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io_context sharing - anticipatory changes 

changes to anticipatory io scheduler for io_context sharing

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Jens Axboe 2008-01-21 20:03:12 +01:00
parent 4ac845a2e9
commit 521f3bbdba
1 changed files with 28 additions and 6 deletions
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34
block/as-iosched.c
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@ -170,9 +170,11 @@ static void free_as_io_context(struct as_io_context *aic)
static void as_trim(struct io_context *ioc)
{
spin_lock(&ioc->lock);
if (ioc->aic)
free_as_io_context(ioc->aic);
ioc->aic = NULL;
spin_unlock(&ioc->lock);
}
/* Called when the task exits */
@ -462,7 +464,9 @@ static void as_antic_timeout(unsigned long data)
spin_lock_irqsave(q->queue_lock, flags);
if (ad->antic_status == ANTIC_WAIT_REQ
|| ad->antic_status == ANTIC_WAIT_NEXT) {
struct as_io_context *aic = ad->io_context->aic;
struct as_io_context *aic;
spin_lock(&ad->io_context->lock);
aic = ad->io_context->aic;
ad->antic_status = ANTIC_FINISHED;
kblockd_schedule_work(&ad->antic_work);
@ -475,6 +479,7 @@ static void as_antic_timeout(unsigned long data)
/* process not "saved" by a cooperating request */
ad->exit_no_coop = (7*ad->exit_no_coop + 256)/8;
}
spin_unlock(&ad->io_context->lock);
}
spin_unlock_irqrestore(q->queue_lock, flags);
}
@ -635,9 +640,11 @@ static int as_can_break_anticipation(struct as_data *ad, struct request *rq)
ioc = ad->io_context;
BUG_ON(!ioc);
spin_lock(&ioc->lock);
if (rq && ioc == RQ_IOC(rq)) {
/* request from same process */
spin_unlock(&ioc->lock);
return 1;
}
@ -646,20 +653,25 @@ static int as_can_break_anticipation(struct as_data *ad, struct request *rq)
* In this situation status should really be FINISHED,
* however the timer hasn't had the chance to run yet.
*/
spin_unlock(&ioc->lock);
return 1;
}
aic = ioc->aic;
if (!aic)
if (!aic) {
spin_unlock(&ioc->lock);
return 0;
}
if (atomic_read(&aic->nr_queued) > 0) {
/* process has more requests queued */
spin_unlock(&ioc->lock);
return 1;
}
if (atomic_read(&aic->nr_dispatched) > 0) {
/* process has more requests dispatched */
spin_unlock(&ioc->lock);
return 1;
}
@ -680,6 +692,7 @@ static int as_can_break_anticipation(struct as_data *ad, struct request *rq)
}
as_update_iohist(ad, aic, rq);
spin_unlock(&ioc->lock);
return 1;
}
@ -688,20 +701,27 @@ static int as_can_break_anticipation(struct as_data *ad, struct request *rq)
if (aic->ttime_samples == 0)
ad->exit_prob = (7*ad->exit_prob + 256)/8;
if (ad->exit_no_coop > 128)
if (ad->exit_no_coop > 128) {
spin_unlock(&ioc->lock);
return 1;
}
}
if (aic->ttime_samples == 0) {
if (ad->new_ttime_mean > ad->antic_expire)
if (ad->new_ttime_mean > ad->antic_expire) {
spin_unlock(&ioc->lock);
return 1;
if (ad->exit_prob * ad->exit_no_coop > 128*256)
}
if (ad->exit_prob * ad->exit_no_coop > 128*256) {
spin_unlock(&ioc->lock);
return 1;
}
} else if (aic->ttime_mean > ad->antic_expire) {
/* the process thinks too much between requests */
spin_unlock(&ioc->lock);
return 1;
}
spin_unlock(&ioc->lock);
return 0;
}
@ -1255,7 +1275,9 @@ static void as_merged_requests(struct request_queue *q, struct request *req,
* Don't copy here but swap, because when anext is
* removed below, it must contain the unused context
*/
double_spin_lock(&rioc->lock, &nioc->lock, rioc < nioc);
swap_io_context(&rioc, &nioc);
double_spin_unlock(&rioc->lock, &nioc->lock, rioc < nioc);
}
}