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authorPaolo Valente <paolo.valente@linaro.org>2019-01-29 12:06:33 +0100
committerJens Axboe <axboe@kernel.dk>2019-01-31 12:50:23 -0700
commitd87447d84fe194b0e4f5413b5344dc82cc100711 (patch)
tree6e469ba122fea2651bd34d931dca46f755f0b799 /block
parent530c4cbb3c62f9e42dbf39279fb346f2d2ab4dbb (diff)
downloadlinux-d87447d84fe194b0e4f5413b5344dc82cc100711.tar.bz2
block, bfq: fix sequential rq detection in rate estimation
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 <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/bfq-iosched.c12
1 files 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,