- 07 Apr, 2017 16 commits
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Bart Van Assche authored
Since the next patch in this series will use RCU to iterate over tag_list, make this safe. Add lockdep_assert_held() statements in functions that iterate over tag_list to make clear that using list_for_each_entry() instead of list_for_each_entry_rcu() is fine in these functions. Signed-off-by:
Bart Van Assche <bart.vanassche@sandisk.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.com> Signed-off-by:
Jens Axboe <axboe@fb.com>
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Omar Sandoval authored
Trivial cleanup. Signed-off-by:
Omar Sandoval <osandov@fb.com> Signed-off-by:
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Omar Sandoval authored
Minor cleanup that makes it easier to figure out what's going on in the driver tag allocation failure path of blk_mq_dispatch_rq_list(). Signed-off-by:
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Omar Sandoval authored
Schedulers need to be informed when a hardware queue is added or removed at runtime so they can allocate/free per-hardware queue data. So, replace the blk_mq_sched_init_hctx_data() helper, which only makes sense at init time, with .init_hctx() and .exit_hctx() hooks. Signed-off-by:
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Jens Axboe authored
We've added a considerable amount of fixes for stalls and issues with the blk-mq scheduling in the 4.11 series since forking off the for-4.12/block branch. We need to do improvements on top of that for 4.12, so pull in the previous fixes to make our lives easier going forward. Signed-off-by: -
Bart Van Assche authored
To improve scalability, if hardware queues are shared, restart a single hardware queue in round-robin fashion. Rename blk_mq_sched_restart_queues() to reflect the new semantics. Remove blk_mq_sched_mark_restart_queue() because this function has no callers. Remove flag QUEUE_FLAG_RESTART because this patch removes the code that uses this flag. Signed-off-by:
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Bart Van Assche authored
While running the srp-test software I noticed that request processing stalls sporadically at the beginning of a test, namely when mkfs is run against a dm-mpath device. Every time when that happened the following command was sufficient to resume request processing: echo run >/sys/kernel/debug/block/dm-0/state This patch avoids that such request processing stalls occur. The test I ran is as follows: while srp-test/run_tests -d -r 30 -t 02-mq; do :; done Signed-off-by: -
Bart Van Assche authored
If a .queue_rq() function returns BLK_MQ_RQ_QUEUE_BUSY then the block driver that implements that function is responsible for rerunning the hardware queue once requests can be queued again successfully. commit 52d7f1b5 ("blk-mq: Avoid that requeueing starts stopped queues") removed the blk_mq_stop_hw_queue() call from scsi_queue_rq() for the BLK_MQ_RQ_QUEUE_BUSY case. Hence change all calls to functions that are intended to rerun a busy queue such that these examine all hardware queues instead of only stopped queues. Since no other functions than scsi_internal_device_block() and scsi_internal_device_unblock() should ever stop or restart a SCSI queue, change the blk_mq_delay_queue() call into a blk_mq_delay_run_hw_queue() call. Fixes: commit 52d7f1b5 ("blk-mq: Avoid that requeueing starts stopped queues") Fixes: commit 7e79dadc ("blk-mq: stop hardware queue in blk_mq_delay_queue()") Signed-off-by:
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Bart Van Assche authored
Introduce a function that runs a hardware queue unconditionally after a delay. Note: there is already a function that stops and restarts a hardware queue after a delay, namely blk_mq_delay_queue(). This function will be used in the next patch in this series. Signed-off-by:
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NeilBrown authored
Currently only dm and md/raid5 bios trigger trace_block_bio_complete(). Now that we have bio_chain() and bio_inc_remaining(), it is not possible, in general, for a driver to know when the bio is really complete. Only bio_endio() knows that. So move the trace_block_bio_complete() call to bio_endio(). Now trace_block_bio_complete() pairs with trace_block_bio_queue(). Any bio for which a 'queue' event is traced, will subsequently generate a 'complete' event. There are a few cases where completion tracing is not wanted. 1/ If blk_update_request() has already generated a completion trace event at the 'request' level, there is no point generating one at the bio level too. In this case the bi_sector and bi_size will have changed, so the bio level event would be wrong 2/ If the bio hasn't actually been queued yet, but is being aborted early, then a trace event could be confusing. Some filesystems call bio_endio() but do not want tracing. 3/ The bio_integrity code interposes itself by replacing bi_end_io, then restoring it and calling bio_endio() again. This would produce two identical trace events if left like that. To handle these, we introduce a flag BIO_TRACE_COMPLETION and only produce the trace event when this is set. We address point 1 above by clearing the flag in blk_update_request(). We address point 2 above by only setting the flag when generic_make_request() is called. We address point 3 above by clearing the flag after generating a completion event. When bio_split() is used on a bio, particularly in blk_queue_split(), there is an extra complication. A new bio is split off the front, and may be handle directly without going through generic_make_request(). The old bio, which has been advanced, is passed to generic_make_request(), so it will trigger a trace event a second time. Probably the best result when a split happens is to see a single 'queue' event for the whole bio, then multiple 'complete' events - one for each component. To achieve this was can: - copy the BIO_TRACE_COMPLETION flag to the new bio in bio_split() - avoid generating a 'queue' event if BIO_TRACE_COMPLETION is already set. This way, the split-off bio won't create a queue event, the original won't either even if it re-submitted to generic_make_request(), but both will produce completion events, each for their own range. So if generic_make_request() is called (which generates a QUEUED event), then bi_endio() will create a single COMPLETE event for each range that the bio is split into, unless the driver has explicitly requested it not to. Signed-off-by:
NeilBrown <neilb@suse.com> Signed-off-by:
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NeilBrown authored
The comment for the 'flags' field of 'bio' mentions "command" which is no longer stored there, and doesn't mention the bvec pool number, which is. BIO_RESET_BITS is set in such a way that it would need to be updated if new bits were added, which is easy to miss. BVEC_POOL_BITS is larger than needed. The BVEC_POOL_IDX() ranges from 0 to 6, so 3 bits are sufficient. This patch make improvements in each of these areas. Signed-off-by:
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Omar Sandoval authored
blk_mq_update_nr_hw_queues() used to remap hardware queues, which is the behavior that drivers expect. However, commit 4e68a011 changed blk_mq_queue_reinit() to not remap queues for the case of CPU hotplugging, inadvertently making blk_mq_update_nr_hw_queues() not remap queues as well. This breaks, for example, NBD's multi-connection mode, leaving the added hardware queues unused. Fix it by making blk_mq_update_nr_hw_queues() explicitly remap the queues. Fixes: 4e68a011 ("blk-mq: don't redistribute hardware queues on a CPU hotplug event") Reviewed-by:
Keith Busch <keith.busch@intel.com> Reviewed-by:
Christoph Hellwig <hch@lst.de> Reviewed-by:
Sagi Grimberg <sagi@grimberg.me> Signed-off-by:
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Omar Sandoval authored
In elevator_switch(), if blk_mq_init_sched() fails, we attempt to fall back to the original scheduler. However, at this point, we've already torn down the original scheduler's tags, so this causes a crash. Doing the fallback like the legacy elevator path is much harder for mq, so fix it by just falling back to none, instead. Signed-off-by:
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Omar Sandoval authored
If a new hardware queue is added at runtime, we don't allocate scheduler tags for it, leading to a crash. This hooks up the scheduler framework to blk_mq_{init,exit}_hctx() to make sure everything gets properly initialized/freed. Signed-off-by: -
Omar Sandoval authored
Preparation cleanup for the next couple of fixes, push blk_mq_sched_setup() and e->ops.mq.init_sched() into a helper. Signed-off-by:
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Omar Sandoval authored
While dispatching requests, if we fail to get a driver tag, we mark the hardware queue as waiting for a tag and put the requests on a hctx->dispatch list to be run later when a driver tag is freed. However, blk_mq_dispatch_rq_list() may dispatch requests from multiple hardware queues if using a single-queue scheduler with a multiqueue device. If blk_mq_get_driver_tag() fails, it doesn't update the hardware queue we are processing. This means we end up using the hardware queue of the previous request, which may or may not be the same as that of the current request. If it isn't, the wrong hardware queue will end up waiting for a tag, and the requests will be on the wrong dispatch list, leading to a hang. The fix is twofold: 1. Make sure we save which hardware queue we were trying to get a request for in blk_mq_get_driver_tag() regardless of whether it succeeds or not. 2. Make blk_mq_dispatch_rq_list() take a request_queue instead of a blk_mq_hw_queue to make it clear that it must handle multiple hardware queues, since I've already messed this up on a couple of occasions. This didn't appear in testing with nvme and mq-deadline because nvme has more driver tags than the default number of scheduler tags. However, with the blk_mq_update_nr_hw_queues() fix, it showed up with nbd. Signed-off-by:
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- 05 Apr, 2017 9 commits
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Jens Axboe authored
After commit 64c7f1d1, we went from 1 to 2 holes in my test setup. If we move the timeout field a bit, we remove both of those holes and shrink struct request by 8 bytes. Reviewed-by:
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Christoph Hellwig authored
Instead of bloating the generic struct request with it. Signed-off-by:
Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by:
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Christoph Hellwig authored
The way NVMe uses this field is entirely different from the older SCSI/BLOCK_PC usage, so move it into struct nvme_request. Also reduce the size of the file to a unsigned char so that we leave space for additional smaller fields that will appear soon. Signed-off-by:
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Christoph Hellwig authored
Signed-off-by:
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Christoph Hellwig authored
Don't pass the status explicitly but derive it from the requeust, and unwind the complex condition to be more readable. Signed-off-by:
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Christoph Hellwig authored
->retries is counting the number of times a command is resubmitted, and be cleared on the first time we see the command. We currently don't do that for non-PCIe command, which is easily fixed by moving the setup to common code. Signed-off-by:
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Christoph Hellwig authored
This driver is for pre-IDE hardisk that are only found in PC from the stoneage of personal computing, and which we don't support elsewhere in the kernel these days. It's also been marked broken forever. Signed-off-by:
Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by:
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Bart Van Assche authored
The block layer core sets blk_mq_queue_data.list but no block drivers read that member. Hence remove it and also the code that is used to set this member. Signed-off-by:
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Jan Kara authored
Writeback throttling does not play well with CFQ since that also tries to throttle async writes. As a result async writeback can get starved in presence of readers. As an example take a benchmark simulating postgreSQL database running over a standard rotating SATA drive. There are 16 processes doing random reads from a huge file (2*machine memory), 1 process doing random writes to the huge file and calling fsync once per 50000 writes and 1 process doing sequential 8k writes to a relatively small file wrapping around at the end of the file and calling fsync every 5 writes. Under this load read latency easily exceeds the target latency of 75 ms (just because there are so many reads happening against a relatively slow disk) and thus writeback is throttled to a point where only 1 write request is allowed at a time. Blktrace data then looks like: 8,0 1 0 8.347751764 0 m N cfq workload slice:40000000 8,0 1 0 8.347755256 0 m N cfq293A / set_active wl_class: 0 wl_type:0 8,0 1 0 8.347784100 0 m N cfq293A / Not idling. st->count:1 8,0 1 3814 8.347763916 5839 UT N [kworker/u9:2] 1 8,0 0 0 8.347777605 0 m N cfq293A / Not idling. st->count:1 8,0 1 0 8.347784100 0 m N cfq293A / Not idling. st->count:1 8,0 3 1596 8.354364057 0 C R 156109528 + 8 (6906954) [0] 8,0 3 0 8.354383193 0 m N cfq6196SN / complete rqnoidle 0 8,0 3 0 8.354386476 0 m N cfq schedule dispatch 8,0 3 0 8.354399397 0 m N cfq293A / Not idling. st->count:1 8,0 3 0 8.354404705 0 m N cfq293A / dispatch_insert 8,0 3 0 8.354409454 0 m N cfq293A / dispatched a request 8,0 3 0 8.354412527 0 m N cfq293A / activate rq, drv=1 8,0 3 1597 8.354414692 0 D W 145961400 + 24 (6718452) [swapper/0] 8,0 3 0 8.354484184 0 m N cfq293A / Not idling. st->count:1 8,0 3 0 8.354487536 0 m N cfq293A / slice expired t=0 8,0 3 0 8.354498013 0 m N / served: vt=5888102466265088 min_vt=5888074869387264 8,0 3 0 8.354502692 0 m N cfq293A / sl_used=6737519 disp=1 charge=6737519 iops=0 sect=24 8,0 3 0 8.354505695 0 m N cfq293A / del_from_rr ... 8,0 0 1810 8.354728768 0 C W 145961400 + 24 (314076) [0] 8,0 0 0 8.354746927 0 m N cfq293A / complete rqnoidle 0 ... 8,0 1 3829 8.389886102 5839 G W 145962968 + 24 [kworker/u9:2] 8,0 1 3830 8.389888127 5839 P N [kworker/u9:2] 8,0 1 3831 8.389908102 5839 A W 145978336 + 24 <- (8,4) 44000 8,0 1 3832 8.389910477 5839 Q W 145978336 + 24 [kworker/u9:2] 8,0 1 3833 8.389914248 5839 I W 145962968 + 24 (28146) [kworker/u9:2] 8,0 1 0 8.389919137 0 m N cfq293A / insert_request 8,0 1 0 8.389924305 0 m N cfq293A / add_to_rr 8,0 1 3834 8.389933175 5839 UT N [kworker/u9:2] 1 ... 8,0 0 0 9.455290997 0 m N cfq workload slice:40000000 8,0 0 0 9.455294769 0 m N cfq293A / set_active wl_class:0 wl_type:0 8,0 0 0 9.455303499 0 m N cfq293A / fifo=ffff880003166090 8,0 0 0 9.455306851 0 m N cfq293A / dispatch_insert 8,0 0 0 9.455311251 0 m N cfq293A / dispatched a request 8,0 0 0 9.455314324 0 m N cfq293A / activate rq, drv=1 8,0 0 2043 9.455316210 6204 D W 145962968 + 24 (1065401962) [pgioperf] 8,0 0 0 9.455392407 0 m N cfq293A / Not idling. st->count:1 8,0 0 0 9.455395969 0 m N cfq293A / slice expired t=0 8,0 0 0 9.455404210 0 m N / served: vt=5888958194597888 min_vt=5888941810597888 8,0 0 0 9.455410077 0 m N cfq293A / sl_used=4000000 disp=1 charge=4000000 iops=0 sect=24 8,0 0 0 9.455416851 0 m N cfq293A / del_from_rr ... 8,0 0 2045 9.455648515 0 C W 145962968 + 24 (332305) [0] 8,0 0 0 9.455668350 0 m N cfq293A / complete rqnoidle 0 ... 8,0 1 4371 9.455710115 5839 G W 145978336 + 24 [kworker/u9:2] 8,0 1 4372 9.455712350 5839 P N [kworker/u9:2] 8,0 1 4373 9.455730159 5839 A W 145986616 + 24 <- (8,4) 52280 8,0 1 4374 9.455732674 5839 Q W 145986616 + 24 [kworker/u9:2] 8,0 1 4375 9.455737563 5839 I W 145978336 + 24 (27448) [kworker/u9:2] 8,0 1 0 9.455742871 0 m N cfq293A / insert_request 8,0 1 0 9.455747550 0 m N cfq293A / add_to_rr 8,0 1 4376 9.455756629 5839 UT N [kworker/u9:2] 1 So we can see a Q event for a write request, then IO is blocked by writeback throttling and G and I events for the request happen only once other writeback IO is completed. Thus CFQ always sees only one write request. When it sees it, it queues the async queue behind all the read queues and the async queue gets scheduled after about one second. When it is scheduled, that one request gets dispatched and async queue is expired as it has no more requests to submit. Overall we submit about one write request per second. Although this scheduling is beneficial for read latency, writes are heavily starved and this causes large delays all over the system (due to processes blocking on page lock, transaction starts, etc.). When writeback throttling is disabled, write throughput is about one fifth of a read throughput which roughly matches readers/writers ratio and overall the system stalls are much shorter. Mixing writeback throttling logic with CFQ throttling logic is always a recipe for surprises as CFQ assumes it sees the big part of the picture which is not necessarily true when writeback throttling is blocking requests. So disable writeback throttling logic by default when CFQ is used as an IO scheduler. Signed-off-by:
Jan Kara <jack@suse.cz> Signed-off-by:
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- 04 Apr, 2017 15 commits
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Adam Manzanares authored
In 4.10 I introduced a patch that associates the ioc priority with each request in the block layer. This work was done in the single queue block layer code. This patch unifies ioc priority to request mapping across the single/multi queue block layers. I have tested this patch with the null block device driver with the following parameters. null_blk queue_mode=2 irqmode=0 use_per_node_hctx=1 nr_devices=1 I have not seen a performance regression with this patch and I would appreciate any feedback or additional testing. I have also verified that io priorities are passed to the device when using the SQ and MQ path to a SATA HDD that supports io priorities. Reviewed-by:
Adam Manzanares <adam.manzanares@wdc.com> Reviewed-by:
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Christoph Hellwig authored
This avoids duplicating the logic four times, and it also allows to keep some helpers static in core.c or just opencode them. Note that this loses printing the aborted status on completions in the PCI driver as that uses a data structure not available any more. Signed-off-by:
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Christoph Hellwig authored
A requeue means we go through nvme_fc_start_fcp_op again and get another controller reference. To make sure the refcount doesn't leak we also need to drop it for every completion that came from the LLDD. Signed-off-by:
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Sagi Grimberg authored
This way our max retry limit holds as well. Signed-off-by:
Max Gurtovoy <maxg@mellanox.com> Reviewed-by:
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Sagi Grimberg authored
This way our max retry limit holds as well. Signed-off-by:
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Sagi Grimberg authored
This way our max retry limit holds as well. Signed-off-by:
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James Smart authored
As Dan Carpenter pointed out: mixing 16-bit nvme status with 32-bit error status from driver. Corrected comment on fcp request struct status field, and converted done routine to explicitly set nvme status codes for nvme status. Signed-off-by:
James Smart <james.smart@broadcom.com> Reported-by:
Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by:
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James Smart authored
Clear SG list to avoid double frees of payload page list Signed-off-by:
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James Smart authored
LS validations shouldn't have been independent checks. Signed-off-by:
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James Smart authored
nvmet_fc: Sync NVME LS reject reasons with spec Signed-off-by:
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James Smart authored
Add check of status_code in ERSP_IU Signed-off-by:
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James Smart authored
Update FC-NVME definitions to match FC-NVME r1.14 (16-020vB) plus change voted in by 2/22 FC-NVME Adhoc (see HOSTID below). Includes the following: - Addition of "status_code" field to ERSP IU - Addition of FC-NVME LS RJT reason_codes and reason_explanations - CreateAssociation payload, HostID field shortened to 16 bytes Signed-off-by:
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Sagi Grimberg authored
Before scheduling a reconnect attempt, check nr_reconnects against max_reconnects, if not exhausted (or max_reconnects is not -1), schedule a reconnect attempts, otherwise schedule ctrl removal. Reviewed-by:
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Sagi Grimberg authored
When a host sense that its controller session is damaged, it tries to re-establish it periodically (reconnect every reconnect_delay). It may very well be that the controller is gone and never coming back, in this case the host will try to reconnect forever. Add a ctrl_loss_tmo to bound the number of reconnect attempts to a specific controller (default to a reasonable 10 minutes). The timeout configuration is actually translated into number of reconnect attempts and not a schedule on its own but rather divided with reconnect_delay. This is useful to prevent racing flows of remove and reconnect, and it doesn't really matter if we remove slightly sooner than what the user requested. Reviewed-by:
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Sagi Grimberg authored
we already have it in opts. Reviewed-by:
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