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Commit 4822e902 authored by Konstantin Khlebnikov's avatar Konstantin Khlebnikov Committed by Jens Axboe
Browse files

block: describe difference between flags IO_STAT and STATS 



This adds reasonable comments, but they definitely needs better names.

Signed-off-by: default avatarKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 486c6fba

include/linux/blkdev.h

+4 −4
Original line number Original line Diff line number Diff line
@@ -108,7 +108,7 @@ typedef __u32 __bitwise req_flags_t; 
#define RQF_QUIET		((__force req_flags_t)(1 << 11))

#define RQF_QUIET		((__force req_flags_t)(1 << 11))

/* elevator private data attached */

/* elevator private data attached */

#define RQF_ELVPRIV		((__force req_flags_t)(1 << 12))

#define RQF_ELVPRIV		((__force req_flags_t)(1 << 12))

/* account I/O stat */

/* account into disk and partition IO statistics */

#define RQF_IO_STAT		((__force req_flags_t)(1 << 13))

#define RQF_IO_STAT		((__force req_flags_t)(1 << 13))

/* request came from our alloc pool */

/* request came from our alloc pool */

#define RQF_ALLOCED		((__force req_flags_t)(1 << 14))

#define RQF_ALLOCED		((__force req_flags_t)(1 << 14))
@@ -116,7 +116,7 @@ typedef __u32 __bitwise req_flags_t; 
#define RQF_PM			((__force req_flags_t)(1 << 15))

#define RQF_PM			((__force req_flags_t)(1 << 15))

/* on IO scheduler merge hash */

/* on IO scheduler merge hash */

#define RQF_HASHED		((__force req_flags_t)(1 << 16))

#define RQF_HASHED		((__force req_flags_t)(1 << 16))

/* IO stats tracking on */

/* track IO completion time */

#define RQF_STATS		((__force req_flags_t)(1 << 17))

#define RQF_STATS		((__force req_flags_t)(1 << 17))

/* Look at ->special_vec for the actual data payload instead of the

/* Look at ->special_vec for the actual data payload instead of the

   bio chain. */

   bio chain. */
@@ -685,7 +685,7 @@ struct request_queue { 
#define QUEUE_FLAG_FAIL_IO	7	/* fake timeout */

#define QUEUE_FLAG_FAIL_IO	7	/* fake timeout */

#define QUEUE_FLAG_NONROT	9	/* non-rotational device (SSD) */

#define QUEUE_FLAG_NONROT	9	/* non-rotational device (SSD) */

#define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */

#define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */

#define QUEUE_FLAG_IO_STAT     10	/* do IO stats */

#define QUEUE_FLAG_IO_STAT     10	/* do disk/partitions IO accounting */

#define QUEUE_FLAG_DISCARD     11	/* supports DISCARD */

#define QUEUE_FLAG_DISCARD     11	/* supports DISCARD */

#define QUEUE_FLAG_NOXMERGES   12	/* No extended merges */

#define QUEUE_FLAG_NOXMERGES   12	/* No extended merges */

#define QUEUE_FLAG_ADD_RANDOM  13	/* Contributes to random pool */

#define QUEUE_FLAG_ADD_RANDOM  13	/* Contributes to random pool */
@@ -699,7 +699,7 @@ struct request_queue { 
#define QUEUE_FLAG_FUA	       21	/* device supports FUA writes */

#define QUEUE_FLAG_FUA	       21	/* device supports FUA writes */

#define QUEUE_FLAG_FLUSH_NQ    22	/* flush not queueuable */

#define QUEUE_FLAG_FLUSH_NQ    22	/* flush not queueuable */

#define QUEUE_FLAG_DAX         23	/* device supports DAX */

#define QUEUE_FLAG_DAX         23	/* device supports DAX */

#define QUEUE_FLAG_STATS       24	/* track rq completion times */

#define QUEUE_FLAG_STATS       24	/* track IO start and completion times */

#define QUEUE_FLAG_POLL_STATS  25	/* collecting stats for hybrid polling */

#define QUEUE_FLAG_POLL_STATS  25	/* collecting stats for hybrid polling */

#define QUEUE_FLAG_REGISTERED  26	/* queue has been registered to a disk */

#define QUEUE_FLAG_REGISTERED  26	/* queue has been registered to a disk */

#define QUEUE_FLAG_SCSI_PASSTHROUGH 27	/* queue supports SCSI commands */

#define QUEUE_FLAG_SCSI_PASSTHROUGH 27	/* queue supports SCSI commands */