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path: root/block/blk-rq-qos.h
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2019-04-30block: add SPDX tags to block layer files missing licensing informationChristoph Hellwig
Various block layer files do not have any licensing information at all. Add SPDX tags for the default kernel GPLv2 license to those. Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-17block: fix blk-iolatency accounting underflowDennis Zhou
The blk-iolatency controller measures the time from rq_qos_throttle() to rq_qos_done_bio() and attributes this time to the first bio that needs to create the request. This means if a bio is plug-mergeable or bio-mergeable, it gets to bypass the blk-iolatency controller. The recent series [1], to tag all bios w/ blkgs undermined how iolatency was determining which bios it was charging and should process in rq_qos_done_bio(). Because all bios are being tagged, this caused the atomic_t for the struct rq_wait inflight count to underflow and result in a stall. This patch adds a new flag BIO_TRACKED to let controllers know that a bio is going through the rq_qos path. blk-iolatency now checks if this flag is set to see if it should process the bio in rq_qos_done_bio(). Overloading BLK_QUEUE_ENTERED works, but makes the flag rules confusing. BIO_THROTTLED was another candidate, but the flag is set for all bios that have gone through blk-throttle code. Overloading a flag comes with the burden of making sure that when either implementation changes, a change in setting rules for one doesn't cause a bug in the other. So here, we unfortunately opt for adding a new flag. [1] https://lore.kernel.org/lkml/20181205171039.73066-1-dennis@kernel.org/ Fixes: 5cdf2e3fea5e ("blkcg: associate blkg when associating a device") Signed-off-by: Dennis Zhou <dennis@kernel.org> Cc: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-16blk-mq-debugfs: support rq_qosMing Lei
blk-mq-debugfs has been proved as very helpful for debug some tough issues, such as IO hang. We have seen blk-wbt related IO hang several times, even inside Red Hat BZ, there is such report not sovled yet, so this patch adds support debugfs on rq_qos. Cc: Bart Van Assche <bart.vanassche@wdc.com> Cc: Omar Sandoval <osandov@fb.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-07block: add rq_qos_wait to rq_qosJosef Bacik
Originally when I split out the common code from blk-wbt into rq_qos I left the wbt_wait() where it was and simply copied and modified it slightly to work for io-latency. However they are both basically the same thing, and as time has gone on wbt_wait() has ended up much smarter and kinder than it was when I copied it into io-latency, which means io-latency has lost out on these improvements. Since they are the same thing essentially except for a few minor things, create rq_qos_wait() that replicates what wbt_wait() currently does with callbacks that can be passed in for the snowflakes to do their own thing as appropriate. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-16blk-rq-qos: inline check for q->rq_qos functionsJens Axboe
Put the short code in the fast path, where we don't have any functions attached to the queue. This minimizes the impact on the hot path in the core code. Cc: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-15block: remove the unused lock argument to rq_qos_throttleChristoph Hellwig
Unused now that the legacy request path is gone. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-07-22blk-rq-qos: make depth comparisons unsignedJosef Bacik
With the change to use UINT_MAX I broke the depth check as any value of inflight (ie 0) would be less than (int)UINT_MAX. Fix this by changing everything to unsigned int to match the depth. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-07-09rq-qos: introduce dio_bio callbackJosef Bacik
wbt cares only about request completion time, but controllers may need information that is on the bio itself, so add a done_bio callback for rq-qos so things like blk-iolatency can use it to have the bio when it completes. Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-07-09block: remove external dependency on wbt_flagsJosef Bacik
We don't really need to save this stuff in the core block code, we can just pass the bio back into the helpers later on to derive the same flags and update the rq->wbt_flags appropriately. Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-07-09blk-rq-qos: refactor out common elements of blk-wbtJosef Bacik
blkcg-qos is going to do essentially what wbt does, only on a cgroup basis. Break out the common code that will be shared between blkcg-qos and wbt into blk-rq-qos.* so they can both utilize the same infrastructure. Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>