[PATCH] Update cfq io scheduler to time sliced design
This updates the CFQ io scheduler to the new time sliced design (cfq
v3). It provides full process fairness, while giving excellent
aggregate system throughput even for many competing processes. It
supports io priorities, either inherited from the cpu nice value or set
directly with the ioprio_get/set syscalls. The latter closely mimic
set/getpriority.
This import is based on my latest from -mm.
Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c
index 60e6409..234fdcf 100644
--- a/drivers/block/ll_rw_blk.c
+++ b/drivers/block/ll_rw_blk.c
@@ -276,6 +276,7 @@
rq->errors = 0;
rq->rq_status = RQ_ACTIVE;
rq->bio = rq->biotail = NULL;
+ rq->ioprio = 0;
rq->buffer = NULL;
rq->ref_count = 1;
rq->q = q;
@@ -1442,11 +1443,7 @@
if (!blk_remove_plug(q))
return;
- /*
- * was plugged, fire request_fn if queue has stuff to do
- */
- if (elv_next_request(q))
- q->request_fn(q);
+ q->request_fn(q);
}
EXPORT_SYMBOL(__generic_unplug_device);
@@ -1776,8 +1773,8 @@
mempool_free(rq, q->rq.rq_pool);
}
-static inline struct request *blk_alloc_request(request_queue_t *q, int rw,
- int gfp_mask)
+static inline struct request *
+blk_alloc_request(request_queue_t *q, int rw, struct bio *bio, int gfp_mask)
{
struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask);
@@ -1790,7 +1787,7 @@
*/
rq->flags = rw;
- if (!elv_set_request(q, rq, gfp_mask))
+ if (!elv_set_request(q, rq, bio, gfp_mask))
return rq;
mempool_free(rq, q->rq.rq_pool);
@@ -1872,7 +1869,8 @@
/*
* Get a free request, queue_lock must not be held
*/
-static struct request *get_request(request_queue_t *q, int rw, int gfp_mask)
+static struct request *get_request(request_queue_t *q, int rw, struct bio *bio,
+ int gfp_mask)
{
struct request *rq = NULL;
struct request_list *rl = &q->rq;
@@ -1895,7 +1893,7 @@
}
}
- switch (elv_may_queue(q, rw)) {
+ switch (elv_may_queue(q, rw, bio)) {
case ELV_MQUEUE_NO:
goto rq_starved;
case ELV_MQUEUE_MAY:
@@ -1920,7 +1918,7 @@
set_queue_congested(q, rw);
spin_unlock_irq(q->queue_lock);
- rq = blk_alloc_request(q, rw, gfp_mask);
+ rq = blk_alloc_request(q, rw, bio, gfp_mask);
if (!rq) {
/*
* Allocation failed presumably due to memory. Undo anything
@@ -1961,7 +1959,8 @@
* No available requests for this queue, unplug the device and wait for some
* requests to become available.
*/
-static struct request *get_request_wait(request_queue_t *q, int rw)
+static struct request *get_request_wait(request_queue_t *q, int rw,
+ struct bio *bio)
{
DEFINE_WAIT(wait);
struct request *rq;
@@ -1972,7 +1971,7 @@
prepare_to_wait_exclusive(&rl->wait[rw], &wait,
TASK_UNINTERRUPTIBLE);
- rq = get_request(q, rw, GFP_NOIO);
+ rq = get_request(q, rw, bio, GFP_NOIO);
if (!rq) {
struct io_context *ioc;
@@ -2003,9 +2002,9 @@
BUG_ON(rw != READ && rw != WRITE);
if (gfp_mask & __GFP_WAIT)
- rq = get_request_wait(q, rw);
+ rq = get_request_wait(q, rw, NULL);
else
- rq = get_request(q, rw, gfp_mask);
+ rq = get_request(q, rw, NULL, gfp_mask);
return rq;
}
@@ -2333,7 +2332,6 @@
return;
req->rq_status = RQ_INACTIVE;
- req->q = NULL;
req->rl = NULL;
/*
@@ -2462,6 +2460,8 @@
req->rq_disk->in_flight--;
}
+ req->ioprio = ioprio_best(req->ioprio, next->ioprio);
+
__blk_put_request(q, next);
return 1;
}
@@ -2514,11 +2514,13 @@
{
struct request *req, *freereq = NULL;
int el_ret, rw, nr_sectors, cur_nr_sectors, barrier, err, sync;
+ unsigned short prio;
sector_t sector;
sector = bio->bi_sector;
nr_sectors = bio_sectors(bio);
cur_nr_sectors = bio_cur_sectors(bio);
+ prio = bio_prio(bio);
rw = bio_data_dir(bio);
sync = bio_sync(bio);
@@ -2559,6 +2561,7 @@
req->biotail->bi_next = bio;
req->biotail = bio;
req->nr_sectors = req->hard_nr_sectors += nr_sectors;
+ req->ioprio = ioprio_best(req->ioprio, prio);
drive_stat_acct(req, nr_sectors, 0);
if (!attempt_back_merge(q, req))
elv_merged_request(q, req);
@@ -2583,6 +2586,7 @@
req->hard_cur_sectors = cur_nr_sectors;
req->sector = req->hard_sector = sector;
req->nr_sectors = req->hard_nr_sectors += nr_sectors;
+ req->ioprio = ioprio_best(req->ioprio, prio);
drive_stat_acct(req, nr_sectors, 0);
if (!attempt_front_merge(q, req))
elv_merged_request(q, req);
@@ -2610,7 +2614,7 @@
freereq = NULL;
} else {
spin_unlock_irq(q->queue_lock);
- if ((freereq = get_request(q, rw, GFP_ATOMIC)) == NULL) {
+ if ((freereq = get_request(q, rw, bio, GFP_ATOMIC)) == NULL) {
/*
* READA bit set
*/
@@ -2618,7 +2622,7 @@
if (bio_rw_ahead(bio))
goto end_io;
- freereq = get_request_wait(q, rw);
+ freereq = get_request_wait(q, rw, bio);
}
goto again;
}
@@ -2646,6 +2650,7 @@
req->buffer = bio_data(bio); /* see ->buffer comment above */
req->waiting = NULL;
req->bio = req->biotail = bio;
+ req->ioprio = prio;
req->rq_disk = bio->bi_bdev->bd_disk;
req->start_time = jiffies;
@@ -2674,7 +2679,7 @@
if (bdev != bdev->bd_contains) {
struct hd_struct *p = bdev->bd_part;
- switch (bio->bi_rw) {
+ switch (bio_data_dir(bio)) {
case READ:
p->read_sectors += bio_sectors(bio);
p->reads++;
@@ -2693,6 +2698,7 @@
{
struct request_list *rl = &q->rq;
struct request *rq;
+ int requeued = 0;
spin_lock_irq(q->queue_lock);
clear_bit(QUEUE_FLAG_DRAIN, &q->queue_flags);
@@ -2701,9 +2707,13 @@
rq = list_entry_rq(q->drain_list.next);
list_del_init(&rq->queuelist);
- __elv_add_request(q, rq, ELEVATOR_INSERT_BACK, 1);
+ elv_requeue_request(q, rq);
+ requeued++;
}
+ if (requeued)
+ q->request_fn(q);
+
spin_unlock_irq(q->queue_lock);
wake_up(&rl->wait[0]);
@@ -2900,7 +2910,7 @@
BIO_BUG_ON(!bio->bi_size);
BIO_BUG_ON(!bio->bi_io_vec);
- bio->bi_rw = rw;
+ bio->bi_rw |= rw;
if (rw & WRITE)
mod_page_state(pgpgout, count);
else
@@ -3257,8 +3267,11 @@
struct io_context *ioc;
local_irq_save(flags);
+ task_lock(current);
ioc = current->io_context;
current->io_context = NULL;
+ ioc->task = NULL;
+ task_unlock(current);
local_irq_restore(flags);
if (ioc->aic && ioc->aic->exit)
@@ -3293,12 +3306,12 @@
ret = kmem_cache_alloc(iocontext_cachep, gfp_flags);
if (ret) {
atomic_set(&ret->refcount, 1);
- ret->pid = tsk->pid;
+ ret->task = current;
+ ret->set_ioprio = NULL;
ret->last_waited = jiffies; /* doesn't matter... */
ret->nr_batch_requests = 0; /* because this is 0 */
ret->aic = NULL;
ret->cic = NULL;
- spin_lock_init(&ret->lock);
local_irq_save(flags);