linux-stable.git/include/linux/blk-mq.h, branch v4.20.2

blk-mq: provide helper for setting up an SQ queue and tag set

2018-10-16T02:05:18+00:00

This pattern is repeated throughout all the blk-mq conversions.
Provide a basic helper to get it done.

Reviewed-by: Ming Lei 
Signed-off-by: Jens Axboe

Merge tag 'for-4.19/block-20180812' of git://git.kernel.dk/linux-block

2018-08-14T17:23:25+00:00

Pull block updates from Jens Axboe:
 "First pull request for this merge window, there will also be a
  followup request with some stragglers.

  This pull request contains:

   - Fix for a thundering heard issue in the wbt block code (Anchal
     Agarwal)

   - A few NVMe pull requests:
      * Improved tracepoints (Keith)
      * Larger inline data support for RDMA (Steve Wise)
      * RDMA setup/teardown fixes (Sagi)
      * Effects log suppor for NVMe target (Chaitanya Kulkarni)
      * Buffered IO suppor for NVMe target (Chaitanya Kulkarni)
      * TP4004 (ANA) support (Christoph)
      * Various NVMe fixes

   - Block io-latency controller support. Much needed support for
     properly containing block devices. (Josef)

   - Series improving how we handle sense information on the stack
     (Kees)

   - Lightnvm fixes and updates/improvements (Mathias/Javier et al)

   - Zoned device support for null_blk (Matias)

   - AIX partition fixes (Mauricio Faria de Oliveira)

   - DIF checksum code made generic (Max Gurtovoy)

   - Add support for discard in iostats (Michael Callahan / Tejun)

   - Set of updates for BFQ (Paolo)

   - Removal of async write support for bsg (Christoph)

   - Bio page dirtying and clone fixups (Christoph)

   - Set of bcache fix/changes (via Coly)

   - Series improving blk-mq queue setup/teardown speed (Ming)

   - Series improving merging performance on blk-mq (Ming)

   - Lots of other fixes and cleanups from a slew of folks"

* tag 'for-4.19/block-20180812' of git://git.kernel.dk/linux-block: (190 commits)
  blkcg: Make blkg_root_lookup() work for queues in bypass mode
  bcache: fix error setting writeback_rate through sysfs interface
  null_blk: add lock drop/acquire annotation
  Blk-throttle: reduce tail io latency when iops limit is enforced
  block: paride: pd: mark expected switch fall-throughs
  block: Ensure that a request queue is dissociated from the cgroup controller
  block: Introduce blk_exit_queue()
  blkcg: Introduce blkg_root_lookup()
  block: Remove two superfluous #include directives
  blk-mq: count the hctx as active before allocating tag
  block: bvec_nr_vecs() returns value for wrong slab
  bcache: trivial - remove tailing backslash in macro BTREE_FLAG
  bcache: make the pr_err statement used for ENOENT only in sysfs_attatch section
  bcache: set max writeback rate when I/O request is idle
  bcache: add code comments for bset.c
  bcache: fix mistaken comments in request.c
  bcache: fix mistaken code comments in bcache.h
  bcache: add a comment in super.c
  bcache: avoid unncessary cache prefetch bch_btree_node_get()
  bcache: display rate debug parameters to 0 when writeback is not running
  ...

blk-mq: export setting request completion state

2018-07-24T20:41:50+00:00

This is preparing for drivers that want to directly alter the state of
their requests. No functional change here.

Reviewed-by: Christoph Hellwig 
Signed-off-by: Keith Busch 
Signed-off-by: Jens Axboe

blk-mq: dequeue request one by one from sw queue if hctx is busy

2018-07-09T15:07:53+00:00

It won't be efficient to dequeue request one by one from sw queue,
but we have to do that when queue is busy for better merge performance.

This patch takes the Exponential Weighted Moving Average(EWMA) to figure
out if queue is busy, then only dequeue request one by one from sw queue
when queue is busy.

Fixes: b347689ffbca ("blk-mq-sched: improve dispatching from sw queue")
Cc: Kashyap Desai 
Cc: Laurence Oberman 
Cc: Omar Sandoval 
Cc: Christoph Hellwig 
Cc: Bart Van Assche 
Cc: Hannes Reinecke 
Reported-by: Kashyap Desai 
Tested-by: Kashyap Desai 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

blk-mq: introduce new lock for protecting hctx->dispatch_wait

2018-07-09T15:07:52+00:00

Now hctx->lock is only acquired when adding hctx->dispatch_wait to
one wait queue, but not held when removing it from the wait queue.

IO hang can be observed easily if SCHED RESTART is disabled, that means
now RESTART exits just for fixing the issue in blk_mq_mark_tag_wait().

This patch fixes the issue by introducing hctx->dispatch_wait_lock and
holding it for removing hctx->dispatch_wait in blk_mq_dispatch_wake(),
since we need to avoid acquiring hctx->lock in irq context.

Fixes: eb619fdb2d4cb8b3d3419 ("blk-mq: fix issue with shared tag queue re-running")
Cc: Christoph Hellwig 
Cc: Omar Sandoval 
Cc: Bart Van Assche 
Tested-by: Andrew Jones 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

blk-mq: remove blk_mq_tagset_iter

2018-06-14T15:01:45+00:00

Unused now that nvme stopped using it.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Jens Axboe

blk-mq: abstract out blk-mq-sched rq list iteration bio merge helper

2018-05-30T16:43:58+00:00

No functional changes in this patch, just a prep patch for utilizing
this in an IO scheduler.

Signed-off-by: Jens Axboe 
Reviewed-by: Omar Sandoval

block: mq: Add some minor doc for core structs

2018-04-25T13:58:18+00:00

As it came up in discussion on the mailing list that the semantic
meaning of 'blk_mq_ctx' and 'blk_mq_hw_ctx' isn't completely
obvious to everyone, let's add some minimal kerneldoc for a
starter.

Signed-off-by: Linus Walleij 
Signed-off-by: Jens Axboe

blk-mq: remove blk_mq_delay_queue()

2018-04-10T14:38:46+00:00

No driver uses this interface any more, so remove it.

Cc: Stefan Haberland 
Tested-by: Christian Borntraeger 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Sagi Grimberg 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

blk-mq: rename blk_mq_hw_ctx->queue_rq_srcu to ->srcu

2018-01-09T16:31:15+00:00

The RCU protection has been expanded to cover both queueing and
completion paths making ->queue_rq_srcu a misnomer.  Rename it to
->srcu as suggested by Bart.

Signed-off-by: Tejun Heo 
Cc: Bart Van Assche 
Signed-off-by: Jens Axboe