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| author | Bart Van Assche <bart.vanassche@wdc.com> | 2018-01-10 19:33:33 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-01-10 19:45:29 +0300 |
| commit | fcd36c36f381f534adad5a6c6485db4405d5ea42 (patch) | |
| tree | 1f97dc35dc4382215a15a5112fc559b1b5dd7f2d /block/blk-mq.c | |
| parent | 5f15684bd5e5ef39d4337988864fec8012471dda (diff) | |
| download | linux-fcd36c36f381f534adad5a6c6485db4405d5ea42.tar.xz | |
blk-mq: Explain when 'active_queues' is decremented
It is nontrivial to derive from the blk-mq source code when
blk_mq_tags.active_queues is decremented. Hence add a comment that
explains this.
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-mq.c')
| -rw-r--r-- | block/blk-mq.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index 9aa24c9508f9..266fc4f6b046 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -954,6 +954,12 @@ static void blk_mq_timeout_work(struct work_struct *work) data.next = blk_rq_timeout(round_jiffies_up(data.next)); mod_timer(&q->timeout, data.next); } else { + /* + * Request timeouts are handled as a forward rolling timer. If + * we end up here it means that no requests are pending and + * also that no request has been pending for a while. Mark + * each hctx as idle. + */ queue_for_each_hw_ctx(q, hctx, i) { /* the hctx may be unmapped, so check it here */ if (blk_mq_hw_queue_mapped(hctx)) |