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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
parent097102c2d04974bdfcfa16a5f3062d499842139c (diff)
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>
-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
-rw-r--r--include/linux/blkdev.h3
5 files changed, 12 insertions, 13 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index 07ab75403e1..2998fe3a237 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 63760ca3da0..23d2a6fe34a 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 cac4e9febe6..3ff9bba3379 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 5dfc41267a0..79c85f7c9ff 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
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ba54c834a59..2755d5c6da2 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -118,6 +118,7 @@ enum rq_flag_bits {
__REQ_COPY_USER, /* contains copies of user pages */
__REQ_INTEGRITY, /* integrity metadata has been remapped */
__REQ_NOIDLE, /* Don't anticipate more IO after this one */
+ __REQ_IO_STAT, /* account I/O stat */
__REQ_NR_BITS, /* stops here */
};
@@ -145,6 +146,7 @@ enum rq_flag_bits {
#define REQ_COPY_USER (1 << __REQ_COPY_USER)
#define REQ_INTEGRITY (1 << __REQ_INTEGRITY)
#define REQ_NOIDLE (1 << __REQ_NOIDLE)
+#define REQ_IO_STAT (1 << __REQ_IO_STAT)
#define BLK_MAX_CDB 16
@@ -598,6 +600,7 @@ enum {
blk_failfast_transport(rq) || \
blk_failfast_driver(rq))
#define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED)
+#define blk_rq_io_stat(rq) ((rq)->cmd_flags & REQ_IO_STAT)
#define blk_account_rq(rq) (blk_rq_started(rq) && (blk_fs_request(rq) || blk_discard_rq(rq)))