Commit Graph

1044565 Commits

Author SHA1 Message Date
Pavel Begunkov
e94f68527a block: kill extra rcu lock/unlock in queue enter
blk_try_enter_queue() already takes rcu_read_lock/unlock, so we can
avoid the second pair in percpu_ref_tryget_live(), use a newly added
percpu_ref_tryget_live_rcu().

As rcu_read_lock/unlock imply barrier()s, it's pretty noticeable,
especially for for !CONFIG_PREEMPT_RCU (default for some distributions),
where __rcu_read_lock/unlock() are not inlined.

3.20%  io_uring  [kernel.vmlinux]  [k] __rcu_read_unlock
3.05%  io_uring  [kernel.vmlinux]  [k] __rcu_read_lock

2.52%  io_uring  [kernel.vmlinux]  [k] __rcu_read_unlock
2.28%  io_uring  [kernel.vmlinux]  [k] __rcu_read_lock

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/6b11c67ea495ed9d44f067622d852de4a510ce65.1634822969.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-21 08:37:26 -06:00
Pavel Begunkov
3b13c16818 percpu_ref: percpu_ref_tryget_live() version holding RCU
Add percpu_ref_tryget_live_rcu(), which is a version of
percpu_ref_tryget_live() but the user is responsible for enclosing it in
a RCU read lock section.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Acked-by: Dennis Zhou <dennis@kernel.org>
Link: https://lore.kernel.org/r/3066500d7a6eb3e03f10adf98b87fdb3b1c49db8.1634822969.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-21 08:37:26 -06:00
Pavel Begunkov
6549a874fb block: convert fops.c magic constants to SHIFT_SECTOR
Don't use shifting by a magic number 9 but replace with a more
descriptive SHIFT_SECTOR.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/068782b9f7e97569fb59a99529b23bb17ea4c5e2.1634755800.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-21 08:27:17 -06:00
Pavel Begunkov
179ae84f7e block: clean up blk_mq_submit_bio() merging
Combine blk_mq_sched_bio_merge() and blk_attempt_plug_merge() under a
common if, so we don't check it twice.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/daedc90d4029a5d1d73344771632b1faca3aaf81.1634755800.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-21 08:27:17 -06:00
Pavel Begunkov
6450fe1f66 block: optimise boundary blkdev_read_iter's checks
Combine pos and len checks and mark unlikely. Also, don't reexpand if
it's not truncated.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/fff34e613aeaae1ad12977dc4592cb1a1f5d3190.1634755800.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-21 08:27:17 -06:00
Jackie Liu
057178cf51 fs: bdev: fix conflicting comment from lookup_bdev
We switched to directly use dev_t to get block device, lookup changed the
meaning of use, now we fix this conflicting comment.

Fixes: 4e7b5671c6 ("block: remove i_bdev")
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211021071344.1600362-1-liu.yun@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-21 08:24:14 -06:00
John Garry
0994c64eb4 blk-mq: Fix blk_mq_tagset_busy_iter() for shared tags
Since it is now possible for a tagset to share a single set of tags, the
iter function should not re-iter the tags for the count of #hw queues in
that case. Rather it should just iter once.

Fixes: e155b0c238 ("blk-mq: Use shared tags for shared sbitmap support")
Reported-by: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Kashyap Desai <kashyap.desai@broadcom.com>
Link: https://lore.kernel.org/r/1634550083-202815-1-git-send-email-john.garry@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-21 08:21:52 -06:00
Christoph Hellwig
008f75a20e block: cleanup the flush plug helpers
Consolidate the various helpers into a single blk_flush_plug helper that
takes a plk_plug and the from_scheduler bool and switch all callsites to
call it directly.  Checks that the plug is non-NULL must be performed by
the caller, something that most already do anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211020144119.142582-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-20 09:56:11 -06:00
Pavel Begunkov
b600455d84 block: optimise blk_flush_plug_list
Don't call flush_plug_callbacks if there are no plug callbacks.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[hch: split from a larger patch]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211020144119.142582-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-20 09:56:11 -06:00
Christoph Hellwig
dbb6f764a0 blk-mq: move blk_mq_flush_plug_list to block/blk-mq.h
This helper is internal to the block layer.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211020144119.142582-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-20 09:56:11 -06:00
Christoph Hellwig
a214b949d8 blk-mq: only flush requests from the plug in blk_mq_submit_bio
Replace the call to blk_flush_plug_list in blk_mq_submit_bio with a
direct call to blk_mq_flush_plug_list.  This means we do not flush
plug callback from stackable devices, which doesn't really help with
the accumulated requests anyway, and it also means the cached requests
aren't freed here as they can still be used later on.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211020144119.142582-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-20 09:56:11 -06:00
Jens Axboe
037057a5a9 block: remove inaccurate requeue check
This check is meant to catch cases where a requeue is attempted on a
request that is still inserted. It's never really been useful to catch any
misuse, and now it's actively wrong. Outside of that, this should not be a
BUG_ON() to begin with.

Remove the check as it's now causing active harm, as requeue off the plug
path will trigger it even though the request state is just fine.

Reported-by: Yi Zhang <yi.zhang@redhat.com>
Link: https://lore.kernel.org/linux-block/CAHj4cs80zAUc2grnCZ015-2Rvd-=gXRfB_dFKy=RTm+wRo09HQ@mail.gmail.com/
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-20 08:21:40 -06:00
Pavel Begunkov
c809084ab0 block: inline a part of bio_release_pages()
Inline BIO_NO_PAGE_REF check of bio_release_pages() to avoid function
call.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-20 08:08:07 -06:00
Pavel Begunkov
1497a51a32 block: don't bloat enter_queue with percpu_ref
percpu_ref_put() are inlined for performance and bloat the binary, we
don't care about the fail case of blk_try_enter_queue(), so we can
replace it with a call to blk_queue_exit().

Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-20 08:08:06 -06:00
Pavel Begunkov
478eb72b81 block: optimise req_bio_endio()
First, get rid of an extra branch and chain error checks. Also reshuffle
it with bio_advance(), so it goes closer to the final check, with that
the compiler loads rq->rq_flags only once, and also doesn't reload
bio->bi_iter.bi_size if bio_advance() didn't actually advanced the iter.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-20 08:08:05 -06:00
Pavel Begunkov
859897c3fb block: convert leftovers to bdev_get_queue
Convert bdev->bd_disk->queue to bdev_get_queue(), which is faster.
Apparently, there are a few such spots in block that got lost during
rebases.

Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-20 08:08:03 -06:00
Pavel Begunkov
cf6d6238cd block: turn macro helpers into inline functions
Replace bio_set_dev() with an identical inline helper and move it
further to fix a dependency problem with bio_associate_blkg(). Do the
same for bio_copy_dev().

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-20 08:08:02 -06:00
Ming Lei
e70feb8b3e blk-mq: support concurrent queue quiesce/unquiesce
blk_mq_quiesce_queue() has been used a bit wide now, so far we don't support
concurrent/nested quiesce. One biggest issue is that unquiesce can happen
unexpectedly in case that quiesce/unquiesce are run concurrently from
more than one context.

This patch introduces q->mq_quiesce_depth to deal concurrent quiesce,
and we only unquiesce queue when it is the last/outer-most one of all
contexts.

Several kernel panic issue has been reported[1][2][3] when running stress
quiesce test. And this patch has been verified in these reports.

[1] https://lore.kernel.org/linux-block/9b21c797-e505-3821-4f5b-df7bf9380328@huawei.com/T/#m1fc52431fad7f33b1ffc3f12c4450e4238540787
[2] https://lore.kernel.org/linux-block/9b21c797-e505-3821-4f5b-df7bf9380328@huawei.com/T/#m10ad90afeb9c8cc318334190a7c24c8b5c5e0722
[3] https://listman.redhat.com/archives/dm-devel/2021-September/msg00189.html

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211014081710.1871747-7-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19 18:27:58 -06:00
Ming Lei
1d35d519d8 nvme: loop: clear NVME_CTRL_ADMIN_Q_STOPPED after admin queue is reallocated
The nvme-loop's admin queue may be freed and reallocated, and we have to
reset the flag of NVME_CTRL_ADMIN_Q_STOPPED so that the flag can match
with the quiesce state of the admin queue.

nvme-loop is the only driver to reallocate request queue, and not see
such usage in other nvme drivers.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211014081710.1871747-6-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19 18:27:58 -06:00
Ming Lei
9e6a6b1212 nvme: paring quiesce/unquiesce
The current blk_mq_quiesce_queue() and blk_mq_unquiesce_queue() always
stops and starts the queue unconditionally. And there can be concurrent
quiesce/unquiesce coming from different unrelated code paths, so
unquiesce may come unexpectedly and start queue too early.

Prepare for supporting concurrent quiesce/unquiesce from multiple
contexts, so that we can address the above issue.

NVMe has very complicated quiesce/unquiesce use pattern, add one atomic
bit for makeiing sure that blk-mq quiece/unquiesce is always called in
pair.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211014081710.1871747-5-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19 18:27:58 -06:00
Ming Lei
ebc9b95260 nvme: prepare for pairing quiescing and unquiescing
Add two helpers so that we can prepare for pairing quiescing and
unquiescing which will be done in next patch.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211014081710.1871747-4-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19 18:27:58 -06:00
Ming Lei
6ca1d9027e nvme: apply nvme API to quiesce/unquiesce admin queue
Apply the added two APIs to quiesce/unquiesce admin queue.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211014081710.1871747-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19 18:27:58 -06:00
Ming Lei
a277654baf nvme: add APIs for stopping/starting admin queue
Add two APIs for stopping and starting admin queue.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211014081710.1871747-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19 18:27:58 -06:00
Zheng Liang
2fc428f6b7 block, bfq: fix UAF problem in bfqg_stats_init()
In bfq_pd_alloc(), the function bfqg_stats_init() init bfqg. If
blkg_rwstat_init() init bfqg_stats->bytes successful and init
bfqg_stats->ios failed, bfqg_stats_init() return failed, bfqg will
be freed. But blkg_rwstat->cpu_cnt is not deleted from the list of
percpu_counters. If we traverse the list of percpu_counters, It will
have UAF problem.

we should use blkg_rwstat_exit() to cleanup bfqg_stats bytes in the
above scenario.

Fixes: commit fd41e60331 ("bfq-iosched: stop using blkg->stat_bytes and ->stat_ios")
Signed-off-by: Zheng Liang <zhengliang6@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20211018024225.1493938-1-zhengliang6@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19 15:18:30 -06:00
Jens Axboe
a808a9d545 block: inline fast path of driver tag allocation
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>
2021-10-19 15:18:25 -06:00
Christoph Hellwig
d92ca9d834 blk-mq: don't handle non-flush requests in blk_insert_flush
Return to the normal blk_mq_submit_bio flow if the bio did not end up
actually being a flush because the device didn't support it.  Note that
this is basically impossible to hit without special instrumentation given
that submit_bio_checks already clears these flags usually, so we'd need a
tight race to actually hit this code path.

With this the call to blk_mq_run_hw_queue for the flush requests can be
removed given that the actual flush requests are always issued via the
requeue workqueue which runs the queue unconditionally.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211019122553.2467817-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19 11:10:09 -06:00
Jens Axboe
dc5fc361d8 block: attempt direct issue of plug list
If we have just one queue type in the plug list, then we can extend our
direct issue to cover a full plug list as well. This allows sending a
batch of requests for direct issue, which is more efficient than doing
one-at-a-time kind of issue.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19 09:22:04 -06:00
Jens Axboe
bc490f8173 block: change plugging to use a singly linked list
Use a singly linked list for the blk_plug. This saves 8 bytes in the
blk_plug struct, and makes for faster list manipulations than doubly
linked lists. As we don't use the doubly linked lists for anything,
singly linked is just fine.

This yields a bump in default (merging enabled) performance from 7.0
to 7.1M IOPS, and ~7.5M IOPS with merging disabled.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19 09:21:42 -06:00
Andrea Righi
480d42dc00 blk-wbt: prevent NULL pointer dereference in wb_timer_fn
The timer callback used to evaluate if the latency is exceeded can be
executed after the corresponding disk has been released, causing the
following NULL pointer dereference:

[ 119.987108] BUG: kernel NULL pointer dereference, address: 0000000000000098
[ 119.987617] #PF: supervisor read access in kernel mode
[ 119.987971] #PF: error_code(0x0000) - not-present page
[ 119.988325] PGD 7c4a4067 P4D 7c4a4067 PUD 7bf63067 PMD 0
[ 119.988697] Oops: 0000 [#1] SMP NOPTI
[ 119.988959] CPU: 1 PID: 9353 Comm: cloud-init Not tainted 5.15-rc5+arighi #rc5+arighi
[ 119.989520] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
[ 119.990055] RIP: 0010:wb_timer_fn+0x44/0x3c0
[ 119.990376] Code: 41 8b 9c 24 98 00 00 00 41 8b 94 24 b8 00 00 00 41 8b 84 24 d8 00 00 00 4d 8b 74 24 28 01 d3 01 c3 49 8b 44 24 60 48 8b 40 78 <4c> 8b b8 98 00 00 00 4d 85 f6 0f 84 c4 00 00 00 49 83 7c 24 30 00
[ 119.991578] RSP: 0000:ffffb5f580957da8 EFLAGS: 00010246
[ 119.991937] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000004
[ 119.992412] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88f476d7f780
[ 119.992895] RBP: ffffb5f580957dd0 R08: 0000000000000000 R09: 0000000000000000
[ 119.993371] R10: 0000000000000004 R11: 0000000000000002 R12: ffff88f476c84500
[ 119.993847] R13: ffff88f4434390c0 R14: 0000000000000000 R15: ffff88f4bdc98c00
[ 119.994323] FS: 00007fb90bcd9c00(0000) GS:ffff88f4bdc80000(0000) knlGS:0000000000000000
[ 119.994952] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 119.995380] CR2: 0000000000000098 CR3: 000000007c0d6000 CR4: 00000000000006e0
[ 119.995906] Call Trace:
[ 119.996130] ? blk_stat_free_callback_rcu+0x30/0x30
[ 119.996505] blk_stat_timer_fn+0x138/0x140
[ 119.996830] call_timer_fn+0x2b/0x100
[ 119.997136] __run_timers.part.0+0x1d1/0x240
[ 119.997470] ? kvm_clock_get_cycles+0x11/0x20
[ 119.997826] ? ktime_get+0x3e/0xa0
[ 119.998110] ? native_apic_msr_write+0x2c/0x30
[ 119.998456] ? lapic_next_event+0x20/0x30
[ 119.998779] ? clockevents_program_event+0x94/0xf0
[ 119.999150] run_timer_softirq+0x2a/0x50
[ 119.999465] __do_softirq+0xcb/0x26f
[ 119.999764] irq_exit_rcu+0x8c/0xb0
[ 120.000057] sysvec_apic_timer_interrupt+0x43/0x90
[ 120.000429] ? asm_sysvec_apic_timer_interrupt+0xa/0x20
[ 120.000836] asm_sysvec_apic_timer_interrupt+0x12/0x20

In this case simply return from the timer callback (no action
required) to prevent the NULL pointer dereference.

BugLink: https://bugs.launchpad.net/bugs/1947557
Link: https://lore.kernel.org/linux-mm/YWRNVTk9N8K0RMst@arighi-desktop/
Fixes: 34dbad5d26 ("blk-stat: convert to callback-based statistics reporting")
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Link: https://lore.kernel.org/r/YW6N2qXpBU3oc50q@arighi-desktop
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19 06:13:41 -06:00
Jens Axboe
6155631a0c block: align blkdev_dio inlined bio to a cacheline
We get all sorts of unreliable and funky results since the bio is
designed to align on a cacheline, which it does not when inlined like
this.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19 05:55:52 -06:00
Jens Axboe
e028f167ec block: move blk_mq_tag_to_rq() inline
This is in the fast path of driver issue or completion, and it's a single
array index operation. Move it inline to avoid a function call for it.

This does mean making struct blk_mq_tags block layer public, but there's
not really much in there.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19 05:55:41 -06:00
Jens Axboe
df87eb0fce block: get rid of plug list sorting
Even if we have multiple queues in the plug list, chances that they
are very interspersed is minimal. Don't bother spending CPU cycles
sorting the list.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19 05:55:26 -06:00
Jens Axboe
87c037d11b block: return whether or not to unplug through boolean
Instead of returning the same queue request through a request pointer,
use a boolean to accomplish the same.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19 05:55:04 -06:00
Christoph Hellwig
8a7d267b4a block: don't call blk_status_to_errno in blk_update_request
We only need to call it to resolve the blk_status_t -> errno mapping for
tracing, so move the conversion into the tracepoints that are not called
at all when tracing isn't enabled.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19 05:54:57 -06:00
Jens Axboe
db9a02baa2 block: move bdev_read_only() into the header
This is called for every write in the fast path, move it inline next
to get_disk_ro() which is called internally.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19 05:53:22 -06:00
Jens Axboe
e0d78afeb8 block: fix too broad elevator check in blk_mq_free_request()
We added RQF_ELV to tell whether there's an IO scheduler attached, and
RQF_ELVPRIV tells us whether there's an IO scheduler with private data
attached. Don't check RQF_ELV in blk_mq_free_request(), what we care
about here is just if we have scheduler private data attached.

This fixes a boot crash

Fixes: 2ff0682da6 ("block: store elevator state in request")
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Reported-by: syzbot+eb8104072aeab6cc1195@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19 05:48:15 -06:00
Jens Axboe
4f5022453a nvme: wire up completion batching for the IRQ path
Trivial to do now, just need our own io_comp_batch on the stack and pass
that in to the usual command completion handling.

I pondered making this dependent on how many entries we had to process,
but even for a single entry there's no discernable difference in
performance or latency. Running a sync workload over io_uring:

t/io_uring -b512 -d1 -s1 -c1 -p0 -F1 -B1 -n2 /dev/nvme1n1 /dev/nvme2n1

yields the below performance before the patch:

IOPS=254820, BW=124MiB/s, IOS/call=1/1, inflight=(1 1)
IOPS=251174, BW=122MiB/s, IOS/call=1/1, inflight=(1 1)
IOPS=250806, BW=122MiB/s, IOS/call=1/1, inflight=(1 1)

and the following after:

IOPS=255972, BW=124MiB/s, IOS/call=1/1, inflight=(1 1)
IOPS=251920, BW=123MiB/s, IOS/call=1/1, inflight=(1 1)
IOPS=251794, BW=122MiB/s, IOS/call=1/1, inflight=(1 1)

which definitely isn't slower, about the same if you factor in a bit of
variance. For peak performance workloads, benchmarking shows a 2%
improvement.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:40:47 -06:00
Jens Axboe
b688f11e86 io_uring: utilize the io batching infrastructure for more efficient polled IO
Wire up using an io_comp_batch for f_op->iopoll(). If the lower stack
supports it, we can handle high rates of polled IO more efficiently.

This raises the single core efficiency on my system from ~6.1M IOPS to
~6.6M IOPS running a random read workload at depth 128 on two gen2
Optane drives.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:40:46 -06:00
Jens Axboe
c234a65392 nvme: add support for batched completion of polled IO
Take advantage of struct io_comp_batch, if passed in to the nvme poll
handler. If it's set, rather than complete each request individually
inline, store them in the io_comp_batch list. We only do so for requests
that will complete successfully, anything else will be completed inline as
before.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:40:45 -06:00
Jens Axboe
f794f3351f block: add support for blk_mq_end_request_batch()
Instead of calling blk_mq_end_request() on a single request, add a helper
that takes the new struct io_comp_batch and completes any request stored
in there.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:40:43 -06:00
Jens Axboe
1aec5e4a29 sbitmap: add helper to clear a batch of tags
sbitmap currently only supports clearing tags one-by-one, add a helper
that allows the caller to pass in an array of tags to clear.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:40:42 -06:00
Jens Axboe
5a72e899ce block: add a struct io_comp_batch argument to fops->iopoll()
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>
2021-10-18 14:40:40 -06:00
Jens Axboe
013a7f9543 block: provide helpers for rq_list manipulation
Instead of open-coding the list additions, traversal, and removal,
provide a basic set of helpers.

Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:40:39 -06:00
Jens Axboe
afd7de03c5 block: remove some blk_mq_hw_ctx debugfs entries
Just like the blk_mq_ctx counterparts, we've got a bunch of counters
in here that are only for debugfs and are of questionnable value. They
are:

- dispatched, index of how many requests were dispatched in one go

- poll_{considered,invoked,success}, which track poll sucess rates. We're
  confident in the iopoll implementation at this point, don't bother
  tracking these.

As a bonus, this shrinks each hardware queue from 576 bytes to 512 bytes,
dropping a whole cacheline.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:40:33 -06:00
Jens Axboe
9a14d6ce41 block: remove debugfs blk_mq_ctx dispatched/merged/completed attributes
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>
2021-10-18 14:39:48 -06:00
Pavel Begunkov
128459062b block: cache rq_flags inside blk_mq_rq_ctx_init()
Add a local variable for rq_flags, it helps to compile out some of
rq_flags reloads.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:38:45 -06:00
Pavel Begunkov
605f784e4f block: blk_mq_rq_ctx_init cache ctx/q/hctx
We should have enough of registers in blk_mq_rq_ctx_init(), store them
in local vars, so we don't keep reloading them.

note: keeping q->elevator may look unnecessary, but it's also used
inside inlined blk_mq_tags_from_data().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:38:43 -06:00
Pavel Begunkov
4f266f2be8 block: skip elevator fields init for non-elv queue
Don't init rq->hash and rq->rb_node in blk_mq_rq_ctx_init() if there is
no elevator. Also, move some other initialisers that imply barriers to
the end, so the compiler is free to rearrange and optimise other the
rest of them.

note: fold in a change from Jens leaving queue_list unconditional, as
it might lead to problems otherwise.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:38:42 -06:00
Jens Axboe
2ff0682da6 block: store elevator state in request
Add an rq private RQF_ELV flag, which tells the block layer that this
request was initialized on a queue that has an IO scheduler attached.
This allows for faster checking in the fast path, rather than having to
deference rq->q later on.

Elevator switching does full quiesce of the queue before detaching an
IO scheduler, so it's safe to cache this in the request itself.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 08:51:52 -06:00
Jens Axboe
90b8faa0e8 block: only mark bio as tracked if it really is tracked
We set BIO_TRACKED unconditionally when rq_qos_throttle() is called, even
though we may not even have an rq_qos handler. Only mark it as TRACKED if
it really is potentially tracked.

This saves considerable time for the case where the bio isn't tracked:

     2.64%     -1.65%  [kernel.vmlinux]  [k] bio_endio

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 08:50:47 -06:00