[PATCH BUGFIX IMPROVEMENT 09/14] block, bfq: fix sequential rq detection in rate estimation
From: Paolo Valente <hidden>
Date: 2019-01-29 11:07:14
Also in:
lkml
Subsystem:
bfq i/o scheduler, block layer, the rest · Maintainers:
Yu Kuai, Jens Axboe, Linus Torvalds
In bfq_update_peak_rate, to check whether an I/O request rq is sequential, only the seek distance of rq w.r.t. the last request dispatched is controlled. This is not sufficient for non-rotational storage, where the size of rq is at least as relevant. This commit adds the missing control. Signed-off-by: Paolo Valente <redacted> --- block/bfq-iosched.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index c1bb5e5fcdc4..12228af16198 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c@@ -235,6 +235,11 @@ static struct kmem_cache *bfq_pool; #define BFQQ_SEEK_THR (sector_t)(8 * 100) #define BFQQ_SECT_THR_NONROT (sector_t)(2 * 32) +#define BFQ_RQ_SEEKY(bfqd, last_pos, rq) \ + (get_sdist(last_pos, rq) > \ + BFQQ_SEEK_THR && \ + (!blk_queue_nonrot(bfqd->queue) || \ + blk_rq_sectors(rq) < BFQQ_SECT_THR_NONROT)) #define BFQQ_CLOSE_THR (sector_t)(8 * 1024) #define BFQQ_SEEKY(bfqq) (hweight32(bfqq->seek_history) > 19)
@@ -2754,7 +2759,7 @@ static void bfq_update_peak_rate(struct bfq_data *bfqd, struct request *rq) if ((bfqd->rq_in_driver > 0 || now_ns - bfqd->last_completion < BFQ_MIN_TT) - && get_sdist(bfqd->last_position, rq) < BFQQ_SEEK_THR) + && !BFQ_RQ_SEEKY(bfqd, bfqd->last_position, rq)) bfqd->sequential_samples++; bfqd->tot_sectors_dispatched += blk_rq_sectors(rq);
@@ -4511,10 +4516,7 @@ bfq_update_io_seektime(struct bfq_data *bfqd, struct bfq_queue *bfqq, struct request *rq) { bfqq->seek_history <<= 1; - bfqq->seek_history |= - get_sdist(bfqq->last_request_pos, rq) > BFQQ_SEEK_THR && - (!blk_queue_nonrot(bfqd->queue) || - blk_rq_sectors(rq) < BFQQ_SECT_THR_NONROT); + bfqq->seek_history |= BFQ_RQ_SEEKY(bfqd, bfqq->last_request_pos, rq); } static void bfq_update_has_short_ttime(struct bfq_data *bfqd,
--
2.20.1