path: root/block/mq-deadline.c
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* block drivers/block: Use octal not symbolic permissionsJoe Perches2018-05-241-2/+1
| | | | | | | | | | | | | | | | | | | Convert the S_<FOO> symbolic permissions to their octal equivalents as using octal and not symbolic permissions is preferred by many as more readable. see: Done with automated conversion via: $ ./scripts/ -f --types=SYMBOLIC_PERMS --fix-inplace <files...> Miscellanea: o Wrapped modified multi-line calls to a single line where appropriate o Realign modified multi-line calls to open parenthesis Signed-off-by: Joe Perches <> Signed-off-by: Jens Axboe <>
* mq-deadline: Make sure to always unlock zonesDamien Le Moal2018-03-011-3/+13
| | | | | | | | | | | | | | | | | | | | | | | | | In case of a failed write request (all retries failed) and when using libata, the SCSI error handler calls scsi_finish_command(). In the case of blk-mq this means that scsi_mq_done() does not get called, that blk_mq_complete_request() does not get called and also that the mq-deadline .completed_request() method is not called. This results in the target zone of the failed write request being left in a locked state, preventing that any new write requests are issued to the same zone. Fix this by replacing the .completed_request() method with the .finish_request() method as this method is always called whether or not a request completes successfully. Since the .finish_request() method is only called by the blk-mq core if a .prepare_request() method exists, add a dummy .prepare_request() method. Fixes: 5700f69178e9 ("mq-deadline: Introduce zone locking support") Cc: Hannes Reinecke <> Reviewed-by: Ming Lei <> Signed-off-by: Damien Le Moal <> [ bvanassche: edited patch description ] Signed-off-by: Bart Van Assche <> Signed-off-by: Jens Axboe <>
* mq-deadline: make it clear that __dd_dispatch_request() works on all hw queuesJens Axboe2018-01-061-3/+8
| | | | | | | | | | | | Don't pass in the hardware queue to __dd_dispatch_request(), since it leads the reader to believe that we are returning a request for that specific hardware queue. That's not how mq-deadline works, the state for determining which request to serve next is shared across all hardware queues for a device. Reviewed-by: Omar Sandoval <> Reviewed-by: Ming Lei <> Signed-off-by: Jens Axboe <>
* mq-deadline: Introduce zone locking supportDamien Le Moal2018-01-051-3/+86
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce zone write locking to avoid write request reordering with zoned block devices. This is achieved using a finer selection of the next request to dispatch: 1) Any non-write request is always allowed to proceed. 2) Any write to a conventional zone is always allowed to proceed. 3) For a write to a sequential zone, the zone lock is first checked. a) If the zone is not locked, the write is allowed to proceed after its target zone is locked. b) If the zone is locked, the write request is skipped and the next request in the dispatch queue tested (back to step 1). For a write request that has locked its target zone, the zone is unlocked either when the request completes with a call to the method deadline_request_completed() or when the request is requeued using dd_insert_request(). Requests targeting a locked zone are always left in the scheduler queue to preserve the lba ordering for write requests. If no write request can be dispatched, allow reads to be dispatched even if the write batch is not done. If the device used is not a zoned block device, or if zoned block device support is disabled, this patch does not modify mq-deadline behavior. Signed-off-by: Damien Le Moal <> Reviewed-by: Christoph Hellwig <> Reviewed-by: Martin K. Petersen <> Signed-off-by: Jens Axboe <>
* mq-deadline: Introduce dispatch helpersDamien Le Moal2018-01-051-8/+37
| | | | | | | | | | | | | Avoid directly referencing the next_rq and fifo_list arrays using the helper functions deadline_next_request() and deadline_fifo_request() to facilitate changes in the dispatch request selection in __dd_dispatch_request() for zoned block devices. Signed-off-by: Damien Le Moal <> Reviewed-by: Bart Van Assche <> Reviewed-by: Christoph Hellwig <> Reviewed-by: Martin K. Petersen <> Signed-off-by: Jens Axboe <>
* mq-deadline: add 'deadline' as a name aliasJens Axboe2017-10-251-0/+1
| | | | | | | | | | | The scheduler framework now supports looking up the appropriate scheduler with the {name,mq} tupple. We can register mq-deadline with the alias of 'deadline', so that switching to 'deadline' will do the right thing based on the type of driver attached to it. Reviewed-by: Omar Sandoval <> Signed-off-by: Jens Axboe <>
* mq-deadline: Enable auto-loading when built as moduleBen Hutchings2017-08-291-0/+1
| | | | | | | | | | The block core requests modules with the "-iosched" name suffix, but mq-deadline does not have that suffix. Add an alias. Fixes: 945ffb60c11d ("mq-deadline: add blk-mq adaptation of the deadline ...") Reviewed-by: Ming Lei <> Signed-off-by: Ben Hutchings <> Signed-off-by: Jens Axboe <>
* block, scheduler: convert xxx_var_store to voidweiping zhang2017-08-281-5/+4
| | | | | | | | The last parameter "count" never be used in xxx_var_store, convert these functions to void. Signed-off-by: weiping zhang <> Signed-off-by: Jens Axboe <>
* mq-deadline: add debugfs attributesOmar Sandoval2017-05-041-0/+123
| | | | | | | | | | Expose the fifo lists, cached next requests, batching state, and dispatch list. It'd also be possible to add the sorted lists, but there aren't already seq_file helpers for rbtrees. Signed-off-by: Omar Sandoval <> Reviewed-by: Hannes Reinecke <> Signed-off-by: Jens Axboe <>
* block: enumify ELEVATOR_*_MERGEChristoph Hellwig2017-02-081-1/+1
| | | | | | | | Switch these constants to an enum, and make let the compiler ensure that all callers of blk_try_merge and elv_merge handle all potential values. Signed-off-by: Christoph Hellwig <> Signed-off-by: Jens Axboe <>
* block: free merged request in the callerJens Axboe2017-02-031-2/+6
| | | | | | | | | | | | | | | | | | | If we end up doing a request-to-request merge when we have completed a bio-to-request merge, we free the request from deep down in that path. For blk-mq-sched, the merge path has to hold the appropriate lock, but we don't need it for freeing the request. And in fact holding the lock is problematic, since we are now calling the mq sched put_rq_private() hook with the lock held. Other call paths do not hold this lock. Fix this inconsistency by ensuring that the caller frees a merged request. Then we can do it outside of the lock, making it both more efficient and fixing the blk-mq-sched problem of invoking parts of the scheduler with an unknown lock state. Reported-by: Paolo Valente <> Signed-off-by: Jens Axboe <> Reviewed-by: Omar Sandoval <>
* blk-mq-sched: bypass the scheduler for flushes entirelyOmar Sandoval2017-02-021-3/+0
| | | | | | | | | | There's a weird inconsistency that flushes are mostly hidden from the scheduler, but it needs to be aware of them in ->insert_requests(). Instead of having every scheduler call blk_mq_sched_bypass_insert(), let's do it in the common framework. Signed-off-by: Omar Sandoval <> Signed-off-by: Jens Axboe <>
* block: introduce blk_rq_is_passthroughChristoph Hellwig2017-01-311-1/+1
| | | | | | | | | This can be used to check for fs vs non-fs requests and basically removes all knowledge of BLOCK_PC specific from the block layer, as well as preparing for removing the cmd_type field in struct request. Signed-off-by: Christoph Hellwig <> Signed-off-by: Jens Axboe <>
* blk-mq-sched: change ->dispatch_requests() to ->dispatch_request()Jens Axboe2017-01-271-4/+6
| | | | | | | | | | | | | | | | When we invoke dispatch_requests(), the scheduler empties everything into the passed in list. This isn't always a good thing, since it means that we remove items that we could have potentially merged with. Change the function to dispatch single requests at the time. If we do that, we can backoff exactly at the point where the device can't consume more IO, and leave the rest with the scheduler for better merging and future dispatch decision making. Signed-off-by: Jens Axboe <> Reviewed-by: Omar Sandoval <> Tested-by: Hannes Reinecke <>
* mq-deadline: add blk-mq adaptation of the deadline IO schedulerJens Axboe2017-01-171-0/+553
This is basically identical to deadline-iosched, except it registers as a MQ capable scheduler. This is still a single queue design. Signed-off-by: Jens Axboe <> Reviewed-by: Bart Van Assche <> Reviewed-by: Omar Sandoval <>