diff options
| author | Jens Axboe <axboe@kernel.dk> | 2018-08-23 09:34:46 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-08-23 09:34:46 -0600 |
| commit | c125311d96b1bfcce0f5930a4f0fdfe39ea14f7c (patch) | |
| tree | 64bef9e91ac97c6c1d4fbd39b6f259b08ddc1670 /block | |
| parent | c45e6a037a536530bd25781ac7c989e52deb2a63 (diff) | |
| download | lwn-c125311d96b1bfcce0f5930a4f0fdfe39ea14f7c.tar.gz lwn-c125311d96b1bfcce0f5930a4f0fdfe39ea14f7c.zip | |
blk-wbt: don't maintain inflight counts if disabled
A previous commit removed the ability to have per-rq flags. We used
those flags to maintain inflight counts. Since we don't have those
anymore, we have to always maintain inflight counts, even if wbt is
disabled. This is clearly suboptimal.
Add a queue quiesce around changing the wbt latency settings from sysfs
to work around this. With that, we can reliably put the enabled check in
our bio_to_wbt_flags(), since we know the WBT_TRACKED flag will be
consistent for the lifetime of the request.
Fixes: c1c80384c8f ("block: remove external dependency on wbt_flags")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-sysfs.c | 19 | ||||
| -rw-r--r-- | block/blk-wbt.c | 3 |
2 files changed, 21 insertions, 1 deletions
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index bb109bb0a055..3772671cf2bc 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -453,9 +453,26 @@ static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page, else if (val >= 0) val *= 1000ULL; - wbt_set_min_lat(q, val); + /* + * Ensure that the queue is idled, in case the latency update + * ends up either enabling or disabling wbt completely. We can't + * have IO inflight if that happens. + */ + if (q->mq_ops) { + blk_mq_freeze_queue(q); + blk_mq_quiesce_queue(q); + } else + blk_queue_bypass_start(q); + wbt_set_min_lat(q, val); wbt_update_limits(q); + + if (q->mq_ops) { + blk_mq_unquiesce_queue(q); + blk_mq_unfreeze_queue(q); + } else + blk_queue_bypass_end(q); + return count; } diff --git a/block/blk-wbt.c b/block/blk-wbt.c index c9358f1981fb..84507d3e9a98 100644 --- a/block/blk-wbt.c +++ b/block/blk-wbt.c @@ -540,6 +540,9 @@ static enum wbt_flags bio_to_wbt_flags(struct rq_wb *rwb, struct bio *bio) { enum wbt_flags flags = 0; + if (!rwb_enabled(rwb)) + return 0; + if (bio_op(bio) == REQ_OP_READ) { flags = WBT_READ; } else if (wbt_should_throttle(rwb, bio)) { |