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Merge branch 'generic-dispatch' of git://brick.kernel.dk/data/git/linux-2.6-block

Browse source
This commit is contained in:
Linus Torvalds 2005-10-28 08:53:49 -07:00
commit 28d721e24c
9 changed files with 459 additions and 847 deletions
Download patch file Download diff file Expand all files Collapse all files

333
drivers/block/as-iosched.c
View file

@ -98,7 +98,6 @@ struct as_data {
struct as_rq *next_arq[2]; /* next in sort order */
sector_t last_sector[2]; /* last REQ_SYNC & REQ_ASYNC sectors */
struct list_head *dispatch; /* driver dispatch queue */
struct list_head *hash; /* request hash */
unsigned long exit_prob; /* probability a task will exit while
@ -239,6 +238,25 @@ static struct io_context *as_get_io_context(void)
return ioc;
}
static void as_put_io_context(struct as_rq *arq)
{
struct as_io_context *aic;
if (unlikely(!arq->io_context))
return;
aic = arq->io_context->aic;
if (arq->is_sync == REQ_SYNC && aic) {
spin_lock(&aic->lock);
set_bit(AS_TASK_IORUNNING, &aic->state);
aic->last_end_request = jiffies;
spin_unlock(&aic->lock);
}
put_io_context(arq->io_context);
}
/*
* the back merge hash support functions
*/
@ -261,14 +279,6 @@ static inline void as_del_arq_hash(struct as_rq *arq)
__as_del_arq_hash(arq);
}
static void as_remove_merge_hints(request_queue_t *q, struct as_rq *arq)
{
as_del_arq_hash(arq);
if (q->last_merge == arq->request)
q->last_merge = NULL;
}
static void as_add_arq_hash(struct as_data *ad, struct as_rq *arq)
{
struct request *rq = arq->request;
@ -312,7 +322,7 @@ static struct request *as_find_arq_hash(struct as_data *ad, sector_t offset)
BUG_ON(!arq->on_hash);
if (!rq_mergeable(__rq)) {
as_remove_merge_hints(ad->q, arq);
as_del_arq_hash(arq);
continue;
}
@ -950,23 +960,12 @@ static void as_completed_request(request_queue_t *q, struct request *rq)
WARN_ON(!list_empty(&rq->queuelist));
if (arq->state == AS_RQ_PRESCHED) {
WARN_ON(arq->io_context);
goto out;
}
if (arq->state == AS_RQ_MERGED)
goto out_ioc;
if (arq->state != AS_RQ_REMOVED) {
printk("arq->state %d\n", arq->state);
WARN_ON(1);
goto out;
}
if (!blk_fs_request(rq))
goto out;
if (ad->changed_batch && ad->nr_dispatched == 1) {
kblockd_schedule_work(&ad->antic_work);
ad->changed_batch = 0;
@ -1001,21 +1000,7 @@ static void as_completed_request(request_queue_t *q, struct request *rq)
}
}
out_ioc:
if (!arq->io_context)
goto out;
if (arq->is_sync == REQ_SYNC) {
struct as_io_context *aic = arq->io_context->aic;
if (aic) {
spin_lock(&aic->lock);
set_bit(AS_TASK_IORUNNING, &aic->state);
aic->last_end_request = jiffies;
spin_unlock(&aic->lock);
}
}
put_io_context(arq->io_context);
as_put_io_context(arq);
out:
arq->state = AS_RQ_POSTSCHED;
}
@ -1047,72 +1032,10 @@ static void as_remove_queued_request(request_queue_t *q, struct request *rq)
ad->next_arq[data_dir] = as_find_next_arq(ad, arq);
list_del_init(&arq->fifo);
as_remove_merge_hints(q, arq);
as_del_arq_hash(arq);
as_del_arq_rb(ad, arq);
}
/*
* as_remove_dispatched_request is called to remove a request which has gone
* to the dispatch list.
*/
static void as_remove_dispatched_request(request_queue_t *q, struct request *rq)
{
struct as_rq *arq = RQ_DATA(rq);
struct as_io_context *aic;
if (!arq) {
WARN_ON(1);
return;
}
WARN_ON(arq->state != AS_RQ_DISPATCHED);
WARN_ON(ON_RB(&arq->rb_node));
if (arq->io_context && arq->io_context->aic) {
aic = arq->io_context->aic;
if (aic) {
WARN_ON(!atomic_read(&aic->nr_dispatched));
atomic_dec(&aic->nr_dispatched);
}
}
}
/*
* as_remove_request is called when a driver has finished with a request.
* This should be only called for dispatched requests, but for some reason
* a POWER4 box running hwscan it does not.
*/
static void as_remove_request(request_queue_t *q, struct request *rq)
{
struct as_rq *arq = RQ_DATA(rq);
if (unlikely(arq->state == AS_RQ_NEW))
goto out;
if (ON_RB(&arq->rb_node)) {
if (arq->state != AS_RQ_QUEUED) {
printk("arq->state %d\n", arq->state);
WARN_ON(1);
goto out;
}
/*
* We'll lose the aliased request(s) here. I don't think this
* will ever happen, but if it does, hopefully someone will
* report it.
*/
WARN_ON(!list_empty(&rq->queuelist));
as_remove_queued_request(q, rq);
} else {
if (arq->state != AS_RQ_DISPATCHED) {
printk("arq->state %d\n", arq->state);
WARN_ON(1);
goto out;
}
as_remove_dispatched_request(q, rq);
}
out:
arq->state = AS_RQ_REMOVED;
}
/*
* as_fifo_expired returns 0 if there are no expired reads on the fifo,
* 1 otherwise. It is ratelimited so that we only perform the check once per
@ -1165,7 +1088,6 @@ static inline int as_batch_expired(struct as_data *ad)
static void as_move_to_dispatch(struct as_data *ad, struct as_rq *arq)
{
struct request *rq = arq->request;
struct list_head *insert;
const int data_dir = arq->is_sync;
BUG_ON(!ON_RB(&arq->rb_node));
@ -1198,13 +1120,13 @@ static void as_move_to_dispatch(struct as_data *ad, struct as_rq *arq)
/*
* take it off the sort and fifo list, add to dispatch queue
*/
insert = ad->dispatch->prev;
while (!list_empty(&rq->queuelist)) {
struct request *__rq = list_entry_rq(rq->queuelist.next);
struct as_rq *__arq = RQ_DATA(__rq);
list_move_tail(&__rq->queuelist, ad->dispatch);
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);
@ -1218,7 +1140,8 @@ static void as_move_to_dispatch(struct as_data *ad, struct as_rq *arq)
as_remove_queued_request(ad->q, rq);
WARN_ON(arq->state != AS_RQ_QUEUED);
list_add(&rq->queuelist, insert);
elv_dispatch_sort(ad->q, rq);
arq->state = AS_RQ_DISPATCHED;
if (arq->io_context && arq->io_context->aic)
atomic_inc(&arq->io_context->aic->nr_dispatched);
@ -1230,12 +1153,42 @@ static void as_move_to_dispatch(struct as_data *ad, struct as_rq *arq)
* read/write expire, batch expire, etc, and moves it to the dispatch
* queue. Returns 1 if a request was found, 0 otherwise.
*/
static int as_dispatch_request(struct as_data *ad)
static int as_dispatch_request(request_queue_t *q, int force)
{
struct as_data *ad = q->elevator->elevator_data;
struct as_rq *arq;
const int reads = !list_empty(&ad->fifo_list[REQ_SYNC]);
const int writes = !list_empty(&ad->fifo_list[REQ_ASYNC]);
if (unlikely(force)) {
/*
* Forced dispatch, accounting is useless. Reset
* accounting states and dump fifo_lists. Note that
* batch_data_dir is reset to REQ_SYNC to avoid
* screwing write batch accounting as write batch
* accounting occurs on W->R transition.
*/
int dispatched = 0;
ad->batch_data_dir = REQ_SYNC;
ad->changed_batch = 0;
ad->new_batch = 0;
while (ad->next_arq[REQ_SYNC]) {
as_move_to_dispatch(ad, ad->next_arq[REQ_SYNC]);
dispatched++;
}
ad->last_check_fifo[REQ_SYNC] = jiffies;
while (ad->next_arq[REQ_ASYNC]) {
as_move_to_dispatch(ad, ad->next_arq[REQ_ASYNC]);
dispatched++;
}
ad->last_check_fifo[REQ_ASYNC] = jiffies;
return dispatched;
}
/* Signal that the write batch was uncontended, so we can't time it */
if (ad->batch_data_dir == REQ_ASYNC && !reads) {
if (ad->current_write_count == 0 || !writes)
@ -1359,20 +1312,6 @@ fifo_expired:
return 1;
}
static struct request *as_next_request(request_queue_t *q)
{
struct as_data *ad = q->elevator->elevator_data;
struct request *rq = NULL;
/*
* if there are still requests on the dispatch queue, grab the first
*/
if (!list_empty(ad->dispatch) || as_dispatch_request(ad))
rq = list_entry_rq(ad->dispatch->next);
return rq;
}
/*
* Add arq to a list behind alias
*/
@ -1404,17 +1343,25 @@ as_add_aliased_request(struct as_data *ad, struct as_rq *arq, struct as_rq *alia
/*
* Don't want to have to handle merges.
*/
as_remove_merge_hints(ad->q, arq);
as_del_arq_hash(arq);
}
/*
* add arq to rbtree and fifo
*/
static void as_add_request(struct as_data *ad, struct as_rq *arq)
static void as_add_request(request_queue_t *q, struct request *rq)
{
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
|| current->flags&PF_SYNCWRITE)
arq->is_sync = 1;
@ -1437,12 +1384,8 @@ static void as_add_request(struct as_data *ad, struct as_rq *arq)
arq->expires = jiffies + ad->fifo_expire[data_dir];
list_add_tail(&arq->fifo, &ad->fifo_list[data_dir]);
if (rq_mergeable(arq->request)) {
if (rq_mergeable(arq->request))
as_add_arq_hash(ad, arq);
if (!ad->q->last_merge)
ad->q->last_merge = arq->request;
}
as_update_arq(ad, arq); /* keep state machine up to date */
} else {
@ -1463,96 +1406,24 @@ static void as_add_request(struct as_data *ad, struct as_rq *arq)
arq->state = AS_RQ_QUEUED;
}
static void as_activate_request(request_queue_t *q, struct request *rq)
{
struct as_rq *arq = RQ_DATA(rq);
WARN_ON(arq->state != AS_RQ_DISPATCHED);
arq->state = AS_RQ_REMOVED;
if (arq->io_context && arq->io_context->aic)
atomic_dec(&arq->io_context->aic->nr_dispatched);
}
static void as_deactivate_request(request_queue_t *q, struct request *rq)
{
struct as_data *ad = q->elevator->elevator_data;
struct as_rq *arq = RQ_DATA(rq);
if (arq) {
if (arq->state == AS_RQ_REMOVED) {
arq->state = AS_RQ_DISPATCHED;
if (arq->io_context && arq->io_context->aic)
atomic_inc(&arq->io_context->aic->nr_dispatched);
}
} else
WARN_ON(blk_fs_request(rq)
&& (!(rq->flags & (REQ_HARDBARRIER|REQ_SOFTBARRIER))) );
/* Stop anticipating - let this request get through */
as_antic_stop(ad);
}
/*
* requeue the request. The request has not been completed, nor is it a
* new request, so don't touch accounting.
*/
static void as_requeue_request(request_queue_t *q, struct request *rq)
{
as_deactivate_request(q, rq);
list_add(&rq->queuelist, &q->queue_head);
}
/*
* Account a request that is inserted directly onto the dispatch queue.
* arq->io_context->aic->nr_dispatched should not need to be incremented
* because only new requests should come through here: requeues go through
* our explicit requeue handler.
*/
static void as_account_queued_request(struct as_data *ad, struct request *rq)
{
if (blk_fs_request(rq)) {
struct as_rq *arq = RQ_DATA(rq);
arq->state = AS_RQ_DISPATCHED;
ad->nr_dispatched++;
}
}
static void
as_insert_request(request_queue_t *q, struct request *rq, int where)
{
struct as_data *ad = q->elevator->elevator_data;
struct as_rq *arq = RQ_DATA(rq);
if (arq) {
if (arq->state != AS_RQ_PRESCHED) {
printk("arq->state: %d\n", arq->state);
WARN_ON(1);
}
arq->state = AS_RQ_NEW;
}
/* barriers must flush the reorder queue */
if (unlikely(rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)
&& where == ELEVATOR_INSERT_SORT)) {
WARN_ON(1);
where = ELEVATOR_INSERT_BACK;
}
switch (where) {
case ELEVATOR_INSERT_BACK:
while (ad->next_arq[REQ_SYNC])
as_move_to_dispatch(ad, ad->next_arq[REQ_SYNC]);
while (ad->next_arq[REQ_ASYNC])
as_move_to_dispatch(ad, ad->next_arq[REQ_ASYNC]);
list_add_tail(&rq->queuelist, ad->dispatch);
as_account_queued_request(ad, rq);
as_antic_stop(ad);
break;
case ELEVATOR_INSERT_FRONT:
list_add(&rq->queuelist, ad->dispatch);
as_account_queued_request(ad, rq);
as_antic_stop(ad);
break;
case ELEVATOR_INSERT_SORT:
BUG_ON(!blk_fs_request(rq));
as_add_request(ad, arq);
break;
default:
BUG();
return;
}
WARN_ON(arq->state != AS_RQ_REMOVED);
arq->state = AS_RQ_DISPATCHED;
if (arq->io_context && arq->io_context->aic)
atomic_inc(&arq->io_context->aic->nr_dispatched);
}
/*
@ -1565,12 +1436,8 @@ static int as_queue_empty(request_queue_t *q)
{
struct as_data *ad = q->elevator->elevator_data;
if (!list_empty(&ad->fifo_list[REQ_ASYNC])
|| !list_empty(&ad->fifo_list[REQ_SYNC])
|| !list_empty(ad->dispatch))
return 0;
return 1;
return list_empty(&ad->fifo_list[REQ_ASYNC])
&& list_empty(&ad->fifo_list[REQ_SYNC]);
}
static struct request *
@ -1607,15 +1474,6 @@ as_merge(request_queue_t *q, struct request **req, struct bio *bio)
struct request *__rq;
int ret;
/*
* try last_merge to avoid going to hash
*/
ret = elv_try_last_merge(q, bio);
if (ret != ELEVATOR_NO_MERGE) {
__rq = q->last_merge;
goto out_insert;
}
/*
* see if the merge hash can satisfy a back merge
*/
@ -1644,9 +1502,6 @@ as_merge(request_queue_t *q, struct request **req, struct bio *bio)
return ELEVATOR_NO_MERGE;
out:
if (rq_mergeable(__rq))
q->last_merge = __rq;
out_insert:
if (ret) {
if (rq_mergeable(__rq))
as_hot_arq_hash(ad, RQ_DATA(__rq));
@ -1693,9 +1548,6 @@ static void as_merged_request(request_queue_t *q, struct request *req)
* behind the disk head. We currently don't bother adjusting.
*/
}
if (arq->on_hash)
q->last_merge = req;
}
static void
@ -1763,6 +1615,7 @@ as_merged_requests(request_queue_t *q, struct request *req,
* kill knowledge of next, this one is a goner
*/
as_remove_queued_request(q, next);
as_put_io_context(anext);
anext->state = AS_RQ_MERGED;
}
@ -1782,7 +1635,7 @@ static void as_work_handler(void *data)
unsigned long flags;
spin_lock_irqsave(q->queue_lock, flags);
if (as_next_request(q))
if (!as_queue_empty(q))
q->request_fn(q);
spin_unlock_irqrestore(q->queue_lock, flags);
}
@ -1797,7 +1650,9 @@ static void as_put_request(request_queue_t *q, struct request *rq)
return;
}
if (arq->state != AS_RQ_POSTSCHED && arq->state != AS_RQ_PRESCHED) {
if (unlikely(arq->state != AS_RQ_POSTSCHED &&
arq->state != AS_RQ_PRESCHED &&
arq->state != AS_RQ_MERGED)) {
printk("arq->state %d\n", arq->state);
WARN_ON(1);
}
@ -1907,7 +1762,6 @@ static int as_init_queue(request_queue_t *q, elevator_t *e)
INIT_LIST_HEAD(&ad->fifo_list[REQ_ASYNC]);
ad->sort_list[REQ_SYNC] = RB_ROOT;
ad->sort_list[REQ_ASYNC] = RB_ROOT;
ad->dispatch = &q->queue_head;
ad->fifo_expire[REQ_SYNC] = default_read_expire;
ad->fifo_expire[REQ_ASYNC] = default_write_expire;
ad->antic_expire = default_antic_expire;
@ -2072,10 +1926,9 @@ static struct elevator_type iosched_as = {
.elevator_merge_fn = as_merge,
.elevator_merged_fn = as_merged_request,
.elevator_merge_req_fn = as_merged_requests,
.elevator_next_req_fn = as_next_request,
.elevator_add_req_fn = as_insert_request,
.elevator_remove_req_fn = as_remove_request,
.elevator_requeue_req_fn = as_requeue_request,
.elevator_dispatch_fn = as_dispatch_request,
.elevator_add_req_fn = as_add_request,
.elevator_activate_req_fn = as_activate_request,
.elevator_deactivate_req_fn = as_deactivate_request,
.elevator_queue_empty_fn = as_queue_empty,
.elevator_completed_req_fn = as_completed_request,

368
drivers/block/cfq-iosched.c
View file

@ -84,7 +84,6 @@ static int cfq_max_depth = 2;
(node)->rb_left = NULL; \
} while (0)
#define RB_CLEAR_ROOT(root) ((root)->rb_node = NULL)
#define ON_RB(node) ((node)->rb_color != RB_NONE)
#define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node)
#define rq_rb_key(rq) (rq)->sector
@ -271,10 +270,7 @@ CFQ_CFQQ_FNS(expired);
#undef CFQ_CFQQ_FNS
enum cfq_rq_state_flags {
CFQ_CRQ_FLAG_in_flight = 0,
CFQ_CRQ_FLAG_in_driver,
CFQ_CRQ_FLAG_is_sync,
CFQ_CRQ_FLAG_requeued,
CFQ_CRQ_FLAG_is_sync = 0,
};
#define CFQ_CRQ_FNS(name) \
@ -291,14 +287,11 @@ static inline int cfq_crq_##name(const struct cfq_rq *crq) \
return (crq->crq_flags & (1 << CFQ_CRQ_FLAG_##name)) != 0; \
}
CFQ_CRQ_FNS(in_flight);
CFQ_CRQ_FNS(in_driver);
CFQ_CRQ_FNS(is_sync);
CFQ_CRQ_FNS(requeued);
#undef CFQ_CRQ_FNS
static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short);
static void cfq_dispatch_sort(request_queue_t *, struct cfq_rq *);
static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *);
static void cfq_put_cfqd(struct cfq_data *cfqd);
#define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE)
@ -311,14 +304,6 @@ static inline void cfq_del_crq_hash(struct cfq_rq *crq)
hlist_del_init(&crq->hash);
}
static void cfq_remove_merge_hints(request_queue_t *q, struct cfq_rq *crq)
{
cfq_del_crq_hash(crq);
if (q->last_merge == crq->request)
q->last_merge = NULL;
}
static inline void cfq_add_crq_hash(struct cfq_data *cfqd, struct cfq_rq *crq)
{
const int hash_idx = CFQ_MHASH_FN(rq_hash_key(crq->request));
@ -347,18 +332,13 @@ static struct request *cfq_find_rq_hash(struct cfq_data *cfqd, sector_t offset)
return NULL;
}
static inline int cfq_pending_requests(struct cfq_data *cfqd)
{
return !list_empty(&cfqd->queue->queue_head) || cfqd->busy_queues;
}
/*
* scheduler run of queue, if there are requests pending and no one in the
* driver that will restart queueing
*/
static inline void cfq_schedule_dispatch(struct cfq_data *cfqd)
{
if (!cfqd->rq_in_driver && cfq_pending_requests(cfqd))
if (!cfqd->rq_in_driver && cfqd->busy_queues)
kblockd_schedule_work(&cfqd->unplug_work);
}
@ -366,7 +346,7 @@ static int cfq_queue_empty(request_queue_t *q)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
return !cfq_pending_requests(cfqd);
return !cfqd->busy_queues;
}
/*
@ -386,11 +366,6 @@ cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2)
if (crq2 == NULL)
return crq1;
if (cfq_crq_requeued(crq1) && !cfq_crq_requeued(crq2))
return crq1;
else if (cfq_crq_requeued(crq2) && !cfq_crq_requeued(crq1))
return crq2;
if (cfq_crq_is_sync(crq1) && !cfq_crq_is_sync(crq2))
return crq1;
else if (cfq_crq_is_sync(crq2) && !cfq_crq_is_sync(crq1))
@ -461,10 +436,7 @@ cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct cfq_rq *crq_next = NULL, *crq_prev = NULL;
struct rb_node *rbnext, *rbprev;
rbnext = NULL;
if (ON_RB(&last->rb_node))
rbnext = rb_next(&last->rb_node);
if (!rbnext) {
if (!(rbnext = rb_next(&last->rb_node))) {
rbnext = rb_first(&cfqq->sort_list);
if (rbnext == &last->rb_node)
rbnext = NULL;
@ -545,13 +517,13 @@ static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
* the pending list according to last request service
*/
static inline void
cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq, int requeue)
cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
BUG_ON(cfq_cfqq_on_rr(cfqq));
cfq_mark_cfqq_on_rr(cfqq);
cfqd->busy_queues++;
cfq_resort_rr_list(cfqq, requeue);
cfq_resort_rr_list(cfqq, 0);
}
static inline void
@ -571,22 +543,19 @@ cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
static inline void cfq_del_crq_rb(struct cfq_rq *crq)
{
struct cfq_queue *cfqq = crq->cfq_queue;
struct cfq_data *cfqd = cfqq->cfqd;
const int sync = cfq_crq_is_sync(crq);
if (ON_RB(&crq->rb_node)) {
struct cfq_data *cfqd = cfqq->cfqd;
const int sync = cfq_crq_is_sync(crq);
BUG_ON(!cfqq->queued[sync]);
cfqq->queued[sync]--;
BUG_ON(!cfqq->queued[sync]);
cfqq->queued[sync]--;
cfq_update_next_crq(crq);
cfq_update_next_crq(crq);
rb_erase(&crq->rb_node, &cfqq->sort_list);
RB_CLEAR_COLOR(&crq->rb_node);
rb_erase(&crq->rb_node, &cfqq->sort_list);
RB_CLEAR_COLOR(&crq->rb_node);
if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list))
cfq_del_cfqq_rr(cfqd, cfqq);
}
if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list))
cfq_del_cfqq_rr(cfqd, cfqq);
}
static struct cfq_rq *
@ -627,12 +596,12 @@ static void cfq_add_crq_rb(struct cfq_rq *crq)
* if that happens, put the alias on the dispatch list
*/
while ((__alias = __cfq_add_crq_rb(crq)) != NULL)
cfq_dispatch_sort(cfqd->queue, __alias);
cfq_dispatch_insert(cfqd->queue, __alias);
rb_insert_color(&crq->rb_node, &cfqq->sort_list);
if (!cfq_cfqq_on_rr(cfqq))
cfq_add_cfqq_rr(cfqd, cfqq, cfq_crq_requeued(crq));
cfq_add_cfqq_rr(cfqd, cfqq);
/*
* check if this request is a better next-serve candidate
@ -643,10 +612,8 @@ static void cfq_add_crq_rb(struct cfq_rq *crq)
static inline void
cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq)
{
if (ON_RB(&crq->rb_node)) {
rb_erase(&crq->rb_node, &cfqq->sort_list);
cfqq->queued[cfq_crq_is_sync(crq)]--;
}
rb_erase(&crq->rb_node, &cfqq->sort_list);
cfqq->queued[cfq_crq_is_sync(crq)]--;
cfq_add_crq_rb(crq);
}
@ -676,49 +643,28 @@ out:
return NULL;
}
static void cfq_activate_request(request_queue_t *q, struct request *rq)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
cfqd->rq_in_driver++;
}
static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_rq *crq = RQ_DATA(rq);
if (crq) {
struct cfq_queue *cfqq = crq->cfq_queue;
if (cfq_crq_in_driver(crq)) {
cfq_clear_crq_in_driver(crq);
WARN_ON(!cfqd->rq_in_driver);
cfqd->rq_in_driver--;
}
if (cfq_crq_in_flight(crq)) {
const int sync = cfq_crq_is_sync(crq);
cfq_clear_crq_in_flight(crq);
WARN_ON(!cfqq->on_dispatch[sync]);
cfqq->on_dispatch[sync]--;
}
cfq_mark_crq_requeued(crq);
}
WARN_ON(!cfqd->rq_in_driver);
cfqd->rq_in_driver--;
}
/*
* make sure the service time gets corrected on reissue of this request
*/
static void cfq_requeue_request(request_queue_t *q, struct request *rq)
{
cfq_deactivate_request(q, rq);
list_add(&rq->queuelist, &q->queue_head);
}
static void cfq_remove_request(request_queue_t *q, struct request *rq)
static void cfq_remove_request(struct request *rq)
{
struct cfq_rq *crq = RQ_DATA(rq);
if (crq) {
list_del_init(&rq->queuelist);
cfq_del_crq_rb(crq);
cfq_remove_merge_hints(q, crq);
}
list_del_init(&rq->queuelist);
cfq_del_crq_rb(crq);
cfq_del_crq_hash(crq);
}
static int
@ -728,12 +674,6 @@ cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
struct request *__rq;
int ret;
ret = elv_try_last_merge(q, bio);
if (ret != ELEVATOR_NO_MERGE) {
__rq = q->last_merge;
goto out_insert;
}
__rq = cfq_find_rq_hash(cfqd, bio->bi_sector);
if (__rq && elv_rq_merge_ok(__rq, bio)) {
ret = ELEVATOR_BACK_MERGE;
@ -748,8 +688,6 @@ cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
return ELEVATOR_NO_MERGE;
out:
q->last_merge = __rq;
out_insert:
*req = __rq;
return ret;
}
@ -762,14 +700,12 @@ static void cfq_merged_request(request_queue_t *q, struct request *req)
cfq_del_crq_hash(crq);
cfq_add_crq_hash(cfqd, crq);
if (ON_RB(&crq->rb_node) && (rq_rb_key(req) != crq->rb_key)) {
if (rq_rb_key(req) != crq->rb_key) {
struct cfq_queue *cfqq = crq->cfq_queue;
cfq_update_next_crq(crq);
cfq_reposition_crq_rb(cfqq, crq);
}
q->last_merge = req;
}
static void
@ -785,7 +721,7 @@ cfq_merged_requests(request_queue_t *q, struct request *rq,
time_before(next->start_time, rq->start_time))
list_move(&rq->queuelist, &next->queuelist);
cfq_remove_request(q, next);
cfq_remove_request(next);
}
static inline void
@ -992,53 +928,15 @@ static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
return 1;
}
/*
* we dispatch cfqd->cfq_quantum requests in total from the rr_list queues,
* this function sector sorts the selected request to minimize seeks. we start
* at cfqd->last_sector, not 0.
*/
static void cfq_dispatch_sort(request_queue_t *q, struct cfq_rq *crq)
static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_queue *cfqq = crq->cfq_queue;
struct list_head *head = &q->queue_head, *entry = head;
struct request *__rq;
sector_t last;
list_del(&crq->request->queuelist);
last = cfqd->last_sector;
list_for_each_entry_reverse(__rq, head, queuelist) {
struct cfq_rq *__crq = RQ_DATA(__rq);
if (blk_barrier_rq(__rq))
break;
if (!blk_fs_request(__rq))
break;
if (cfq_crq_requeued(__crq))
break;
if (__rq->sector <= crq->request->sector)
break;
if (__rq->sector > last && crq->request->sector < last) {
last = crq->request->sector + crq->request->nr_sectors;
break;
}
entry = &__rq->queuelist;
}
cfqd->last_sector = last;
cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq);
cfq_del_crq_rb(crq);
cfq_remove_merge_hints(q, crq);
cfq_mark_crq_in_flight(crq);
cfq_clear_crq_requeued(crq);
cfq_remove_request(crq->request);
cfqq->on_dispatch[cfq_crq_is_sync(crq)]++;
list_add_tail(&crq->request->queuelist, entry);
elv_dispatch_sort(q, crq->request);
}
/*
@ -1159,7 +1057,7 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
/*
* finally, insert request into driver dispatch list
*/
cfq_dispatch_sort(cfqd->queue, crq);
cfq_dispatch_insert(cfqd->queue, crq);
cfqd->dispatch_slice++;
dispatched++;
@ -1194,7 +1092,7 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
}
static int
cfq_dispatch_requests(request_queue_t *q, int max_dispatch, int force)
cfq_dispatch_requests(request_queue_t *q, int force)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_queue *cfqq;
@ -1204,12 +1102,25 @@ cfq_dispatch_requests(request_queue_t *q, int max_dispatch, int force)
cfqq = cfq_select_queue(cfqd, force);
if (cfqq) {
int max_dispatch;
/*
* if idle window is disabled, allow queue buildup
*/
if (!cfq_cfqq_idle_window(cfqq) &&
cfqd->rq_in_driver >= cfqd->cfq_max_depth)
return 0;
cfq_clear_cfqq_must_dispatch(cfqq);
cfq_clear_cfqq_wait_request(cfqq);
del_timer(&cfqd->idle_slice_timer);
if (cfq_class_idle(cfqq))
max_dispatch = 1;
if (!force) {
max_dispatch = cfqd->cfq_quantum;
if (cfq_class_idle(cfqq))
max_dispatch = 1;
} else
max_dispatch = INT_MAX;
return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
}
@ -1217,93 +1128,6 @@ cfq_dispatch_requests(request_queue_t *q, int max_dispatch, int force)
return 0;
}
static inline void cfq_account_dispatch(struct cfq_rq *crq)
{
struct cfq_queue *cfqq = crq->cfq_queue;
struct cfq_data *cfqd = cfqq->cfqd;
if (unlikely(!blk_fs_request(crq->request)))
return;
/*
* accounted bit is necessary since some drivers will call
* elv_next_request() many times for the same request (eg ide)
*/
if (cfq_crq_in_driver(crq))
return;
cfq_mark_crq_in_driver(crq);
cfqd->rq_in_driver++;
}
static inline void
cfq_account_completion(struct cfq_queue *cfqq, struct cfq_rq *crq)
{
struct cfq_data *cfqd = cfqq->cfqd;
unsigned long now;
if (!cfq_crq_in_driver(crq))
return;
now = jiffies;
WARN_ON(!cfqd->rq_in_driver);
cfqd->rq_in_driver--;
if (!cfq_class_idle(cfqq))
cfqd->last_end_request = now;
if (!cfq_cfqq_dispatched(cfqq)) {
if (cfq_cfqq_on_rr(cfqq)) {
cfqq->service_last = now;
cfq_resort_rr_list(cfqq, 0);
}
if (cfq_cfqq_expired(cfqq)) {
__cfq_slice_expired(cfqd, cfqq, 0);
cfq_schedule_dispatch(cfqd);
}
}
if (cfq_crq_is_sync(crq))
crq->io_context->last_end_request = now;
}
static struct request *cfq_next_request(request_queue_t *q)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct request *rq;
if (!list_empty(&q->queue_head)) {
struct cfq_rq *crq;
dispatch:
rq = list_entry_rq(q->queue_head.next);
crq = RQ_DATA(rq);
if (crq) {
struct cfq_queue *cfqq = crq->cfq_queue;
/*
* if idle window is disabled, allow queue buildup
*/
if (!cfq_crq_in_driver(crq) &&
!cfq_cfqq_idle_window(cfqq) &&
!blk_barrier_rq(rq) &&
cfqd->rq_in_driver >= cfqd->cfq_max_depth)
return NULL;
cfq_remove_merge_hints(q, crq);
cfq_account_dispatch(crq);
}
return rq;
}
if (cfq_dispatch_requests(q, cfqd->cfq_quantum, 0))
goto dispatch;
return NULL;
}
/*
* task holds one reference to the queue, dropped when task exits. each crq
* in-flight on this queue also holds a reference, dropped when crq is freed.
@ -1816,8 +1640,9 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
}
}
static void cfq_enqueue(struct cfq_data *cfqd, struct request *rq)
static void cfq_insert_request(request_queue_t *q, struct request *rq)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_rq *crq = RQ_DATA(rq);
struct cfq_queue *cfqq = crq->cfq_queue;
@ -1827,66 +1652,43 @@ static void cfq_enqueue(struct cfq_data *cfqd, struct request *rq)
list_add_tail(&rq->queuelist, &cfqq->fifo);
if (rq_mergeable(rq)) {
if (rq_mergeable(rq))
cfq_add_crq_hash(cfqd, crq);
if (!cfqd->queue->last_merge)
cfqd->queue->last_merge = rq;
}
cfq_crq_enqueued(cfqd, cfqq, crq);
}
static void
cfq_insert_request(request_queue_t *q, struct request *rq, int where)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
switch (where) {
case ELEVATOR_INSERT_BACK:
while (cfq_dispatch_requests(q, INT_MAX, 1))
;
list_add_tail(&rq->queuelist, &q->queue_head);
/*
* If we were idling with pending requests on
* inactive cfqqs, force dispatching will
* remove the idle timer and the queue won't
* be kicked by __make_request() afterward.
* Kick it here.
*/
cfq_schedule_dispatch(cfqd);
break;
case ELEVATOR_INSERT_FRONT:
list_add(&rq->queuelist, &q->queue_head);
break;
case ELEVATOR_INSERT_SORT:
BUG_ON(!blk_fs_request(rq));
cfq_enqueue(cfqd, rq);
break;
default:
printk("%s: bad insert point %d\n", __FUNCTION__,where);
return;
}
}
static void cfq_completed_request(request_queue_t *q, struct request *rq)
{
struct cfq_rq *crq = RQ_DATA(rq);
struct cfq_queue *cfqq;
struct cfq_queue *cfqq = crq->cfq_queue;
struct cfq_data *cfqd = cfqq->cfqd;
const int sync = cfq_crq_is_sync(crq);
unsigned long now;
if (unlikely(!blk_fs_request(rq)))
return;
now = jiffies;
cfqq = crq->cfq_queue;
WARN_ON(!cfqd->rq_in_driver);
WARN_ON(!cfqq->on_dispatch[sync]);
cfqd->rq_in_driver--;
cfqq->on_dispatch[sync]--;
if (cfq_crq_in_flight(crq)) {
const int sync = cfq_crq_is_sync(crq);
if (!cfq_class_idle(cfqq))
cfqd->last_end_request = now;
WARN_ON(!cfqq->on_dispatch[sync]);
cfqq->on_dispatch[sync]--;
if (!cfq_cfqq_dispatched(cfqq)) {
if (cfq_cfqq_on_rr(cfqq)) {
cfqq->service_last = now;
cfq_resort_rr_list(cfqq, 0);
}
if (cfq_cfqq_expired(cfqq)) {
__cfq_slice_expired(cfqd, cfqq, 0);
cfq_schedule_dispatch(cfqd);
}
}
cfq_account_completion(cfqq, crq);
if (cfq_crq_is_sync(crq))
crq->io_context->last_end_request = now;
}
static struct request *
@ -2118,9 +1920,6 @@ cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
INIT_HLIST_NODE(&crq->hash);
crq->cfq_queue = cfqq;
crq->io_context = cic;
cfq_clear_crq_in_flight(crq);
cfq_clear_crq_in_driver(crq);
cfq_clear_crq_requeued(crq);
if (rw == READ || process_sync(tsk))
cfq_mark_crq_is_sync(crq);
@ -2201,7 +2000,7 @@ static void cfq_idle_slice_timer(unsigned long data)
* only expire and reinvoke request handler, if there are
* other queues with pending requests
*/
if (!cfq_pending_requests(cfqd)) {
if (!cfqd->busy_queues) {
cfqd->idle_slice_timer.expires = min(now + cfqd->cfq_slice_idle, cfqq->slice_end);
add_timer(&cfqd->idle_slice_timer);
goto out_cont;
@ -2576,10 +2375,9 @@ static struct elevator_type iosched_cfq = {
.elevator_merge_fn = cfq_merge,
.elevator_merged_fn = cfq_merged_request,
.elevator_merge_req_fn = cfq_merged_requests,
.elevator_next_req_fn = cfq_next_request,
.elevator_dispatch_fn = cfq_dispatch_requests,
.elevator_add_req_fn = cfq_insert_request,
.elevator_remove_req_fn = cfq_remove_request,
.elevator_requeue_req_fn = cfq_requeue_request,
.elevator_activate_req_fn = cfq_activate_request,
.elevator_deactivate_req_fn = cfq_deactivate_request,
.elevator_queue_empty_fn = cfq_queue_empty,
.elevator_completed_req_fn = cfq_completed_request,

123
drivers/block/deadline-iosched.c
View file

@ -50,7 +50,6 @@ struct deadline_data {
* next in sort order. read, write or both are NULL
*/
struct deadline_rq *next_drq[2];
struct list_head *dispatch; /* driver dispatch queue */
struct list_head *hash; /* request hash */
unsigned int batching; /* number of sequential requests made */
sector_t last_sector; /* head position */
@ -113,15 +112,6 @@ static inline void deadline_del_drq_hash(struct deadline_rq *drq)
__deadline_del_drq_hash(drq);
}
static void
deadline_remove_merge_hints(request_queue_t *q, struct deadline_rq *drq)
{
deadline_del_drq_hash(drq);
if (q->last_merge == drq->request)
q->last_merge = NULL;
}
static inline void
deadline_add_drq_hash(struct deadline_data *dd, struct deadline_rq *drq)
{
@ -239,10 +229,9 @@ deadline_del_drq_rb(struct deadline_data *dd, struct deadline_rq *drq)
dd->next_drq[data_dir] = rb_entry_drq(rbnext);
}
if (ON_RB(&drq->rb_node)) {
rb_erase(&drq->rb_node, DRQ_RB_ROOT(dd, drq));
RB_CLEAR(&drq->rb_node);
}
BUG_ON(!ON_RB(&drq->rb_node));
rb_erase(&drq->rb_node, DRQ_RB_ROOT(dd, drq));
RB_CLEAR(&drq->rb_node);
}
static struct request *
@ -286,7 +275,7 @@ deadline_find_first_drq(struct deadline_data *dd, int data_dir)
/*
* add drq to rbtree and fifo
*/
static inline void
static void
deadline_add_request(struct request_queue *q, struct request *rq)
{
struct deadline_data *dd = q->elevator->elevator_data;
@ -301,12 +290,8 @@ deadline_add_request(struct request_queue *q, struct request *rq)
drq->expires = jiffies + dd->fifo_expire[data_dir];
list_add_tail(&drq->fifo, &dd->fifo_list[data_dir]);
if (rq_mergeable(rq)) {
if (rq_mergeable(rq))
deadline_add_drq_hash(dd, drq);
if (!q->last_merge)
q->last_merge = rq;
}
}
/*
@ -315,14 +300,11 @@ deadline_add_request(struct request_queue *q, struct request *rq)
static void deadline_remove_request(request_queue_t *q, struct request *rq)
{
struct deadline_rq *drq = RQ_DATA(rq);
struct deadline_data *dd = q->elevator->elevator_data;
if (drq) {
struct deadline_data *dd = q->elevator->elevator_data;
list_del_init(&drq->fifo);
deadline_remove_merge_hints(q, drq);
deadline_del_drq_rb(dd, drq);
}
list_del_init(&drq->fifo);
deadline_del_drq_rb(dd, drq);
deadline_del_drq_hash(drq);
}
static int
@ -332,15 +314,6 @@ deadline_merge(request_queue_t *q, struct request **req, struct bio *bio)
struct request *__rq;
int ret;
/*
* try last_merge to avoid going to hash
*/
ret = elv_try_last_merge(q, bio);
if (ret != ELEVATOR_NO_MERGE) {
__rq = q->last_merge;
goto out_insert;
}
/*
* see if the merge hash can satisfy a back merge
*/
@ -373,8 +346,6 @@ deadline_merge(request_queue_t *q, struct request **req, struct bio *bio)
return ELEVATOR_NO_MERGE;
out:
q->last_merge = __rq;
out_insert:
if (ret)
deadline_hot_drq_hash(dd, RQ_DATA(__rq));
*req = __rq;
@ -399,8 +370,6 @@ static void deadline_merged_request(request_queue_t *q, struct request *req)
deadline_del_drq_rb(dd, drq);
deadline_add_drq_rb(dd, drq);
}
q->last_merge = req;
}
static void
@ -452,7 +421,7 @@ deadline_move_to_dispatch(struct deadline_data *dd, struct deadline_rq *drq)
request_queue_t *q = drq->request->q;
deadline_remove_request(q, drq->request);
list_add_tail(&drq->request->queuelist, dd->dispatch);
elv_dispatch_add_tail(q, drq->request);
}
/*
@ -502,8 +471,9 @@ static inline int deadline_check_fifo(struct deadline_data *dd, int ddir)
* deadline_dispatch_requests selects the best request according to
* read/write expire, fifo_batch, etc
*/
static int deadline_dispatch_requests(struct deadline_data *dd)
static int deadline_dispatch_requests(request_queue_t *q, int force)
{
struct deadline_data *dd = q->elevator->elevator_data;
const int reads = !list_empty(&dd->fifo_list[READ]);
const int writes = !list_empty(&dd->fifo_list[WRITE]);
struct deadline_rq *drq;
@ -597,65 +567,12 @@ dispatch_request:
return 1;
}
static struct request *deadline_next_request(request_queue_t *q)
{
struct deadline_data *dd = q->elevator->elevator_data;
struct request *rq;
/*
* if there are still requests on the dispatch queue, grab the first one
*/
if (!list_empty(dd->dispatch)) {
dispatch:
rq = list_entry_rq(dd->dispatch->next);
return rq;
}
if (deadline_dispatch_requests(dd))
goto dispatch;
return NULL;
}
static void
deadline_insert_request(request_queue_t *q, struct request *rq, int where)
{
struct deadline_data *dd = q->elevator->elevator_data;
/* barriers must flush the reorder queue */
if (unlikely(rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)
&& where == ELEVATOR_INSERT_SORT))
where = ELEVATOR_INSERT_BACK;
switch (where) {
case ELEVATOR_INSERT_BACK:
while (deadline_dispatch_requests(dd))
;
list_add_tail(&rq->queuelist, dd->dispatch);
break;
case ELEVATOR_INSERT_FRONT:
list_add(&rq->queuelist, dd->dispatch);
break;
case ELEVATOR_INSERT_SORT:
BUG_ON(!blk_fs_request(rq));
deadline_add_request(q, rq);
break;
default:
printk("%s: bad insert point %d\n", __FUNCTION__,where);
return;
}
}
static int deadline_queue_empty(request_queue_t *q)
{
struct deadline_data *dd = q->elevator->elevator_data;
if (!list_empty(&dd->fifo_list[WRITE])
|| !list_empty(&dd->fifo_list[READ])
|| !list_empty(dd->dispatch))
return 0;
return 1;
return list_empty(&dd->fifo_list[WRITE])
&& list_empty(&dd->fifo_list[READ]);
}
static struct request *
@ -733,7 +650,6 @@ static int deadline_init_queue(request_queue_t *q, elevator_t *e)
INIT_LIST_HEAD(&dd->fifo_list[WRITE]);
dd->sort_list[READ] = RB_ROOT;
dd->sort_list[WRITE] = RB_ROOT;
dd->dispatch = &q->queue_head;
dd->fifo_expire[READ] = read_expire;
dd->fifo_expire[WRITE] = write_expire;
dd->writes_starved = writes_starved;
@ -748,10 +664,8 @@ static void deadline_put_request(request_queue_t *q, struct request *rq)
struct deadline_data *dd = q->elevator->elevator_data;
struct deadline_rq *drq = RQ_DATA(rq);
if (drq) {
mempool_free(drq, dd->drq_pool);
rq->elevator_private = NULL;
}
mempool_free(drq, dd->drq_pool);
rq->elevator_private = NULL;
}
static int
@ -917,9 +831,8 @@ static struct elevator_type iosched_deadline = {
.elevator_merge_fn = deadline_merge,
.elevator_merged_fn = deadline_merged_request,
.elevator_merge_req_fn = deadline_merged_requests,
.elevator_next_req_fn = deadline_next_request,
.elevator_add_req_fn = deadline_insert_request,
.elevator_remove_req_fn = deadline_remove_request,
.elevator_dispatch_fn = deadline_dispatch_requests,
.elevator_add_req_fn = deadline_add_request,
.elevator_queue_empty_fn = deadline_queue_empty,
.elevator_former_req_fn = deadline_former_request,
.elevator_latter_req_fn = deadline_latter_request,

266
drivers/block/elevator.c
View file

@ -83,15 +83,6 @@ inline int elv_try_merge(struct request *__rq, struct bio *bio)
}
EXPORT_SYMBOL(elv_try_merge);
inline int elv_try_last_merge(request_queue_t *q, struct bio *bio)
{
if (q->last_merge)
return elv_try_merge(q->last_merge, bio);
return ELEVATOR_NO_MERGE;
}
EXPORT_SYMBOL(elv_try_last_merge);
static struct elevator_type *elevator_find(const char *name)
{
struct elevator_type *e = NULL;
@ -143,6 +134,8 @@ static int elevator_attach(request_queue_t *q, struct elevator_type *e,
INIT_LIST_HEAD(&q->queue_head);
q->last_merge = NULL;
q->elevator = eq;
q->end_sector = 0;
q->boundary_rq = NULL;
if (eq->ops->elevator_init_fn)
ret = eq->ops->elevator_init_fn(q, eq);
@ -225,9 +218,52 @@ void elevator_exit(elevator_t *e)
kfree(e);
}
/*
* Insert rq into dispatch queue of q. Queue lock must be held on
* entry. If sort != 0, rq is sort-inserted; otherwise, rq will be
* appended to the dispatch queue. To be used by specific elevators.
*/
void elv_dispatch_sort(request_queue_t *q, struct request *rq)
{
sector_t boundary;
struct list_head *entry;
if (q->last_merge == rq)
q->last_merge = NULL;
boundary = q->end_sector;
list_for_each_prev(entry, &q->queue_head) {
struct request *pos = list_entry_rq(entry);
if (pos->flags & (REQ_SOFTBARRIER|REQ_HARDBARRIER|REQ_STARTED))
break;
if (rq->sector >= boundary) {
if (pos->sector < boundary)
continue;
} else {
if (pos->sector >= boundary)
break;
}
if (rq->sector >= pos->sector)
break;
}
list_add(&rq->queuelist, entry);
}
int elv_merge(request_queue_t *q, struct request **req, struct bio *bio)
{
elevator_t *e = q->elevator;
int ret;
if (q->last_merge) {
ret = elv_try_merge(q->last_merge, bio);
if (ret != ELEVATOR_NO_MERGE) {
*req = q->last_merge;
return ret;
}
}
if (e->ops->elevator_merge_fn)
return e->ops->elevator_merge_fn(q, req, bio);
@ -241,6 +277,8 @@ void elv_merged_request(request_queue_t *q, struct request *rq)
if (e->ops->elevator_merged_fn)
e->ops->elevator_merged_fn(q, rq);
q->last_merge = rq;
}
void elv_merge_requests(request_queue_t *q, struct request *rq,
@ -248,20 +286,13 @@ void elv_merge_requests(request_queue_t *q, struct request *rq,
{
elevator_t *e = q->elevator;
if (q->last_merge == next)
q->last_merge = NULL;
if (e->ops->elevator_merge_req_fn)
e->ops->elevator_merge_req_fn(q, rq, next);
q->last_merge = rq;
}
/*
* For careful internal use by the block layer. Essentially the same as
* a requeue in that it tells the io scheduler that this request is not
* active in the driver or hardware anymore, but we don't want the request
* added back to the scheduler. Function is not exported.
*/
void elv_deactivate_request(request_queue_t *q, struct request *rq)
void elv_requeue_request(request_queue_t *q, struct request *rq)
{
elevator_t *e = q->elevator;
@ -269,19 +300,14 @@ void elv_deactivate_request(request_queue_t *q, struct request *rq)
* it already went through dequeue, we need to decrement the
* in_flight count again
*/
if (blk_account_rq(rq))
if (blk_account_rq(rq)) {
q->in_flight--;
if (blk_sorted_rq(rq) && e->ops->elevator_deactivate_req_fn)
e->ops->elevator_deactivate_req_fn(q, rq);
}
rq->flags &= ~REQ_STARTED;
if (e->ops->elevator_deactivate_req_fn)
e->ops->elevator_deactivate_req_fn(q, rq);
}
void elv_requeue_request(request_queue_t *q, struct request *rq)
{
elv_deactivate_request(q, rq);
/*
* if this is the flush, requeue the original instead and drop the flush
*/
@ -290,55 +316,91 @@ void elv_requeue_request(request_queue_t *q, struct request *rq)
rq = rq->end_io_data;
}
/*
* the request is prepped and may have some resources allocated.
* allowing unprepped requests to pass this one may cause resource
* deadlock. turn on softbarrier.
*/
rq->flags |= REQ_SOFTBARRIER;
/*
* if iosched has an explicit requeue hook, then use that. otherwise
* just put the request at the front of the queue
*/
if (q->elevator->ops->elevator_requeue_req_fn)
q->elevator->ops->elevator_requeue_req_fn(q, rq);
else
__elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 0);
__elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 0);
}
void __elv_add_request(request_queue_t *q, struct request *rq, int where,
int plug)
{
/*
* barriers implicitly indicate back insertion
*/
if (rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER) &&
where == ELEVATOR_INSERT_SORT)
where = ELEVATOR_INSERT_BACK;
if (rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) {
/*
* barriers implicitly indicate back insertion
*/
if (where == ELEVATOR_INSERT_SORT)
where = ELEVATOR_INSERT_BACK;
/*
* this request is scheduling boundary, update end_sector
*/
if (blk_fs_request(rq)) {
q->end_sector = rq_end_sector(rq);
q->boundary_rq = rq;
}
}
if (plug)
blk_plug_device(q);
rq->q = q;
if (!test_bit(QUEUE_FLAG_DRAIN, &q->queue_flags)) {
q->elevator->ops->elevator_add_req_fn(q, rq, where);
if (blk_queue_plugged(q)) {
int nrq = q->rq.count[READ] + q->rq.count[WRITE]
- q->in_flight;
if (nrq >= q->unplug_thresh)
__generic_unplug_device(q);
}
} else
if (unlikely(test_bit(QUEUE_FLAG_DRAIN, &q->queue_flags))) {
/*
* if drain is set, store the request "locally". when the drain
* is finished, the requests will be handed ordered to the io
* scheduler
*/
list_add_tail(&rq->queuelist, &q->drain_list);
return;
}
switch (where) {
case ELEVATOR_INSERT_FRONT:
rq->flags |= REQ_SOFTBARRIER;
list_add(&rq->queuelist, &q->queue_head);
break;
case ELEVATOR_INSERT_BACK:
rq->flags |= REQ_SOFTBARRIER;
while (q->elevator->ops->elevator_dispatch_fn(q, 1))
;
list_add_tail(&rq->queuelist, &q->queue_head);
/*
* We kick the queue here for the following reasons.
* - The elevator might have returned NULL previously
* to delay requests and returned them now. As the
* queue wasn't empty before this request, ll_rw_blk
* won't run the queue on return, resulting in hang.
* - Usually, back inserted requests won't be merged
* with anything. There's no point in delaying queue
* processing.
*/
blk_remove_plug(q);
q->request_fn(q);
break;
case ELEVATOR_INSERT_SORT:
BUG_ON(!blk_fs_request(rq));
rq->flags |= REQ_SORTED;
q->elevator->ops->elevator_add_req_fn(q, rq);
if (q->last_merge == NULL && rq_mergeable(rq))
q->last_merge = rq;
break;
default:
printk(KERN_ERR "%s: bad insertion point %d\n",
__FUNCTION__, where);
BUG();
}
if (blk_queue_plugged(q)) {
int nrq = q->rq.count[READ] + q->rq.count[WRITE]
- q->in_flight;
if (nrq >= q->unplug_thresh)
__generic_unplug_device(q);
}
}
void elv_add_request(request_queue_t *q, struct request *rq, int where,
@ -353,13 +415,19 @@ void elv_add_request(request_queue_t *q, struct request *rq, int where,
static inline struct request *__elv_next_request(request_queue_t *q)
{
struct request *rq = q->elevator->ops->elevator_next_req_fn(q);
struct request *rq;
if (unlikely(list_empty(&q->queue_head) &&
!q->elevator->ops->elevator_dispatch_fn(q, 0)))
return NULL;
rq = list_entry_rq(q->queue_head.next);
/*
* if this is a barrier write and the device has to issue a
* flush sequence to support it, check how far we are
*/
if (rq && blk_fs_request(rq) && blk_barrier_rq(rq)) {
if (blk_fs_request(rq) && blk_barrier_rq(rq)) {
BUG_ON(q->ordered == QUEUE_ORDERED_NONE);
if (q->ordered == QUEUE_ORDERED_FLUSH &&
@ -376,15 +444,30 @@ struct request *elv_next_request(request_queue_t *q)
int ret;
while ((rq = __elv_next_request(q)) != NULL) {
/*
* just mark as started even if we don't start it, a request
* that has been delayed should not be passed by new incoming
* requests
*/
rq->flags |= REQ_STARTED;
if (!(rq->flags & REQ_STARTED)) {
elevator_t *e = q->elevator;
if (rq == q->last_merge)
q->last_merge = NULL;
/*
* This is the first time the device driver
* sees this request (possibly after
* requeueing). Notify IO scheduler.
*/
if (blk_sorted_rq(rq) &&
e->ops->elevator_activate_req_fn)
e->ops->elevator_activate_req_fn(q, rq);
/*
* just mark as started even if we don't start
* it, a request that has been delayed should
* not be passed by new incoming requests
*/
rq->flags |= REQ_STARTED;
}
if (!q->boundary_rq || q->boundary_rq == rq) {
q->end_sector = rq_end_sector(rq);
q->boundary_rq = NULL;
}
if ((rq->flags & REQ_DONTPREP) || !q->prep_rq_fn)
break;
@ -396,9 +479,9 @@ struct request *elv_next_request(request_queue_t *q)
/*
* the request may have been (partially) prepped.
* we need to keep this request in the front to
* avoid resource deadlock. turn on softbarrier.
* avoid resource deadlock. REQ_STARTED will
* prevent other fs requests from passing this one.
*/
rq->flags |= REQ_SOFTBARRIER;
rq = NULL;
break;
} else if (ret == BLKPREP_KILL) {
@ -421,42 +504,32 @@ struct request *elv_next_request(request_queue_t *q)
return rq;
}
void elv_remove_request(request_queue_t *q, struct request *rq)
void elv_dequeue_request(request_queue_t *q, struct request *rq)
{
elevator_t *e = q->elevator;
BUG_ON(list_empty(&rq->queuelist));
list_del_init(&rq->queuelist);
/*
* the time frame between a request being removed from the lists
* and to it is freed is accounted as io that is in progress at
* the driver side. note that we only account requests that the
* driver has seen (REQ_STARTED set), to avoid false accounting
* for request-request merges
* the driver side.
*/
if (blk_account_rq(rq))
q->in_flight++;
/*
* the main clearing point for q->last_merge is on retrieval of
* request by driver (it calls elv_next_request()), but it _can_
* also happen here if a request is added to the queue but later
* deleted without ever being given to driver (merged with another
* request).
*/
if (rq == q->last_merge)
q->last_merge = NULL;
if (e->ops->elevator_remove_req_fn)
e->ops->elevator_remove_req_fn(q, rq);
}
int elv_queue_empty(request_queue_t *q)
{
elevator_t *e = q->elevator;
if (!list_empty(&q->queue_head))
return 0;
if (e->ops->elevator_queue_empty_fn)
return e->ops->elevator_queue_empty_fn(q);
return list_empty(&q->queue_head);
return 1;
}
struct request *elv_latter_request(request_queue_t *q, struct request *rq)
@ -528,11 +601,11 @@ void elv_completed_request(request_queue_t *q, struct request *rq)
/*
* request is released from the driver, io must be done
*/
if (blk_account_rq(rq))
if (blk_account_rq(rq)) {
q->in_flight--;
if (e->ops->elevator_completed_req_fn)
e->ops->elevator_completed_req_fn(q, rq);
if (blk_sorted_rq(rq) && e->ops->elevator_completed_req_fn)
e->ops->elevator_completed_req_fn(q, rq);
}
}
int elv_register_queue(struct request_queue *q)
@ -705,11 +778,12 @@ ssize_t elv_iosched_show(request_queue_t *q, char *name)
return len;
}
EXPORT_SYMBOL(elv_dispatch_sort);
EXPORT_SYMBOL(elv_add_request);
EXPORT_SYMBOL(__elv_add_request);
EXPORT_SYMBOL(elv_requeue_request);
EXPORT_SYMBOL(elv_next_request);
EXPORT_SYMBOL(elv_remove_request);
EXPORT_SYMBOL(elv_dequeue_request);
EXPORT_SYMBOL(elv_queue_empty);
EXPORT_SYMBOL(elv_completed_request);
EXPORT_SYMBOL(elevator_exit);

25
drivers/block/ll_rw_blk.c
View file

@ -353,6 +353,8 @@ static void blk_pre_flush_end_io(struct request *flush_rq)
struct request *rq = flush_rq->end_io_data;
request_queue_t *q = rq->q;
elv_completed_request(q, flush_rq);
rq->flags |= REQ_BAR_PREFLUSH;
if (!flush_rq->errors)
@ -369,6 +371,8 @@ static void blk_post_flush_end_io(struct request *flush_rq)
struct request *rq = flush_rq->end_io_data;
request_queue_t *q = rq->q;
elv_completed_request(q, flush_rq);
rq->flags |= REQ_BAR_POSTFLUSH;
q->end_flush_fn(q, flush_rq);
@ -408,8 +412,6 @@ struct request *blk_start_pre_flush(request_queue_t *q, struct request *rq)
if (!list_empty(&rq->queuelist))
blkdev_dequeue_request(rq);
elv_deactivate_request(q, rq);
flush_rq->end_io_data = rq;
flush_rq->end_io = blk_pre_flush_end_io;
@ -1040,6 +1042,7 @@ EXPORT_SYMBOL(blk_queue_invalidate_tags);
static char *rq_flags[] = {
"REQ_RW",
"REQ_FAILFAST",
"REQ_SORTED",
"REQ_SOFTBARRIER",
"REQ_HARDBARRIER",
"REQ_CMD",
@ -2456,6 +2459,8 @@ static void __blk_put_request(request_queue_t *q, struct request *req)
if (unlikely(--req->ref_count))
return;
elv_completed_request(q, req);
req->rq_status = RQ_INACTIVE;
req->rl = NULL;
@ -2466,8 +2471,6 @@ static void __blk_put_request(request_queue_t *q, struct request *req)
if (rl) {
int rw = rq_data_dir(req);
elv_completed_request(q, req);
BUG_ON(!list_empty(&req->queuelist));
blk_free_request(q, req);
@ -2477,14 +2480,14 @@ static void __blk_put_request(request_queue_t *q, struct request *req)
void blk_put_request(struct request *req)
{
/*
* if req->rl isn't set, this request didnt originate from the
* block layer, so it's safe to just disregard it
*/
if (req->rl) {
unsigned long flags;
request_queue_t *q = req->q;
unsigned long flags;
request_queue_t *q = req->q;
/*
* Gee, IDE calls in w/ NULL q. Fix IDE and remove the
* following if (q) test.
*/
if (q) {
spin_lock_irqsave(q->queue_lock, flags);
__blk_put_request(q, req);
spin_unlock_irqrestore(q->queue_lock, flags);

48
drivers/block/noop-iosched.c
View file

@ -7,57 +7,19 @@
#include <linux/module.h>
#include <linux/init.h>
/*
* See if we can find a request that this buffer can be coalesced with.
*/
static int elevator_noop_merge(request_queue_t *q, struct request **req,
struct bio *bio)
static void elevator_noop_add_request(request_queue_t *q, struct request *rq)
{
int ret;
ret = elv_try_last_merge(q, bio);
if (ret != ELEVATOR_NO_MERGE)
*req = q->last_merge;
return ret;
elv_dispatch_add_tail(q, rq);
}
static void elevator_noop_merge_requests(request_queue_t *q, struct request *req,
struct request *next)
static int elevator_noop_dispatch(request_queue_t *q, int force)
{
list_del_init(&next->queuelist);
}
static void elevator_noop_add_request(request_queue_t *q, struct request *rq,
int where)
{
if (where == ELEVATOR_INSERT_FRONT)
list_add(&rq->queuelist, &q->queue_head);
else
list_add_tail(&rq->queuelist, &q->queue_head);
/*
* new merges must not precede this barrier
*/
if (rq->flags & REQ_HARDBARRIER)
q->last_merge = NULL;
else if (!q->last_merge)
q->last_merge = rq;
}
static struct request *elevator_noop_next_request(request_queue_t *q)
{
if (!list_empty(&q->queue_head))
return list_entry_rq(q->queue_head.next);
return NULL;
return 0;
}
static struct elevator_type elevator_noop = {
.ops = {
.elevator_merge_fn = elevator_noop_merge,
.elevator_merge_req_fn = elevator_noop_merge_requests,
.elevator_next_req_fn = elevator_noop_next_request,
.elevator_dispatch_fn = elevator_noop_dispatch,
.elevator_add_req_fn = elevator_noop_add_request,
},
.elevator_name = "noop",