Commit Graph

2902 Commits

Author SHA1 Message Date
Bart Van Assche
5d1b25c1ec blk-mq: Introduce blk_mq_hctx_stopped()
Multiple functions test the BLK_MQ_S_STOPPED bit so introduce
a helper function that performs this test.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-11-02 12:50:19 -06:00
Bart Van Assche
bc27c01b5c blk-mq: Do not invoke .queue_rq() for a stopped queue
The meaning of the BLK_MQ_S_STOPPED flag is "do not call
.queue_rq()". Hence modify blk_mq_make_request() such that requests
are queued instead of issued if a queue has been stopped.

Reported-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-11-02 12:50:19 -06:00
Kent Overstreet
2cefe4dbaa block: add bio_iov_iter_get_pages()
This is a helper that pins down a range from an iov_iter and adds it to
a bio without requiring a separate memory allocation for the page array.
It will be used for upcoming direct I/O implementations for block devices
and iomap based file systems.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
[hch: ported to the iov_iter interface, renamed and added comments.
      All blame should be directed to me and all fame should go to Kent
      after this!]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-11-02 10:50:18 -06:00
Christoph Hellwig
70fd76140a block,fs: use REQ_* flags directly
Remove the WRITE_* and READ_SYNC wrappers, and just use the flags
directly.  Where applicable this also drops usage of the
bio_set_op_attrs wrapper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-11-01 09:43:26 -06:00
Christoph Hellwig
a2b809672e block: replace REQ_NOIDLE with REQ_IDLE
Noidle should be the default for writes as seen by all the compounds
definitions in fs.h using it.  In fact only direct I/O really should
be using NODILE, so turn the whole flag around to get the defaults
right, which will make our life much easier especially onces the
WRITE_* defines go away.

This assumes all the existing "raw" users of REQ_SYNC for writes
want noidle behavior, which seems to be spot on from a quick audit.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-11-01 09:43:26 -06:00
Christoph Hellwig
aa39ebd404 cfq-iosched: use op_is_sync instead of opencoding it
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-11-01 09:43:26 -06:00
Christoph Hellwig
ef295ecf09 block: better op and flags encoding
Now that we don't need the common flags to overflow outside the range
of a 32-bit type we can encode them the same way for both the bio and
request fields.  This in addition allows us to place the operation
first (and make some room for more ops while we're at it) and to
stop having to shift around the operation values.

In addition this allows passing around only one value in the block layer
instead of two (and eventuall also in the file systems, but we can do
that later) and thus clean up a lot of code.

Last but not least this allows decreasing the size of the cmd_flags
field in struct request to 32-bits.  Various functions passing this
value could also be updated, but I'd like to avoid the churn for now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-28 08:48:16 -06:00
Christoph Hellwig
e806402130 block: split out request-only flags into a new namespace
A lot of the REQ_* flags are only used on struct requests, and only of
use to the block layer and a few drivers that dig into struct request
internals.

This patch adds a new req_flags_t rq_flags field to struct request for
them, and thus dramatically shrinks the number of common requests.  It
also removes the unfortunate situation where we have to fit the fields
from the same enum into 32 bits for struct bio and 64 bits for
struct request.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-28 08:45:17 -06:00
Christoph Hellwig
8d2bbd4c82 block: replace REQ_THROTTLED with a bio flag
It's the last bio-only REQ_* flag, and we have space for it in the bio
bi_flags field.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-28 08:45:17 -06:00
Christoph Hellwig
c4aebd0332 block: remove bio_is_rw
With the addition of the zoned operations the tests in this function
became incorrect.  But I think it's much better to just open code the
allow operations in the only caller anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-28 08:45:17 -06:00
Jens Axboe
2552e3f878 blk-mq: get rid of confusing blk_map_ctx structure
We can just use struct blk_mq_alloc_data - it has a few more
members, but we allocate it further down the stack anyway. So
this cleans up the code, and reduces the stack overhead a bit.

Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-27 19:13:58 -06:00
Jens Axboe
7dd2fb6877 blk-mq: update hardware and software queues for sleeping alloc
If we end up sleeping due to running out of requests, we should
update the hardware and software queues in the map ctx structure.
Otherwise we could end up having rq->mq_ctx point to the pre-sleep
context, and risk corrupting ctx->rq_list since we'll be
grabbing the wrong lock when inserting the request.

Reported-by: Dave Jones <davej@codemonkey.org.uk>
Reported-by: Chris Mason <clm@fb.com>
Tested-by: Chris Mason <clm@fb.com>
Fixes: 63581af3f3 ("blk-mq: remove non-blocking pass in blk_mq_map_request")
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-27 19:13:56 -06:00
Arnd Bergmann
3c4da75814 block: zoned: fix harmless maybe-uninitialized warning
The blkdev_report_zones produces a harmless warning when
-Wmaybe-uninitialized is set, after gcc gets a little confused
about the multiple 'goto' here:

block/blk-zoned.c: In function 'blkdev_report_zones':
block/blk-zoned.c:188:13: error: 'nz' may be used uninitialized in this function [-Werror=maybe-uninitialized]

Moving the assignment to nr_zones makes this a little simpler
while also avoiding the warning reliably. I'm removing the
extraneous initialization of 'int ret' in the same patch, as
that is semi-related and could cause an uninitialized use of
that variable to not produce a warning.

Fixes: 6a0cb1bc10 ("block: Implement support for zoned block devices")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-24 20:51:22 -06:00
Shaun Tancheff
3ed05a987e blk-zoned: implement ioctls
Adds the new BLKREPORTZONE and BLKRESETZONE ioctls for respectively
obtaining the zone configuration of a zoned block device and resetting
the write pointer of sequential zones of a zoned block device.

The BLKREPORTZONE ioctl maps directly to a single call of the function
blkdev_report_zones. The zone information result is passed as an array
of struct blk_zone identical to the structure used internally for
processing the REQ_OP_ZONE_REPORT operation.  The BLKRESETZONE ioctl
maps to a single call of the blkdev_reset_zones function.

Signed-off-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Signed-off-by: Damien Le Moal <damien.lemoal@hgst.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-18 10:05:42 -06:00
Hannes Reinecke
6a0cb1bc10 block: Implement support for zoned block devices
Implement zoned block device zone information reporting and reset.
Zone information are reported as struct blk_zone. This implementation
does not differentiate between host-aware and host-managed device
models and is valid for both. Two functions are provided:
blkdev_report_zones for discovering the zone configuration of a
zoned block device, and blkdev_reset_zones for resetting the write
pointer of sequential zones. The helper function blk_queue_zone_size
and bdev_zone_size are also provided for, as the name suggest,
obtaining the zone size (in 512B sectors) of the zones of the device.

Signed-off-by: Hannes Reinecke <hare@suse.de>

[Damien: * Removed the zone cache
         * Implement report zones operation based on earlier proposal
           by Shaun Tancheff <shaun.tancheff@seagate.com>]
Signed-off-by: Damien Le Moal <damien.lemoal@hgst.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-18 10:05:40 -06:00
Shaun Tancheff
2d253440b5 block: Define zoned block device operations
Define REQ_OP_ZONE_REPORT and REQ_OP_ZONE_RESET for handling zones of
host-managed and host-aware zoned block devices. With with these two
new operations, the total number of operations defined reaches 8 and
still fits with the 3 bits definition of REQ_OP_BITS.

Signed-off-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Signed-off-by: Damien Le Moal <damien.lemoal@hgst.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-18 10:02:05 -06:00
Hannes Reinecke
987b3b26eb block: update chunk_sectors in blk_stack_limits()
Signed-off-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Damien Le Moal <damien.lemoal@hgst.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-18 10:02:04 -06:00
Hannes Reinecke
87caf97cf5 blk-sysfs: Add 'chunk_sectors' to sysfs attributes
The queue limits already have a 'chunk_sectors' setting, so
we should be presenting it via sysfs.

Signed-off-by: Hannes Reinecke <hare@suse.de>

[Damien: Updated Documentation/ABI/testing/sysfs-block]

Signed-off-by: Damien Le Moal <damien.lemoal@hgst.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-18 10:02:02 -06:00
Damien Le Moal
797476b88b block: Add 'zoned' queue limit
Add the zoned queue limit to indicate the zoning model of a block device.
Defined values are 0 (BLK_ZONED_NONE) for regular block devices,
1 (BLK_ZONED_HA) for host-aware zone block devices and 2 (BLK_ZONED_HM)
for host-managed zone block devices. The standards defined drive managed
model is not defined here since these block devices do not provide any
command for accessing zone information. Drive managed model devices will
be reported as BLK_ZONED_NONE.

The helper functions blk_queue_zoned_model and bdev_zoned_model return
the zoned limit and the functions blk_queue_is_zoned and bdev_is_zoned
return a boolean for callers to test if a block device is zoned.

The zoned attribute is also exported as a string to applications via
sysfs. BLK_ZONED_NONE shows as "none", BLK_ZONED_HA as "host-aware" and
BLK_ZONED_HM as "host-managed".

Signed-off-by: Damien Le Moal <damien.lemoal@hgst.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-18 10:02:00 -06:00
Linus Torvalds
9ffc66941d This adds a new gcc plugin named "latent_entropy". It is designed to
extract as much possible uncertainty from a running system at boot time as
 possible, hoping to capitalize on any possible variation in CPU operation
 (due to runtime data differences, hardware differences, SMP ordering,
 thermal timing variation, cache behavior, etc).
 
 At the very least, this plugin is a much more comprehensive example for
 how to manipulate kernel code using the gcc plugin internals.
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Merge tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull gcc plugins update from Kees Cook:
 "This adds a new gcc plugin named "latent_entropy". It is designed to
  extract as much possible uncertainty from a running system at boot
  time as possible, hoping to capitalize on any possible variation in
  CPU operation (due to runtime data differences, hardware differences,
  SMP ordering, thermal timing variation, cache behavior, etc).

  At the very least, this plugin is a much more comprehensive example
  for how to manipulate kernel code using the gcc plugin internals"

* tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  latent_entropy: Mark functions with __latent_entropy
  gcc-plugins: Add latent_entropy plugin
2016-10-15 10:03:15 -07:00
Linus Torvalds
f34d3606f7 Merge branch 'for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:

 - tracepoints for basic cgroup management operations added

 - kernfs and cgroup path formatting functions updated to behave in the
   style of strlcpy()

 - non-critical bug fixes

* 'for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  blkcg: Unlock blkcg_pol_mutex only once when cpd == NULL
  cgroup: fix error handling regressions in proc_cgroup_show() and cgroup_release_agent()
  cpuset: fix error handling regression in proc_cpuset_show()
  cgroup: add tracepoints for basic operations
  cgroup: make cgroup_path() and friends behave in the style of strlcpy()
  kernfs: remove kernfs_path_len()
  kernfs: make kernfs_path*() behave in the style of strlcpy()
  kernfs: add dummy implementation of kernfs_path_from_node()
2016-10-14 12:18:50 -07:00
Darrick J. Wong
28b2be203e block: require write_same and discard requests align to logical block size
Make sure that the offset and length arguments that we're using to
construct WRITE SAME and DISCARD requests are actually aligned to the
logical block size.  Failure to do this causes other errors in other parts
of the block layer or the SCSI layer because disks don't support partial
logical block writes.

Link: http://lkml.kernel.org/r/147518379026.22791.4437508871355153928.stgit@birch.djwong.org
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Mike Snitzer <snitzer@redhat.com> # tweaked header
Cc: Brian Foster <bfoster@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:30 -07:00
Darrick J. Wong
22dd6d3566 block: invalidate the page cache when issuing BLKZEROOUT
Patch series "fallocate for block devices", v11.

This is a patchset to fix page cache coherency with BLKZEROOUT and
implement fallocate for block devices.

The first patch is a fix to the existing BLKZEROOUT ioctl to invalidate
the page cache if the zeroing command to the underlying device succeeds.
Without this patch we still have the pagecache coherence bug that's been
in the kernel forever.

The second patch changes the internal block device functions to reject
attempts to discard or zeroout that are not aligned to the logical block
size.  Previously, we only checked that the start/len parameters were
512-byte aligned, which caused kernel BUG_ONs for unaligned IOs to 4k-LBA
devices.

The third patch creates an fallocate handler for block devices, wires up
the FALLOC_FL_PUNCH_HOLE flag to zeroing-discard, and connects
FALLOC_FL_ZERO_RANGE to write-same so that we can have a consistent
fallocate interface between files and block devices.  It also allows the
combination of PUNCH_HOLE and NO_HIDE_STALE to invoke non-zeroing discard.

Test cases for the new block device fallocate are now in xfstests as
generic/349-351.

This patch (of 3):

Invalidate the page cache (as a regular O_DIRECT write would do) to avoid
returning stale cache contents at a later time.

Link: http://lkml.kernel.org/r/147518378313.22791.16649519283678515021.stgit@birch.djwong.org
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:30 -07:00
Emese Revfy
0766f788eb latent_entropy: Mark functions with __latent_entropy
The __latent_entropy gcc attribute can be used only on functions and
variables.  If it is on a function then the plugin will instrument it for
gathering control-flow entropy. If the attribute is on a variable then
the plugin will initialize it with random contents.  The variable must
be an integer, an integer array type or a structure with integer fields.

These specific functions have been selected because they are init
functions (to help gather boot-time entropy), are called at unpredictable
times, or they have variable loops, each of which provide some level of
latent entropy.

Signed-off-by: Emese Revfy <re.emese@gmail.com>
[kees: expanded commit message]
Signed-off-by: Kees Cook <keescook@chromium.org>
2016-10-10 14:51:45 -07:00
Linus Torvalds
24532f7681 Merge branch 'for-4.9/block-smp' of git://git.kernel.dk/linux-block
Pull blk-mq CPU hotplug update from Jens Axboe:
 "This is the conversion of blk-mq to the new hotplug state machine"

* 'for-4.9/block-smp' of git://git.kernel.dk/linux-block:
  blk-mq: fixup "Convert to new hotplug state machine"
  blk-mq: Convert to new hotplug state machine
  blk-mq/cpu-notif: Convert to new hotplug state machine
2016-10-09 17:32:20 -07:00
Linus Torvalds
12e3d3cdd9 Merge branch 'for-4.9/block-irq' of git://git.kernel.dk/linux-block
Pull blk-mq irq/cpu mapping updates from Jens Axboe:
 "This is the block-irq topic branch for 4.9-rc. It's mostly from
  Christoph, and it allows drivers to specify their own mappings, and
  more importantly, to share the blk-mq mappings with the IRQ affinity
  mappings. It's a good step towards making this work better out of the
  box"

* 'for-4.9/block-irq' of git://git.kernel.dk/linux-block:
  blk_mq: linux/blk-mq.h does not include all the headers it depends on
  blk-mq: kill unused blk_mq_create_mq_map()
  blk-mq: get rid of the cpumask in struct blk_mq_tags
  nvme: remove the post_scan callout
  nvme: switch to use pci_alloc_irq_vectors
  blk-mq: provide a default queue mapping for PCI device
  blk-mq: allow the driver to pass in a queue mapping
  blk-mq: remove ->map_queue
  blk-mq: only allocate a single mq_map per tag_set
  blk-mq: don't redistribute hardware queues on a CPU hotplug event
2016-10-09 17:29:33 -07:00
Linus Torvalds
513a4befae Merge branch 'for-4.9/block' of git://git.kernel.dk/linux-block
Pull block layer updates from Jens Axboe:
 "This is the main pull request for block layer changes in 4.9.

  As mentioned at the last merge window, I've changed things up and now
  do just one branch for core block layer changes, and driver changes.
  This avoids dependencies between the two branches. Outside of this
  main pull request, there are two topical branches coming as well.

  This pull request contains:

   - A set of fixes, and a conversion to blk-mq, of nbd. From Josef.

   - Set of fixes and updates for lightnvm from Matias, Simon, and Arnd.
     Followup dependency fix from Geert.

   - General fixes from Bart, Baoyou, Guoqing, and Linus W.

   - CFQ async write starvation fix from Glauber.

   - Add supprot for delayed kick of the requeue list, from Mike.

   - Pull out the scalable bitmap code from blk-mq-tag.c and make it
     generally available under the name of sbitmap. Only blk-mq-tag uses
     it for now, but the blk-mq scheduling bits will use it as well.
     From Omar.

   - bdev thaw error progagation from Pierre.

   - Improve the blk polling statistics, and allow the user to clear
     them. From Stephen.

   - Set of minor cleanups from Christoph in block/blk-mq.

   - Set of cleanups and optimizations from me for block/blk-mq.

   - Various nvme/nvmet/nvmeof fixes from the various folks"

* 'for-4.9/block' of git://git.kernel.dk/linux-block: (54 commits)
  fs/block_dev.c: return the right error in thaw_bdev()
  nvme: Pass pointers, not dma addresses, to nvme_get/set_features()
  nvme/scsi: Remove power management support
  nvmet: Make dsm number of ranges zero based
  nvmet: Use direct IO for writes
  admin-cmd: Added smart-log command support.
  nvme-fabrics: Add host_traddr options field to host infrastructure
  nvme-fabrics: revise host transport option descriptions
  nvme-fabrics: rework nvmf_get_address() for variable options
  nbd: use BLK_MQ_F_BLOCKING
  blkcg: Annotate blkg_hint correctly
  cfq: fix starvation of asynchronous writes
  blk-mq: add flag for drivers wanting blocking ->queue_rq()
  blk-mq: remove non-blocking pass in blk_mq_map_request
  blk-mq: get rid of manual run of queue with __blk_mq_run_hw_queue()
  block: export bio_free_pages to other modules
  lightnvm: propagate device_add() error code
  lightnvm: expose device geometry through sysfs
  lightnvm: control life of nvm_dev in driver
  blk-mq: register device instead of disk
  ...
2016-10-07 14:42:05 -07:00
Linus Torvalds
597f03f9d1 Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull CPU hotplug updates from Thomas Gleixner:
 "Yet another batch of cpu hotplug core updates and conversions:

   - Provide core infrastructure for multi instance drivers so the
     drivers do not have to keep custom lists.

   - Convert custom lists to the new infrastructure. The block-mq custom
     list conversion comes through the block tree and makes the diffstat
     tip over to more lines removed than added.

   - Handle unbalanced hotplug enable/disable calls more gracefully.

   - Remove the obsolete CPU_STARTING/DYING notifier support.

   - Convert another batch of notifier users.

   The relayfs changes which conflicted with the conversion have been
   shipped to me by Andrew.

   The remaining lot is targeted for 4.10 so that we finally can remove
   the rest of the notifiers"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (46 commits)
  cpufreq: Fix up conversion to hotplug state machine
  blk/mq: Reserve hotplug states for block multiqueue
  x86/apic/uv: Convert to hotplug state machine
  s390/mm/pfault: Convert to hotplug state machine
  mips/loongson/smp: Convert to hotplug state machine
  mips/octeon/smp: Convert to hotplug state machine
  fault-injection/cpu: Convert to hotplug state machine
  padata: Convert to hotplug state machine
  cpufreq: Convert to hotplug state machine
  ACPI/processor: Convert to hotplug state machine
  virtio scsi: Convert to hotplug state machine
  oprofile/timer: Convert to hotplug state machine
  block/softirq: Convert to hotplug state machine
  lib/irq_poll: Convert to hotplug state machine
  x86/microcode: Convert to hotplug state machine
  sh/SH-X3 SMP: Convert to hotplug state machine
  ia64/mca: Convert to hotplug state machine
  ARM/OMAP/wakeupgen: Convert to hotplug state machine
  ARM/shmobile: Convert to hotplug state machine
  arm64/FP/SIMD: Convert to hotplug state machine
  ...
2016-10-03 19:43:08 -07:00
Bart Van Assche
bbb427e342 blkcg: Unlock blkcg_pol_mutex only once when cpd == NULL
Unlocking a mutex twice is wrong. Hence modify blkcg_policy_register()
such that blkcg_pol_mutex is unlocked once if cpd == NULL. This patch
avoids that smatch reports the following error:

block/blk-cgroup.c:1378: blkcg_policy_register() error: double unlock 'mutex:&blkcg_pol_mutex'

Fixes: 06b285bd11 ("blkcg: fix blkcg_policy_data allocation bug")
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org> # v4.2+
Signed-off-by: Tejun Heo <tj@kernel.org>
2016-09-30 10:31:20 +02:00
Christoph Hellwig
c8712c6a67 blk-mq: skip unmapped queues in blk_mq_alloc_request_hctx
This provides the caller a feedback that a given hctx is not mapped and thus
no command can be sent on it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-23 10:25:48 -06:00
Glauber Costa
3932a86b4b cfq: fix starvation of asynchronous writes
While debugging timeouts happening in my application workload (ScyllaDB), I have
observed calls to open() taking a long time, ranging everywhere from 2 seconds -
the first ones that are enough to time out my application - to more than 30
seconds.

The problem seems to happen because XFS may block on pending metadata updates
under certain circumnstances, and that's confirmed with the following backtrace
taken by the offcputime tool (iovisor/bcc):

    ffffffffb90c57b1 finish_task_switch
    ffffffffb97dffb5 schedule
    ffffffffb97e310c schedule_timeout
    ffffffffb97e1f12 __down
    ffffffffb90ea821 down
    ffffffffc046a9dc xfs_buf_lock
    ffffffffc046abfb _xfs_buf_find
    ffffffffc046ae4a xfs_buf_get_map
    ffffffffc046babd xfs_buf_read_map
    ffffffffc0499931 xfs_trans_read_buf_map
    ffffffffc044a561 xfs_da_read_buf
    ffffffffc0451390 xfs_dir3_leaf_read.constprop.16
    ffffffffc0452b90 xfs_dir2_leaf_lookup_int
    ffffffffc0452e0f xfs_dir2_leaf_lookup
    ffffffffc044d9d3 xfs_dir_lookup
    ffffffffc047d1d9 xfs_lookup
    ffffffffc0479e53 xfs_vn_lookup
    ffffffffb925347a path_openat
    ffffffffb9254a71 do_filp_open
    ffffffffb9242a94 do_sys_open
    ffffffffb9242b9e sys_open
    ffffffffb97e42b2 entry_SYSCALL_64_fastpath
    00007fb0698162ed [unknown]

Inspecting my run with blktrace, I can see that the xfsaild kthread exhibit very
high "Dispatch wait" times, on the dozens of seconds range and consistent with
the open() times I have saw in that run.

Still from the blktrace output, we can after searching a bit, identify the
request that wasn't dispatched:

  8,0   11      152    81.092472813   804  A  WM 141698288 + 8 <- (8,1) 141696240
  8,0   11      153    81.092472889   804  Q  WM 141698288 + 8 [xfsaild/sda1]
  8,0   11      154    81.092473207   804  G  WM 141698288 + 8 [xfsaild/sda1]
  8,0   11      206    81.092496118   804  I  WM 141698288 + 8 (   22911) [xfsaild/sda1]
  <==== 'I' means Inserted (into the IO scheduler) ===================================>
  8,0    0   289372    96.718761435     0  D  WM 141698288 + 8 (15626265317) [swapper/0]
  <==== Only 15s later the CFQ scheduler dispatches the request ======================>

As we can see above, in this particular example CFQ took 15 seconds to dispatch
this request. Going back to the full trace, we can see that the xfsaild queue
had plenty of opportunity to run, and it was selected as the active queue many
times. It would just always be preempted by something else (example):

  8,0    1        0    81.117912979     0  m   N cfq1618SN / insert_request
  8,0    1        0    81.117913419     0  m   N cfq1618SN / add_to_rr
  8,0    1        0    81.117914044     0  m   N cfq1618SN / preempt
  8,0    1        0    81.117914398     0  m   N cfq767A  / slice expired t=1
  8,0    1        0    81.117914755     0  m   N cfq767A  / resid=40
  8,0    1        0    81.117915340     0  m   N / served: vt=1948520448 min_vt=1948520448
  8,0    1        0    81.117915858     0  m   N cfq767A  / sl_used=1 disp=0 charge=0 iops=1 sect=0

where cfq767 is the xfsaild queue and cfq1618 corresponds to one of the ScyllaDB
IO dispatchers.

The requests preempting the xfsaild queue are synchronous requests. That's a
characteristic of ScyllaDB workloads, as we only ever issue O_DIRECT requests.
While it can be argued that preempting ASYNC requests in favor of SYNC is part
of the CFQ logic, I don't believe that doing so for 15+ seconds is anyone's
goal.

Moreover, unless I am misunderstanding something, that breaks the expectation
set by the "fifo_expire_async" tunable, which in my system is set to the
default.

Looking at the code, it seems to me that the issue is that after we make
an async queue active, there is no guarantee that it will execute any request.

When the queue itself tests if it cfq_may_dispatch() it can bail if it sees SYNC
requests in flight. An incoming request from another queue can also preempt it
in such situation before we have the chance to execute anything (as seen in the
trace above).

This patch sets the must_dispatch flag if we notice that we have requests
that are already fifo_expired. This flag is always cleared after
cfq_dispatch_request() returns from cfq_dispatch_requests(), so it won't pin
the queue for subsequent requests (unless they are themselves expired)

Care is taken during preempt to still allow rt requests to preempt us
regardless.

Testing my workload with this patch applied produces much better results.
From the application side I see no timeouts, and the open() latency histogram
generated by systemtap looks much better, with the worst outlier at 131ms:

Latency histogram of xfs_buf_lock acquisition (microseconds):
 value |-------------------------------------------------- count
     0 |                                                     11
     1 |@@@@                                                161
     2 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@  1966
     4 |@                                                    54
     8 |                                                     36
    16 |                                                      7
    32 |                                                      0
    64 |                                                      0
       ~
  1024 |                                                      0
  2048 |                                                      0
  4096 |                                                      1
  8192 |                                                      1
 16384 |                                                      2
 32768 |                                                      0
 65536 |                                                      0
131072 |                                                      1
262144 |                                                      0
524288 |                                                      0

Signed-off-by: Glauber Costa <glauber@scylladb.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: linux-block@vger.kernel.org
CC: linux-kernel@vger.kernel.org

Signed-off-by: Glauber Costa <glauber@scylladb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-23 10:01:24 -06:00
Sebastian Andrzej Siewior
97a32864e6 blk-mq: fixup "Convert to new hotplug state machine"
The "blk_mq_queue_reinit_dead()" just cleared the cpumask instead doing
a copy. Since we might never had an online callback we could end up with
a ZERO mask which in turn leads to crash as test robot demonstarted.

Fixes: 65d5291eee ("blk-mq: Convert to new hotplug state machine")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-23 09:49:32 -06:00
Jens Axboe
1b792f2f92 blk-mq: add flag for drivers wanting blocking ->queue_rq()
If a driver sets BLK_MQ_F_BLOCKING, it is allowed to block in its
->queue_rq() handler. For that case, blk-mq ensures that we always
calls it from a safe context.

Signed-off-by: Jens Axboe <axboe@fb.com>
Tested-by: Josef Bacik <jbacik@fb.com>
2016-09-22 14:28:38 -06:00
Christoph Hellwig
63581af3f3 blk-mq: remove non-blocking pass in blk_mq_map_request
bt_get already does a non-blocking pass as well as running the queue
when scheduling internally, no need to duplicate it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-22 14:27:39 -06:00
Jens Axboe
841bac2c87 blk-mq: get rid of manual run of queue with __blk_mq_run_hw_queue()
Two cases:

1) blk_mq_alloc_request() needlessly re-runs the queue, after
   calling into the tag allocation without NOWAIT set. We don't
   need to do that.

2) blk_mq_map_request() should just use blk_mq_run_hw_queue() with
   the async flag set to false.

Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2016-09-22 09:39:53 -06:00
Sebastian Andrzej Siewior
65d5291eee blk-mq: Convert to new hotplug state machine
Install the callbacks via the state machine so we can phase out the cpu
hotplug notifiers mess.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-block@vger.kernel.org
Cc: rt@linutronix.de
Cc: Christoph Hellwing <hch@lst.de>
Link: http://lkml.kernel.org/r/20160919212601.180033814@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-22 08:05:19 -06:00
Thomas Gleixner
9467f85960 blk-mq/cpu-notif: Convert to new hotplug state machine
Replace the block-mq notifier list management with the multi instance
facility in the cpu hotplug state machine.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-block@vger.kernel.org
Cc: rt@linutronix.de
Cc: Christoph Hellwing <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-22 08:05:17 -06:00
Guoqing Jiang
491221f88d block: export bio_free_pages to other modules
bio_free_pages is introduced in commit 1dfa0f68c0
("block: add a helper to free bio bounce buffer pages"),
we can reuse the func in other modules after it was
imported.

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jens Axboe <axboe@fb.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Acked-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-22 07:48:03 -06:00
Matias Bjørling
b21d5b3017 blk-mq: register device instead of disk
Enable devices without a gendisk instance to register itself with blk-mq
and expose the associated multi-queue sysfs entries.

Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-21 07:56:16 -06:00
Vivek Goyal
164c80ed84 blk-throttle: Extend slice if throttle group is not empty
Right now, if slice is expired, we start a new slice. If a bio is
queued, we keep on extending slice by throtle_slice interval (100ms).

This worked well as long as pending timer function got executed with-in
few milli seconds of scheduled time. But looks like with recent changes
in timer subsystem, slack can be much longer depending on the expiry time
of the scheduled timer.

commit 500462a9de ("timers: Switch to a non-cascading wheel")

This means, by the time timer function gets executed, it is possible the
delay from scheduled time is more than 100ms. That means current code
will conclude that existing slice has expired and a new one needs to
be started. New slice will be 100ms by default and that will not be
sufficient to meet rate requirement of group given the bio size and
bio will not be dispatched and we will start a new timer function to
wait. And when that timer expires, same process will repeat and we
will wait again and this can easily be an infinite loop.

Solve this issue by starting a new slice only if throttle gropup is
empty. If it is not empty, that means there should be an active slice
going on. Ideally it should not be expired but given the slack, it is
possible that it has expired.

Reported-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-19 15:12:41 -06:00
Sebastian Andrzej Siewior
9a659f43df block/softirq: Convert to hotplug state machine
Install the callbacks via the state machine.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160906170457.32393-9-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-09-19 21:44:28 +02:00
Stephen Rothwell
8ec2ef2b66 blk_mq: linux/blk-mq.h does not include all the headers it depends on
and building block/blk-mq-pci.o should depend on CONFIG_BLOCK

Fixes: 973c4e372c ("blk-mq: provide a default queue mapping for PCI device")
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-19 08:21:51 -06:00
Omar Sandoval
98d95416db sbitmap: randomize initial alloc_hint values
In order to get good cache behavior from a sbitmap, we want each CPU to
stick to its own cacheline(s) as much as possible. This might happen
naturally as the bitmap gets filled up and the alloc_hint values spread
out, but we really want this behavior from the start. blk-mq apparently
intended to do this, but the code to do this was never wired up. Get rid
of the dead code and make it part of the sbitmap library.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-17 08:39:14 -06:00
Omar Sandoval
f4a644db86 sbitmap: push alloc policy into sbitmap_queue
Again, there's no point in passing this in every time. Make it part of
struct sbitmap_queue and clean up the API.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-17 08:39:12 -06:00
Omar Sandoval
40aabb6746 sbitmap: push per-cpu last_tag into sbitmap_queue
Allocating your own per-cpu allocation hint separately makes for an
awkward API. Instead, allocate the per-cpu hint as part of the struct
sbitmap_queue. There's no point for a struct sbitmap_queue without the
cache, but you can still use a bare struct sbitmap.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-17 08:39:10 -06:00
Omar Sandoval
88459642cb blk-mq: abstract tag allocation out into sbitmap library
This is a generally useful data structure, so make it available to
anyone else who might want to use it. It's also a nice cleanup
separating the allocation logic from the rest of the tag handling logic.

The code is behind a new Kconfig option, CONFIG_SBITMAP, which is only
selected by CONFIG_BLOCK for now.

This should be a complete noop functionality-wise.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-17 08:38:44 -06:00
Jens Axboe
703fd1c0f1 blk-mq: account higher order dispatch
We currently account a '0' dispatch, and anything above that still falls
below the range set by BLK_MQ_MAX_DISPATCH_ORDER. If we dispatch more,
we don't account it.

Change the last bucket to be inclusive of anything above the range we
track, and have the sysfs file reflect that by including a '+' in the
output:

$ cat /sys/block/nvme0n1/mq/0/dispatched
        0	1006
        1	20229
        2	1
        4	0
        8	0
       16	0
       32+	0

Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
2016-09-16 14:03:04 -06:00
Jens Axboe
9151bcb4fb blk-mq: kill unused blk_mq_create_mq_map()
Fixes 1b157939f9 ("blk-mq: get rid of the cpumask in struct blk_mq_tags")
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-15 08:45:45 -06:00
Christoph Hellwig
1b157939f9 blk-mq: get rid of the cpumask in struct blk_mq_tags
Unused now that NVMe sets up irq affinity before calling into blk-mq.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-15 08:42:03 -06:00
Christoph Hellwig
973c4e372c blk-mq: provide a default queue mapping for PCI device
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-15 08:42:03 -06:00