &req->queuelist);
-
- WARN_ON(__arq->state != AS_RQ_QUEUED);
- }
-
/*
* kill knowledge of next, this one is a goner
*/
/*
* sysfs parts below
*/
-struct as_fs_entry {
- struct attribute attr;
- ssize_t (*show)(struct as_data *, char *);
- ssize_t (*store)(struct as_data *, const char *, size_t);
-};
static ssize_t
as_var_show(unsigned int var, char *page)
return count;
}
-static ssize_t as_est_show(struct as_data *ad, char *page)
+static ssize_t est_time_show(elevator_t *e, char *page)
{
+ struct as_data *ad = e->elevator_data;
int pos = 0;
pos += sprintf(page+pos, "%lu %% exit probability\n",
}
#define SHOW_FUNCTION(__FUNC, __VAR) \
-static ssize_t __FUNC(struct as_data *ad, char *page) \
+static ssize_t __FUNC(elevator_t *e, char *page) \
{ \
+ struct as_data *ad = e->elevator_data; \
return as_var_show(jiffies_to_msecs((__VAR)), (page)); \
}
-SHOW_FUNCTION(as_readexpire_show, ad->fifo_expire[REQ_SYNC]);
-SHOW_FUNCTION(as_writeexpire_show, ad->fifo_expire[REQ_ASYNC]);
-SHOW_FUNCTION(as_anticexpire_show, ad->antic_expire);
-SHOW_FUNCTION(as_read_batchexpire_show, ad->batch_expire[REQ_SYNC]);
-SHOW_FUNCTION(as_write_batchexpire_show, ad->batch_expire[REQ_ASYNC]);
+SHOW_FUNCTION(as_read_expire_show, ad->fifo_expire[REQ_SYNC]);
+SHOW_FUNCTION(as_write_expire_show, ad->fifo_expire[REQ_ASYNC]);
+SHOW_FUNCTION(as_antic_expire_show, ad->antic_expire);
+SHOW_FUNCTION(as_read_batch_expire_show, ad->batch_expire[REQ_SYNC]);
+SHOW_FUNCTION(as_write_batch_expire_show, ad->batch_expire[REQ_ASYNC]);
#undef SHOW_FUNCTION
#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX) \
-static ssize_t __FUNC(struct as_data *ad, const char *page, size_t count) \
+static ssize_t __FUNC(elevator_t *e, const char *page, size_t count) \
{ \
- int ret = as_var_store(__PTR, (page), count); \
+ struct as_data *ad = e->elevator_data; \
+ int ret = as_var_store(__PTR, (page), count); \
if (*(__PTR) < (MIN)) \
*(__PTR) = (MIN); \
else if (*(__PTR) > (MAX)) \
*(__PTR) = msecs_to_jiffies(*(__PTR)); \
return ret; \
}
-STORE_FUNCTION(as_readexpire_store, &ad->fifo_expire[REQ_SYNC], 0, INT_MAX);
-STORE_FUNCTION(as_writeexpire_store, &ad->fifo_expire[REQ_ASYNC], 0, INT_MAX);
-STORE_FUNCTION(as_anticexpire_store, &ad->antic_expire, 0, INT_MAX);
-STORE_FUNCTION(as_read_batchexpire_store,
+STORE_FUNCTION(as_read_expire_store, &ad->fifo_expire[REQ_SYNC], 0, INT_MAX);
+STORE_FUNCTION(as_write_expire_store, &ad->fifo_expire[REQ_ASYNC], 0, INT_MAX);
+STORE_FUNCTION(as_antic_expire_store, &ad->antic_expire, 0, INT_MAX);
+STORE_FUNCTION(as_read_batch_expire_store,
&ad->batch_expire[REQ_SYNC], 0, INT_MAX);
-STORE_FUNCTION(as_write_batchexpire_store,
+STORE_FUNCTION(as_write_batch_expire_store,
&ad->batch_expire[REQ_ASYNC], 0, INT_MAX);
#undef STORE_FUNCTION
-static struct as_fs_entry as_est_entry = {
- .attr = {.name = "est_time", .mode = S_IRUGO },
- .show = as_est_show,
-};
-static struct as_fs_entry as_readexpire_entry = {
- .attr = {.name = "read_expire", .mode = S_IRUGO | S_IWUSR },
- .show = as_readexpire_show,
- .store = as_readexpire_store,
-};
-static struct as_fs_entry as_writeexpire_entry = {
- .attr = {.name = "write_expire", .mode = S_IRUGO | S_IWUSR },
- .show = as_writeexpire_show,
- .store = as_writeexpire_store,
-};
-static struct as_fs_entry as_anticexpire_entry = {
- .attr = {.name = "antic_expire", .mode = S_IRUGO | S_IWUSR },
- .show = as_anticexpire_show,
- .store = as_anticexpire_store,
-};
-static struct as_fs_entry as_read_batchexpire_entry = {
- .attr = {.name = "read_batch_expire", .mode = S_IRUGO | S_IWUSR },
- .show = as_read_batchexpire_show,
- .store = as_read_batchexpire_store,
-};
-static struct as_fs_entry as_write_batchexpire_entry = {
- .attr = {.name = "write_batch_expire", .mode = S_IRUGO | S_IWUSR },
- .show = as_write_batchexpire_show,
- .store = as_write_batchexpire_store,
-};
-
-static struct attribute *default_attrs[] = {
- &as_est_entry.attr,
- &as_readexpire_entry.attr,
- &as_writeexpire_entry.attr,
- &as_anticexpire_entry.attr,
- &as_read_batchexpire_entry.attr,
- &as_write_batchexpire_entry.attr,
- NULL,
-};
-
-#define to_as(atr) container_of((atr), struct as_fs_entry, attr)
-
-static ssize_t
-as_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
-{
- elevator_t *e = container_of(kobj, elevator_t, kobj);
- struct as_fs_entry *entry = to_as(attr);
-
- if (!entry->show)
- return -EIO;
-
- return entry->show(e->elevator_data, page);
-}
-
-static ssize_t
-as_attr_store(struct kobject *kobj, struct attribute *attr,
- const char *page, size_t length)
-{
- elevator_t *e = container_of(kobj, elevator_t, kobj);
- struct as_fs_entry *entry = to_as(attr);
-
- if (!entry->store)
- return -EIO;
-
- return entry->store(e->elevator_data, page, length);
-}
-
-static struct sysfs_ops as_sysfs_ops = {
- .show = as_attr_show,
- .store = as_attr_store,
-};
-
-static struct kobj_type as_ktype = {
- .sysfs_ops = &as_sysfs_ops,
- .default_attrs = default_attrs,
+#define AS_ATTR(name) \
+ __ATTR(name, S_IRUGO|S_IWUSR, as_##name##_show, as_##name##_store)
+
+static struct elv_fs_entry as_attrs[] = {
+ __ATTR_RO(est_time),
+ AS_ATTR(read_expire),
+ AS_ATTR(write_expire),
+ AS_ATTR(antic_expire),
+ AS_ATTR(read_batch_expire),
+ AS_ATTR(write_batch_expire),
+ __ATTR_NULL
};
static struct elevator_type iosched_as = {
.elevator_may_queue_fn = as_may_queue,
.elevator_init_fn = as_init_queue,
.elevator_exit_fn = as_exit_queue,
+ .trim = as_trim,
},
- .elevator_ktype = &as_ktype,
+ .elevator_attrs = as_attrs,
.elevator_name = "anticipatory",
.elevator_owner = THIS_MODULE,
};
static void __exit as_exit(void)
{
+ DECLARE_COMPLETION(all_gone);
elv_unregister(&iosched_as);
+ ioc_gone = &all_gone;
+ barrier();
+ if (atomic_read(&ioc_count))
+ complete(ioc_gone);
+ synchronize_rcu();
kmem_cache_destroy(arq_pool);
}
Code Review / linux-3.10.git / blobdiff