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1846 commits

Author SHA1 Message Date
Pavel Begunkov
2bbb146d96 io_uring: refactor poll update
Clean up io_poll_update() and unify cancellation paths for remove and
update.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/5937138b6265a1285220e2fab1b28132c1d73ce3.1639605189.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-12-28 09:51:14 -08:00
Pavel Begunkov
e840b4baf3 io_uring: remove double poll on poll update
Before updating a poll request we should remove it from poll queues,
including the double poll entry.

Fixes: b69de288e9 ("io_uring: allow events and user_data update of running poll requests")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/ac39e7f80152613603b8a6cc29a2b6063ac2434f.1639605189.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-12-28 09:51:14 -08:00
Jens Axboe
7b9762a5e8 io_uring: zero iocb->ki_pos for stream file types
io_uring supports using offset == -1 for using the current file position,
and we read that in as part of read/write command setup. For the non-iter
read/write types we pass in NULL for the position pointer, but for the
iter types we should not be passing any anything but 0 for the position
for a stream.

Clear kiocb->ki_pos if the file is a stream, don't leave it as -1. If we
do, then the request will error with -ESPIPE.

Fixes: ba04291eb6 ("io_uring: allow use of offset == -1 to mean file position")
Link: https://github.com/axboe/liburing/discussions/501
Reported-by: Samuel Williams <samuel.williams@oriontransfer.co.nz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-12-22 20:34:32 -07:00
Hao Xu
33ce2aff7d io_uring: code clean for some ctx usage
There are some functions doing ctx = req->ctx while still using
req->ctx, update those places.

Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20211214055904.61772-1-haoxu@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-12-14 06:49:06 -07:00
Jens Axboe
78a7806020 io_uring: ensure task_work gets run as part of cancelations
If we successfully cancel a work item but that work item needs to be
processed through task_work, then we can be sleeping uninterruptibly
in io_uring_cancel_generic() and never process it. Hence we don't
make forward progress and we end up with an uninterruptible sleep
warning.

While in there, correct a comment that should be IFF, not IIF.

Reported-and-tested-by: syzbot+21e6887c0be14181206d@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-12-10 13:56:28 -07:00
Hao Xu
f28c240e71 io_uring: batch completion in prior_task_list
In previous patches, we have already gathered some tw with
io_req_task_complete() as callback in prior_task_list, let's complete
them in batch while we cannot grab uring lock. In this way, we batch
the req_complete_post path.

Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20211208052125.351587-1-haoxu@linux.alibaba.com
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-12-08 11:34:48 -07:00
Hao Xu
a37fae8aaa io_uring: split io_req_complete_post() and add a helper
Split io_req_complete_post(), this is a prep for the next patch.

Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20211207093951.247840-5-haoxu@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-12-07 15:02:42 -07:00
Hao Xu
9f8d032a36 io_uring: add helper for task work execution code
Add a helper for task work execution code. We will use it later.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20211207093951.247840-4-haoxu@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-12-07 15:01:57 -07:00
Hao Xu
4813c37792 io_uring: add a priority tw list for irq completion work
Now we have a lot of task_work users, some are just to complete a req
and generate a cqe. Let's put the work to a new tw list which has a
higher priority, so that it can be handled quickly and thus to reduce
avg req latency and users can issue next round of sqes earlier.
An explanatory case:

origin timeline:
    submit_sqe-->irq-->add completion task_work
    -->run heavy work0~n-->run completion task_work
now timeline:
    submit_sqe-->irq-->add completion task_work
    -->run completion task_work-->run heavy work0~n

Limitation: this optimization is only for those that submission and
reaping process are in different threads. Otherwise anyhow we have to
submit new sqes after returning to userspace, then the order of TWs
doesn't matter.

Tested this patch(and the following ones) by manually replace
__io_queue_sqe() in io_queue_sqe() by io_req_task_queue() to construct
'heavy' task works. Then test with fio:

ioengine=io_uring
sqpoll=1
thread=1
bs=4k
direct=1
rw=randread
time_based=1
runtime=600
randrepeat=0
group_reporting=1
filename=/dev/nvme0n1

Tried various iodepth.
The peak IOPS for this patch is 710K, while the old one is 665K.
For avg latency, difference shows when iodepth grow:
depth and avg latency(usec):
	depth      new          old
	 1        7.05         7.10
	 2        8.47         8.60
	 4        10.42        10.42
	 8        13.78        13.22
	 16       27.41        24.33
	 32       49.40        53.08
	 64       102.53       103.36
	 128      196.98       205.61
	 256      372.99       414.88
         512      747.23       791.30
         1024     1472.59      1538.72
         2048     3153.49      3329.01
         4096     6387.86      6682.54
         8192     12150.25     12774.14
         16384    23085.58     26044.71

Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20211207093951.247840-3-haoxu@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-12-07 15:01:57 -07:00
Pavel Begunkov
a90c8bf659 io_uring: reuse io_req_task_complete for timeouts
With kbuf unification io_req_task_complete() is now a generic function,
use it for timeout's tw completions.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/7142fa3cbaf3a4140d59bcba45cbe168cf40fac2.1638714983.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-12-05 08:56:24 -07:00
Pavel Begunkov
83a13a4181 io_uring: tweak iopoll CQE_SKIP event counting
When iopolling the userspace specifies the minimum number of "events" it
expects. Previously, we had one CQE per request, so the definition of
an "event" was unequivocal, but that's not more the case anymore with
REQ_F_CQE_SKIP.

Currently it counts the number of completed requests, replace it with
the number of posted CQEs. This allows users of the "one CQE per link"
scheme to wait for all N links in a single syscall, which is not
possible without the patch and requires extra context switches.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d5a965c4d2249827392037bbd0186f87fea49c55.1638714983.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-12-05 08:56:24 -07:00
Pavel Begunkov
d1fd1c201d io_uring: simplify selected buf handling
As selected buffers are now stored in a separate field in a request, get
rid of rw/recv specific helpers and simplify the code.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/bd4a866d8d91b044f748c40efff9e4eacd07536e.1638714983.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-12-05 08:56:24 -07:00
Hao Xu
3648e5265c io_uring: move up io_put_kbuf() and io_put_rw_kbuf()
Move them up to avoid explicit declaration. We will use them in later
patches.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/3631243d6fc4a79bbba0cd62597fc8cd5be95924.1638714983.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-12-05 08:56:24 -07:00
Ye Bin
2087009c74 io_uring: validate timespec for timeout removals
Like commit f6223ff799, timeout removal should also validate the
timespec that is being passed in.

Signed-off-by: Ye Bin <yebin10@huawei.com>
Link: https://lore.kernel.org/r/20211129041537.1936270-1-yebin10@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-29 06:46:39 -07:00
Ye Bin
f6223ff799 io_uring: Fix undefined-behaviour in io_issue_sqe
We got issue as follows:
================================================================================
UBSAN: Undefined behaviour in ./include/linux/ktime.h:42:14
signed integer overflow:
-4966321760114568020 * 1000000000 cannot be represented in type 'long long int'
CPU: 1 PID: 2186 Comm: syz-executor.2 Not tainted 4.19.90+ #12
Hardware name: linux,dummy-virt (DT)
Call trace:
 dump_backtrace+0x0/0x3f0 arch/arm64/kernel/time.c:78
 show_stack+0x28/0x38 arch/arm64/kernel/traps.c:158
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x170/0x1dc lib/dump_stack.c:118
 ubsan_epilogue+0x18/0xb4 lib/ubsan.c:161
 handle_overflow+0x188/0x1dc lib/ubsan.c:192
 __ubsan_handle_mul_overflow+0x34/0x44 lib/ubsan.c:213
 ktime_set include/linux/ktime.h:42 [inline]
 timespec64_to_ktime include/linux/ktime.h:78 [inline]
 io_timeout fs/io_uring.c:5153 [inline]
 io_issue_sqe+0x42c8/0x4550 fs/io_uring.c:5599
 __io_queue_sqe+0x1b0/0xbc0 fs/io_uring.c:5988
 io_queue_sqe+0x1ac/0x248 fs/io_uring.c:6067
 io_submit_sqe fs/io_uring.c:6137 [inline]
 io_submit_sqes+0xed8/0x1c88 fs/io_uring.c:6331
 __do_sys_io_uring_enter fs/io_uring.c:8170 [inline]
 __se_sys_io_uring_enter fs/io_uring.c:8129 [inline]
 __arm64_sys_io_uring_enter+0x490/0x980 fs/io_uring.c:8129
 invoke_syscall arch/arm64/kernel/syscall.c:53 [inline]
 el0_svc_common+0x374/0x570 arch/arm64/kernel/syscall.c:121
 el0_svc_handler+0x190/0x260 arch/arm64/kernel/syscall.c:190
 el0_svc+0x10/0x218 arch/arm64/kernel/entry.S:1017
================================================================================

As ktime_set only judge 'secs' if big than KTIME_SEC_MAX, but if we pass
negative value maybe lead to overflow.
To address this issue, we must check if 'sec' is negative.

Signed-off-by: Ye Bin <yebin10@huawei.com>
Link: https://lore.kernel.org/r/20211118015907.844807-1-yebin10@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-27 06:41:38 -07:00
Ye Bin
1d0254e6b4 io_uring: fix soft lockup when call __io_remove_buffers
I got issue as follows:
[ 567.094140] __io_remove_buffers: [1]start ctx=0xffff8881067bf000 bgid=65533 buf=0xffff8881fefe1680
[  594.360799] watchdog: BUG: soft lockup - CPU#2 stuck for 26s! [kworker/u32:5:108]
[  594.364987] Modules linked in:
[  594.365405] irq event stamp: 604180238
[  594.365906] hardirqs last  enabled at (604180237): [<ffffffff93fec9bd>] _raw_spin_unlock_irqrestore+0x2d/0x50
[  594.367181] hardirqs last disabled at (604180238): [<ffffffff93fbbadb>] sysvec_apic_timer_interrupt+0xb/0xc0
[  594.368420] softirqs last  enabled at (569080666): [<ffffffff94200654>] __do_softirq+0x654/0xa9e
[  594.369551] softirqs last disabled at (569080575): [<ffffffff913e1d6a>] irq_exit_rcu+0x1ca/0x250
[  594.370692] CPU: 2 PID: 108 Comm: kworker/u32:5 Tainted: G            L    5.15.0-next-20211112+ #88
[  594.371891] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014
[  594.373604] Workqueue: events_unbound io_ring_exit_work
[  594.374303] RIP: 0010:_raw_spin_unlock_irqrestore+0x33/0x50
[  594.375037] Code: 48 83 c7 18 53 48 89 f3 48 8b 74 24 10 e8 55 f5 55 fd 48 89 ef e8 ed a7 56 fd 80 e7 02 74 06 e8 43 13 7b fd fb bf 01 00 00 00 <e8> f8 78 474
[  594.377433] RSP: 0018:ffff888101587a70 EFLAGS: 00000202
[  594.378120] RAX: 0000000024030f0d RBX: 0000000000000246 RCX: 1ffffffff2f09106
[  594.379053] RDX: 0000000000000000 RSI: ffffffff9449f0e0 RDI: 0000000000000001
[  594.379991] RBP: ffffffff9586cdc0 R08: 0000000000000001 R09: fffffbfff2effcab
[  594.380923] R10: ffffffff977fe557 R11: fffffbfff2effcaa R12: ffff8881b8f3def0
[  594.381858] R13: 0000000000000246 R14: ffff888153a8b070 R15: 0000000000000000
[  594.382787] FS:  0000000000000000(0000) GS:ffff888399c00000(0000) knlGS:0000000000000000
[  594.383851] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  594.384602] CR2: 00007fcbe71d2000 CR3: 00000000b4216000 CR4: 00000000000006e0
[  594.385540] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  594.386474] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  594.387403] Call Trace:
[  594.387738]  <TASK>
[  594.388042]  find_and_remove_object+0x118/0x160
[  594.389321]  delete_object_full+0xc/0x20
[  594.389852]  kfree+0x193/0x470
[  594.390275]  __io_remove_buffers.part.0+0xed/0x147
[  594.390931]  io_ring_ctx_free+0x342/0x6a2
[  594.392159]  io_ring_exit_work+0x41e/0x486
[  594.396419]  process_one_work+0x906/0x15a0
[  594.399185]  worker_thread+0x8b/0xd80
[  594.400259]  kthread+0x3bf/0x4a0
[  594.401847]  ret_from_fork+0x22/0x30
[  594.402343]  </TASK>

Message from syslogd@localhost at Nov 13 09:09:54 ...
kernel:watchdog: BUG: soft lockup - CPU#2 stuck for 26s! [kworker/u32:5:108]
[  596.793660] __io_remove_buffers: [2099199]start ctx=0xffff8881067bf000 bgid=65533 buf=0xffff8881fefe1680

We can reproduce this issue by follow syzkaller log:
r0 = syz_io_uring_setup(0x401, &(0x7f0000000300), &(0x7f0000003000/0x2000)=nil, &(0x7f0000ff8000/0x4000)=nil, &(0x7f0000000280)=<r1=>0x0, &(0x7f0000000380)=<r2=>0x0)
sendmsg$ETHTOOL_MSG_FEATURES_SET(0xffffffffffffffff, &(0x7f0000003080)={0x0, 0x0, &(0x7f0000003040)={&(0x7f0000000040)=ANY=[], 0x18}}, 0x0)
syz_io_uring_submit(r1, r2, &(0x7f0000000240)=@IORING_OP_PROVIDE_BUFFERS={0x1f, 0x5, 0x0, 0x401, 0x1, 0x0, 0x100, 0x0, 0x1, {0xfffd}}, 0x0)
io_uring_enter(r0, 0x3a2d, 0x0, 0x0, 0x0, 0x0)

The reason above issue  is 'buf->list' has 2,100,000 nodes, occupied cpu lead
to soft lockup.
To solve this issue, we need add schedule point when do while loop in
'__io_remove_buffers'.
After add  schedule point we do regression, get follow data.
[  240.141864] __io_remove_buffers: [1]start ctx=0xffff888170603000 bgid=65533 buf=0xffff8881116fcb00
[  268.408260] __io_remove_buffers: [1]start ctx=0xffff8881b92d2000 bgid=65533 buf=0xffff888130c83180
[  275.899234] __io_remove_buffers: [2099199]start ctx=0xffff888170603000 bgid=65533 buf=0xffff8881116fcb00
[  296.741404] __io_remove_buffers: [1]start ctx=0xffff8881b659c000 bgid=65533 buf=0xffff8881010fe380
[  305.090059] __io_remove_buffers: [2099199]start ctx=0xffff8881b92d2000 bgid=65533 buf=0xffff888130c83180
[  325.415746] __io_remove_buffers: [1]start ctx=0xffff8881b92d1000 bgid=65533 buf=0xffff8881a17d8f00
[  333.160318] __io_remove_buffers: [2099199]start ctx=0xffff8881b659c000 bgid=65533 buf=0xffff8881010fe380
...

Fixes:8bab4c09f24e("io_uring: allow conditional reschedule for intensive iterators")
Signed-off-by: Ye Bin <yebin10@huawei.com>
Link: https://lore.kernel.org/r/20211122024737.2198530-1-yebin10@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-27 06:41:32 -07:00
Pavel Begunkov
6af3f48bf6 io_uring: fix link traversal locking
WARNING: inconsistent lock state
5.16.0-rc2-syzkaller #0 Not tainted
inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
ffff888078e11418 (&ctx->timeout_lock
){?.+.}-{2:2}
, at: io_timeout_fn+0x6f/0x360 fs/io_uring.c:5943
{HARDIRQ-ON-W} state was registered at:
  [...]
  spin_unlock_irq include/linux/spinlock.h:399 [inline]
  __io_poll_remove_one fs/io_uring.c:5669 [inline]
  __io_poll_remove_one fs/io_uring.c:5654 [inline]
  io_poll_remove_one+0x236/0x870 fs/io_uring.c:5680
  io_poll_remove_all+0x1af/0x235 fs/io_uring.c:5709
  io_ring_ctx_wait_and_kill+0x1cc/0x322 fs/io_uring.c:9534
  io_uring_release+0x42/0x46 fs/io_uring.c:9554
  __fput+0x286/0x9f0 fs/file_table.c:280
  task_work_run+0xdd/0x1a0 kernel/task_work.c:164
  exit_task_work include/linux/task_work.h:32 [inline]
  do_exit+0xc14/0x2b40 kernel/exit.c:832

674ee8e1b4 ("io_uring: correct link-list traversal locking") fixed a
data race but introduced a possible deadlock and inconsistentcy in irq
states. E.g.

io_poll_remove_all()
    spin_lock_irq(timeout_lock)
    io_poll_remove_one()
        spin_lock/unlock_irq(poll_lock);
    spin_unlock_irq(timeout_lock)

Another type of problem is freeing a request while holding
->timeout_lock, which may leads to a deadlock in
io_commit_cqring() -> io_flush_timeouts() and other places.

Having 3 nested locks is also too ugly. Add io_match_task_safe(), which
would briefly take and release timeout_lock for race prevention inside,
so the actuall request cancellation / free / etc. code doesn't have it
taken.

Reported-by: syzbot+ff49a3059d49b0ca0eec@syzkaller.appspotmail.com
Reported-by: syzbot+847f02ec20a6609a328b@syzkaller.appspotmail.com
Reported-by: syzbot+3368aadcd30425ceb53b@syzkaller.appspotmail.com
Reported-by: syzbot+51ce8887cdef77c9ac83@syzkaller.appspotmail.com
Reported-by: syzbot+3cb756a49d2f394a9ee3@syzkaller.appspotmail.com
Fixes: 674ee8e1b4 ("io_uring: correct link-list traversal locking")
Cc: stable@kernel.org # 5.15+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/397f7ebf3f4171f1abe41f708ac1ecb5766f0b68.1637937097.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-26 08:35:57 -07:00
Pavel Begunkov
617a89484d io_uring: fail cancellation for EXITING tasks
WARNING: CPU: 1 PID: 20 at fs/io_uring.c:6269 io_try_cancel_userdata+0x3c5/0x640 fs/io_uring.c:6269
CPU: 1 PID: 20 Comm: kworker/1:0 Not tainted 5.16.0-rc1-syzkaller #0
Workqueue: events io_fallback_req_func
RIP: 0010:io_try_cancel_userdata+0x3c5/0x640 fs/io_uring.c:6269
Call Trace:
 <TASK>
 io_req_task_link_timeout+0x6b/0x1e0 fs/io_uring.c:6886
 io_fallback_req_func+0xf9/0x1ae fs/io_uring.c:1334
 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445
 kthread+0x405/0x4f0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

We need original task's context to do cancellations, so if it's dying
and the callback is executed in a fallback mode, fail the cancellation
attempt.

Fixes: 89b263f6d5 ("io_uring: run linked timeouts from task_work")
Cc: stable@kernel.org # 5.15+
Reported-by: syzbot+ab0cfe96c2b3cd1c1153@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/4c41c5f379c6941ad5a07cd48cb66ed62199cf7e.1637937097.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-26 08:35:43 -07:00
Hao Xu
b6c7db3218 io_uring: better to use REQ_F_IO_DRAIN for req->flags
It's better to use REQ_F_IO_DRAIN for req->flags rather than
IOSQE_IO_DRAIN though they have same value.

Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20211125092103.224502-3-haoxu@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-25 09:00:42 -07:00
Hao Xu
e302f1046f io_uring: fix no lock protection for ctx->cq_extra
ctx->cq_extra should be protected by completion lock so that the
req_need_defer() does the right check.

Cc: stable@vger.kernel.org
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20211125092103.224502-2-haoxu@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-25 09:00:42 -07:00
Pavel Begunkov
5562a8d71a io_uring: disable drain with cqe skip
Current IOSQE_IO_DRAIN implementation doesn't work well with CQE
skipping and it's not allowed, otherwise some requests might be not
executed until the ring is destroyed and the userspace would hang.

Let's fail all drain requests after seeing IOSQE_CQE_SKIP_SUCCESS at
least once. All drained requests prior to that will get run normally,
so there should be no stalls. However, even though such mixing wouldn't
lead to issues at the moment, it's still not allowed as the behaviour
may change.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/bcf7164f8bf3eb54b7bb7b4fd119907fa4d4d43b.1636559119.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-24 11:17:53 -07:00
Pavel Begunkov
3d4aeb9f98 io_uring: don't spinlock when not posting CQEs
When no of queued for the batch completion requests need to post an CQE,
see IOSQE_CQE_SKIP_SUCCESS, avoid grabbing ->completion_lock and other
commit/post.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/8d4b4a08bca022cbe19af00266407116775b3e4d.1636559119.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-24 11:17:53 -07:00
Pavel Begunkov
04c76b41ca io_uring: add option to skip CQE posting
Emitting a CQE is expensive from the kernel perspective. Often, it's
also not convenient for the userspace, spends some cycles on processing
and just complicates the logic. A similar problems goes for linked
requests, where we post an CQE for each request in the link.

Introduce a new flags, IOSQE_CQE_SKIP_SUCCESS, trying to help with it.
When set and a request completed successfully, it won't generate a CQE.
When fails, it produces an CQE, but all following linked requests will
be CQE-less, regardless whether they have IOSQE_CQE_SKIP_SUCCESS or not.
The notion of "fail" is the same as for link failing-cancellation, where
it's opcode dependent, and _usually_ result >= 0 is a success, but not
always.

Linked timeouts are a bit special. When the requests it's linked to was
not attempted to be executed, e.g. failing linked requests, it follows
the description above. Otherwise, whether a linked timeout will post a
completion or not solely depends on IOSQE_CQE_SKIP_SUCCESS of that
linked timeout request. Linked timeout never "fail" during execution, so
for them it's unconditional. It's expected for users to not really care
about the result of it but rely solely on the result of the master
request. Another reason for such a treatment is that it's racy, and the
timeout callback may be running awhile the master request posts its
completion.

use case 1:
If one doesn't care about results of some requests, e.g. normal
timeouts, just set IOSQE_CQE_SKIP_SUCCESS. Error result will still be
posted and need to be handled.

use case 2:
Set IOSQE_CQE_SKIP_SUCCESS for all requests of a link but the last,
and it'll post a completion only for the last one if everything goes
right, otherwise there will be one only one CQE for the first failed
request.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0220fbe06f7cf99e6fc71b4297bb1cb6c0e89c2c.1636559119.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-24 11:17:53 -07:00
Pavel Begunkov
913a571aff io_uring: clean cqe filling functions
Split io_cqring_fill_event() into a couple of more targeted functions.
The first on is io_fill_cqe_aux() for completions that are not
associated with request completions and doing the ->cq_extra accounting.
Examples are additional CQEs from multishot poll and rsrc notifications.

The second is io_fill_cqe_req(), should be called when it's a normal
request completion. Nothing more to it at the moment, will be used in
later patches.

The last one is inlined __io_fill_cqe() for a finer grained control,
should be used with caution and in hottest places.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/59a9117a4a44fc9efcf04b3afa51e0d080f5943c.1636559119.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-24 11:17:53 -07:00
Pavel Begunkov
2ea537ca02 io_uring: improve argument types of kiocb_done()
kiocb_done() accepts a pointer to struct kiocb, pass struct io_kiocb
(i.e. io_uring's request) instead so we can get rid of useless
container_of().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/252016eed77806f58b48251a85cd8c645f900433.1637524285.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-23 12:24:20 -07:00
Pavel Begunkov
f3251183b2 io_uring: clean __io_import_iovec()
Apparently, implicit 0 to NULL conversion with ERR_PTR is not
recommended and makes some tooling like Smatch to complain. Handle it
explicitly, compilers are perfectly capable to optimise it out.

Link: https://lore.kernel.org/all/20211108134937.GA2863@kili/
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/5c6ed369ad95075dab345df679f8677b8fe66656.1637524285.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-23 12:24:20 -07:00
Pavel Begunkov
7297ce3d59 io_uring: improve send/recv error handling
Hide all error handling under common if block, removes two extra ifs on
the success path and keeps the handling more condensed.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/5761545158a12968f3caf30f747eea65ed75dfc1.1637524285.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-23 12:24:20 -07:00
Pavel Begunkov
06bdea20c1 io_uring: simplify reissue in kiocb_done
Simplify failed resubmission prep in kiocb_done(), it's a bit ugly with
conditional logic and hand handling cflags / select buffers. Instead,
punt to tw and use io_req_task_complete() already handling all the
cases.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/667c33484b05b612e9420e1b1d5f4dc46d0ee9ce.1637524285.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-23 12:24:20 -07:00
Pavel Begunkov
674ee8e1b4 io_uring: correct link-list traversal locking
As io_remove_next_linked() is now under ->timeout_lock (see
io_link_timeout_fn), we should update locking around io_for_each_link()
and io_match_task() to use the new lock.

Cc: stable@kernel.org # 5.15+
Fixes: 89850fce16 ("io_uring: run timeouts from task_work")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b54541cedf7de59cb5ae36109e58529ca16e66aa.1637631883.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-22 19:31:54 -07:00
Kamal Mostafa
f6f9b278f2 io_uring: fix missed comment from *task_file rename
Fix comment referring to function "io_uring_del_task_file()", now called
"io_uring_del_tctx_node()".

Fixes: eef51daa72 ("io_uring: rename function *task_file")
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Link: https://lore.kernel.org/r/20211116175530.31608-1-kamal@canonical.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-16 17:24:34 -07:00
Pavel Begunkov
bad119b9a0 io_uring: honour zeroes as io-wq worker limits
When we pass in zero as an io-wq worker number limit it shouldn't
actually change the limits but return the old value, follow that
behaviour with deferred limits setup as well.

Cc: stable@kernel.org # 5.15
Reported-by: Beld Zhang <beldzhang@gmail.com>
Fixes: e139a1ec92 ("io_uring: apply max_workers limit to all future users")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1b222a92f7a78a24b042763805e891a4cdd4b544.1636384034.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-08 08:39:48 -07:00
Jens Axboe
a19577808f io_uring: remove dead 'sqe' store
The kernel test robot correctly identifies that we store sqe twice,
remove the earlier one that is done before validating the index.

Fixes: f75d118349 ("io_uring: harder fdinfo sq/cq ring iterating")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-05 09:31:05 -06:00
Nghia Le
83956c86ff io_uring: remove redundant assignment to ret in io_register_iowq_max_workers()
After the assignment, only exit path with label 'err' uses ret as
return value. However,before exiting through this path with label 'err',
ret is assigned with the return value of io_wq_max_workers(). Hence, the
initial assignment is redundant and can be removed.

Signed-off-by: Nghia Le <nghialm78@gmail.com>
Link: https://lore.kernel.org/r/20211102190521.28291-1-nghialm78@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-02 14:29:12 -06:00
Pavel Begunkov
9881024aab io_uring: clean up io_queue_sqe_arm_apoll
The fix for linked timeout unprep got a bit distored with two rebases,
handle linked timeouts for IO_APOLL_READY as with all other cases, i.e.
queue it at the end of the function.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/130b1ea5605bbd81d7b874a95332295799d33b81.1635863773.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-02 09:26:14 -06:00
Linus Torvalds
cdab10bf32 selinux/stable-5.16 PR 20211101
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Merge tag 'selinux-pr-20211101' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:

 - Add LSM/SELinux/Smack controls and auditing for io-uring.

   As usual, the individual commit descriptions have more detail, but we
   were basically missing two things which we're adding here:

      + establishment of a proper audit context so that auditing of
        io-uring ops works similarly to how it does for syscalls (with
        some io-uring additions because io-uring ops are *not* syscalls)

      + additional LSM hooks to enable access control points for some of
        the more unusual io-uring features, e.g. credential overrides.

   The additional audit callouts and LSM hooks were done in conjunction
   with the io-uring folks, based on conversations and RFC patches
   earlier in the year.

 - Fixup the binder credential handling so that the proper credentials
   are used in the LSM hooks; the commit description and the code
   comment which is removed in these patches are helpful to understand
   the background and why this is the proper fix.

 - Enable SELinux genfscon policy support for securityfs, allowing
   improved SELinux filesystem labeling for other subsystems which make
   use of securityfs, e.g. IMA.

* tag 'selinux-pr-20211101' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  security: Return xattr name from security_dentry_init_security()
  selinux: fix a sock regression in selinux_ip_postroute_compat()
  binder: use cred instead of task for getsecid
  binder: use cred instead of task for selinux checks
  binder: use euid from cred instead of using task
  LSM: Avoid warnings about potentially unused hook variables
  selinux: fix all of the W=1 build warnings
  selinux: make better use of the nf_hook_state passed to the NF hooks
  selinux: fix race condition when computing ocontext SIDs
  selinux: remove unneeded ipv6 hook wrappers
  selinux: remove the SELinux lockdown implementation
  selinux: enable genfscon labeling for securityfs
  Smack: Brutalist io_uring support
  selinux: add support for the io_uring access controls
  lsm,io_uring: add LSM hooks to io_uring
  io_uring: convert io_uring to the secure anon inode interface
  fs: add anon_inode_getfile_secure() similar to anon_inode_getfd_secure()
  audit: add filtering for io_uring records
  audit,io_uring,io-wq: add some basic audit support to io_uring
  audit: prepare audit_context for use in calling contexts beyond syscalls
2021-11-01 21:06:18 -07:00
Linus Torvalds
b6773cdb0e for-5.16/ki_complete-2021-10-29
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Merge tag 'for-5.16/ki_complete-2021-10-29' of git://git.kernel.dk/linux-block

Pull kiocb->ki_complete() cleanup from Jens Axboe:
 "This removes the res2 argument from kiocb->ki_complete().

  Only the USB gadget code used it, everybody else passes 0. The USB
  guys checked the user gadget code they could find, and everybody just
  uses res as expected for the async interface"

* tag 'for-5.16/ki_complete-2021-10-29' of git://git.kernel.dk/linux-block:
  fs: get rid of the res2 iocb->ki_complete argument
  usb: remove res2 argument from gadget code completions
2021-11-01 10:17:11 -07:00
Linus Torvalds
8d1f01775f for-5.16/io_uring-2021-10-29
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Merge tag 'for-5.16/io_uring-2021-10-29' of git://git.kernel.dk/linux-block

Pull io_uring updates from Jens Axboe:
 "Light on new features - basically just the hybrid mode support.

  Outside of that it's just fixes, cleanups, and performance
  improvements.

  In detail:

   - Add ring related information to the fdinfo output (Hao)

   - Hybrid async mode (Hao)

   - Support for batched issue on block (me)

   - sqe error trace improvement (me)

   - IOPOLL efficiency improvements (Pavel)

   - submit state cleanups and improvements (Pavel)

   - Completion side improvements (Pavel)

   - Drain improvements (Pavel)

   - Buffer selection cleanups (Pavel)

   - Fixed file node improvements (Pavel)

   - io-wq setup cancelation fix (Pavel)

   - Various other performance improvements and cleanups (Pavel)

   - Misc fixes (Arnd, Bixuan, Changcheng, Hao, me, Noah)"

* tag 'for-5.16/io_uring-2021-10-29' of git://git.kernel.dk/linux-block: (97 commits)
  io-wq: remove worker to owner tw dependency
  io_uring: harder fdinfo sq/cq ring iterating
  io_uring: don't assign write hint in the read path
  io_uring: clusterise ki_flags access in rw_prep
  io_uring: kill unused param from io_file_supports_nowait
  io_uring: clean up timeout async_data allocation
  io_uring: don't try io-wq polling if not supported
  io_uring: check if opcode needs poll first on arming
  io_uring: clean iowq submit work cancellation
  io_uring: clean io_wq_submit_work()'s main loop
  io-wq: use helper for worker refcounting
  io_uring: implement async hybrid mode for pollable requests
  io_uring: Use ERR_CAST() instead of ERR_PTR(PTR_ERR())
  io_uring: split logic of force_nonblock
  io_uring: warning about unused-but-set parameter
  io_uring: inform block layer of how many requests we are submitting
  io_uring: simplify io_file_supports_nowait()
  io_uring: combine REQ_F_NOWAIT_{READ,WRITE} flags
  io_uring: arm poll for non-nowait files
  fs/io_uring: Prioritise checking faster conditions first in io_write
  ...
2021-11-01 09:41:33 -07:00
Linus Torvalds
33c8846c81 for-5.16/block-2021-10-29
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Merge tag 'for-5.16/block-2021-10-29' of git://git.kernel.dk/linux-block

Pull block updates from Jens Axboe:

 - mq-deadline accounting improvements (Bart)

 - blk-wbt timer fix (Andrea)

 - Untangle the block layer includes (Christoph)

 - Rework the poll support to be bio based, which will enable adding
   support for polling for bio based drivers (Christoph)

 - Block layer core support for multi-actuator drives (Damien)

 - blk-crypto improvements (Eric)

 - Batched tag allocation support (me)

 - Request completion batching support (me)

 - Plugging improvements (me)

 - Shared tag set improvements (John)

 - Concurrent queue quiesce support (Ming)

 - Cache bdev in ->private_data for block devices (Pavel)

 - bdev dio improvements (Pavel)

 - Block device invalidation and block size improvements (Xie)

 - Various cleanups, fixes, and improvements (Christoph, Jackie,
   Masahira, Tejun, Yu, Pavel, Zheng, me)

* tag 'for-5.16/block-2021-10-29' of git://git.kernel.dk/linux-block: (174 commits)
  blk-mq-debugfs: Show active requests per queue for shared tags
  block: improve readability of blk_mq_end_request_batch()
  virtio-blk: Use blk_validate_block_size() to validate block size
  loop: Use blk_validate_block_size() to validate block size
  nbd: Use blk_validate_block_size() to validate block size
  block: Add a helper to validate the block size
  block: re-flow blk_mq_rq_ctx_init()
  block: prefetch request to be initialized
  block: pass in blk_mq_tags to blk_mq_rq_ctx_init()
  block: add rq_flags to struct blk_mq_alloc_data
  block: add async version of bio_set_polled
  block: kill DIO_MULTI_BIO
  block: kill unused polling bits in __blkdev_direct_IO()
  block: avoid extra iter advance with async iocb
  block: Add independent access ranges support
  blk-mq: don't issue request directly in case that current is to be blocked
  sbitmap: silence data race warning
  blk-cgroup: synchronize blkg creation against policy deactivation
  block: refactor bio_iov_bvec_set()
  block: add single bio async direct IO helper
  ...
2021-11-01 09:19:50 -07:00
Linus Torvalds
49f8275c7d Memory folios
Add memory folios, a new type to represent either order-0 pages or
 the head page of a compound page.  This should be enough infrastructure
 to support filesystems converting from pages to folios.
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Merge tag 'folio-5.16' of git://git.infradead.org/users/willy/pagecache

Pull memory folios from Matthew Wilcox:
 "Add memory folios, a new type to represent either order-0 pages or the
  head page of a compound page. This should be enough infrastructure to
  support filesystems converting from pages to folios.

  The point of all this churn is to allow filesystems and the page cache
  to manage memory in larger chunks than PAGE_SIZE. The original plan
  was to use compound pages like THP does, but I ran into problems with
  some functions expecting only a head page while others expect the
  precise page containing a particular byte.

  The folio type allows a function to declare that it's expecting only a
  head page. Almost incidentally, this allows us to remove various calls
  to VM_BUG_ON(PageTail(page)) and compound_head().

  This converts just parts of the core MM and the page cache. For 5.17,
  we intend to convert various filesystems (XFS and AFS are ready; other
  filesystems may make it) and also convert more of the MM and page
  cache to folios. For 5.18, multi-page folios should be ready.

  The multi-page folios offer some improvement to some workloads. The
  80% win is real, but appears to be an artificial benchmark (postgres
  startup, which isn't a serious workload). Real workloads (eg building
  the kernel, running postgres in a steady state, etc) seem to benefit
  between 0-10%. I haven't heard of any performance losses as a result
  of this series. Nobody has done any serious performance tuning; I
  imagine that tweaking the readahead algorithm could provide some more
  interesting wins. There are also other places where we could choose to
  create large folios and currently do not, such as writes that are
  larger than PAGE_SIZE.

  I'd like to thank all my reviewers who've offered review/ack tags:
  Christoph Hellwig, David Howells, Jan Kara, Jeff Layton, Johannes
  Weiner, Kirill A. Shutemov, Michal Hocko, Mike Rapoport, Vlastimil
  Babka, William Kucharski, Yu Zhao and Zi Yan.

  I'd also like to thank those who gave feedback I incorporated but
  haven't offered up review tags for this part of the series: Nick
  Piggin, Mel Gorman, Ming Lei, Darrick Wong, Ted Ts'o, John Hubbard,
  Hugh Dickins, and probably a few others who I forget"

* tag 'folio-5.16' of git://git.infradead.org/users/willy/pagecache: (90 commits)
  mm/writeback: Add folio_write_one
  mm/filemap: Add FGP_STABLE
  mm/filemap: Add filemap_get_folio
  mm/filemap: Convert mapping_get_entry to return a folio
  mm/filemap: Add filemap_add_folio()
  mm/filemap: Add filemap_alloc_folio
  mm/page_alloc: Add folio allocation functions
  mm/lru: Add folio_add_lru()
  mm/lru: Convert __pagevec_lru_add_fn to take a folio
  mm: Add folio_evictable()
  mm/workingset: Convert workingset_refault() to take a folio
  mm/filemap: Add readahead_folio()
  mm/filemap: Add folio_mkwrite_check_truncate()
  mm/filemap: Add i_blocks_per_folio()
  mm/writeback: Add folio_redirty_for_writepage()
  mm/writeback: Add folio_account_redirty()
  mm/writeback: Add folio_clear_dirty_for_io()
  mm/writeback: Add folio_cancel_dirty()
  mm/writeback: Add folio_account_cleaned()
  mm/writeback: Add filemap_dirty_folio()
  ...
2021-11-01 08:47:59 -07:00
Jens Axboe
f75d118349 io_uring: harder fdinfo sq/cq ring iterating
The ring iteration is racy, which isn't necessarily a problem except it
can cause us to iterate the whole thing. That isn't desired or ideal,
and it can lead to excessive runtimes of reading fdinfo.

Cap the iteration at tail - head OR the ring size. While in there, clean
up the ring masking and just dump the raw values along with the masks.
That provides more useful debug info.

Fixes: 83f84356bc ("io_uring: add more uring info to fdinfo for debug")
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-29 09:49:33 -06:00
Jens Axboe
3884b83dff io_uring: don't assign write hint in the read path
Move this out of the generic read/write prep path, and place it in the
write specific kiocb setup instead.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-26 15:54:40 -06:00
Jens Axboe
6b19b766e8 fs: get rid of the res2 iocb->ki_complete argument
The second argument was only used by the USB gadget code, yet everyone
pays the overhead of passing a zero to be passed into aio, where it
ends up being part of the aio res2 value.

Now that everybody is passing in zero, kill off the extra argument.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-25 10:36:24 -06:00
Pavel Begunkov
fb27274a90 io_uring: clusterise ki_flags access in rw_prep
ioprio setup doesn't depend on other fields that are modified in
io_prep_rw() and we can move it down in the function without worrying
about performance. It's useful as it makes iocb->ki_flags
accesses/modifications closer together, so it's more likely the compiler
will cache it in a register and avoid extra reloads.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/8ee98779c06f1b59f6039b1e292db4332efd664b.1634987320.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-25 07:42:35 -06:00
Pavel Begunkov
b9a6b8f92f io_uring: kill unused param from io_file_supports_nowait
io_file_supports_nowait() doesn't use rw argument anymore, remove it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/4bd6709fc573d70c866ea656cb7a7dbe94be8026.1634987320.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-25 07:42:35 -06:00
Pavel Begunkov
d6a644a795 io_uring: clean up timeout async_data allocation
opcode prep functions are one of the first things that are called, we
can't have ->async_data allocated at this point and it's certainly a
bug. Reflect this assumption in io_timeout_prep() and add a WARN_ONCE
just in case.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/75a28ca7dbcc5af8b6cd9092819e8384c24dedd4.1634987320.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-25 07:42:35 -06:00
Pavel Begunkov
afb7f56fc6 io_uring: don't try io-wq polling if not supported
If an opcode doesn't support polling, just let it be executed
synchronously in iowq, otherwise it will do a nonblock attempt just to
fail in io_arm_poll_handler() and return back to blocking execution.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/6401256db01b88f448f15fcd241439cb76f5b940.1634987320.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-25 07:42:33 -06:00
Pavel Begunkov
658d0a4016 io_uring: check if opcode needs poll first on arming
->pollout or ->pollin are set only for opcodes that need a file, so if
io_arm_poll_handler() tests them first we can be sure that the request
has file set and the ->file check can be removed.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9adfe4f543d984875e516fce6da35348aab48668.1634987320.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-25 07:42:31 -06:00
Pavel Begunkov
d01905db14 io_uring: clean iowq submit work cancellation
If we've got IO_WQ_WORK_CANCEL in io_wq_submit_work(), handle the error
on the same lines as the check instead of having a weird code flow. The
main loop doesn't change but goes one indention left.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/ff4a09cf41f7a22bbb294b6f1faea721e21fe615.1634987320.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-25 07:42:29 -06:00
Pavel Begunkov
255657d237 io_uring: clean io_wq_submit_work()'s main loop
Do a bit of cleaning for the main loop of io_wq_submit_work(). Get rid
of switch, just replace it with a single if as we're retrying in both
other cases. Kill issue_sqe label, Get rid of needs_poll nesting and
disambiguate a bit the comment.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/ed12ce0c64e051f9a6b8a37a24f8ea554d299c29.1634987320.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-25 07:42:20 -06:00
Hao Xu
90fa02883f io_uring: implement async hybrid mode for pollable requests
The current logic of requests with IOSQE_ASYNC is first queueing it to
io-worker, then execute it in a synchronous way. For unbound works like
pollable requests(e.g. read/write a socketfd), the io-worker may stuck
there waiting for events for a long time. And thus other works wait in
the list for a long time too.
Let's introduce a new way for unbound works (currently pollable
requests), with this a request will first be queued to io-worker, then
executed in a nonblock try rather than a synchronous way. Failure of
that leads it to arm poll stuff and then the worker can begin to handle
other works.
The detail process of this kind of requests is:

step1: original context:
           queue it to io-worker
step2: io-worker context:
           nonblock try(the old logic is a synchronous try here)
               |
               |--fail--> arm poll
                            |
                            |--(fail/ready)-->synchronous issue
                            |
                            |--(succeed)-->worker finish it's job, tw
                                           take over the req

This works much better than the old IOSQE_ASYNC logic in cases where
unbound max_worker is relatively small. In this case, number of
io-worker eazily increments to max_worker, new worker cannot be created
and running workers stuck there handling old works in IOSQE_ASYNC mode.

In my 64-core machine, set unbound max_worker to 20, run echo-server,
turns out:
(arguments: register_file, connetion number is 1000, message size is 12
Byte)
original IOSQE_ASYNC: 76664.151 tps
after this patch: 166934.985 tps

Suggested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20211018133445.103438-1-haoxu@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-22 19:20:57 -06:00