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>
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ba54c83..2755d5c 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -118,6 +118,7 @@
__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 @@
#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 @@
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)))