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block: add q->nr_rqs[] and move q->rq.elvpriv to q->nr_rqs_elvpriv

Add q->nr_rqs[] which currently behaves the same as q->rq.count[] and
move q->rq.elvpriv to q->nr_rqs_elvpriv.  blk_drain_queue() is updated
to use q->nr_rqs[] instead of q->rq.count[].

These counters separates queue-wide request statistics from the
request list and allow implementation of per-queue request allocation.

While at it, properly indent fields of struct request_list.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
master
Tejun Heo 10 years ago
committed by Jens Axboe
parent
commit
8a5ecdd428
  1. 13
      block/blk-core.c
  2. 11
      include/linux/blkdev.h

13
block/blk-core.c

@ -387,7 +387,7 @@ void blk_drain_queue(struct request_queue *q, bool drain_all)
if (!list_empty(&q->queue_head) && q->request_fn)
__blk_run_queue(q);
drain |= q->rq.elvpriv;
drain |= q->nr_rqs_elvpriv;
/*
* Unfortunately, requests are queued at and tracked from
@ -397,7 +397,7 @@ void blk_drain_queue(struct request_queue *q, bool drain_all)
if (drain_all) {
drain |= !list_empty(&q->queue_head);
for (i = 0; i < 2; i++) {
drain |= q->rq.count[i];
drain |= q->nr_rqs[i];
drain |= q->in_flight[i];
drain |= !list_empty(&q->flush_queue[i]);
}
@ -526,7 +526,6 @@ static int blk_init_free_list(struct request_queue *q)
rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0;
rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0;
rl->elvpriv = 0;
init_waitqueue_head(&rl->wait[BLK_RW_SYNC]);
init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]);
@ -791,9 +790,10 @@ static void freed_request(struct request_queue *q, unsigned int flags)
struct request_list *rl = &q->rq;
int sync = rw_is_sync(flags);
q->nr_rqs[sync]--;
rl->count[sync]--;
if (flags & REQ_ELVPRIV)
rl->elvpriv--;
q->nr_rqs_elvpriv--;
__freed_request(q, sync);
@ -902,6 +902,7 @@ static struct request *__get_request(struct request_queue *q, int rw_flags,
if (rl->count[is_sync] >= (3 * q->nr_requests / 2))
return NULL;
q->nr_rqs[is_sync]++;
rl->count[is_sync]++;
rl->starved[is_sync] = 0;
@ -917,7 +918,7 @@ static struct request *__get_request(struct request_queue *q, int rw_flags,
*/
if (blk_rq_should_init_elevator(bio) && !blk_queue_bypass(q)) {
rw_flags |= REQ_ELVPRIV;
rl->elvpriv++;
q->nr_rqs_elvpriv++;
if (et->icq_cache && ioc)
icq = ioc_lookup_icq(ioc, q);
}
@ -978,7 +979,7 @@ fail_elvpriv:
rq->elv.icq = NULL;
spin_lock_irq(q->queue_lock);
rl->elvpriv--;
q->nr_rqs_elvpriv--;
spin_unlock_irq(q->queue_lock);
goto out;

11
include/linux/blkdev.h

@ -51,11 +51,10 @@ struct request_list {
* count[], starved[], and wait[] are indexed by
* BLK_RW_SYNC/BLK_RW_ASYNC
*/
int count[2];
int starved[2];
int elvpriv;
mempool_t *rq_pool;
wait_queue_head_t wait[2];
int count[2];
int starved[2];
mempool_t *rq_pool;
wait_queue_head_t wait[2];
};
/*
@ -282,6 +281,8 @@ struct request_queue {
struct list_head queue_head;
struct request *last_merge;
struct elevator_queue *elevator;
int nr_rqs[2]; /* # allocated [a]sync rqs */
int nr_rqs_elvpriv; /* # allocated rqs w/ elvpriv */
/*
* the queue request freelist, one for reads and one for writes

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