From: Hou Tao houtao1@huawei.com
[ Upstream commit 3d24430694077313c75c6b89f618db09943621e4 ]
Currently rq->data_len will be decreased by partial completion or zeroed by completion, so when blk_stat_add() is invoked, data_len will be zero and there will never be samples in poll_cb because blk_mq_poll_stats_bkt() will return -1 if data_len is zero.
We could move blk_stat_add() back to __blk_mq_complete_request(), but that would make the effort of trying to call ktime_get_ns() once in vain. Instead we can reuse throtl_size field, and use it for both block stats and block throttle, and adjust the logic in blk_mq_poll_stats_bkt() accordingly.
Fixes: 4bc6339a583c ("block: move blk_stat_add() to __blk_mq_end_request()") Tested-by: Pavel Begunkov asml.silence@gmail.com Signed-off-by: Hou Tao houtao1@huawei.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/blk-mq.c | 11 +++++------ block/blk-throttle.c | 3 ++- include/linux/blkdev.h | 15 ++++++++++++--- 3 files changed, 19 insertions(+), 10 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c index a38ebb2a380c2..9b56428cad0e7 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -44,12 +44,12 @@ static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb);
static int blk_mq_poll_stats_bkt(const struct request *rq) { - int ddir, bytes, bucket; + int ddir, sectors, bucket;
ddir = rq_data_dir(rq); - bytes = blk_rq_bytes(rq); + sectors = blk_rq_stats_sectors(rq);
- bucket = ddir + 2*(ilog2(bytes) - 9); + bucket = ddir + 2 * ilog2(sectors);
if (bucket < 0) return -1; @@ -330,6 +330,7 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, else rq->start_time_ns = 0; rq->io_start_time_ns = 0; + rq->stats_sectors = 0; rq->nr_phys_segments = 0; #if defined(CONFIG_BLK_DEV_INTEGRITY) rq->nr_integrity_segments = 0; @@ -673,9 +674,7 @@ void blk_mq_start_request(struct request *rq)
if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags)) { rq->io_start_time_ns = ktime_get_ns(); -#ifdef CONFIG_BLK_DEV_THROTTLING_LOW - rq->throtl_size = blk_rq_sectors(rq); -#endif + rq->stats_sectors = blk_rq_sectors(rq); rq->rq_flags |= RQF_STATS; rq_qos_issue(q, rq); } diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 8ab6c81532236..ee74bffe3504d 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -2246,7 +2246,8 @@ void blk_throtl_stat_add(struct request *rq, u64 time_ns) struct request_queue *q = rq->q; struct throtl_data *td = q->td;
- throtl_track_latency(td, rq->throtl_size, req_op(rq), time_ns >> 10); + throtl_track_latency(td, blk_rq_stats_sectors(rq), req_op(rq), + time_ns >> 10); }
void blk_throtl_bio_endio(struct bio *bio) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 1ef375dafb1c1..ae51050c50949 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -202,9 +202,12 @@ struct request { #ifdef CONFIG_BLK_WBT unsigned short wbt_flags; #endif -#ifdef CONFIG_BLK_DEV_THROTTLING_LOW - unsigned short throtl_size; -#endif + /* + * rq sectors used for blk stats. It has the same value + * with blk_rq_sectors(rq), except that it never be zeroed + * by completion. + */ + unsigned short stats_sectors;
/* * Number of scatter-gather DMA addr+len pairs after @@ -903,6 +906,7 @@ static inline struct request_queue *bdev_get_queue(struct block_device *bdev) * blk_rq_err_bytes() : bytes left till the next error boundary * blk_rq_sectors() : sectors left in the entire request * blk_rq_cur_sectors() : sectors left in the current segment + * blk_rq_stats_sectors() : sectors of the entire request used for stats */ static inline sector_t blk_rq_pos(const struct request *rq) { @@ -931,6 +935,11 @@ static inline unsigned int blk_rq_cur_sectors(const struct request *rq) return blk_rq_cur_bytes(rq) >> SECTOR_SHIFT; }
+static inline unsigned int blk_rq_stats_sectors(const struct request *rq) +{ + return rq->stats_sectors; +} + #ifdef CONFIG_BLK_DEV_ZONED static inline unsigned int blk_rq_zone_no(struct request *rq) {