If we need to drain a queue we need to run all queues, even if they
are marked stopped to make sure the driver has a chance to error out
on all queued requests.
This fixes surprise removal with scsi-mq.
Reported-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
blk-mq issues async requests through kblockd. To issue a work request on
a specific CPU, kblockd_schedule_delayed_work_on is used. However, the
specific CPU choice may not be honored, if the power_efficient option
for workqueues is set. blk-mq requires that we have strict per-cpu
scheduling, so it wont work properly if kblockd is marked
POWER_EFFICIENT and power_efficient is set.
Remove the kblockd WQ_POWER_EFFICIENT flag to prevent this behavior.
This essentially reverts part of commit 695588f945, which added
the WQ_POWER_EFFICIENT marker to kblockd.
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
elv_abort_queue has no callers, and blk_abort_flushes is only called by
elv_abort_queue.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Pull block layer fixes from Jens Axboe:
"Final small batch of fixes to be included before -rc1. Some general
cleanups in here as well, but some of the blk-mq fixes we need for the
NVMe conversion and/or scsi-mq. The pull request contains:
- Support for not merging across a specified "chunk size", if set by
the driver. Some NVMe devices perform poorly for IO that crosses
such a chunk, so we need to support it generically as part of
request merging avoid having to do complicated split logic. From
me.
- Bump max tag depth to 10Ki tags. Some scsi devices have a huge
shared tag space. Before we failed with EINVAL if a too large tag
depth was specified, now we truncate it and pass back the actual
value. From me.
- Various blk-mq rq init fixes from me and others.
- A fix for enter on a dying queue for blk-mq from Keith. This is
needed to prevent oopsing on hot device removal.
- Fixup for blk-mq timer addition from Ming Lei.
- Small round of performance fixes for mtip32xx from Sam Bradshaw.
- Minor stack leak fix from Rickard Strandqvist.
- Two __init annotations from Fabian Frederick"
* 'for-linus' of git://git.kernel.dk/linux-block:
block: add __init to blkcg_policy_register
block: add __init to elv_register
block: ensure that bio_add_page() always accepts a page for an empty bio
blk-mq: add timer in blk_mq_start_request
blk-mq: always initialize request->start_time
block: blk-exec.c: Cleaning up local variable address returnd
mtip32xx: minor performance enhancements
blk-mq: ->timeout should be cleared in blk_mq_rq_ctx_init()
blk-mq: don't allow queue entering for a dying queue
blk-mq: bump max tag depth to 10K tags
block: add blk_rq_set_block_pc()
block: add notion of a chunk size for request merging
blkcg_policy_register is only called by
__init functions:
__init cfq_init
__init throtl_init
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>
elv_register is only called by elevator init functions:
__init cfq_init
__init deadline_init
__init noop_init
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>
With commit 762380ad93 added support for chunk sizes and no merging
across them, it broke the rule of always allowing adding of a single
page to an empty bio. So relax the restriction a bit to allow for that,
similarly to what we have always done.
This fixes a crash with mkfs.xfs and 512b sector sizes on NVMe.
Reported-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Pull cgroup updates from Tejun Heo:
"A lot of activities on cgroup side. Heavy restructuring including
locking simplification took place to improve the code base and enable
implementation of the unified hierarchy, which currently exists behind
a __DEVEL__ mount option. The core support is mostly complete but
individual controllers need further work. To explain the design and
rationales of the the unified hierarchy
Documentation/cgroups/unified-hierarchy.txt
is added.
Another notable change is css (cgroup_subsys_state - what each
controller uses to identify and interact with a cgroup) iteration
update. This is part of continuing updates on css object lifetime and
visibility. cgroup started with reference count draining on removal
way back and is now reaching a point where csses behave and are
iterated like normal refcnted objects albeit with some complexities to
allow distinguishing the state where they're being deleted. The css
iteration update isn't taken advantage of yet but is planned to be
used to simplify memcg significantly"
* 'for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (77 commits)
cgroup: disallow disabled controllers on the default hierarchy
cgroup: don't destroy the default root
cgroup: disallow debug controller on the default hierarchy
cgroup: clean up MAINTAINERS entries
cgroup: implement css_tryget()
device_cgroup: use css_has_online_children() instead of has_children()
cgroup: convert cgroup_has_live_children() into css_has_online_children()
cgroup: use CSS_ONLINE instead of CGRP_DEAD
cgroup: iterate cgroup_subsys_states directly
cgroup: introduce CSS_RELEASED and reduce css iteration fallback window
cgroup: move cgroup->serial_nr into cgroup_subsys_state
cgroup: link all cgroup_subsys_states in their sibling lists
cgroup: move cgroup->sibling and ->children into cgroup_subsys_state
cgroup: remove cgroup->parent
device_cgroup: remove direct access to cgroup->children
memcg: update memcg_has_children() to use css_next_child()
memcg: remove tasks/children test from mem_cgroup_force_empty()
cgroup: remove css_parent()
cgroup: skip refcnting on normal root csses and cgrp_dfl_root self css
cgroup: use cgroup->self.refcnt for cgroup refcnting
...
This way will become consistent with non-mq case, also
avoid to update rq->deadline twice for mq.
The comment said: "We do this early, to ensure we are on
the right CPU.", but no percpu stuff is used in blk_add_timer(),
so it isn't necessary. Even when inserting from plug list, there
is no such guarantee at all.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
The blk-mq core only initializes this if io stats are enabled, since
blk-mq only reads the field in that case. But drivers could
potentially use it internally, so ensure that we always set it to
the current time when the request is allocated.
Reported-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Address of local variable assigned to a function parameter
This was partly found using a static code analysis program called cppcheck.
Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Signed-off-by: Jens Axboe <axboe@fb.com>
printk is meant to be used with an associated log level. There are some
instances of printk scattered around the mm code where the log level is
missing. Add a log level and adhere to suggestions by
scripts/checkpatch.pl by moving to the pr_* macros.
Also add the typical pr_fmt definition so that print statements can be
easily traced back to the modules where they occur, correlated one with
another, etc. This will require the removal of some (now redundant)
prefixes on a few print statements.
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It'll be used in blk_mq_start_request() to set a potential timeout
for the request, so clear it to zero at alloc time to ensure that
we know if someone has set it or not.
Fixes random early timeouts on NVMe testing.
Signed-off-by: Jens Axboe <axboe@fb.com>
If the queue is going away, don't let new allocs or queueing
happen on it. Go through the normal wait process, and exit with
ENODEV in that case.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
For some scsi-mq cases, the tag map can be huge. So increase the
max number of tags we support.
Additionally, don't fail with EINVAL if a user requests too many
tags. Warn that the tag depth has been adjusted down, and store
the new value inside the tag_set passed in.
Signed-off-by: Jens Axboe <axboe@fb.com>
With the optimizations around not clearing the full request at alloc
time, we are leaving some of the needed init for REQ_TYPE_BLOCK_PC
up to the user allocating the request.
Add a blk_rq_set_block_pc() that sets the command type to
REQ_TYPE_BLOCK_PC, and properly initializes the members associated
with this type of request. Update callers to use this function instead
of manipulating rq->cmd_type directly.
Includes fixes from Christoph Hellwig <hch@lst.de> for my half-assed
attempt.
Signed-off-by: Jens Axboe <axboe@fb.com>
Some drivers have different limits on what size a request should
optimally be, depending on the offset of the request. Similar to
dividing a device into chunks. Add a setting that allows the driver
to inform the block layer of such a chunk size. The block layer will
then prevent merging across the chunks.
This is needed to optimally support NVMe with a non-zero stripe size.
Signed-off-by: Jens Axboe <axboe@fb.com>
blk_mq_tag_to_rq() needs to be able to tell if it should return
the original request, or the flush request if we are doing a flush
sequence. Clear the flush tag when IO completes for a flush, since
that is what we are comparing against.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
We currently pass in the hardware queue, and get the tags from there.
But from scsi-mq, with a shared tag space, it's a lot more convenient
to pass in the blk_mq_tags instead as the hardware queue isn't always
directly available. So instead of having to re-map to a given
hardware queue from rq->mq_ctx, just pass in the tags structure.
Signed-off-by: Jens Axboe <axboe@fb.com>
When the code was collapsed to avoid duplication, the recent patch
for ensuring that a queue is idled before free was dropped, which was
added by commit 19c5d84f14.
Add back the blk_mq_tag_idle(), to ensure we don't leak a reference
to an active queue when it is freed.
Signed-off-by: Jens Axboe <axboe@fb.com>
blk_mq_map_request() can return NULL if we fail entering the queue
(dying, or removed), in which case it has already ended IO on the
bio. So nothing more to do, except just return.
Signed-off-by: Jens Axboe <axboe@fb.com>
'struct blk_mq_ctx' is __percpu, so add the annotation
and fix the sparse warning reported from Fengguang:
[block:for-linus 2/3] block/blk-mq.h:75:16: sparse: incorrect
type in initializer (different address spaces)
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
blk_mq_put_ctx() has to be called before io_schedule() in
bt_get().
This patch fixes the problem by taking similar approach from
percpu_ida allocation for the situation.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Pull block driver changes from Jens Axboe:
"Now that the core bits are in, here's the pull request for the driver
related changes for 3.16. Nothing out of the ordinary here, mostly
business as usual. There are a few pulls of for-3.16/core into this
branch, which were done when the blk-mq was modified after the
mtip32xx conversion was put in.
The pull request contains:
- skd and cciss converted to use pci_enable_msix_exact(). From
Alexander Gordeev.
- A few mtip32xx fixes from Asai @ Micron.
- The conversion of mtip32xx from make_request_fn to blk-mq, and a
later small fix for that conversion on quiescing for non-queued IO.
From me.
- A fix for bsg to use an exported function to check whether this
driver is request based or not. Needed updating for blk-mq, which
is request based, but does not have a request_fn hook. From me.
- Small floppy bug fix from Jiri.
- A series of cleanups for the cdrom uniform layer from Joe Perches.
Gets rid of various old ugly macros, making the code conform more
to the modern coding style.
- A series of patches for drbd from the drbd crew (Lars Ellenberg and
Philipp Reisner).
- A use-after-free fix for null_blk from Ming Lei.
- Also from Ming Lei is a performance patch for virtio-blk, which can
net us a 3x win on kvm platforms where world notification is
expensive.
- Ming Lei also fixed a stall issue in virtio-blk, due to a race
between queue start/stop and resource limits.
- A small batch of fixes for xen-blk{back,front} from Olaf Hering and
Valentin Priescu"
* 'for-3.16/drivers' of git://git.kernel.dk/linux-block: (54 commits)
block: virtio_blk: don't hold spin lock during world switch
xen-blkback: defer freeing blkif to avoid blocking xenwatch
xen blkif.h: fix comment typo in discard-alignment
xen/blkback: disable discard feature if requested by toolstack
xen-blkfront: remove type check from blkfront_setup_discard
floppy: do not corrupt bio.bi_flags when reading block 0
mtip32xx: move error handling to service thread
virtio_blk: fix race between start and stop queue
mtip32xx: stop block hardware queues before quiescing IO
mtip32xx: blk_mq_init_queue() returns an ERR_PTR
mtip32xx: convert to use blk-mq
cdrom: Remove unnecessary prototype for cdrom_get_disc_info
cdrom: Remove unnecessary prototype for cdrom_mrw_exit
cdrom: Remove cdrom_count_tracks prototype
cdrom: Remove cdrom_get_next_writeable prototype
cdrom: Remove cdrom_get_last_written prototype
cdrom: Move mmc_ioctls above cdrom_ioctl to remove unnecessary prototype
cdrom: Remove unnecessary sanitize_format prototype
cdrom: Remove unnecessary check_for_audio_disc prototype
cdrom: Remove prototype for open_for_data
...
Pull block core updates from Jens Axboe:
"It's a big(ish) round this time, lots of development effort has gone
into blk-mq in the last 3 months. Generally we're heading to where
3.16 will be a feature complete and performant blk-mq. scsi-mq is
progressing nicely and will hopefully be in 3.17. A nvme port is in
progress, and the Micron pci-e flash driver, mtip32xx, is converted
and will be sent in with the driver pull request for 3.16.
This pull request contains:
- Lots of prep and support patches for scsi-mq have been integrated.
All from Christoph.
- API and code cleanups for blk-mq from Christoph.
- Lots of good corner case and error handling cleanup fixes for
blk-mq from Ming Lei.
- A flew of blk-mq updates from me:
* Provide strict mappings so that the driver can rely on the CPU
to queue mapping. This enables optimizations in the driver.
* Provided a bitmap tagging instead of percpu_ida, which never
really worked well for blk-mq. percpu_ida relies on the fact
that we have a lot more tags available than we really need, it
fails miserably for cases where we exhaust (or are close to
exhausting) the tag space.
* Provide sane support for shared tag maps, as utilized by scsi-mq
* Various fixes for IO timeouts.
* API cleanups, and lots of perf tweaks and optimizations.
- Remove 'buffer' from struct request. This is ancient code, from
when requests were always virtually mapped. Kill it, to reclaim
some space in struct request. From me.
- Remove 'magic' from blk_plug. Since we store these on the stack
and since we've never caught any actual bugs with this, lets just
get rid of it. From me.
- Only call part_in_flight() once for IO completion, as includes two
atomic reads. Hopefully we'll get a better implementation soon, as
the part IO stats are now one of the more expensive parts of doing
IO on blk-mq. From me.
- File migration of block code from {mm,fs}/ to block/. This
includes bio.c, bio-integrity.c, bounce.c, and ioprio.c. From me,
from a discussion on lkml.
That should describe the meat of the pull request. Also has various
little fixes and cleanups from Dave Jones, Shaohua Li, Duan Jiong,
Fengguang Wu, Fabian Frederick, Randy Dunlap, Robert Elliott, and Sam
Bradshaw"
* 'for-3.16/core' of git://git.kernel.dk/linux-block: (100 commits)
blk-mq: push IPI or local end_io decision to __blk_mq_complete_request()
blk-mq: remember to start timeout handler for direct queue
block: ensure that the timer is always added
blk-mq: blk_mq_unregister_hctx() can be static
blk-mq: make the sysfs mq/ layout reflect current mappings
blk-mq: blk_mq_tag_to_rq should handle flush request
block: remove dead code in scsi_ioctl:blk_verify_command
blk-mq: request initialization optimizations
block: add queue flag for disabling SG merging
block: remove 'magic' from struct blk_plug
blk-mq: remove alloc_hctx and free_hctx methods
blk-mq: add file comments and update copyright notices
blk-mq: remove blk_mq_alloc_request_pinned
blk-mq: do not use blk_mq_alloc_request_pinned in blk_mq_map_request
blk-mq: remove blk_mq_wait_for_tags
blk-mq: initialize request in __blk_mq_alloc_request
blk-mq: merge blk_mq_alloc_reserved_request into blk_mq_alloc_request
blk-mq: add helper to insert requests from irq context
blk-mq: remove stale comment for blk_mq_complete_request()
blk-mq: allow non-softirq completions
...
We have callers outside of the blk-mq proper (like timeouts) that
want to call __blk_mq_complete_request(), so rename the function
and put the decision code for whether to use ->softirq_done_fn
or blk_mq_endio() into __blk_mq_complete_request().
This also makes the interface more logical again.
blk_mq_complete_request() attempts to atomically mark the request
completed, and calls __blk_mq_complete_request() if successful.
__blk_mq_complete_request() then just ends the request.
Signed-off-by: Jens Axboe <axboe@fb.com>
Commit 07068d5b8e added a direct-to-hw-queue mode, but this mode
needs to remember to add the request timeout handler as well.
Without it, we don't track timeouts for these requests.
Signed-off-by: Jens Axboe <axboe@fb.com>
Commit f793aa5378 relaxed the timer addition a little too much.
If the timer isn't pending, we always need to add it.
Signed-off-by: Jens Axboe <axboe@fb.com>
Currently blk-mq registers all the hardware queues in sysfs,
regardless of whether it uses them (e.g. they have CPU mappings)
or not. The unused hardware queues lack the cpux/ directories,
and the other sysfs entries (like active, pending, etc) are all
zeroes.
Change this so that sysfs correctly reflects the current mappings
of the hardware queues.
Signed-off-by: Jens Axboe <axboe@fb.com>
flush request is special, which borrows the tag from the parent
request. Hence blk_mq_tag_to_rq needs special handling to return
the flush request from the tag.
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
filter gets assigned the address of blk_default_cmd_filter on
entry to this function, so the !filter condition can never be true.
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
We currently clear a lot more than we need to, so make that a bit
more clever. Make some of the init dependent on features, like
only setting start_time if we are going to use it.
Signed-off-by: Jens Axboe <axboe@fb.com>
If devices are not SG starved, we waste a lot of time potentially
collapsing SG segments. Enough that 1.5% of the CPU time goes
to this, at only 400K IOPS. Add a queue flag, QUEUE_FLAG_NO_SG_MERGE,
which just returns the number of vectors in a bio instead of looping
over all segments and checking for collapsible ones.
Add a BLK_MQ_F_SG_MERGE flag so that drivers can opt-in on the sg
merging, if they so desire.
Signed-off-by: Jens Axboe <axboe@fb.com>
I don't think we've ever caught any bugs with this, and there's the
list poisoning for the plug lists to catch uninitialized cases.
So remove the magic member and save 8 bytes in the struct.
Signed-off-by: Jens Axboe <axboe@fb.com>
Pull in core changes (again), since we got rid of the alloc/free
hctx mq_ops hooks and mtip32xx then needed updating again.
Signed-off-by: Jens Axboe <axboe@fb.com>
There is no need for drivers to control hardware context allocation
now that we do the context to node mapping in common code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
None of the blk-mq files have an explanatory comment at the top
for what that particular file does. Add that and add appropriate
copyright notices as well.
Signed-off-by: Jens Axboe <axboe@fb.com>
mtip32xx uses blk_mq_alloc_reserved_request(), so pull in the
core changes so we have a properly merged end result.
Signed-off-by: Jens Axboe <axboe@fb.com>
We now only have one caller left and can open code it there in a cleaner
way.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
We already do a non-blocking allocation in blk_mq_map_request, no need
to repeat it. Just call __blk_mq_alloc_request to wait directly.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
The current logic for blocking tag allocation is rather confusing, as we
first allocated and then free again a tag in blk_mq_wait_for_tags, just
to attempt a non-blocking allocation and then repeat if someone else
managed to grab the tag before us.
Instead change blk_mq_alloc_request_pinned to simply do a blocking tag
allocation itself and use the request we get back from it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Both callers if __blk_mq_alloc_request want to initialize the request, so
lift it into the common path.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Instead of having two almost identical copies of the same code just let
the callers pass in the reserved flag directly.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Both the cache flush state machine and the SCSI midlayer want to submit
requests from irq context, and the current per-request requeue_work
unfortunately causes corruption due to sharing with the csd field for
flushes. Replace them with a per-request_queue list of requests to
be requeued.
Based on an earlier test by Ming Lei.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Ming Lei <tom.leiming@gmail.com>
Tested-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Right now we export two ways of completing a request:
1) blk_mq_complete_request(). This uses an IPI (if needed) and
completes through q->softirq_done_fn(). It also works with
timeouts.
2) blk_mq_end_io(). This completes inline, and ignores any timeout
state of the request.
Let blk_mq_complete_request() handle non-softirq_done_fn completions
as well, by just completing inline. If a driver has enough completion
ports to place completions correctly, it need not define a
mq_ops->complete() and we can avoid an indirect function call by
doing the completion inline.
Signed-off-by: Jens Axboe <axboe@fb.com>
Drivers currently have to figure this out on their own, and they
are missing information to do it properly. The ones that did
attempt to do it, do it wrong.
So just pass in the suggested node directly to the alloc
function.
Signed-off-by: Jens Axboe <axboe@fb.com>
The percpu counter is only used for blk-mq, so move
its allocation and free inside blk-mq, and don't
allocate it for legacy queue device.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
blk_mq_exit_hw_queues() and blk_mq_free_hw_queues()
are introduced to avoid code duplication.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
hctx->ctx_map should have been freed inside blk_mq_free_queue().
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
__blkdev_issue_zeroout is only used in blk-lib.c
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>
Without this we can leak the active_queues reference if a command is
freed while it is considered active.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Currently blk-mq uses the queue timeout for all requests. But
for some commands, drivers may want to set a specific timeout
for special requests. Allow this to be passed in through
request->timeout, and use it if set.
Signed-off-by: Jens Axboe <axboe@fb.com>
Export the blk-mq in-flight tag iterator for driver consumption.
This is particularly useful in exception paths or SRSI where
in-flight IOs need to be cancelled and/or reissued. The NVMe driver
conversion will use this.
Signed-off-by: Sam Bradshaw <sbradshaw@micron.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
We want slightly different behavior from them:
- On single queue devices, we currently use the per-process plug
for deferred IO and for merging.
- On multi queue devices, we don't use the per-process plug, but
we want to go straight to hardware for SYNC IO.
Split blk_mq_make_request() into a blk_sq_make_request() for single
queue devices, and retain blk_mq_make_request() for multi queue
devices. Then we don't need multiple checks for q->nr_hw_queues
in the request mapping.
Signed-off-by: Jens Axboe <axboe@fb.com>
Depending on the topology of the machine and the number of queues
exposed by a device, we can end up in a situation where some of
the hardware queues are unused (as in, they don't map to any
software queues). For this case, free up the memory used by the
request map, as we will not use it. This can be a substantial
amount of memory, depending on the number of queues vs CPUs and
the queue depth of the device.
Signed-off-by: Jens Axboe <axboe@fb.com>
Prepare this for the next patch which adds more smarts in the
plugging logic, so that we can save some memory.
Signed-off-by: Jens Axboe <axboe@fb.com>
In blk_mq_make_request(), do the blk_queue_nomerges() check
outside the call to blk_attempt_plug_merge() to eliminate
function call overhead when nomerges=2 (disabled)
Signed-off-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
blk_queue_make_requests() overwrites our set value for q->nr_requests,
turning it into the default of 128. Set this appropriately after
initializing queue values in blk_queue_make_request().
Signed-off-by: Jens Axboe <axboe@fb.com>
For request_fn based devices, the block layer exports a 'nr_requests'
file through sysfs to allow adjusting of queue depth on the fly.
Currently this returns -EINVAL for blk-mq, since it's not wired up.
Wire this up for blk-mq, so that it now also always dynamic
adjustments of the allowed queue depth for any given block device
managed by blk-mq.
Signed-off-by: Jens Axboe <axboe@fb.com>
Continue moving some of the block files that are scattered around.
bounce.c contains only code for bouncing the contents of a bio.
It's block proper code, not mm code.
Suggested-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Each hardware queue has a bitmap of software queues with pending
requests. When new IO is queued on a software queue, the bit is
set, and when IO is pruned on a hardware queue run, the bit is
cleared. This causes a lot of traffic. Switch this from the regular
BITS_PER_LONG bitmap to a sparser layout, similarly to what was
done for blk-mq tagging.
20% performance increase was observed for single threaded IO, and
about 15% performanc increase on multiple threads driving the
same device.
Signed-off-by: Jens Axboe <axboe@fb.com>
They really belong in block/, especially now since it's not in
drivers/block/ anymore. Additionally, the get_maintainer script
gets it wrong when in fs/.
Suggested-by: Christoph Hellwig <hch@infradead.org>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Jens Axboe <axboe@fb.com>
cgroup in general is moving towards using cgroup_subsys_state as the
fundamental structural component and css_parent() was introduced to
convert from using cgroup->parent to css->parent. It was quite some
time ago and we're moving forward with making css more prominent.
This patch drops the trivial wrapper css_parent() and let the users
dereference css->parent. While at it, explicitly mark fields of css
which are public and immutable.
v2: New usage from device_cgroup.c converted.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: "David S. Miller" <davem@davemloft.net>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Johannes Weiner <hannes@cmpxchg.org>
This adds support for active queue tracking, meaning that the
blk-mq tagging maintains a count of active users of a tag set.
This allows us to maintain a notion of fairness between users,
so that we can distribute the tag depth evenly without starving
some users while allowing others to try unfair deep queues.
If sharing of a tag set is detected, each hardware queue will
track the depth of its own queue. And if this exceeds the total
depth divided by the number of active queues, the user is actively
throttled down.
The active queue count is done lazily to avoid bouncing that data
between submitter and completer. Each hardware queue gets marked
active when it allocates its first tag, and gets marked inactive
when 1) the last tag is cleared, and 2) the queue timeout grace
period has passed.
Signed-off-by: Jens Axboe <axboe@fb.com>
Convert all cftype->write_string() users to the new cftype->write()
which maps directly to kernfs write operation and has full access to
kernfs and cgroup contexts. The conversions are mostly mechanical.
* @css and @cft are accessed using of_css() and of_cft() accessors
respectively instead of being specified as arguments.
* Should return @nbytes on success instead of 0.
* @buf is not trimmed automatically. Trim if necessary. Note that
blkcg and netprio don't need this as the parsers already handle
whitespaces.
cftype->write_string() has no user left after the conversions and
removed.
While at it, remove unnecessary local variable @p in
cgroup_subtree_control_write() and stale comment about
CGROUP_LOCAL_BUFFER_SIZE in cgroup_freezer.c.
This patch doesn't introduce any visible behavior changes.
v2: netprio was missing from conversion. Converted.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Aristeu Rozanski <arozansk@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: "David S. Miller" <davem@davemloft.net>
Unlike the more usual refcnting, what css_tryget() provides is the
distinction between online and offline csses instead of protection
against upping a refcnt which already reached zero. cgroup is
planning to provide actual tryget which fails if the refcnt already
reached zero. Let's rename the existing trygets so that they clearly
indicate that they're onliness.
I thought about keeping the existing names as-are and introducing new
names for the planned actual tryget; however, given that each
controller participates in the synchronization of the online state, it
seems worthwhile to make it explicit that these functions are about
on/offline state.
Rename css_tryget() to css_tryget_online() and css_tryget_from_dir()
to css_tryget_online_from_dir(). This is pure rename.
v2: cgroup_freezer grew new usages of css_tryget(). Update
accordingly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Both nr_cache and nr_tags arn't needed for bitmap tag anymore.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
The selected tag should be selected at random between 0 and
(depth - 1) with probability 1/depth, instead between 0 and
(depth - 2) with probability 1/(depth - 1).
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
The barrier isn't necessary because both atomic_dec_and_test()
and wake_up() implicate one barrier.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
The unlock memory barrier need to order access to req in free
path and clearing tag bit, otherwise either request free path
may see a allocated request, or initialized request in allocate
path might be modified by the ongoing free path.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
We first check if we have inflight IO, then retrieve that
same number again. Usually this isn't that costly since the
chance of having the data dirtied in between is small, but
there's no reason for calling part_in_flight() twice.
Signed-off-by: Jens Axboe <axboe@fb.com>
Commit c6d600c6 opened up a small race where we could attempt to
account IO completion on a request, racing with IO start accounting.
Fix this up by ensuring that we've accounted for IO start before
inserting the request.
Signed-off-by: Jens Axboe <axboe@fb.com>
For best performance, spreading tags over multiple cachelines
makes the tagging more efficient on multicore systems. But since
we have 8 * sizeof(unsigned long) tags per cacheline, we don't
always get a nice spread.
Attempt to spread the tags over at least 4 cachelines, using fewer
number of bits per unsigned long if we have to. This improves
tagging performance in setups with 32-128 tags. For higher depths,
the spread is the same as before (BITS_PER_LONG tags per cacheline).
Signed-off-by: Jens Axboe <axboe@fb.com>
blk-mq currently uses percpu_ida for tag allocation. But that only
works well if the ratio between tag space and number of CPUs is
sufficiently high. For most devices and systems, that is not the
case. The end result if that we either only utilize the tag space
partially, or we end up attempting to fully exhaust it and run
into lots of lock contention with stealing between CPUs. This is
not optimal.
This new tagging scheme is a hybrid bitmap allocator. It uses
two tricks to both be SMP friendly and allow full exhaustion
of the space:
1) We cache the last allocated (or freed) tag on a per blk-mq
software context basis. This allows us to limit the space
we have to search. The key element here is not caching it
in the shared tag structure, otherwise we end up dirtying
more shared cache lines on each allocate/free operation.
2) The tag space is split into cache line sized groups, and
each context will start off randomly in that space. Even up
to full utilization of the space, this divides the tag users
efficiently into cache line groups, avoiding dirtying the same
one both between allocators and between allocator and freeer.
This scheme shows drastically better behaviour, both on small
tag spaces but on large ones as well. It has been tested extensively
to show better performance for all the cases blk-mq cares about.
Signed-off-by: Jens Axboe <axboe@fb.com>
This allows us to avoid a non-atomic memset over ->atomic_flags as well
as killing lots of duplicate initializations.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Right now we just pick the first CPU in the mask, but that can
easily overload that one. Add some basic batching and round-robin
all the entries in the mask instead.
Signed-off-by: Jens Axboe <axboe@fb.com>
Adding tracepoints for bio_complete and block_split into nvme to help
with gathering IO info using blktrace and blkparse.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
All blk_iopoll functions use iop for parent iopoll structure except
blk_iopoll_complete.This also fixes one kernel-doc warning.
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>
We already issue a blktrace requeue event in
__blk_mq_requeue_request(), don't do it from the original caller
as well.
Signed-off-by: Jens Axboe <axboe@fb.com>
Refactor the logic around adding a new bio to a software queue,
so we nest the ctx->lock where we really need it (merge and
insertion) and don't hold it when we don't (init and IO start
accounting).
Signed-off-by: Jens Axboe <axboe@fb.com>
blk_mq_wait_for_tags() is only able to wait for "normal" tags,
not reserved tags. Pass in which one we should attempt to get
a tag for, so that waiting for reserved tags will work.
Reserved tags are used for internal commands, which are usually
serialized. Hence no waiting generally takes place, but we should
ensure that it actually works if users need that functionality.
Signed-off-by: Jens Axboe <axboe@fb.com>
The blk-mq code is using it's own version of the I/O completion affinity
tunables, which causes a few issues:
- the rq_affinity sysfs file doesn't work for blk-mq devices, even if it
still is present, thus breaking existing tuning setups.
- the rq_affinity = 1 mode, which is the defauly for legacy request based
drivers isn't implemented at all.
- blk-mq drivers don't implement any completion affinity with the default
flag settings.
This patches removes the blk-mq ipi_redirect flag and sysfs file, as well
as the internal BLK_MQ_F_SHOULD_IPI flag and replaces it with code that
respects the queue-wide rq_affinity flags and also implements the
rq_affinity = 1 mode.
This means I/O completion affinity can now only be tuned block-queue wide
instead of per context, which seems more sensible to me anyway.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
If a requeue event races with a timeout, we can get into the
situation where we attempt to complete a request from the
timeout handler when it's not start anymore. This causes a crash.
So have the timeout handler check that REQ_ATOM_STARTED is still
set on the request - if not, we ignore the event. If this happens,
the request has now been marked as complete. As a consequence, we
need to ensure to clear REQ_ATOM_COMPLETE in blk_mq_start_request(),
as to maintain proper request state.
Signed-off-by: Jens Axboe <axboe@fb.com>
This reverts commit 6a3c8a3ac0.
We need selective clearing of the request to make the init-at-free
time completely safe. Otherwise we end up stomping on
rq->atomic_flags, which we don't want to do.
blk_throtl_dispatch_work_fn is only used in blk-throttle.c
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>
The patch basically reverts the patch of(blk-mq:
initialize request on allocation) in Jens's tree(already
in -next), and only initialize req->q in allocation
for two reasons:
- presumed cache hotness on completion
- blk_rq_tagged(rq) depends on reset of req->mq_ctx
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
type of set->tags is struct blk_mq_tags **.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Avoid memory leak in the failure path.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
bsg currently checks ->request_fn to check whether a queue can
handle struct request. But with blk-mq, we don't have a request_fn
yet are request based. Add a queue_is_rq_based() helper and use
that in bsg, I'm guessing this is not the last place we need to
update for this. Besides, it better explains what is being
checked.
Signed-off-by: Jens Axboe <axboe@fb.com>
Since we are now, by default, applying timer slack to expiry times,
the logic for when to modify a timer in the block code is suboptimal.
The block layer keeps a forward rolling timer per queue for all
requests, and modifies this timer if a request has a shorter timeout
than what the current expiry time is. However, this breaks down
when our rounded timer values get applied slack. Then each new
request ends up modifying the timer, since we're still a little
in front of the timer + slack.
Fix this by allowing a tolerance of HZ / 2, the timeout handling
doesn't need to be very precise. This drastically cuts down
the number of timer modifications we have to make.
Signed-off-by: Jens Axboe <axboe@fb.com>
This allows to mirror the blk-mq code flow for more a more readable I/O
completion handler in SCSI.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
We will use this work_struct to requeue scsi commands from the
completion handler as well, so give it a more generic name.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
This allows to requeue a request that has been accepted by ->queue_rq
earlier. This is needed by the SCSI layer in various error conditions.
The existing internal blk_mq_requeue_request is renamed to
__blk_mq_requeue_request as it is a lower level building block for this
funtionality.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Add a helper to unconditionally kick contexts of a queue. This will
be needed by the SCSI layer to provide fair queueing between multiple
devices on a single host.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Add a blk-mq equivalent to blk_delay_queue so that the scsi layer can ask
to be kicked again after a delay.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Modified by me to kill the unnecessary preempt disable/enable
in the delayed workqueue handler.
Signed-off-by: Jens Axboe <axboe@fb.com>
Add two unlinkely branches to make sure the resid is initialized correctly
for bidi request pairs, and the second request gets properly freed.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Split out the bottom half of blk_mq_end_io so that drivers can perform
work when they know a request has been completed, but before it has been
freed. This also obsoletes blk_mq_end_io_partial as drivers can now
pass any value to blk_update_request directly.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
blk_mq_work_fn() is always invoked off the bounded workqueues,
so it can happily preempt among the queues in that set without
causing any issues for blk-mq.
Signed-off-by: Jens Axboe <axboe@fb.com>
UP or CONFIG_PREEMPT_NONE will return 0, and what we really
want to check is whether or not we are on the right CPU.
So don't make PREEMPT part of this, just test the CPU in
the mask directly.
Signed-off-by: Jens Axboe <axboe@fb.com>
Add a new blk_mq_tag_set structure that gets set up before we initialize
the queue. A single blk_mq_tag_set structure can be shared by multiple
queues.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Modular export of blk_mq_{alloc,free}_tagset added by me.
Signed-off-by: Jens Axboe <axboe@fb.com>
If we want to share tag and request allocation between queues we cannot
initialize the request at init/free time, but need to initialize it
at allocation time as it might get used for different queues over its
lifetime.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
The current blk_mq_init_commands/blk_mq_free_commands interface has a
two problems:
1) Because only the constructor is passed to blk_mq_init_commands there
is no easy way to clean up when a comman initialization failed. The
current code simply leaks the allocations done in the constructor.
2) There is no good place to call blk_mq_free_commands: before
blk_cleanup_queue there is no guarantee that all outstanding
commands have completed, so we can't free them yet. After
blk_cleanup_queue the queue has usually been freed. This can be
worked around by grabbing an unconditional reference before calling
blk_cleanup_queue and dropping it after blk_mq_free_commands is
done, although that's not exatly pretty and driver writers are
guaranteed to get it wrong sooner or later.
Both issues are easily fixed by making the request constructor and
destructor normal blk_mq_ops methods.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Drivers shouldn't have to care about the block layer setting aside a
request to implement the flush state machine. We already override the
mq context and tag to make it more transparent, but so far haven't deal
with the driver private data in the request. Make sure to override this
as well, and while we're at it add a proper helper sitting in blk-mq.c
that implements the full impersonation.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Drivers can reach their private data easily using the blk_mq_rq_to_pdu
helper and don't need req->special. By not initializing it code can
be simplified nicely, and we also shave off a few more instructions from
the I/O path.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
This was used in the olden days, back when onions were proper
yellow. Basically it mapped to the current buffer to be
transferred. With highmem being added more than a decade ago,
most drivers map pages out of a bio, and rq->buffer isn't
pointing at anything valid.
Convert old style drivers to just use bio_data().
For the discard payload use case, just reference the page
in the bio.
Signed-off-by: Jens Axboe <axboe@fb.com>
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Merge tag 'v3.15-rc1' into for-3.16/core
We don't like this, but things have diverged with the blk-mq fixes
in 3.15-rc1. So merge it in.
Pull vfs updates from Al Viro:
"The first vfs pile, with deep apologies for being very late in this
window.
Assorted cleanups and fixes, plus a large preparatory part of iov_iter
work. There's a lot more of that, but it'll probably go into the next
merge window - it *does* shape up nicely, removes a lot of
boilerplate, gets rid of locking inconsistencie between aio_write and
splice_write and I hope to get Kent's direct-io rewrite merged into
the same queue, but some of the stuff after this point is having
(mostly trivial) conflicts with the things already merged into
mainline and with some I want more testing.
This one passes LTP and xfstests without regressions, in addition to
usual beating. BTW, readahead02 in ltp syscalls testsuite has started
giving failures since "mm/readahead.c: fix readahead failure for
memoryless NUMA nodes and limit readahead pages" - might be a false
positive, might be a real regression..."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
missing bits of "splice: fix racy pipe->buffers uses"
cifs: fix the race in cifs_writev()
ceph_sync_{,direct_}write: fix an oops on ceph_osdc_new_request() failure
kill generic_file_buffered_write()
ocfs2_file_aio_write(): switch to generic_perform_write()
ceph_aio_write(): switch to generic_perform_write()
xfs_file_buffered_aio_write(): switch to generic_perform_write()
export generic_perform_write(), start getting rid of generic_file_buffer_write()
generic_file_direct_write(): get rid of ppos argument
btrfs_file_aio_write(): get rid of ppos
kill the 5th argument of generic_file_buffered_write()
kill the 4th argument of __generic_file_aio_write()
lustre: don't open-code kernel_recvmsg()
ocfs2: don't open-code kernel_recvmsg()
drbd: don't open-code kernel_recvmsg()
constify blk_rq_map_user_iov() and friends
lustre: switch to kernel_sendmsg()
ocfs2: don't open-code kernel_sendmsg()
take iov_iter stuff to mm/iov_iter.c
process_vm_access: tidy up a bit
...
Martin reported that his test system would not boot with
current git, it oopsed with this:
BUG: unable to handle kernel paging request at ffff88046c6c9e80
IP: [<ffffffff812971e0>] blk_queue_start_tag+0x90/0x150
PGD 1ddf067 PUD 1de2067 PMD 47fc7d067 PTE 800000046c6c9060
Oops: 0002 [#1] SMP DEBUG_PAGEALLOC
Modules linked in: sd_mod lpfc(+) scsi_transport_fc scsi_tgt oracleasm
rpcsec_gss_krb5 ipv6 igb dca i2c_algo_bit i2c_core hwmon
CPU: 3 PID: 87 Comm: kworker/u17:1 Not tainted 3.14.0+ #246
Hardware name: Supermicro X9DRX+-F/X9DRX+-F, BIOS 3.00 07/09/2013
Workqueue: events_unbound async_run_entry_fn
task: ffff8802743c2150 ti: ffff880273d02000 task.ti: ffff880273d02000
RIP: 0010:[<ffffffff812971e0>] [<ffffffff812971e0>]
blk_queue_start_tag+0x90/0x150
RSP: 0018:ffff880273d03a58 EFLAGS: 00010092
RAX: ffff88046c6c9e78 RBX: ffff880077208e78 RCX: 00000000fffc8da6
RDX: 00000000fffc186d RSI: 0000000000000009 RDI: 00000000fffc8d9d
RBP: ffff880273d03a88 R08: 0000000000000001 R09: ffff8800021c2410
R10: 0000000000000005 R11: 0000000000015b30 R12: ffff88046c5bb8a0
R13: ffff88046c5c0890 R14: 000000000000001e R15: 000000000000001e
FS: 0000000000000000(0000) GS:ffff880277b00000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff88046c6c9e80 CR3: 00000000018f6000 CR4: 00000000000407e0
Stack:
ffff880273d03a98 ffff880474b18800 0000000000000000 ffff880474157000
ffff88046c5c0890 ffff880077208e78 ffff880273d03ae8 ffffffff813b9e62
ffff880200000010 ffff880474b18968 ffff880474b18848 ffff88046c5c0cd8
Call Trace:
[<ffffffff813b9e62>] scsi_request_fn+0xf2/0x510
[<ffffffff81293167>] __blk_run_queue+0x37/0x50
[<ffffffff8129ac43>] blk_execute_rq_nowait+0xb3/0x130
[<ffffffff8129ad24>] blk_execute_rq+0x64/0xf0
[<ffffffff8108d2b0>] ? bit_waitqueue+0xd0/0xd0
[<ffffffff813bba35>] scsi_execute+0xe5/0x180
[<ffffffff813bbe4a>] scsi_execute_req_flags+0x9a/0x110
[<ffffffffa01b1304>] sd_spinup_disk+0x94/0x460 [sd_mod]
[<ffffffff81160000>] ? __unmap_hugepage_range+0x200/0x2f0
[<ffffffffa01b2b9a>] sd_revalidate_disk+0xaa/0x3f0 [sd_mod]
[<ffffffffa01b2fb8>] sd_probe_async+0xd8/0x200 [sd_mod]
[<ffffffff8107703f>] async_run_entry_fn+0x3f/0x140
[<ffffffff8106a1c5>] process_one_work+0x175/0x410
[<ffffffff8106b373>] worker_thread+0x123/0x400
[<ffffffff8106b250>] ? manage_workers+0x160/0x160
[<ffffffff8107104e>] kthread+0xce/0xf0
[<ffffffff81070f80>] ? kthread_freezable_should_stop+0x70/0x70
[<ffffffff815f0bac>] ret_from_fork+0x7c/0xb0
[<ffffffff81070f80>] ? kthread_freezable_should_stop+0x70/0x70
Code: 48 0f ab 11 72 db 48 81 4b 40 00 00 10 00 89 83 08 01 00 00 48 89
df 49 8b 04 24 48 89 1c d0 e8 f7 a8 ff ff 49 8b 85 28 05 00 00 <48> 89
58 08 48 89 03 49 8d 85 28 05 00 00 48 89 43 08 49 89 9d
RIP [<ffffffff812971e0>] blk_queue_start_tag+0x90/0x150
RSP <ffff880273d03a58>
CR2: ffff88046c6c9e80
Martin bisected and found this to be the problem patch;
commit 6d113398dc
Author: Jan Kara <jack@suse.cz>
Date: Mon Feb 24 16:39:54 2014 +0100
block: Stop abusing rq->csd.list in blk-softirq
and the problem was immediately apparent. The patch states that
it is safe to reuse queuelist at completion time, since it is
no longer used. However, that is not true if a device is using
block enabled tagging. If that is the case, then the queuelist
is reused to keep track of busy tags. If a device also ended
up using softirq completions, we'd reuse ->queuelist for the
IPI handling while block tagging was still using it. Boom.
Fix this by adding a new ipi_list list head, and share the
memory used with the request hash table. The hash table is
never used after the request is moved to the dispatch list,
which happens long before any potential completion of the
request. Add a new request bit for this, so we don't have
cases that check rq->hash while it could potentially have
been reused for the IPI completion.
Reported-by: Martin K. Petersen <martin.petersen@oracle.com>
Tested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
Now that we have a cpu mask of CPUs that are mapped to
a specific hardware queue, we can just iterate that to
display the sysfs num-hw-queue/cpu_list file.
Signed-off-by: Jens Axboe <axboe@fb.com>
Instead of providing soft mappings with no guarantees on hardware
queues always being run on the right CPU, switch to a hard mapping
guarantee that ensure that we always run the hardware queue on
(one of, if more) the mapped CPU.
Signed-off-by: Jens Axboe <axboe@fb.com>
Same function as kblockd_schedule_delayed_work(), but allow the
caller to pass in a CPU that the work should be executed on. This
just directly extends and maps into the workqueue API, and will
be used to make the blk-mq mappings more strict.
Signed-off-by: Jens Axboe <axboe@fb.com>
When a CPU is unplugged, we move the blk_mq_ctx request entries
to the current queue. The current code forgets to remap the
blk_mq_hw_ctx before marking the software context pending,
which breaks if old-cpu and new-cpu don't map to the same
hardware queue.
Additionally, if we mark entries as pending in the new
hardware queue, then make sure we schedule it for running.
Otherwise request could be sitting there until someone else
queues IO for that hardware queue.
Signed-off-by: Jens Axboe <axboe@fb.com>
Pull cgroup updates from Tejun Heo:
"A lot updates for cgroup:
- The biggest one is cgroup's conversion to kernfs. cgroup took
after the long abandoned vfs-entangled sysfs implementation and
made it even more convoluted over time. cgroup's internal objects
were fused with vfs objects which also brought in vfs locking and
object lifetime rules. Naturally, there are places where vfs rules
don't fit and nasty hacks, such as credential switching or lock
dance interleaving inode mutex and cgroup_mutex with object serial
number comparison thrown in to decide whether the operation is
actually necessary, needed to be employed.
After conversion to kernfs, internal object lifetime and locking
rules are mostly isolated from vfs interactions allowing shedding
of several nasty hacks and overall simplification. This will also
allow implmentation of operations which may affect multiple cgroups
which weren't possible before as it would have required nesting
i_mutexes.
- Various simplifications including dropping of module support,
easier cgroup name/path handling, simplified cgroup file type
handling and task_cg_lists optimization.
- Prepatory changes for the planned unified hierarchy, which is still
a patchset away from being actually operational. The dummy
hierarchy is updated to serve as the default unified hierarchy.
Controllers which aren't claimed by other hierarchies are
associated with it, which BTW was what the dummy hierarchy was for
anyway.
- Various fixes from Li and others. This pull request includes some
patches to add missing slab.h to various subsystems. This was
triggered xattr.h include removal from cgroup.h. cgroup.h
indirectly got included a lot of files which brought in xattr.h
which brought in slab.h.
There are several merge commits - one to pull in kernfs updates
necessary for converting cgroup (already in upstream through
driver-core), others for interfering changes in the fixes branch"
* 'for-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (74 commits)
cgroup: remove useless argument from cgroup_exit()
cgroup: fix spurious lockdep warning in cgroup_exit()
cgroup: Use RCU_INIT_POINTER(x, NULL) in cgroup.c
cgroup: break kernfs active_ref protection in cgroup directory operations
cgroup: fix cgroup_taskset walking order
cgroup: implement CFTYPE_ONLY_ON_DFL
cgroup: make cgrp_dfl_root mountable
cgroup: drop const from @buffer of cftype->write_string()
cgroup: rename cgroup_dummy_root and related names
cgroup: move ->subsys_mask from cgroupfs_root to cgroup
cgroup: treat cgroup_dummy_root as an equivalent hierarchy during rebinding
cgroup: remove NULL checks from [pr_cont_]cgroup_{name|path}()
cgroup: use cgroup_setup_root() to initialize cgroup_dummy_root
cgroup: reorganize cgroup bootstrapping
cgroup: relocate setting of CGRP_DEAD
cpuset: use rcu_read_lock() to protect task_cs()
cgroup_freezer: document freezer_fork() subtleties
cgroup: update cgroup_transfer_tasks() to either succeed or fail
cgroup: drop task_lock() protection around task->cgroups
cgroup: update how a newly forked task gets associated with css_set
...
Pull networking updates from David Miller:
"Here is my initial pull request for the networking subsystem during
this merge window:
1) Support for ESN in AH (RFC 4302) from Fan Du.
2) Add full kernel doc for ethtool command structures, from Ben
Hutchings.
3) Add BCM7xxx PHY driver, from Florian Fainelli.
4) Export computed TCP rate information in netlink socket dumps, from
Eric Dumazet.
5) Allow IPSEC SA to be dumped partially using a filter, from Nicolas
Dichtel.
6) Convert many drivers to pci_enable_msix_range(), from Alexander
Gordeev.
7) Record SKB timestamps more efficiently, from Eric Dumazet.
8) Switch to microsecond resolution for TCP round trip times, also
from Eric Dumazet.
9) Clean up and fix 6lowpan fragmentation handling by making use of
the existing inet_frag api for it's implementation.
10) Add TX grant mapping to xen-netback driver, from Zoltan Kiss.
11) Auto size SKB lengths when composing netlink messages based upon
past message sizes used, from Eric Dumazet.
12) qdisc dumps can take a long time, add a cond_resched(), From Eric
Dumazet.
13) Sanitize netpoll core and drivers wrt. SKB handling semantics.
Get rid of never-used-in-tree netpoll RX handling. From Eric W
Biederman.
14) Support inter-address-family and namespace changing in VTI tunnel
driver(s). From Steffen Klassert.
15) Add Altera TSE driver, from Vince Bridgers.
16) Optimizing csum_replace2() so that it doesn't adjust the checksum
by checksumming the entire header, from Eric Dumazet.
17) Expand BPF internal implementation for faster interpreting, more
direct translations into JIT'd code, and much cleaner uses of BPF
filtering in non-socket ocntexts. From Daniel Borkmann and Alexei
Starovoitov"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1976 commits)
netpoll: Use skb_irq_freeable to make zap_completion_queue safe.
net: Add a test to see if a skb is freeable in irq context
qlcnic: Fix build failure due to undefined reference to `vxlan_get_rx_port'
net: ptp: move PTP classifier in its own file
net: sxgbe: make "core_ops" static
net: sxgbe: fix logical vs bitwise operation
net: sxgbe: sxgbe_mdio_register() frees the bus
Call efx_set_channels() before efx->type->dimension_resources()
xen-netback: disable rogue vif in kthread context
net/mlx4: Set proper build dependancy with vxlan
be2net: fix build dependency on VxLAN
mac802154: make csma/cca parameters per-wpan
mac802154: allow only one WPAN to be up at any given time
net: filter: minor: fix kdoc in __sk_run_filter
netlink: don't compare the nul-termination in nla_strcmp
can: c_can: Avoid led toggling for every packet.
can: c_can: Simplify TX interrupt cleanup
can: c_can: Store dlc private
can: c_can: Reduce register access
can: c_can: Make the code readable
...
Pull core block layer updates from Jens Axboe:
"This is the pull request for the core block IO bits for the 3.15
kernel. It's a smaller round this time, it contains:
- Various little blk-mq fixes and additions from Christoph and
myself.
- Cleanup of the IPI usage from the block layer, and associated
helper code. From Frederic Weisbecker and Jan Kara.
- Duplicate code cleanup in bio-integrity from Gu Zheng. This will
give you a merge conflict, but that should be easy to resolve.
- blk-mq notify spinlock fix for RT from Mike Galbraith.
- A blktrace partial accounting bug fix from Roman Pen.
- Missing REQ_SYNC detection fix for blk-mq from Shaohua Li"
* 'for-3.15/core' of git://git.kernel.dk/linux-block: (25 commits)
blk-mq: add REQ_SYNC early
rt,blk,mq: Make blk_mq_cpu_notify_lock a raw spinlock
blk-mq: support partial I/O completions
blk-mq: merge blk_mq_insert_request and blk_mq_run_request
blk-mq: remove blk_mq_alloc_rq
blk-mq: don't dump CPU -> hw queue map on driver load
blk-mq: fix wrong usage of hctx->state vs hctx->flags
blk-mq: allow blk_mq_init_commands() to return failure
block: remove old blk_iopoll_enabled variable
blktrace: fix accounting of partially completed requests
smp: Rename __smp_call_function_single() to smp_call_function_single_async()
smp: Remove wait argument from __smp_call_function_single()
watchdog: Simplify a little the IPI call
smp: Move __smp_call_function_single() below its safe version
smp: Consolidate the various smp_call_function_single() declensions
smp: Teach __smp_call_function_single() to check for offline cpus
smp: Remove unused list_head from csd
smp: Iterate functions through llist_for_each_entry_safe()
block: Stop abusing rq->csd.list in blk-softirq
block: Remove useless IPI struct initialization
...
Conflicts:
Documentation/devicetree/bindings/net/micrel-ks8851.txt
net/core/netpoll.c
The net/core/netpoll.c conflict is a bug fix in 'net' happening
to code which is completely removed in 'net-next'.
In micrel-ks8851.txt we simply have overlapping changes.
Signed-off-by: David S. Miller <davem@davemloft.net>
Add REQ_SYNC early, so rq_dispatched[] in blk_mq_rq_ctx_init
is set correctly.
Signed-off-by: Shaohua Li<shli@fusionio.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Add a new blk_mq_end_io_partial function to partially complete requests
as needed by the SCSI layer. We do this by reusing blk_update_request
to advance the bio instead of having a simplified version of it in
the blk-mq code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
It's almost identical to blk_mq_insert_request, so fold the two into one
slightly more generic function by making the flush special case a bit
smarted.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
There's only one caller, which is a straight wrapper and fits the naming
scheme of the related functions a lot better.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Commit 7982e90c3a ("block: fix q->flush_rq NULL pointer crash on
dm-mpath flush") moved an allocation to blk_init_allocated_queue(), but
neglected to free that allocation on the error paths that follow.
Signed-off-by: Dave Jones <davej@fedoraproject.org>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that we are out of initial debug/bringup mode, remove
the verbose dump of the mapping table.
Provide the mapping table in sysfs, under the hardware queue
directory, in the cpu_list file.
Signed-off-by: Jens Axboe <axboe@fb.com>
BLK_MQ_F_* flags are for hctx->flags, and are non-atomic and
set at registration time. BLK_MQ_S_* flags are dynamic and
atomic, and are accessed through hctx->state.
Some of the BLK_MQ_S_STOPPED uses were wrong. Additionally,
the header file should not use a bit shift for the _S_ flags,
as they are done through the set/test_bit functions.
Signed-off-by: Jens Axboe <axboe@fb.com>
cftype->write_string() just passes on the writeable buffer from kernfs
and there's no reason to add const restriction on the buffer. The
only thing const achieves is unnecessarily complicating parsing of the
buffer. Drop const from @buffer.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Replace the bh safe variant with the hard irq safe variant.
We need a hard irq safe variant to deal with netpoll transmitting
packets from hard irq context, and we need it in most if not all of
the places using the bh safe variant.
Except on 32bit uni-processor the code is exactly the same so don't
bother with a bh variant, just have a hard irq safe variant that
everyone can use.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If drivers do dynamic allocation in the hardware command init
path, then we need to be able to handle and return failures.
And if they do allocations or mappings in the init command path,
then we need a cleanup function to free up that space at exit
time. So add blk_mq_free_commands() as the cleanup function.
This is required for the mtip32xx driver conversion to blk-mq.
Signed-off-by: Jens Axboe <axboe@fb.com>
Christoph Hellwig