Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-22 20:22:09 +00:00
Code Issues Packages Projects Releases Wiki Activity

blk-mq: add BLK_MQ_F_DEFER_ISSUE support flag

Browse Source 
Drivers can now tell blk-mq if they take advantage of the deferred
issue through 'last' or not. If they do, don't do queue-direct
for sync IO. This is a preparation patch for the nvme conversion.

Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Jens Axboe 2014-10-29 11:18:26 -06:00
parent 74c450521d
commit e167dfb53c
2 changed files with 7 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
block/blk-mq.c
View File

@ -1172,7 +1172,12 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
goto run_queue;
}
if (is_sync) {
/*
* If the driver supports defer issued based on 'last', then
* queue it up like normal since we can potentially save some
* CPU this way.
*/
if (is_sync && !(data.hctx->flags & BLK_MQ_F_DEFER_ISSUE)) {
struct blk_mq_queue_data bd = {
.rq = rq,
.list = NULL,

1
include/linux/blk-mq.h
View File

@ -146,6 +146,7 @@ enum {
BLK_MQ_F_TAG_SHARED = 1 << 1,
BLK_MQ_F_SG_MERGE = 1 << 2,
BLK_MQ_F_SYSFS_UP = 1 << 3,
BLK_MQ_F_DEFER_ISSUE = 1 << 4,
BLK_MQ_S_STOPPED = 0,
BLK_MQ_S_TAG_ACTIVE = 1,