Commit Graph

28 Commits

Author SHA1 Message Date
Christoph Hellwig 49f5baa510 blk-mq: pair blk_mq_start_request / blk_mq_requeue_request
Make sure we have a proper pairing between starting and requeueing
requests.  Move the dma drain and REQ_END setup into blk_mq_start_request,
and make sure blk_mq_requeue_request properly undoes them, giving us
a pair of function to prepare and unprepare a request without leaving
side effects.

Together this ensures we always clean up properly after
BLK_MQ_RQ_QUEUE_BUSY returns from ->queue_rq.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-11 09:34:08 -07:00
Christoph Hellwig 1e93b8c274 blk-mq: dont assume rq->errors is set when returning an error from ->queue_rq
rq->errors never has been part of the communication protocol between drivers
and the block stack and most drivers will not have initialized it.

Return -EIO to upper layers when the driver returns BLK_MQ_RQ_QUEUE_ERROR
unconditionally.  If a driver want to return a different error it can easily
do so by returning success after calling blk_mq_end_io itself.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-11 09:34:07 -07:00
Christoph Hellwig 18741986a4 blk-mq: rework flush sequencing logic
Witch to using a preallocated flush_rq for blk-mq similar to what's done
with the old request path.  This allows us to set up the request properly
with a tag from the actually allowed range and ->rq_disk as needed by
some drivers.  To make life easier we also switch to dynamic allocation
of ->flush_rq for the old path.

This effectively reverts most of

    "blk-mq: fix for flush deadlock"

and

    "blk-mq: Don't reserve a tag for flush request"

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-10 09:29:00 -07:00
Christoph Hellwig 30a91cb4ef blk-mq: rework I/O completions
Rework I/O completions to work more like the old code path.  blk_mq_end_io
now stays out of the business of deferring completions to others CPUs
and calling blk_mark_rq_complete.  The latter is very important to allow
completing requests that have timed out and thus are already marked completed,
the former allows using the IPI callout even for driver specific completions
instead of having to reimplement them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-10 09:27:31 -07:00
Nicholas Bellinger 14ec77f352 blk-mq: Add bio_integrity setup to blk_mq_make_request
This patch adds the missing bio_integrity_enabled() +
bio_integrity_prep() setup into blk_mq_make_request()
in order to use DIF protection with scsi-mq.

Cc: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-07 13:45:39 -07:00
Christoph Hellwig 1be036e946 blk-mq: initialize sg_reserved_size
To behave the same way as the old request path.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-07 11:58:54 -07:00
Christoph Hellwig 4f7f418c48 blk-mq: handle dma_drain_size
Make blk-mq handle the dma_drain_size field the same way as the old request
path.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-07 11:58:54 -07:00
Christoph Hellwig 72a0a36e28 blk-mq: support at_head inserations for blk_execute_rq
This is neede for proper SG_IO operation as well as various uses of
blk_execute_rq from the SCSI midlayer.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-07 11:58:54 -07:00
Shaohua Li f0276924fa blk-mq: Don't reserve a tag for flush request
Reserving a tag (request) for flush to avoid dead lock is a overkill. A
tag is valuable resource. We can track the number of flush requests and
disallow having too many pending flush requests allocated. With this
patch, blk_mq_alloc_request_pinned() could do a busy nop (but not a dead
loop) if too many pending requests are allocated and new flush request
is allocated. But this should not be a problem, too many pending flush
requests are very rare case.

I verified this can fix the deadlock caused by too many pending flush
requests.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2014-01-30 12:57:25 -07:00
Dave Hansen 6753471c0c blk-mq: uses page->list incorrectly
'struct page' has two list_head fields: 'lru' and 'list'.  Conveniently,
they are unioned together.  This means that code can use them
interchangably, which gets horribly confusing.

The blk-mq made the logical decision to try to use page->list.  But, that
field was actually introduced just for the slub code.  ->lru is the right
field to use outside of slab/slub.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2014-01-08 20:17:46 -07:00
Christoph Hellwig 3d6efbf62c blk-mq: use __smp_call_function_single directly
__smp_call_function_single already avoids multiple IPIs by internally
queing up the items, and now also is available for non-SMP builds as
a trivially correct stub, so there is no need to wrap it.  If the
additional lock roundtrip cause problems my patch to convert the
generic IPI code to llists is waiting to get merged will fix it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2014-01-08 14:31:27 -07:00
Ming Lei 0fec08b4ec blk-mq: fix initializing request's start time
blk_rq_init() is called in req's complete handler to initialize
the request, so the members of start_time and start_time_ns might
become inaccurate when it is allocated in future.

The patch initializes the two members in blk_mq_rq_ctx_init() to
fix the problem.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2014-01-03 10:00:08 -07:00
Ming Lei 3edcc0ce85 block: blk-mq: don't export blk_mq_free_queue()
blk_mq_free_queue() is called from release handler of
queue kobject, so it needn't be called from drivers.

Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-12-31 09:53:05 -07:00
Ming Lei f04c1fe761 block: blk-mq: make blk_sync_queue support mq
This patch moves synchronization on mq->delay_work
from blk_mq_free_queue() to blk_sync_queue(), so that
blk_sync_queue can work on mq.

Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-12-31 09:53:05 -07:00
Ming Lei 43a5e4e219 block: blk-mq: support draining mq queue
blk_mq_drain_queue() is introduced so that we can drain
mq queue inside blk_cleanup_queue().

Also don't accept new requests any more if queue is marked
as dying.

Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-12-31 09:53:05 -07:00
Jens Axboe b28bc9b38c Linux 3.13-rc6
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Merge tag 'v3.13-rc6' into for-3.14/core

Needed to bring blk-mq uptodate, since changes have been going in
since for-3.14/core was established.

Fixup merge issues related to the immutable biovec changes.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

Conflicts:
	block/blk-flush.c
	fs/btrfs/check-integrity.c
	fs/btrfs/extent_io.c
	fs/btrfs/scrub.c
	fs/logfs/dev_bdev.c
2013-12-31 09:51:02 -07:00
Ming Lei 0d11e6aca3 blk-mq: fix use-after-free of request
If accounting is on, we will do the IO completion accounting after
we have freed the request. Fix that by moving it sooner instead.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-12-05 10:50:39 -07:00
Jeff Moyer 959a35f13e blk-mq: fix dereference of rq->mq_ctx if allocation fails
If __GFP_WAIT isn't set and we fail allocating, when we go
to drop the reference on the ctx, we will attempt to dereference
the NULL rq. Fix that.

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-12-03 14:24:28 -07:00
Kent Overstreet 4f024f3797 block: Abstract out bvec iterator
Immutable biovecs are going to require an explicit iterator. To
implement immutable bvecs, a later patch is going to add a bi_bvec_done
member to this struct; for now, this patch effectively just renames
things.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Yehuda Sadeh <yehuda@inktank.com>
Cc: Sage Weil <sage@inktank.com>
Cc: Alex Elder <elder@inktank.com>
Cc: ceph-devel@vger.kernel.org
Cc: Joshua Morris <josh.h.morris@us.ibm.com>
Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: Boaz Harrosh <bharrosh@panasas.com>
Cc: Benny Halevy <bhalevy@tonian.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: Joern Engel <joern@logfs.org>
Cc: Prasad Joshi <prasadjoshi.linux@gmail.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Ben Myers <bpm@sgi.com>
Cc: xfs@oss.sgi.com
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Guo Chao <yan@linux.vnet.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Asai Thambi S P <asamymuthupa@micron.com>
Cc: Selvan Mani <smani@micron.com>
Cc: Sam Bradshaw <sbradshaw@micron.com>
Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jerome Marchand <jmarchand@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Peng Tao <tao.peng@emc.com>
Cc: Andy Adamson <andros@netapp.com>
Cc: fanchaoting <fanchaoting@cn.fujitsu.com>
Cc: Jie Liu <jeff.liu@oracle.com>
Cc: Sunil Mushran <sunil.mushran@gmail.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Namjae Jeon <namjae.jeon@samsung.com>
Cc: Pankaj Kumar <pankaj.km@samsung.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Mel Gorman <mgorman@suse.de>6
2013-11-23 22:33:47 -08:00
Jens Axboe 01b983c9fc blk-mq: add blktrace insert event trace
We need it to make 'btt' from blktrace happy, otherwise
we are missing one state transition.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-11-19 19:00:45 -07:00
Jens Axboe 94eddfbeaa blk-mq: ensure that we set REQ_IO_STAT so diskstats work
If disk stats are enabled on the queue, a request needs to
be marked with REQ_IO_STAT for accounting to be active on
that request. This fixes an issue with virtio-blk not
showing up in /proc/diskstats after the conversion to
blk-mq.

Add QUEUE_FLAG_MQ_DEFAULT, setting stats and same cpu-group
completion on by default.

Reported-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-11-19 09:25:07 -07:00
Linus Torvalds f412f2c60b Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull second round of block driver updates from Jens Axboe:
 "As mentioned in the original pull request, the bcache bits were pulled
  because of their dependency on the immutable bio vecs.  Kent re-did
  this part and resubmitted it, so here's the 2nd round of (mostly)
  driver updates for 3.13.  It contains:

 - The bcache work from Kent.

 - Conversion of virtio-blk to blk-mq.  This removes the bio and request
   path, and substitutes with the blk-mq path instead.  The end result
   almost 200 deleted lines.  Patch is acked by Asias and Christoph, who
   both did a bunch of testing.

 - A removal of bootmem.h include from Grygorii Strashko, part of a
   larger series of his killing the dependency on that header file.

 - Removal of __cpuinit from blk-mq from Paul Gortmaker"

* 'for-linus' of git://git.kernel.dk/linux-block: (56 commits)
  virtio_blk: blk-mq support
  blk-mq: remove newly added instances of __cpuinit
  bcache: defensively handle format strings
  bcache: Bypass torture test
  bcache: Delete some slower inline asm
  bcache: Use ida for bcache block dev minor
  bcache: Fix sysfs splat on shutdown with flash only devs
  bcache: Better full stripe scanning
  bcache: Have btree_split() insert into parent directly
  bcache: Move spinlock into struct time_stats
  bcache: Kill sequential_merge option
  bcache: Kill bch_next_recurse_key()
  bcache: Avoid deadlocking in garbage collection
  bcache: Incremental gc
  bcache: Add make_btree_freeing_key()
  bcache: Add btree_node_write_sync()
  bcache: PRECEDING_KEY()
  bcache: bch_(btree|extent)_ptr_invalid()
  bcache: Don't bother with bucket refcount for btree node allocations
  bcache: Debug code improvements
  ...
2013-11-15 16:33:41 -08:00
Christoph Hellwig 0a06ff068f kernel: remove CONFIG_USE_GENERIC_SMP_HELPERS
We've switched over every architecture that supports SMP to it, so
remove the new useless config variable.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-15 09:32:22 +09:00
Paul Gortmaker f618ef7c47 blk-mq: remove newly added instances of __cpuinit
The new blk-mq code added new instances of __cpuinit usage.
We removed this a couple versions ago; we now want to remove
the compat no-op stubs.  Introducing new users is not what
we want to see at this point in time, as it will break once
the stubs are gone.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-11-14 08:26:02 -07:00
Shaohua Li 92f399c72a blk-mq: mq plug list breakage
We switched to plug mq_list for mq, but some code are still using old list.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-10-29 12:01:03 -06:00
Christoph Hellwig 3228f48be2 blk-mq: fix for flush deadlock
The flush state machine takes in a struct request, which then is
submitted multiple times to the underling driver.  The old block code
requeses the same request for each of those, so it does not have an
issue with tapping into the request pool.  The new one on the other hand
allocates a new request for each of the actualy steps of the flush
sequence. If have already allocated all of the tags for IO, we will
fail allocating the flush request.

Set aside a reserved request just for flushes.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-10-28 13:33:58 -06:00
Christoph Hellwig 280d45f6c3 blk-mq: add blk_mq_stop_hw_queues
Add a helper to iterate over all hw queues and stop them.  This is useful
for driver that implement PM suspend functionality.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Modified to just call blk_mq_stop_hw_queue() by Jens.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-10-25 14:45:58 +01:00
Jens Axboe 320ae51fee blk-mq: new multi-queue block IO queueing mechanism
Linux currently has two models for block devices:

- The classic request_fn based approach, where drivers use struct
  request units for IO. The block layer provides various helper
  functionalities to let drivers share code, things like tag
  management, timeout handling, queueing, etc.

- The "stacked" approach, where a driver squeezes in between the
  block layer and IO submitter. Since this bypasses the IO stack,
  driver generally have to manage everything themselves.

With drivers being written for new high IOPS devices, the classic
request_fn based driver doesn't work well enough. The design dates
back to when both SMP and high IOPS was rare. It has problems with
scaling to bigger machines, and runs into scaling issues even on
smaller machines when you have IOPS in the hundreds of thousands
per device.

The stacked approach is then most often selected as the model
for the driver. But this means that everybody has to re-invent
everything, and along with that we get all the problems again
that the shared approach solved.

This commit introduces blk-mq, block multi queue support. The
design is centered around per-cpu queues for queueing IO, which
then funnel down into x number of hardware submission queues.
We might have a 1:1 mapping between the two, or it might be
an N:M mapping. That all depends on what the hardware supports.

blk-mq provides various helper functions, which include:

- Scalable support for request tagging. Most devices need to
  be able to uniquely identify a request both in the driver and
  to the hardware. The tagging uses per-cpu caches for freed
  tags, to enable cache hot reuse.

- Timeout handling without tracking request on a per-device
  basis. Basically the driver should be able to get a notification,
  if a request happens to fail.

- Optional support for non 1:1 mappings between issue and
  submission queues. blk-mq can redirect IO completions to the
  desired location.

- Support for per-request payloads. Drivers almost always need
  to associate a request structure with some driver private
  command structure. Drivers can tell blk-mq this at init time,
  and then any request handed to the driver will have the
  required size of memory associated with it.

- Support for merging of IO, and plugging. The stacked model
  gets neither of these. Even for high IOPS devices, merging
  sequential IO reduces per-command overhead and thus
  increases bandwidth.

For now, this is provided as a potential 3rd queueing model, with
the hope being that, as it matures, it can replace both the classic
and stacked model. That would get us back to having just 1 real
model for block devices, leaving the stacked approach to dm/md
devices (as it was originally intended).

Contributions in this patch from the following people:

Shaohua Li <shli@fusionio.com>
Alexander Gordeev <agordeev@redhat.com>
Christoph Hellwig <hch@infradead.org>
Mike Christie <michaelc@cs.wisc.edu>
Matias Bjorling <m@bjorling.me>
Jeff Moyer <jmoyer@redhat.com>

Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-10-25 11:56:00 +01:00