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* blk-mq: Remove generation seqeunceKeith Busch2018-05-291-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | This patch simplifies the timeout handling by relying on the request reference counting to ensure the iterator is operating on an inflight and truly timed out request. Since the reference counting prevents the tag from being reallocated, the block layer no longer needs to prevent drivers from completing their requests while the timeout handler is operating on it: a driver completing a request is allowed to proceed to the next state without additional syncronization with the block layer. This also removes any need for generation sequence numbers since the request lifetime is prevented from being reallocated as a new sequence while timeout handling is operating on it. To enables this a refcount is added to struct request so that request users can be sure they're operating on the same request without it changing while they're processing it. The request's tag won't be released for reuse until both the timeout handler and the completion are done with it. Signed-off-by: Keith Busch <keith.busch@intel.com> [hch: slight cleanups, added back submission side hctx lock, use cmpxchg for completions] Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq: remove blk_mq_delay_queue()Ming Lei2018-04-101-1/+0
| | | | | | | | | | | No driver uses this interface any more, so remove it. Cc: Stefan Haberland <sth@linux.vnet.ibm.com> Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq-debugfs: Show more request state informationBart Van Assche2018-03-171-1/+15
| | | | | | | | | | | | | Since commit 634f9e4631a8 ("blk-mq: remove REQ_ATOM_COMPLETE usages from blk-mq") blk_rq_is_complete() only reports whether or not a request has completed for legacy queues. Hence modify the blk-mq-debugfs code such that it shows the blk-mq request state again. Fixes: 634f9e4631a8 ("blk-mq: remove REQ_ATOM_COMPLETE usages from blk-mq") Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq-debugfs: Show zone locking informationBart Van Assche2018-02-281-0/+16
| | | | | | | | | | | | | | | | When debugging the ZBC code in the mq-deadline scheduler it is very important to know which zones are locked and which zones are not locked. Hence this patch that exports the zone locking information through debugfs. Cc: Omar Sandoval <osandov@fb.com> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Tested-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq-debugfs: Reorder queue show and store methodsBart Van Assche2018-02-281-65/+65
| | | | | | | | | | | | | Make sure that the queue show and store methods are contiguous and also that these appear in alphabetical order. Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Cc: Omar Sandoval <osandov@fb.com> Cc: Damien Le Moal <damien.lemoal@wdc.com> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq-debugfs: don't allow write on attributes with seq_operations setEryu Guan2018-01-241-1/+5
| | | | | | | | | | | | | | | | | Attributes that only implement .seq_ops are read-only, any write to them should be rejected. But currently kernel would crash when writing to such debugfs entries, e.g. chmod +w /sys/kernel/debug/block/<dev>/requeue_list echo 0 > /sys/kernel/debug/block/<dev>/requeue_list chmod -w /sys/kernel/debug/block/<dev>/requeue_list Fix it by returning -EPERM in blk_mq_debugfs_write() when writing to such attributes. Cc: Ming Lei <ming.lei@redhat.com> Signed-off-by: Eryu Guan <eguan@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq: add missing RQF_STARTED to debugfsJens Axboe2018-01-121-0/+1
| | | | | | | | | | | | | Looking at debug output, we see: ./000000009ddfa913/requeue_list:000000009646711c {.op=READ, .state=idle, gen=0x1 18, abort_gen=0x0, .cmd_flags=, .rq_flags=SORTED|1|SOFTBARRIER|IO_STAT, complete =0, .tag=-1, .internal_tag=217} Note the '1' between SORTED and SOFTBARRIER - that's because no name as defined for RQF_STARTED. Fixed that. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: convert REQ_ATOM_COMPLETE to stealing rq->__deadline bitJens Axboe2018-01-101-8/+1
| | | | | | | | | | | | We only have one atomic flag left. Instead of using an entire unsigned long for that, steal the bottom bit of the deadline field that we already reserved. Remove ->atomic_flags, since it's now unused. Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: remove REQ_ATOM_POLL_SLEPTJens Axboe2018-01-101-1/+1
| | | | | | | | | | | We don't need this to be an atomic flag, it can be a regular flag. We either end up on the same CPU for the polling, in which case the state is sane, or we did the sleep which would imply the needed barrier to ensure we see the right state. Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq: add a few missing debugfs RQF_ flagsJens Axboe2018-01-101-0/+2
| | | | | | | We are missing ZONE_WRITE_LOCKED and MQ_TIMEOUT_EXPIRED, add them so the debugfs bits can decode them. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq: remove REQ_ATOM_STARTEDTejun Heo2018-01-091-3/+1
| | | | | | | | | | | | | | After the recent updates to use generation number and state based synchronization, we can easily replace REQ_ATOM_STARTED usages by adding an extra state to distinguish completed but not yet freed state. Add MQ_RQ_COMPLETE and replace REQ_ATOM_STARTED usages with blk_mq_rq_state() tests. REQ_ATOM_STARTED no longer has any users left and is removed. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Merge branch 'for-4.15/block' of git://git.kernel.dk/linux-blockLinus Torvalds2017-11-141-2/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull core block layer updates from Jens Axboe: "This is the main pull request for block storage for 4.15-rc1. Nothing out of the ordinary in here, and no API changes or anything like that. Just various new features for drivers, core changes, etc. In particular, this pull request contains: - A patch series from Bart, closing the whole on blk/scsi-mq queue quescing. - A series from Christoph, building towards hidden gendisks (for multipath) and ability to move bio chains around. - NVMe - Support for native multipath for NVMe (Christoph). - Userspace notifications for AENs (Keith). - Command side-effects support (Keith). - SGL support (Chaitanya Kulkarni) - FC fixes and improvements (James Smart) - Lots of fixes and tweaks (Various) - bcache - New maintainer (Michael Lyle) - Writeback control improvements (Michael) - Various fixes (Coly, Elena, Eric, Liang, et al) - lightnvm updates, mostly centered around the pblk interface (Javier, Hans, and Rakesh). - Removal of unused bio/bvec kmap atomic interfaces (me, Christoph) - Writeback series that fix the much discussed hundreds of millions of sync-all units. This goes all the way, as discussed previously (me). - Fix for missing wakeup on writeback timer adjustments (Yafang Shao). - Fix laptop mode on blk-mq (me). - {mq,name} tupple lookup for IO schedulers, allowing us to have alias names. This means you can use 'deadline' on both !mq and on mq (where it's called mq-deadline). (me). - blktrace race fix, oopsing on sg load (me). - blk-mq optimizations (me). - Obscure waitqueue race fix for kyber (Omar). - NBD fixes (Josef). - Disable writeback throttling by default on bfq, like we do on cfq (Luca Miccio). - Series from Ming that enable us to treat flush requests on blk-mq like any other request. This is a really nice cleanup. - Series from Ming that improves merging on blk-mq with schedulers, getting us closer to flipping the switch on scsi-mq again. - BFQ updates (Paolo). - blk-mq atomic flags memory ordering fixes (Peter Z). - Loop cgroup support (Shaohua). - Lots of minor fixes from lots of different folks, both for core and driver code" * 'for-4.15/block' of git://git.kernel.dk/linux-block: (294 commits) nvme: fix visibility of "uuid" ns attribute blk-mq: fixup some comment typos and lengths ide: ide-atapi: fix compile error with defining macro DEBUG blk-mq: improve tag waiting setup for non-shared tags brd: remove unused brd_mutex blk-mq: only run the hardware queue if IO is pending block: avoid null pointer dereference on null disk fs: guard_bio_eod() needs to consider partitions xtensa/simdisk: fix compile error nvme: expose subsys attribute to sysfs nvme: create 'slaves' and 'holders' entries for hidden controllers block: create 'slaves' and 'holders' entries for hidden gendisks nvme: also expose the namespace identification sysfs files for mpath nodes nvme: implement multipath access to nvme subsystems nvme: track shared namespaces nvme: introduce a nvme_ns_ids structure nvme: track subsystems block, nvme: Introduce blk_mq_req_flags_t block, scsi: Make SCSI quiesce and resume work reliably block: Add the QUEUE_FLAG_PREEMPT_ONLY request queue flag ...
| * block: Add the QUEUE_FLAG_PREEMPT_ONLY request queue flagBart Van Assche2017-11-101-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This flag will be used in the next patch to let the block layer core know whether or not a SCSI request queue has been quiesced. A quiesced SCSI queue namely only processes RQF_PREEMPT requests. Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Tested-by: Martin Steigerwald <martin@lichtvoll.de> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Cc: Ming Lei <ming.lei@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * blk-mq: fix issue with shared tag queue re-runningJens Axboe2017-11-101-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch attempts to make the case of hctx re-running on driver tag failure more robust. Without this patch, it's pretty easy to trigger a stall condition with shared tags. An example is using null_blk like this: modprobe null_blk queue_mode=2 nr_devices=4 shared_tags=1 submit_queues=1 hw_queue_depth=1 which sets up 4 devices, sharing the same tag set with a depth of 1. Running a fio job ala: [global] bs=4k rw=randread norandommap direct=1 ioengine=libaio iodepth=4 [nullb0] filename=/dev/nullb0 [nullb1] filename=/dev/nullb1 [nullb2] filename=/dev/nullb2 [nullb3] filename=/dev/nullb3 will inevitably end with one or more threads being stuck waiting for a scheduler tag. That IO is then stuck forever, until someone else triggers a run of the queue. Ensure that we always re-run the hardware queue, if the driver tag we were waiting for got freed before we added our leftover request entries back on the dispatch list. Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com> Tested-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: remove QUEUE_FLAG_STACKABLEChristoph Hellwig2017-10-051-1/+0
| | | | | | | | | | | | | | | | | | We already have a queue_is_rq_based helper to check if a request_queue is request based, so we can remove the flag for it. Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | blk-mq-debugfs: fix device sched directory for default schedulerOmar Sandoval2017-10-031-1/+5
|/ | | | | | | | | | | In blk_mq_debugfs_register(), I remembered to set up the per-hctx sched directories if a default scheduler was already configured by blk_mq_sched_init() from blk_mq_init_allocated_queue(), but I didn't do the same for the device-wide sched directory. Fix it. Fixes: d332ce091813 ("blk-mq-debugfs: allow schedulers to register debugfs attributes") Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Merge branch 'for-4.14/block' of git://git.kernel.dk/linux-blockLinus Torvalds2017-09-071-3/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull block layer updates from Jens Axboe: "This is the first pull request for 4.14, containing most of the code changes. It's a quiet series this round, which I think we needed after the churn of the last few series. This contains: - Fix for a registration race in loop, from Anton Volkov. - Overflow complaint fix from Arnd for DAC960. - Series of drbd changes from the usual suspects. - Conversion of the stec/skd driver to blk-mq. From Bart. - A few BFQ improvements/fixes from Paolo. - CFQ improvement from Ritesh, allowing idling for group idle. - A few fixes found by Dan's smatch, courtesy of Dan. - A warning fixup for a race between changing the IO scheduler and device remova. From David Jeffery. - A few nbd fixes from Josef. - Support for cgroup info in blktrace, from Shaohua. - Also from Shaohua, new features in the null_blk driver to allow it to actually hold data, among other things. - Various corner cases and error handling fixes from Weiping Zhang. - Improvements to the IO stats tracking for blk-mq from me. Can drastically improve performance for fast devices and/or big machines. - Series from Christoph removing bi_bdev as being needed for IO submission, in preparation for nvme multipathing code. - Series from Bart, including various cleanups and fixes for switch fall through case complaints" * 'for-4.14/block' of git://git.kernel.dk/linux-block: (162 commits) kernfs: checking for IS_ERR() instead of NULL drbd: remove BIOSET_NEED_RESCUER flag from drbd_{md_,}io_bio_set drbd: Fix allyesconfig build, fix recent commit drbd: switch from kmalloc() to kmalloc_array() drbd: abort drbd_start_resync if there is no connection drbd: move global variables to drbd namespace and make some static drbd: rename "usermode_helper" to "drbd_usermode_helper" drbd: fix race between handshake and admin disconnect/down drbd: fix potential deadlock when trying to detach during handshake drbd: A single dot should be put into a sequence. drbd: fix rmmod cleanup, remove _all_ debugfs entries drbd: Use setup_timer() instead of init_timer() to simplify the code. drbd: fix potential get_ldev/put_ldev refcount imbalance during attach drbd: new disk-option disable-write-same drbd: Fix resource role for newly created resources in events2 drbd: mark symbols static where possible drbd: Send P_NEG_ACK upon write error in protocol != C drbd: add explicit plugging when submitting batches drbd: change list_for_each_safe to while(list_first_entry_or_null) drbd: introduce drbd_recv_header_maybe_unplug ...
| * blk-mq-debugfs: Declare a local symbol staticBart Van Assche2017-08-181-1/+1
| | | | | | | | | | | | | | | | | | This was detected by sparse. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: remove unused syncfull/asyncfull queue flagsJens Axboe2017-08-101-2/+0
| | | | | | | | | | | | | | | | We haven't used these in years, but somehow the definitions still remained. Kill them, and renumber the QUEUE_FLAG_ space. We had a hole in the beginning of the space, too. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | blk-mq-debugfs: Add names for recently added flagsBart Van Assche2017-08-251-0/+3
|/ | | | | | | | | | | | The symbolic constants QUEUE_FLAG_SCSI_PASSTHROUGH, QUEUE_FLAG_QUIESCED and REQ_NOWAIT are missing from blk-mq-debugfs.c. Add these to blk-mq-debugfs.c such that these appear as names in debugfs instead of as numbers. Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Cc: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq: expose write hints through debugfsJens Axboe2017-06-271-0/+24
| | | | | | | | | | | | | | | Useful to verify that things are working the way they should. Reading the file will return number of kb written with each write hint. Writing the file will reset the statistics. No care is taken to ensure that we don't race on updates. Drivers will write to q->write_hints[] if they handle a given write hint. Reviewed-by: Andreas Dilger <adilger@dilger.ca> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq-debugfs: Add 'kick' operationBart Van Assche2017-06-011-1/+3
| | | | | | | | | | | | | | Running a queue causes the block layer to examine the per-CPU and hw queues but not the requeue list. Hence add a 'kick' operation that also examines the requeue list. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Eduardo Valentin <eduval@amazon.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.com> Cc: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq-debugfs: Show busy requestsBart Van Assche2017-06-011-0/+31
| | | | | | | | | | | | | | Requests that got stuck in a block driver are neither on blk_mq_ctx.rq_list nor on any hw dispatch queue. Make these visible in debugfs through the "busy" attribute. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Eduardo Valentin <eduval@amazon.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.com> Cc: Omar Sandoval <osandov@fb.com> Cc: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq-debugfs: Show requeue listBart Van Assche2017-06-011-0/+32
| | | | | | | | | | | | | | | When verifying whether or not a blk-mq driver forgot to kick the requeue list after having requeued a request it is important to be able to verify the contents of the requeue list. Hence export that list through debugfs. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Eduardo Valentin <eduval@amazon.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq-debugfs: Show atomic request flagsBart Van Assche2017-06-011-0/+10
| | | | | | | | | | | | | | When analyzing e.g. queue lockups it is important to know whether or not a request has already been started. Hence also show the atomic request flags. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Eduardo Valentin <eduval@amazon.com> Cc: Omar Sandoval <osandov@fb.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* mq-deadline: add debugfs attributesOmar Sandoval2017-05-041-2/+7
| | | | | | | | | | 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 <osandov@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* kyber: add debugfs attributesOmar Sandoval2017-05-041-1/+2
| | | | | | | | | Expose the domain token pools, asynchronous sbitmap depth, domain request lists, and batching state. Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq-debugfs: allow schedulers to register debugfs attributesOmar Sandoval2017-05-041-9/+65
| | | | | | | | | | | | | | This provides the infrastructure for schedulers to expose their internal state through debugfs. We add a list of queue attributes and a list of hctx attributes to struct elevator_type and wire them up when switching schedulers. Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Add missing seq_file.h header in blk-mq-debugfs.h Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: untangle debugfs and sysfsOmar Sandoval2017-05-041-48/+62
| | | | | | | | | | | | | | Originally, I tied debugfs registration/unregistration together with sysfs. There's no reason to do this, and it's getting in the way of letting schedulers define their own debugfs attributes. Instead, tie the debugfs registration to the lifetime of the structures themselves. The saner lifetimes mean we can also get rid of the extra mq directory and move everything one level up. I.e., nvme0n1/mq/hctx0/tags is now just nvme0n1/hctx0/tags. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: move debugfs declarations to a separate header fileOmar Sandoval2017-05-041-0/+1
| | | | | | | | Preparation for adding more declarations. Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Do not invoke queue operations on a dead queueBart Van Assche2017-05-041-0/+8
| | | | | | | | | | | | | | In commit e869b5462f83 ("blk-mq: Unregister debugfs attributes earlier"), we shuffled the debugfs cleanup around so that the "state" attribute was removed before we freed the blk-mq data structures. However, later changes are going to undo that, so we need to explicitly disallow running a dead queue. [Omar: rebased and updated commit message] Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq-debugfs: get rid of a bunch of boilerplateOmar Sandoval2017-05-041-328/+136
| | | | | | | | | | | | | A large part of blk-mq-debugfs.c is file_operations and seq_file boilerplate. This sucks as is but will suck even more when schedulers can define their own debugfs entries. Factor it all out into a single blk_mq_debugfs_fops which multiplexes as needed. We store the request_queue, blk_mq_hw_ctx, or blk_mq_ctx in the parent directory dentry, which is kind of hacky, but it works. Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq-debugfs: rename hw queue directories from <n> to hctx<n>Omar Sandoval2017-05-041-1/+1
| | | | | | | | | It's not clear what these numbered directories represent unless you consult the code. We're about to get rid of the intermediate "mq" directory, so these would be even more confusing without that context. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq-debugfs: don't open code strstrip()Omar Sandoval2017-05-041-5/+4
| | | | | | | | Slightly more readable, plus we also strip leading spaces. Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq-debugfs: error on long write to queue "state" fileOmar Sandoval2017-05-041-7/+12
| | | | | | | | | | | | | | | | | | blk_queue_flags_store() currently truncates and returns a short write if the operation being written is too long. This can give us weird results, like here: $ echo "run bar" echo: write error: invalid argument $ dmesg [ 1103.075435] blk_queue_flags_store: unsupported operation bar. Use either 'run' or 'start' Instead, return an error if the user does this. While we're here, make the argument names consistent with everywhere else in this file. Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq-debugfs: clean up flag definitionsOmar Sandoval2017-05-041-93/+108
| | | | | | | | | | Make sure the spelled out flag names match the definition. This also adds a missing hctx state, BLK_MQ_S_START_ON_RUN, and a missing cmd_flag, __REQ_NOUNMAP. Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq-debugfs: separate flags with |Omar Sandoval2017-05-041-1/+1
| | | | | | | | This reads more naturally than spaces. Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Add blk_mq_ops.show_rq()Bart Van Assche2017-04-261-1/+5
| | | | | | | | | | This new callback function will be used in the next patch to show more information about SCSI requests. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Cc: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Show operation, cmd_flags and rq_flags namesBart Van Assche2017-04-261-3/+69
| | | | | | | | | | Show the operation name, .cmd_flags and .rq_flags as names instead of numbers. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Make blk_flags_show() callers append a newline characterBart Van Assche2017-04-261-1/+3
| | | | | | | | | | | This patch does not change any functionality but makes it possible to produce a single line of output with multiple flag-to-name translations. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Move the "state" debugfs attribute one level downBart Van Assche2017-04-261-8/+1
| | | | | | | | | | Move the "state" attribute from the top level to the "mq" directory as requested by Omar. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq-debugfs: Rename functions for registering and unregistering the mq ↵Bart Van Assche2017-04-261-4/+4
| | | | | | | | | | | | | directory Since the blk_mq_debugfs_*register_hctxs() functions register and unregister all attributes under the "mq" directory, rename these into blk_mq_debugfs_*register_mq(). Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Let blk_mq_debugfs_register() look up the queue nameBart Van Assche2017-04-261-2/+3
| | | | | | | | | | | | A later patch will move the call of blk_mq_debugfs_register() to a function to which the queue name is not passed as an argument. To avoid having to add a 'name' argument to multiple callers, let blk_mq_debugfs_register() look up the queue name. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Fix poll_stat for new size-based bucketing.Stephen Bates2017-04-201-6/+9
| | | | | | | | | | Fixes an issue where the size of the poll_stat array in request_queue does not match the size expected by the new size based bucketing for IO completion polling. Fixes: 720b8ccc4500 ("blk-mq: Add a polling specific stats function") Signed-off-by: Stephen Bates <sbates@raithlin.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Show symbolic names for hctx state and flagsBart Van Assche2017-04-101-3/+34
| | | | | | | | | | Instead of showing the hctx state and flags as numbers, show the names of the flags. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Cc: Omar Sandoval <osandov@fb.com> Cc: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Export queue state through /sys/kernel/debug/block/*/stateBart Van Assche2017-04-101-0/+106
| | | | | | | | | | | Make it possible to check whether or not a block layer queue has been stopped. Make it possible to start and to run a blk-mq queue from user space. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Cc: Omar Sandoval <osandov@fb.com> Cc: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-stat: convert to callback-based statistics reportingOmar Sandoval2017-03-211-55/+44
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, statistics are gathered in ~0.13s windows, and users grab the statistics whenever they need them. This is not ideal for both in-tree users: 1. Writeback throttling wants its own dynamically sized window of statistics. Since the blk-stats statistics are reset after every window and the wbt windows don't line up with the blk-stats windows, wbt doesn't see every I/O. 2. Polling currently grabs the statistics on every I/O. Again, depending on how the window lines up, we may miss some I/Os. It's also unnecessary overhead to get the statistics on every I/O; the hybrid polling heuristic would be just as happy with the statistics from the previous full window. This reworks the blk-stats infrastructure to be callback-based: users register a callback that they want called at a given time with all of the statistics from the window during which the callback was active. Users can dynamically bucketize the statistics. wbt and polling both currently use read vs. write, but polling can be extended to further subdivide based on request size. The callbacks are kept on an RCU list, and each callback has percpu stats buffers. There will only be a few users, so the overhead on the I/O completion side is low. The stats flushing is also simplified considerably: since the timer function is responsible for clearing the statistics, we don't have to worry about stale statistics. wbt is a trivial conversion. After the conversion, the windowing problem mentioned above is fixed. For polling, we register an extra callback that caches the previous window's statistics in the struct request_queue for the hybrid polling heuristic to use. Since we no longer have a single stats buffer for the request queue, this also removes the sysfs and debugfs stats entries. To replace those, we add a debugfs entry for the poll statistics. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-stat: use READ and WRITE instead of BLK_STAT_{READ,WRITE}Omar Sandoval2017-03-211-6/+6
| | | | | | | | | The stats buckets will become generic soon, so make the existing users use the common READ and WRITE definitions instead of one internal to blk-stat. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: use same block debugfs directory for blk-mq and blktraceOmar Sandoval2017-02-021-9/+3
| | | | | | | | | | When I added the blk-mq debugging information to debugfs, I didn't notice that blktrace also creates a "block" directory in debugfs. Make them use the same dentry, now created in the core block code. Based on a patch from Jens. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq-debug: Introduce debugfs_create_files()Bart Van Assche2017-02-011-17/+17
| | | | | | | | | | | Replace the two debugfs_create_file() loops by a call to the new debugfs_create_files() function. Add an empty element at the end of the two attribute arrays such that the array size does not have to be passed to debugfs_create_files(). Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
generated by cgit v1.2.3 (git 2.39.1) at 2024-04-24 04:21:14 +0000