In the function 'response_parse', num_entries will never be 0 as
slen is checked for 0. Hence, the condition 'if (num_entries == 0)'
can never be true.
Signed-off-by: Revanth Rajashekar <revanth.rajashekar@intel.com>
Reviewed-by: Scott Bauer <sbauer@plzdonthack.me>
Reviewed-by: Jon Derrick <jonathan.derrick@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The dispatch list is not used any more, as the legacy block IO stack
has been removed.
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
psi tracks the time tasks wait for refaulting pages to become
uptodate, but it does not track the time spent submitting the IO. The
submission part can be significant if backing storage is contended or
when cgroup throttling (io.latency) is in effect - a lot of time is
spent in submit_bio(). In that case, we underreport memory pressure.
Annotate submit_bio() to account submission time as memory stall when
the bio is reading userspace workingset pages.
Tested-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now that there no module users left of bio_map_kern, stop exporting the
symbol.
Reviewed-by: Javier González <javier@javigon.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hans Holmberg <hans@owltronix.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Spread queues among present CPUs first, then building mapping on other
non-present CPUs.
So we can minimize count of dead queues which are mapped by un-present
CPUs only. Then bad IO performance can be avoided by unbalanced mapping
between present CPUs and queues.
The similar policy has been applied on Managed IRQ affinity.
Cc: Yi Zhang <yi.zhang@redhat.com>
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Reviewed-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This implements REQ_OP_ZONE_RESET_ALL as a special case of the block
device zone reset operations where we just simply issue bio with the
newly introduced req op.
We issue this req op when the number of sectors is equal to the device's
partition's number of sectors and device has no partitions.
We also add support so that blk_op_str() can print the new reset-all
zone operation.
This patch also adds a generic make request check for newly
introduced REQ_OP_ZONE_RESET_ALL req_opf. We simply return error
when queue is zoned and reset-all flag is not set for
REQ_OP_ZONE_RESET_ALL.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Change a reference to the legacy block layer into a reference to blk-mq.
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hannes Reinecke <hare@suse.com>
Cc: James Smart <james.smart@broadcom.com>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Jianchao Wang <jianchao.w.wang@oracle.com>
Cc: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Consider the following example:
* The logical block size is 4 KB.
* The physical block size is 8 KB.
* max_sectors equals (16 KB >> 9) sectors.
* A non-aligned 4 KB and an aligned 64 KB bio are merged into a single
non-aligned 68 KB bio.
The current behavior is to split such a bio into (16 KB + 16 KB + 16 KB
+ 16 KB + 4 KB). The start of none of these five bio's is aligned to a
physical block boundary.
This patch ensures that such a bio is split into four aligned and
one non-aligned bio instead of being split into five non-aligned bios.
This improves performance because most block devices can handle aligned
requests faster than non-aligned requests.
Since the physical block size is larger than or equal to the logical
block size, this patch preserves the guarantee that the returned
value is a multiple of the logical block size.
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move the max_sectors check into bvec_split_segs() such that a single
call to that function can do all the necessary checks. This patch
optimizes the fast path further, namely if a bvec fits in a page.
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Simplify this function by by removing two if-tests. Other than requiring
that the @sectors pointer is not NULL, this patch does not change the
behavior of bvec_split_segs().
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since what the bio splitting functions do is nontrivial, document these
functions.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Make it clear to the compiler and also to humans that the functions
that query request queue properties do not modify any member of the
request_queue data structure.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_mq_tagset_wait_completed_request() has been applied for waiting
for completed request's fn, so not necessary to use
blk_mq_complete_request_sync() any more.
Cc: Max Gurtovoy <maxg@mellanox.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk-mq may schedule to call queue's complete function on remote CPU via
IPI, but doesn't provide any way to synchronize the request's complete
fn. The current queue freeze interface can't provide the synchonization
because aborted requests stay at blk-mq queues during EH.
In some driver's EH(such as NVMe), hardware queue's resource may be freed &
re-allocated. If the completed request's complete fn is run finally after the
hardware queue's resource is released, kernel crash will be triggered.
Prepare for fixing this kind of issue by introducing
blk_mq_tagset_wait_completed_request().
Cc: Max Gurtovoy <maxg@mellanox.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
NVMe needs this function to decide if one request to be aborted has
been completed in normal IO path already.
So introduce it.
Cc: Max Gurtovoy <maxg@mellanox.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We should only set the max segment size to unlimited if we actually
have a virt boundary. Otherwise we accidentally clear that limit
when called from the SCSI midlayer, which always calls
blk_queue_virt_boundary, even if that mask is 0.
Fixes: 7ad388d8e4 ("scsi: core: add a host / host template field for the virt boundary")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-linus-20190726' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
- Several io_uring fixes/improvements:
- Blocking fix for O_DIRECT (me)
- Latter page slowness for registered buffers (me)
- Fix poll hang under certain conditions (me)
- Defer sequence check fix for wrapped rings (Zhengyuan)
- Mismatch in async inc/dec accounting (Zhengyuan)
- Memory ordering issue that could cause stall (Zhengyuan)
- Track sequential defer in bytes, not pages (Zhengyuan)
- NVMe pull request from Christoph
- Set of hang fixes for wbt (Josef)
- Redundant error message kill for libahci (Ding)
- Remove unused blk_mq_sched_started_request() and related ops (Marcos)
- drbd dynamic alloc shash descriptor to reduce stack use (Arnd)
- blkcg ->pd_stat() non-debug print (Tejun)
- bcache memory leak fix (Wei)
- Comment fix (Akinobu)
- BFQ perf regression fix (Paolo)
* tag 'for-linus-20190726' of git://git.kernel.dk/linux-block: (24 commits)
io_uring: ensure ->list is initialized for poll commands
Revert "nvme-pci: don't create a read hctx mapping without read queues"
nvme: fix multipath crash when ANA is deactivated
nvme: fix memory leak caused by incorrect subsystem free
nvme: ignore subnqn for ADATA SX6000LNP
drbd: dynamically allocate shash descriptor
block: blk-mq: Remove blk_mq_sched_started_request and started_request
bcache: fix possible memory leak in bch_cached_dev_run()
io_uring: track io length in async_list based on bytes
io_uring: don't use iov_iter_advance() for fixed buffers
block: properly handle IOCB_NOWAIT for async O_DIRECT IO
blk-mq: allow REQ_NOWAIT to return an error inline
io_uring: add a memory barrier before atomic_read
rq-qos: use a mb for got_token
rq-qos: set ourself TASK_UNINTERRUPTIBLE after we schedule
rq-qos: don't reset has_sleepers on spurious wakeups
rq-qos: fix missed wake-ups in rq_qos_throttle
wait: add wq_has_single_sleeper helper
block, bfq: check also in-flight I/O in dispatch plugging
block: fix sysfs module parameters directory path in comment
...
blk_mq_sched_completed_request is a function that checks if the elevator
related to the request has started_request implemented, but currently, none of
the available IO schedulers implement started_request, so remove both.
Signed-off-by: Marcos Paulo de Souza <marcos.souza.org@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
By default, if a caller sets REQ_NOWAIT and we need to block, we'll
return -EAGAIN through the bio->bi_end_io() callback. For some use
cases, this makes it hard to use.
Allow a caller to ask for inline return of errors related to
blocking by also setting REQ_NOWAIT_INLINE.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Oleg noticed that our checking of data.got_token is unsafe in the
cleanup case, and should really use a memory barrier. Use a wmb on the
write side, and a rmb() on the read side. We don't need one in the main
loop since we're saved by set_current_state().
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In case we get a spurious wakeup we need to make sure to re-set
ourselves to TASK_UNINTERRUPTIBLE so we don't busy wait.
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we raced with somebody else getting an inflight counter we could fail
to get an inflight counter with no sleepers on the list, and thus need
to go to sleep. In this case has_sleepers should be true because we are
now relying on the waker to get our inflight counter for us. And in the
case of spurious wakeups we'd still want this to be the case. So set
has_sleepers to true if we went to sleep to make sure we're woken up the
proper way.
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We saw a hang in production with WBT where there was only one waiter in
the throttle path and no outstanding IO. This is because of the
has_sleepers optimization that is used to make sure we don't steal an
inflight counter for new submitters when there are people already on the
list.
We can race with our check to see if the waitqueue has any waiters (this
is done locklessly) and the time we actually add ourselves to the
waitqueue. If this happens we'll go to sleep and never be woken up
because nobody is doing IO to wake us up.
Fix this by checking if the waitqueue has a single sleeper on the list
after we add ourselves, that way we have an uptodate view of the list.
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Consider a sync bfq_queue Q that remains empty while in service, and
suppose that, when this happens, there is a fair amount of already
in-flight I/O not belonging to Q. In such a situation, I/O dispatching
may need to be plugged (until new I/O arrives for Q), for the
following reason.
The drive may decide to serve in-flight non-Q's I/O requests before
Q's ones, thereby delaying the arrival of new I/O requests for Q
(recall that Q is sync). If I/O-dispatching is not plugged, then,
while Q remains empty, a basically uncontrolled amount of I/O from
other queues may be dispatched too, possibly causing the service of
Q's I/O to be delayed even longer in the drive. This problem gets more
and more serious as the speed and the queue depth of the drive grow,
because, as these two quantities grow, the probability to find no
queue busy but many requests in flight grows too.
If Q has the same weight and priority as the other queues, then the
above delay is unlikely to cause any issue, because all queues tend to
undergo the same treatment. So, since not plugging I/O dispatching is
convenient for throughput, it is better not to plug. Things change in
case Q has a higher weight or priority than some other queue, because
Q's service guarantees may simply be violated. For this reason,
commit 1de0c4cd9e ("block, bfq: reduce idling only in symmetric
scenarios") does plug I/O in such an asymmetric scenario. Plugging
minimizes the delay induced by already in-flight I/O, and enables Q to
recover the bandwidth it may lose because of this delay.
Yet the above commit does not cover the case of weight-raised queues,
for efficiency concerns. For weight-raised queues, I/O-dispatch
plugging is activated simply if not all bfq_queues are
weight-raised. But this check does not handle the case of in-flight
requests, because a bfq_queue may become non busy *before* all its
in-flight requests are completed.
This commit performs I/O-dispatch plugging for weight-raised queues if
there are some in-flight requests.
As a practical example of the resulting recover of control, under
write load on a Samsung SSD 970 PRO, gnome-terminal starts in 1.5
seconds after this fix, against 15 seconds before the fix (as a
reference, gnome-terminal takes about 35 seconds to start with any of
the other I/O schedulers).
Fixes: 1de0c4cd9e ("block, bfq: reduce idling only in symmetric scenarios")
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'docs/v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull rst conversion of docs from Mauro Carvalho Chehab:
"As agreed with Jon, I'm sending this big series directly to you, c/c
him, as this series required a special care, in order to avoid
conflicts with other trees"
* tag 'docs/v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (77 commits)
docs: kbuild: fix build with pdf and fix some minor issues
docs: block: fix pdf output
docs: arm: fix a breakage with pdf output
docs: don't use nested tables
docs: gpio: add sysfs interface to the admin-guide
docs: locking: add it to the main index
docs: add some directories to the main documentation index
docs: add SPDX tags to new index files
docs: add a memory-devices subdir to driver-api
docs: phy: place documentation under driver-api
docs: serial: move it to the driver-api
docs: driver-api: add remaining converted dirs to it
docs: driver-api: add xilinx driver API documentation
docs: driver-api: add a series of orphaned documents
docs: admin-guide: add a series of orphaned documents
docs: cgroup-v1: add it to the admin-guide book
docs: aoe: add it to the driver-api book
docs: add some documentation dirs to the driver-api book
docs: driver-model: move it to the driver-api book
docs: lp855x-driver.rst: add it to the driver-api book
...
The runtime configurable module parameter files are located under
/sys/module/MODULENAME/parameters, not /sys/module/MODULENAME.
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently, ->pd_stat() is called only when moduleparam
blkcg_debug_stats is set which prevents it from printing non-debug
policy-specific statistics. Let's move debug testing down so that
->pd_stat() can print non-debug stat too. This patch doesn't cause
any visible behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There are lots of documents that belong to the admin-guide but
are on random places (most under Documentation root dir).
Move them to the admin guide.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Rename the block documentation files to ReST, add an
index for them and adjust in order to produce a nice html
output via the Sphinx build system.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Limit the size of the struct blk_zone array used in
blk_revalidate_disk_zones() to avoid memory allocation failures leading
to disk revalidation failure. Also further reduce the likelyhood of
such failures by using kvcalloc() (that is vmalloc()) instead of
allocating contiguous pages with alloc_pages().
Fixes: 515ce60613 ("scsi: sd_zbc: Fix sd_zbc_report_zones() buffer allocation")
Fixes: e76239a374 ("block: add a report_zones method")
Cc: stable@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Only GFP_KERNEL and GFP_NOIO are used with blkdev_report_zones(). In
preparation of using vmalloc() for large report buffer and zone array
allocations used by this function, remove its "gfp_t gfp_mask" argument
and rely on the caller context to use memalloc_noio_save/restore() where
necessary (block layer zone revalidation and dm-zoned I/O error path).
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
To allow the SCSI subsystem scsi_execute_req() function to issue
requests using large buffers that are better allocated with vmalloc()
rather than kmalloc(), modify bio_map_kern() to allow passing a buffer
allocated with vmalloc().
To do so, detect vmalloc-ed buffers using is_vmalloc_addr(). For
vmalloc-ed buffers, flush the buffer using flush_kernel_vmap_range(),
use vmalloc_to_page() instead of virt_to_page() to obtain the pages of
the buffer, and invalidate the buffer addresses with
invalidate_kernel_vmap_range() on completion of read BIOs. This last
point is executed using the function bio_invalidate_vmalloc_pages()
which is defined only if the architecture defines
ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE, that is, if the architecture
actually needs the invalidation done.
Fixes: 515ce60613 ("scsi: sd_zbc: Fix sd_zbc_report_zones() buffer allocation")
Fixes: e76239a374 ("block: add a report_zones method")
Cc: stable@vger.kernel.org
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In bio_integrity_prep(), a kernel buffer is allocated through kmalloc() to
hold integrity metadata. Later on, the buffer will be attached to the bio
structure through bio_integrity_add_page(), which returns the number of
bytes of integrity metadata attached. Due to unexpected situations,
bio_integrity_add_page() may return 0. As a result, bio_integrity_prep()
needs to be terminated with 'false' returned to indicate this error.
However, the allocated kernel buffer is not freed on this execution path,
leading to a memory leak.
To fix this issue, free the allocated buffer before returning from
bio_integrity_prep().
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Simultaneously writing to a sequential zone of a zoned block device
from multiple contexts requires mutual exclusion for BIO issuing to
ensure that writes happen sequentially. However, even for a well
behaved user correctly implementing such synchronization, BIO plugging
may interfere and result in BIOs from the different contextx to be
reordered if plugging is done outside of the mutual exclusion section,
e.g. the plug was started by a function higher in the call chain than
the function issuing BIOs.
Context A Context B
| blk_start_plug()
| ...
| seq_write_zone()
| mutex_lock(zone)
| bio-0->bi_iter.bi_sector = zone->wp
| zone->wp += bio_sectors(bio-0)
| submit_bio(bio-0)
| bio-1->bi_iter.bi_sector = zone->wp
| zone->wp += bio_sectors(bio-1)
| submit_bio(bio-1)
| mutex_unlock(zone)
| return
| -----------------------> | seq_write_zone()
| mutex_lock(zone)
| bio-2->bi_iter.bi_sector = zone->wp
| zone->wp += bio_sectors(bio-2)
| submit_bio(bio-2)
| mutex_unlock(zone)
| <------------------------- |
| blk_finish_plug()
In the above example, despite the mutex synchronization ensuring the
correct BIO issuing order 0, 1, 2, context A BIOs 0 and 1 end up being
issued after BIO 2 of context B, when the plug is released with
blk_finish_plug().
While this problem can be addressed using the blk_flush_plug_list()
function (in the above example, the call must be inserted before the
zone mutex lock is released), a simple generic solution in the block
layer avoid this additional code in all zoned block device user code.
The simple generic solution implemented with this patch is to introduce
the internal helper function blk_mq_plug() to access the current
context plug on BIO submission. This helper returns the current plug
only if the target device is not a zoned block device or if the BIO to
be plugged is not a write operation. Otherwise, the caller context plug
is ignored and NULL returned, resulting is all writes to zoned block
device to never be plugged.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
After commit 991f61fe7e ("Blk-throttle: reduce tail io latency when
iops limit is enforced") wait time could be zero even if group is
throttled and cannot issue requests right now. As a result
throtl_select_dispatch() turns into busy-loop under irq-safe queue
spinlock.
Fix is simple: always round up target time to the next throttle slice.
Fixes: 991f61fe7e ("Blk-throttle: reduce tail io latency when iops limit is enforced")
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For large values of the number of zones reported and/or large zone
sizes, the sector increment calculated with
blk_queue_zone_sectors(q) * n
in blk_report_zones() loop can overflow the unsigned int type used for
the calculation as both "n" and blk_queue_zone_sectors() value are
unsigned int. E.g. for a device with 256 MB zones (524288 sectors),
overflow happens with 8192 or more zones reported.
Changing the return type of blk_queue_zone_sectors() to sector_t, fixes
this problem and avoids overflow problem for all other callers of this
helper too. The same change is also applied to the bdev_zone_sectors()
helper.
Fixes: e76239a374 ("block: add a report_zones method")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When a shared kthread needs to issue a bio for a cgroup, doing so
synchronously can lead to priority inversions as the kthread can be
trapped waiting for that cgroup. This patch implements
REQ_CGROUP_PUNT flag which makes submit_bio() punt the actual issuing
to a dedicated per-blkcg work item to avoid such priority inversions.
This will be used to fix priority inversions in btrfs compression and
should be generally useful as we grow filesystem support for
comprehensive IO control.
Cc: Chris Mason <clm@fb.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
btrfs is going to use css_put() and wbc helpers to improve cgroup
writeback support. Add dummy css_get() definition and export wbc
helpers to prepare for module and !CONFIG_CGROUP builds.
Reported-by: kbuild test robot <lkp@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
With the psi stuff in place we can use the memstall flag to indicate
pressure that happens from throttling.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We discovered a problem in newer kernels where a disconnect of a NBD
device while the flush request was pending would result in a hang. This
is because the blk mq timeout handler does
if (!refcount_inc_not_zero(&rq->ref))
return true;
to determine if it's ok to run the timeout handler for the request.
Flush_rq's don't have a ref count set, so we'd skip running the timeout
handler for this request and it would just sit there in limbo forever.
Fix this by always setting the refcount of any request going through
blk_init_rq() to 1. I tested this with a nbd-server that dropped flush
requests to verify that it hung, and then tested with this patch to
verify I got the timeout as expected and the error handling kicked in.
Thanks,
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-5.3/block-20190708' of git://git.kernel.dk/linux-block
Pull block updates from Jens Axboe:
"This is the main block updates for 5.3. Nothing earth shattering or
major in here, just fixes, additions, and improvements all over the
map. This contains:
- Series of documentation fixes (Bart)
- Optimization of the blk-mq ctx get/put (Bart)
- null_blk removal race condition fix (Bob)
- req/bio_op() cleanups (Chaitanya)
- Series cleaning up the segment accounting, and request/bio mapping
(Christoph)
- Series cleaning up the page getting/putting for bios (Christoph)
- block cgroup cleanups and moving it to where it is used (Christoph)
- block cgroup fixes (Tejun)
- Series of fixes and improvements to bcache, most notably a write
deadlock fix (Coly)
- blk-iolatency STS_AGAIN and accounting fixes (Dennis)
- Series of improvements and fixes to BFQ (Douglas, Paolo)
- debugfs_create() return value check removal for drbd (Greg)
- Use struct_size(), where appropriate (Gustavo)
- Two lighnvm fixes (Heiner, Geert)
- MD fixes, including a read balance and corruption fix (Guoqing,
Marcos, Xiao, Yufen)
- block opal shadow mbr additions (Jonas, Revanth)
- sbitmap compare-and-exhange improvemnts (Pavel)
- Fix for potential bio->bi_size overflow (Ming)
- NVMe pull requests:
- improved PCIe suspent support (Keith Busch)
- error injection support for the admin queue (Akinobu Mita)
- Fibre Channel discovery improvements (James Smart)
- tracing improvements including nvmetc tracing support (Minwoo Im)
- misc fixes and cleanups (Anton Eidelman, Minwoo Im, Chaitanya
Kulkarni)"
- Various little fixes and improvements to drivers and core"
* tag 'for-5.3/block-20190708' of git://git.kernel.dk/linux-block: (153 commits)
blk-iolatency: fix STS_AGAIN handling
block: nr_phys_segments needs to be zero for REQ_OP_WRITE_ZEROES
blk-mq: simplify blk_mq_make_request()
blk-mq: remove blk_mq_put_ctx()
sbitmap: Replace cmpxchg with xchg
block: fix .bi_size overflow
block: sed-opal: check size of shadow mbr
block: sed-opal: ioctl for writing to shadow mbr
block: sed-opal: add ioctl for done-mark of shadow mbr
block: never take page references for ITER_BVEC
direct-io: use bio_release_pages in dio_bio_complete
block_dev: use bio_release_pages in bio_unmap_user
block_dev: use bio_release_pages in blkdev_bio_end_io
iomap: use bio_release_pages in iomap_dio_bio_end_io
block: use bio_release_pages in bio_map_user_iov
block: use bio_release_pages in bio_unmap_user
block: optionally mark pages dirty in bio_release_pages
block: move the BIO_NO_PAGE_REF check into bio_release_pages
block: skd_main.c: Remove call to memset after dma_alloc_coherent
block: mtip32xx: Remove call to memset after dma_alloc_coherent
...
Pull cgroup updates from Tejun Heo:
"Documentation updates and the addition of cgroup_parse_float() which
will be used by new controllers including blk-iocost"
* 'for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
docs: cgroup-v1: convert docs to ReST and rename to *.rst
cgroup: Move cgroup_parse_float() implementation out of CONFIG_SYSFS
cgroup: add cgroup_parse_float()
When the blk-mq debugfs file creation logic was "cleaned up" it was
cleaned up too much, causing the queue file to not be created in the
correct location. Turns out the check for the directory being present
is needed as if that has not happened yet, the files should not be
created, and the function will be called later on in the initialization
code so that the files can be created in the correct location.
Fixes: 6cfc0081b0 ("blk-mq: no need to check return value of debugfs_create functions")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: linux-block@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The iolatency controller is based on rq_qos. It increments on
rq_qos_throttle() and decrements on either rq_qos_cleanup() or
rq_qos_done_bio(). a3fb01ba5a fixes the double accounting issue where
blk_mq_make_request() may call both rq_qos_cleanup() and
rq_qos_done_bio() on REQ_NO_WAIT. So checking STS_AGAIN prevents the
double decrement.
The above works upstream as the only way we can get STS_AGAIN is from
blk_mq_get_request() failing. The STS_AGAIN handling isn't a real
problem as bio_endio() skipping only happens on reserved tag allocation
failures which can only be caused by driver bugs and already triggers
WARN.
However, the fix creates a not so great dependency on how STS_AGAIN can
be propagated. Internally, we (Facebook) carry a patch that kills read
ahead if a cgroup is io congested or a fatal signal is pending. This
combined with chained bios progagate their bi_status to the parent is
not already set can can cause the parent bio to not clean up properly
even though it was successful. This consequently leaks the inflight
counter and can hang all IOs under that blkg.
To nip the adverse interaction early, this removes the rq_qos_cleanup()
callback in iolatency in favor of cleaning up always on the
rq_qos_done_bio() path.
Fixes: a3fb01ba5a ("blk-iolatency: only account submitted bios")
Debugged-by: Tejun Heo <tj@kernel.org>
Debugged-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Fix a regression introduced when removing bi_phys_segments for Write Zeroes
requests, which need to have a segment count of zero, as they don't have a
payload.
Fixes: 14ccb66b3f ("block: remove the bi_phys_segments field in struct bio")
Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move the blk_mq_bio_to_request() call in front of the if-statement.
Cc: Hannes Reinecke <hare@suse.com>
Cc: Omar Sandoval <osandov@fb.com>
Reviewed-by: Minwoo Im <minwoo.im.dev@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
