diff options
| author | Tejun Heo <tj@kernel.org> | 2019-08-28 15:05:57 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-08-28 21:17:10 -0600 |
| commit | 6f816b4b746c2241540e537682d30d8e9997d674 (patch) | |
| tree | 367f6fc02a7f8605cb19fd71f683d69bd96fab98 /include | |
| parent | beab17fc2a507e85dd18b3cef83820c5770c5f34 (diff) | |
| download | linux-6f816b4b746c2241540e537682d30d8e9997d674.tar.bz2 | |
blk-mq: add optional request->alloc_time_ns
There are currently two start time timestamps - start_time_ns and
io_start_time_ns. The former marks the request allocation and and the
second issue-to-device time. The planned io.weight controller needs
to measure the total time bios take to execute after it leaves rq_qos
including the time spent waiting for request to become available,
which can easily dominate on saturated devices.
This patch adds request->alloc_time_ns which records when the request
allocation attempt started. As it isn't used for the usual stats,
make it optional behind CONFIG_BLK_RQ_ALLOC_TIME and
QUEUE_FLAG_RQ_ALLOC_TIME so that it can be compiled out when there are
no users and it's active only on queues which need it even when
compiled in.
v2: s/pre_start_time/alloc_time/ and add CONFIG_BLK_RQ_ALLOC_TIME
gating as suggested by Jens.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/blkdev.h | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 1ac790178787..d0ad21e4771b 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -194,7 +194,11 @@ struct request { struct gendisk *rq_disk; struct hd_struct *part; - /* Time that I/O was submitted to the kernel. */ +#ifdef CONFIG_BLK_RQ_ALLOC_TIME + /* Time that the first bio started allocating this request. */ + u64 alloc_time_ns; +#endif + /* Time that this request was allocated for this IO. */ u64 start_time_ns; /* Time that I/O was submitted to the device. */ u64 io_start_time_ns; @@ -609,6 +613,7 @@ struct request_queue { #define QUEUE_FLAG_QUIESCED 24 /* queue has been quiesced */ #define QUEUE_FLAG_PCI_P2PDMA 25 /* device supports PCI p2p requests */ #define QUEUE_FLAG_ZONE_RESETALL 26 /* supports Zone Reset All */ +#define QUEUE_FLAG_RQ_ALLOC_TIME 27 /* record rq->alloc_time_ns */ #define QUEUE_FLAG_MQ_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \ (1 << QUEUE_FLAG_SAME_COMP)) @@ -637,6 +642,12 @@ bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q); test_bit(QUEUE_FLAG_SCSI_PASSTHROUGH, &(q)->queue_flags) #define blk_queue_pci_p2pdma(q) \ test_bit(QUEUE_FLAG_PCI_P2PDMA, &(q)->queue_flags) +#ifdef CONFIG_BLK_RQ_ALLOC_TIME +#define blk_queue_rq_alloc_time(q) \ + test_bit(QUEUE_FLAG_RQ_ALLOC_TIME, &(q)->queue_flags) +#else +#define blk_queue_rq_alloc_time(q) false +#endif #define blk_noretry_request(rq) \ ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \ |