Replace the semi-open coded request list helpers with a proper rq_list
type that mirrors the bio_list and has head and tail pointers. Besides
better type safety this actually allows to insert at the tail of the
list, which will be useful soon.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20241113152050.157179-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Supposing first scenario with a virtio_blk driver.
CPU0 CPU1
blk_mq_try_issue_directly()
__blk_mq_issue_directly()
q->mq_ops->queue_rq()
virtio_queue_rq()
blk_mq_stop_hw_queue()
virtblk_done()
blk_mq_request_bypass_insert() 1) store
blk_mq_start_stopped_hw_queue()
clear_bit(BLK_MQ_S_STOPPED) 3) store
blk_mq_run_hw_queue()
if (!blk_mq_hctx_has_pending()) 4) load
return
blk_mq_sched_dispatch_requests()
blk_mq_run_hw_queue()
if (!blk_mq_hctx_has_pending())
return
blk_mq_sched_dispatch_requests()
if (blk_mq_hctx_stopped()) 2) load
return
__blk_mq_sched_dispatch_requests()
Supposing another scenario.
CPU0 CPU1
blk_mq_requeue_work()
blk_mq_insert_request() 1) store
virtblk_done()
blk_mq_start_stopped_hw_queue()
blk_mq_run_hw_queues() clear_bit(BLK_MQ_S_STOPPED) 3) store
blk_mq_run_hw_queue()
if (!blk_mq_hctx_has_pending()) 4) load
return
blk_mq_sched_dispatch_requests()
if (blk_mq_hctx_stopped()) 2) load
continue
blk_mq_run_hw_queue()
Both scenarios are similar, the full memory barrier should be inserted
between 1) and 2), as well as between 3) and 4) to make sure that either
CPU0 sees BLK_MQ_S_STOPPED is cleared or CPU1 sees dispatch list.
Otherwise, either CPU will not rerun the hardware queue causing
starvation of the request.
The easy way to fix it is to add the essential full memory barrier into
helper of blk_mq_hctx_stopped(). In order to not affect the fast path
(hardware queue is not stopped most of the time), we only insert the
barrier into the slow path. Actually, only slow path needs to care about
missing of dispatching the request to the low-level device driver.
Fixes: 320ae51fee ("blk-mq: new multi-queue block IO queueing mechanism")
Cc: stable@vger.kernel.org
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20241014092934.53630-4-songmuchun@bytedance.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
With the block layer zone write plugging being automatically done for
any write operation to a zone of a zoned block device, a regular request
plugging handled through current->plug can only ever see at most a
single write request per zone. In such case, any potential reordering
of the plugged requests will be harmless. We can thus remove the special
casing for write operations to zones and have these requests plugged as
well. This allows removing the function blk_mq_plug and instead directly
using current->plug where needed.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Hans Holmberg <hans.holmberg@wdc.com>
Tested-by: Dennis Maisenbacher <dennis.maisenbacher@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240408014128.205141-29-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now we update driver tags request table in blk_mq_get_driver_tag(),
so the driver that support queue_rqs() have to update that inflight
table by itself.
Move it to blk_mq_start_request(), which is a better place where
we setup the deadline for request timeout check. And it's just
where the request becomes inflight.
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230913151616.3164338-5-chengming.zhou@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There is a limit that batched queue_rqs() can't work on shared tags
queue, since the account of active requests can't be done there.
Now we account the active requests only in blk_mq_get_driver_tag(),
which is not the time we get driver tag actually (with none elevator).
To support batched queue_rqs() on shared tags queue, we move the
account of active requests to where we get the driver tag:
1. none elevator: blk_mq_get_tags() and blk_mq_get_tag()
2. other elevator: __blk_mq_alloc_driver_tag()
This is clearer and match with the unaccount side, which just happen
when we put the driver tag.
The other good point is that we don't need RQF_MQ_INFLIGHT trick
anymore, which used to avoid double account of flush request.
Now we only account when actually get the driver tag, so all is good.
We will remove RQF_MQ_INFLIGHT in the next patch.
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230913151616.3164338-2-chengming.zhou@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In __blk_mq_tag_busy/idle(), updating 'active_queues' and calculating
'wake_batch' is not atomic:
t1: t2:
_blk_mq_tag_busy blk_mq_tag_busy
inc active_queues
// assume 1->2
inc active_queues
// 2 -> 3
blk_mq_update_wake_batch
// calculate based on 3
blk_mq_update_wake_batch
/* calculate based on 2, while active_queues is actually 3. */
Fix this problem by protecting them wih 'tags->lock', this is not a hot
path, so performance should not be concerned. And now that all writers
are inside the lock, switch 'actives_queues' from atomic to unsigned
int.
Fixes: 180dccb0db ("blk-mq: fix tag_get wait task can't be awakened")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230610023043.2559121-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently both requeues of commands that were already sent to the driver
and flush commands submitted from the flush state machine share the same
requeue_list struct request_queue, despite requeues doing head
insertions and flushes not. Switch to using two separate lists instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230519044050.107790-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If blk_insert_flush decides that a command does not need to use the
flush state machine, return false and let blk_mq_submit_bio handle
it the normal way (including using an I/O scheduler) instead of doing
a bypass insert.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230519044050.107790-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In case of q->elevator, passthrough request can still be marked as
RQF_ELV, so some elevator callbacks will be called for them.
Fix this by splitting RQF_SCHED_TAGS, which is set for all requests that
are issued on a queue that uses an I/O scheduler, and RQF_USE_SCHED for
non-flush, non-passthrough requests on such a queue.
Roughly based on two different patches from
Ming Lei <ming.lei@redhat.com>.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230518053101.760632-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-6.4/block-2023-04-21' of git://git.kernel.dk/linux
Pull block updates from Jens Axboe:
- drbd patches, bringing us closer to unifying the out-of-tree version
and the in tree one (Andreas, Christoph)
- support for auto-quiesce for the s390 dasd driver (Stefan)
- MD pull request via Song:
- md/bitmap: Optimal last page size (Jon Derrick)
- Various raid10 fixes (Yu Kuai, Li Nan)
- md: add error_handlers for raid0 and linear (Mariusz Tkaczyk)
- NVMe pull request via Christoph:
- Drop redundant pci_enable_pcie_error_reporting (Bjorn Helgaas)
- Validate nvmet module parameters (Chaitanya Kulkarni)
- Fence TCP socket on receive error (Chris Leech)
- Fix async event trace event (Keith Busch)
- Minor cleanups (Chaitanya Kulkarni, zhenwei pi)
- Fix and cleanup nvmet Identify handling (Damien Le Moal,
Christoph Hellwig)
- Fix double blk_mq_complete_request race in the timeout handler
(Lei Yin)
- Fix irq locking in nvme-fcloop (Ming Lei)
- Remove queue mapping helper for rdma devices (Sagi Grimberg)
- use structured request attribute checks for nbd (Jakub)
- fix blk-crypto race conditions between keyslot management (Eric)
- add sed-opal support for reading read locking range attributes
(Ondrej)
- make fault injection configurable for null_blk (Akinobu)
- clean up the request insertion API (Christoph)
- clean up the queue running API (Christoph)
- blkg config helper cleanups (Tejun)
- lazy init support for blk-iolatency (Tejun)
- various fixes and tweaks to ublk (Ming)
- remove hybrid polling. It hasn't really been useful since we got
async polled IO support, and these days we don't support sync polled
IO at all (Keith)
- misc fixes, cleanups, improvements (Zhong, Ondrej, Colin, Chengming,
Chaitanya, me)
* tag 'for-6.4/block-2023-04-21' of git://git.kernel.dk/linux: (118 commits)
nbd: fix incomplete validation of ioctl arg
ublk: don't return 0 in case of any failure
sed-opal: geometry feature reporting command
null_blk: Always check queue mode setting from configfs
block: ublk: switch to ioctl command encoding
blk-mq: fix the blk_mq_add_to_requeue_list call in blk_kick_flush
block, bfq: Fix division by zero error on zero wsum
fault-inject: fix build error when FAULT_INJECTION_CONFIGFS=y and CONFIGFS_FS=m
block: store bdev->bd_disk->fops->submit_bio state in bdev
block: re-arrange the struct block_device fields for better layout
md/raid5: remove unused working_disks variable
md/raid10: don't call bio_start_io_acct twice for bio which experienced read error
md/raid10: fix memleak of md thread
md/raid10: fix memleak for 'conf->bio_split'
md/raid10: fix leak of 'r10bio->remaining' for recovery
md/raid10: don't BUG_ON() in raise_barrier()
md: fix soft lockup in status_resync
md: add error_handlers for raid0 and linear
md: Use optimal I/O size for last bitmap page
md: Fix types in sb writer
...
Replace the boolean at_head argument with the same flags that are already
passed to blk_mq_insert_request.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230413064057.707578-21-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace the boolean at_head argument with the same flags that are already
passed to blk_mq_insert_request.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230413064057.707578-19-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace the at_head bool with a flags argument that so far only contains
a single BLK_MQ_INSERT_AT_HEAD value. This makes it much easier to grep
for head insertions into the blk-mq dispatch queues.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230413064057.707578-18-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_mq_add_to_requeue_list takes a bool parameter to control how to kick
the requeue list at the end of the function. Move the call to
blk_mq_kick_requeue_list to the callers that want it instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230413064057.707578-17-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_mq_request_bypass_insert takes a bool parameter to control how to run
the queue at the end of the function. Move the blk_mq_run_hw_queue call
to the callers that want it instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230413064057.707578-16-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There is no good point in keeping the __blk_mq_insert_request around
for two function calls and a singler caller.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230413064057.707578-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_mq_dispatch_plug_list is the only caller of
blk_mq_sched_insert_requests, and it makes sense to just fold it there
as blk_mq_sched_insert_requests isn't specific to I/O schedulers despite
the name.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230413064057.707578-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move all logic related to the direct insert (including the call to
blk_mq_run_hw_queue) into blk_mq_insert_requests to streamline the code
flow up a bit, and to allow marking blk_mq_try_issue_list_directly
static.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230413064057.707578-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block/blk-mq.h needs various definitions from <linux/blk-mq.h>,
include it there instead of relying on the source files to include
both.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230413064057.707578-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk-mq-tag.h is always included by blk-mq.h, and causes recursive
inclusion hell with further changes. Just merge it into blk-mq.h
instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230413064057.707578-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The 'q' parameter of the macro __blk_mq_run_dispatch_ops may not be one
local variable, such as, it is rq->q, then request queue pointed by
this variable could be changed to another queue in case of
BLK_MQ_F_TAG_QUEUE_SHARED after 'dispatch_ops' returns, then
'bad unlock balance' is triggered.
Fixes the issue by adding one local variable for doing srcu lock/unlock.
Fixes: 2a904d0085 ("blk-mq: remove hctx_lock and hctx_unlock")
Cc: Marco Patalano <mpatalan@redhat.com>
Signed-off-by: Chris Leech <cleech@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230310010913.1014789-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
All I/O submissions have fairly similar latencies, and a tagset-wide
quiesce is a fairly common operation.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Chao Leng <lengchao@huawei.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20221101150050.3510-12-hch@lst.de
[axboe: fix whitespace]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The current implementation of blk_mq_plug() disables plugging for all
operations that involves a transfer to the device as we just check if
the last bit in op_is_write() function.
Modify blk_mq_plug() to disable plugging only for REQ_OP_WRITE and
REQ_OP_WRITE_ZEROS as they might require a zone lock.
Suggested-by: Christoph Hellwig <hch@lst.de>
Suggested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220929074745.103073-2-p.raghav@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use the new blk_opf_t type for arguments and variables that represent
request flags or a bitwise combination of a request operation and
request flags. Rename the function arguments and also a structure member
that hold a request operation and flags from 'rw' into 'opf'.
This patch does not change any functionality.
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-7-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Drop the unused q argument, and invert the check to move the exception
into a branch and the regular path as the normal return.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220706070350.1703384-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use bdev_is_zoned in all places where a block_device is available instead
of open coding it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220706070350.1703384-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pass a gendisk to the sysfs register/unregister functions and give
them descriptive names. Also move the unregistration helper next
to the one doing the registration.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220628171850.1313069-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a _hctx postfix to better describe what the functions do, match
the debugfs equivalents and release the old names for functions that
should be using them.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220628171850.1313069-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Before the introduction of blk_mq_get_hctx_type(), blk_mq_map_queue()
only used the flags from its second argument. Since the introduction of
blk_mq_get_hctx_type(), blk_mq_map_queue() uses both the operation and
the flags encoded in that argument. Rename the second argument of
blk_mq_map_queue() to make this clear.
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220615225549.1054905-3-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
First code becomes more clean by switching to xarray from plain array.
Second use-after-free on q->queue_hw_ctx can be fixed because
queue_for_each_hw_ctx() may be run when updating nr_hw_queues is
in-progress. With this patch, q->hctx_table is defined as xarray, and
this structure will share same lifetime with request queue, so
queue_for_each_hw_ctx() can use q->hctx_table to lookup hctx reliably.
Reported-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220308073219.91173-7-ming.lei@redhat.com
[axboe: fix blk_mq_hw_ctx forward declaration]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The operation protected via blk_mq_run_dispatch_ops() in blk_mq_run_hw_queue
won't sleep, so don't run might_sleep() for it.
Reported-and-tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We have switched to allocate srcu into request queue, so it is fine
to pass request queue to blk_mq_run_dispatch_ops().
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211203131534.3668411-4-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In case of BLK_MQ_F_BLOCKING, per-hctx srcu is used to protect dispatch
critical area. However, this srcu instance stays at the end of hctx, and
it often takes standalone cacheline, often cold.
Inside srcu_read_lock() and srcu_read_unlock(), WRITE is always done on
the indirect percpu variable which is allocated from heap instead of
being embedded, srcu->srcu_idx is read only in srcu_read_lock(). It
doesn't matter if srcu structure stays in hctx or request queue.
So switch to per-request-queue srcu for protecting dispatch, and this
way simplifies quiesce a lot, not mention quiesce is always done on the
request queue wide.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211203131534.3668411-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Remove hctx_lock and hctx_unlock, and add one helper of
blk_mq_run_dispatch_ops() to run code block defined in dispatch_ops
with rcu/srcu read held.
Compared with hctx_lock()/hctx_unlock():
1) remove 2 branch to 1, so we just need to check
(hctx->flags & BLK_MQ_F_BLOCKING) once when running one dispatch_ops
2) srcu_idx needn't to be touched in case of non-blocking
3) might_sleep_if() can be moved to the blocking branch
Also put the added blk_mq_run_dispatch_ops() in private header, so that
the following patch can use it out of blk-mq.c.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211203131534.3668411-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Keep all the request based code together.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20211117061404.331732-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
submit_bio_checks() may update bio->bi_opf, so we have to initialize
blk_mq_alloc_data.cmd_flags with bio->bi_opf after submit_bio_checks()
returns when allocating new request.
In case of using cached request, fallback to allocate new request if
cached rq isn't compatible with the incoming bio, otherwise change
rq->cmd_flags with incoming bio->bi_opf.
Fixes: 900e080752 ("block: move queue enter logic into blk_mq_submit_bio()")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
kernel test robot reports that we now trigger some sparse warnings:
block/blk-mq.h:169:32: sparse: sparse: restricted req_flags_t degrades to integer
block/blk-mq.h:169:32: sparse: sparse: restricted req_flags_t degrades to integer
block/blk-mq.h:169:32: sparse: sparse: restricted req_flags_t degrades to integer
which is due to ->rq_flags being an unsigned int, rather than the
stronger type req_flags_t enum.
Change the type to req_flags_t to silence this warning.
Fixes: 56f8da642b ("block: add rq_flags to struct blk_mq_alloc_data")
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In case of shared tags and none io sched, batched completion still may
be run into, and hctx->nr_active is accounted when getting driver tag,
so it has to be updated in blk_mq_end_request_batch().
Otherwise, hctx->nr_active may become same with queue depth, then
hctx_may_queue() always return false, then io hang is caused.
Fixes the issue by updating the counter in batched way.
Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Fixes: f794f3351f ("block: add support for blk_mq_end_request_batch()")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211102153619.3627505-4-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There's a hole here we can use, and it's faster to set this earlier
rather than need to check q->elevator multiple times.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20211019153300.623322-2-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we don't use an IO scheduler or have shared tags, then we don't need
to call into this external function at all. This saves ~2% for such
a setup.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
struct io_comp_batch contains a list head and a completion handler, which
will allow completions to more effciently completed batches of IO.
For now, no functional changes in this patch, we just define the
io_comp_batch structure and add the argument to the file_operations iopoll
handler.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
These were added as part of early days debugging for blk-mq, and they
are not really useful anymore. Rather than spend cycles updating them,
just get rid of them.
As a bonus, this shrinks the per-cpu software queue size from 256b
to 192b. That's a whole cacheline less.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace the blk_poll interface that requires the caller to keep a queue
and cookie from the submissions with polling based on the bio.
Polling for the bio itself leads to a few advantages:
- the cookie construction can made entirely private in blk-mq.c
- the caller does not need to remember the request_queue and cookie
separately and thus sidesteps their lifetime issues
- keeping the device and the cookie inside the bio allows to trivially
support polling BIOs remapping by stacking drivers
- a lot of code to propagate the cookie back up the submission path can
be removed entirely.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-15-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Unlike the RWF_HIPRI userspace ABI which is intentionally kept vague,
the bio flag is specific to the polling implementation, so rename and
document it properly.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-12-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The caller typically has a good (or even exact) idea of how many requests
it needs to submit. We can make the request/tag allocation a lot more
efficient if we just allocate N requests/tags upfront when we queue the
first bio from the batch.
Provide a new plug start helper that allows the caller to specify how many
IOs are expected. This sets plug->nr_ios, and we can use that for smarter
request allocation. The plug provides a holding spot for requests, and
request allocation will check it before calling into the normal request
allocation path.
The blk_finish_plug() is called, check if there are unused requests and
free them. This should not happen in normal operations. The exception is
if we get merging, then we may be left with requests that need freeing
when done.
This raises the per-core performance on my setup from ~5.8M to ~6.1M
IOPS.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently we use separate sbitmap pairs and active_queues atomic_t for
shared sbitmap support.
However a full sets of static requests are used per HW queue, which is
quite wasteful, considering that the total number of requests usable at
any given time across all HW queues is limited by the shared sbitmap depth.
As such, it is considerably more memory efficient in the case of shared
sbitmap to allocate a set of static rqs per tag set or request queue, and
not per HW queue.
So replace the sbitmap pairs and active_queues atomic_t with a shared
tags per tagset and request queue, which will hold a set of shared static
rqs.
Since there is now no valid HW queue index to be passed to the blk_mq_ops
.init and .exit_request callbacks, pass an invalid index token. This
changes the semantics of the APIs, such that the callback would need to
validate the HW queue index before using it. Currently no user of shared
sbitmap actually uses the HW queue index (as would be expected).
Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/1633429419-228500-13-git-send-email-john.garry@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
