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authorJerome Marchand <jmarchan@redhat.com>2009-04-22 14:01:49 +0200
committerJens Axboe <jens.axboe@oracle.com>2009-04-24 08:54:21 +0200
commit42dad7647aec49b3ad20dd0cb832b232a6ae514f (patch)
treeb70d4cb7706f2647e65426e24f078ddf14d6e139 /block
parent097102c2d04974bdfcfa16a5f3062d499842139c (diff)
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block: simplify I/O stat accounting
This simplifies I/O stat accounting switching code and separates it completely from I/O scheduler switch code. Requests are accounted according to the state of their request queue at the time of the request allocation. There is no need anymore to flush the request queue when switching I/O accounting state. Signed-off-by: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block')
-rw-r--r--block/blk-core.c6
-rw-r--r--block/blk-merge.c5
-rw-r--r--block/blk-sysfs.c4
-rw-r--r--block/blk.h7
4 files changed, 9 insertions, 13 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index 07ab754..2998fe3 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -643,7 +643,7 @@ static inline void blk_free_request(struct request_queue *q, struct request *rq)
}
static struct request *
-blk_alloc_request(struct request_queue *q, int rw, int priv, gfp_t gfp_mask)
+blk_alloc_request(struct request_queue *q, int flags, int priv, gfp_t gfp_mask)
{
struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask);
@@ -652,7 +652,7 @@ blk_alloc_request(struct request_queue *q, int rw, int priv, gfp_t gfp_mask)
blk_rq_init(q, rq);
- rq->cmd_flags = rw | REQ_ALLOCED;
+ rq->cmd_flags = flags | REQ_ALLOCED;
if (priv) {
if (unlikely(elv_set_request(q, rq, gfp_mask))) {
@@ -792,6 +792,8 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
if (priv)
rl->elvpriv++;
+ if (blk_queue_io_stat(q))
+ rw_flags |= REQ_IO_STAT;
spin_unlock_irq(q->queue_lock);
rq = blk_alloc_request(q, rw_flags, priv, gfp_mask);
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 63760ca..23d2a6f 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -402,7 +402,10 @@ static int attempt_merge(struct request_queue *q, struct request *req,
elv_merge_requests(q, req, next);
- blk_account_io_merge(req);
+ /*
+ * 'next' is going away, so update stats accordingly
+ */
+ blk_account_io_merge(next);
req->ioprio = ioprio_best(req->ioprio, next->ioprio);
if (blk_rq_cpu_valid(next))
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index cac4e9f..3ff9bba 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -209,14 +209,10 @@ static ssize_t queue_iostats_store(struct request_queue *q, const char *page,
ssize_t ret = queue_var_store(&stats, page, count);
spin_lock_irq(q->queue_lock);
- elv_quiesce_start(q);
-
if (stats)
queue_flag_set(QUEUE_FLAG_IO_STAT, q);
else
queue_flag_clear(QUEUE_FLAG_IO_STAT, q);
-
- elv_quiesce_end(q);
spin_unlock_irq(q->queue_lock);
return ret;
diff --git a/block/blk.h b/block/blk.h
index 5dfc412..79c85f7 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -114,12 +114,7 @@ static inline int blk_cpu_to_group(int cpu)
static inline int blk_do_io_stat(struct request *rq)
{
- struct gendisk *disk = rq->rq_disk;
-
- if (!disk || !disk->queue)
- return 0;
-
- return blk_queue_io_stat(disk->queue) && (rq->cmd_flags & REQ_ELVPRIV);
+ return rq->rq_disk && blk_rq_io_stat(rq);
}
#endif