Commit Graph

27 Commits

Author SHA1 Message Date
Pavel Begunkov 519760df25 io_uring/notif: add constant for ubuf_info flags
Add a constant IO_NOTIF_UBUF_FLAGS for struct ubuf_info flags that
notifications use. That should minimise merge conflicts for planned
changes touching both io_uring and net at the same time.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-04-15 14:21:04 -06:00
Pavel Begunkov 8751d15426 io_uring: reduce scheduling due to tw
Every task_work will try to wake the task to be executed, which causes
excessive scheduling and additional overhead. For some tw it's
justified, but others won't do much but post a single CQE.

When a task waits for multiple cqes, every such task_work will wake it
up. Instead, the task may give a hint about how many cqes it waits for,
io_req_local_work_add() will compare against it and skip wake ups
if #cqes + #tw is not enough to satisfy the waiting condition. Task_work
that uses the optimisation should be simple enough and never post more
than one CQE. It's also ignored for non DEFER_TASKRUN rings.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d2b77e99d1e86624d8a69f7037d764b739dcd225.1680782017.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-04-06 16:23:28 -06:00
Pavel Begunkov a282967c84 io_uring: encapsulate task_work state
For task works we're passing around a bool pointer for whether the
current ring is locked or not, let's wrap it in a structure, that
will make it more opaque preventing abuse and will also help us
to pass more info in the future if needed.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1ecec9483d58696e248d1bfd52cf62b04442df1d.1679931367.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-04-03 07:16:15 -06:00
Pavel Begunkov c8576f3e61 io_uring: refactor req allocation
Follow the io_get_sqe pattern returning the result via a pointer
and hide request cache refill inside io_alloc_req().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/8c37c2e8a3cb5e4cd6a8ae3b91371227a92708a6.1674484266.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29 15:17:41 -07:00
Pavel Begunkov 42385b02ba io_uring/net: move mm accounting to a slower path
We can also move mm accounting to the extended callbacks. It removes a
few cycles from the hot path including skipping one function call and
setting io_req_task_complete as a callback directly. For user backed I/O
it shouldn't make any difference taking into considering atomic mm
accounting and page pinning.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1062f270273ad11c1b7b45ec59a6a317533d5e64.1667557923.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-21 07:38:31 -07:00
Pavel Begunkov 40725d1b96 io_uring: move zc reporting from the hot path
Add custom tw and notif callbacks on top of usual bits also handling zc
reporting. That moves it from the hot path.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/40de4a6409042478e1f35adc4912e23226cb1b5c.1667557923.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-21 07:38:31 -07:00
Pavel Begunkov bedd20bcf3 io_uring/net: inline io_notif_flush()
io_notif_flush() is pretty simple, we can inline it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/332359e7bd124138dfe51340bbec829c9b265c18.1667557923.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-21 07:38:31 -07:00
Pavel Begunkov 7fa8e84192 io_uring/net: rename io_uring_tx_zerocopy_callback
Just a simple renaming patch, io_uring_tx_zerocopy_callback() is too
bulky and doesn't follow usual naming style.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/24d78325403ca6dcb1ec4bced1e33cacc9b832a5.1667557923.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-21 07:38:31 -07:00
Pavel Begunkov fc1dd0d4fa io_uring/net: preset notif tw handler
We're going to have multiple notification tw functions. In preparation
for future changes default the tw callback in advance so later we can
replace it with other versions.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/7acdbea5e20eadd844513320cd454af14ba50f64.1667557923.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-21 07:38:31 -07:00
Pavel Begunkov 5bc8e8884b io_uring/net: remove extra notif rsrc setup
io_send_zc_prep() sets up notification's rsrc_node when needed, don't
unconditionally install it on notif alloc.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/dbe4875ac33e180b9799d8537a5e27935e82aac4.1667557923.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-21 07:38:31 -07:00
Stefan Metzmacher e307e66981 io_uring/net: introduce IORING_SEND_ZC_REPORT_USAGE flag
It might be useful for applications to detect if a zero copy transfer with
SEND[MSG]_ZC was actually possible or not. The application can fallback to
plain SEND[MSG] in order to avoid the overhead of two cqes per request. Or
it can generate a log message that could indicate to an administrator that
no zero copy was possible and could explain degraded performance.

Cc: stable@vger.kernel.org # 6.1
Link: https://lore.kernel.org/io-uring/fb6a7599-8a9b-15e5-9b64-6cd9d01c6ff4@gmail.com/T/#m2b0d9df94ce43b0e69e6c089bdff0ce6babbdfaa
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/8945b01756d902f5d5b0667f20b957ad3f742e5e.1666895626.git.metze@samba.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-21 07:38:31 -07:00
Jiapeng Chong 4fa07edbb7 io_uring/notif: Remove the unused function io_notif_complete()
The function io_notif_complete() is defined in the notif.c file, but not
called elsewhere, so delete this unused function.

io_uring/notif.c:24:20: warning: unused function 'io_notif_complete' [-Wunused-function].

Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=2047
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20220905020436.51894-1-jiapeng.chong@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-05 11:42:39 -06:00
Pavel Begunkov b48c312be0 io_uring/net: simplify zerocopy send user API
Following user feedback, this patch simplifies zerocopy send API. One of
the main complaints is that the current API is difficult with the
userspace managing notification slots, and then send retries with error
handling make it even worse.

Instead of keeping notification slots change it to the per-request
notifications model, which posts both completion and notification CQEs
for each request when any data has been sent, and only one CQE if it
fails. All notification CQEs will have IORING_CQE_F_NOTIF set and
IORING_CQE_F_MORE in completion CQEs indicates whether to wait a
notification or not.

IOSQE_CQE_SKIP_SUCCESS is disallowed with zerocopy sends for now.

This is less flexible, but greatly simplifies the user API and also the
kernel implementation. We reuse notif helpers in this patch, but in the
future there won't be need for keeping two requests.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/95287640ab98fc9417370afb16e310677c63e6ce.1662027856.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-01 09:13:33 -06:00
Pavel Begunkov 57f332246a io_uring/notif: remove notif registration
We're going to remove the userspace exposed zerocopy notification API,
remove notification registration.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/6ff00b97be99869c386958a990593c9c31cf105b.1662027856.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-01 09:13:33 -06:00
Pavel Begunkov 53bdc88aac io_uring/notif: order notif vs send CQEs
Currently, there is no ordering between notification CQEs and
completions of the send flushing it, this quite complicates the
userspace, especially since we don't flush notification when the
send(+flush) request fails, i.e. there will be only one CQE. What we
can do is to make sure that notification completions come only after
sends.

The easiest way to achieve this is to not try to complete a notification
inline from io_sendzc() but defer it to task_work, considering that
io-wq sendzc is disallowed CQEs will be naturally ordered because
task_works will only be executed after we're done with submission and so
inline completion.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/cddfd1c2bf91f22b9fe08e13b7dffdd8f858a151.1661342812.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-08-24 08:57:28 -06:00
Pavel Begunkov 2cacedc873 io_uring/net: fix must_hold annotation
Fix up the io_alloc_notif()'s __must_hold as we don't have a ctx
argument there but should get it from the slot instead.

Reported-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/cbb0a920f18e0aed590bf58300af817b9befb8a3.1661342812.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-08-24 08:57:00 -06:00
Stefan Metzmacher f2ccb5aed7 io_uring: make io_kiocb_to_cmd() typesafe
We need to make sure (at build time) that struct io_cmd_data is not
casted to a structure that's larger.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Link: https://lore.kernel.org/r/c024cdf25ae19fc0319d4180e2298bade8ed17b8.1660201408.git.metze@samba.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-08-12 17:01:00 -06:00
Stefan Metzmacher da2634e89c io_uring: consistently make use of io_notif_to_data()
This makes the assignment typesafe. It prepares
changing io_kiocb_to_cmd() in the next commit.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Link: https://lore.kernel.org/r/8da6e9d12cf95ad4bc73274406d12bca7aabf72e.1660201408.git.metze@samba.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-08-11 10:56:13 -06:00
Pavel Begunkov 14b146b688 io_uring: notification completion optimisation
We want to use all optimisations that we have for io_uring requests like
completion batching, memory caching and more but for zc notifications.
Fortunately, notification perfectly fit the request model so we can
overlay them onto struct io_kiocb and use all the infratructure.

Most of the fields of struct io_notif natively fits into io_kiocb, so we
replace struct io_notif with struct io_kiocb carrying struct
io_notif_data in the cmd cache line. Then we adapt io_alloc_notif() to
use io_alloc_req()/io_alloc_req_refill(), and kill leftovers of hand
coded caching. __io_notif_complete_tw() is converted to use io_uring's
tw infra.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9e010125175e80baf51f0ca63bdc7cc6a4a9fa56.1658913593.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-27 08:50:50 -06:00
Pavel Begunkov 6a9ce66f4d io_uring/net: make page accounting more consistent
Make network page accounting more consistent with how buffer
registration is working, i.e. account all memory to ctx->user.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/4aacfe64bbb81b27f9ecf5d5c219c69a07e5aa56.1658742118.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-25 09:48:25 -06:00
Pavel Begunkov 63809137eb io_uring: flush notifiers after sendzc
Allow to flush notifiers as a part of sendzc request by setting
IORING_SENDZC_FLUSH flag. When the sendzc request succeedes it will
flush the used [active] notifier.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/e0b4d9a6797e2fd6092824fe42953db7a519bbc8.1657643355.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:41:07 -06:00
Pavel Begunkov e29e3bd4b9 io_uring: account locked pages for non-fixed zc
Fixed buffers are RLIMIT_MEMLOCK accounted, however it doesn't cover iovec
based zerocopy sends. Do the accounting on the io_uring side.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/19b6e3975440f59f1f6199c7ee7acf977b4eecdc.1657643355.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:41:07 -06:00
Pavel Begunkov bc24d6bd32 io_uring: add notification slot registration
Let the userspace to register and unregister notification slots.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/a0aa8161fe3ebb2a4cc6e5dbd0cffb96e6881cf5.1657643355.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:41:07 -06:00
Pavel Begunkov 68ef5578ef io_uring: add rsrc referencing for notifiers
In preparation to zerocopy sends with fixed buffers make notifiers to
reference the rsrc node to protect the used fixed buffers. We can't just
grab it for a send request as notifiers can likely outlive requests that
used it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/3cd7a01d26837945b6982fa9cf15a63230f2ed4f.1657643355.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:41:06 -06:00
Pavel Begunkov e58d498e81 io_uring: complete notifiers in tw
We need a task context to post CQEs but using wq is too expensive.
Try to complete notifiers using task_work and fall back to wq if fails.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/089799ab665b10b78fdc614ae6d59fa7ef0d5f91.1657643355.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:41:06 -06:00
Pavel Begunkov eb4a299b2f io_uring: cache struct io_notif
kmalloc'ing struct io_notif is too expensive when done frequently, cache
them as many other resources in io_uring. Keep two list, the first one
is from where we're getting notifiers, it's protected by ->uring_lock.
The second is protected by ->completion_lock, to which we queue released
notifiers. Then we splice one list into another when needed.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9dec18f7fcbab9f4bd40b96e5ae158b119945230.1657643355.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:41:06 -06:00
Pavel Begunkov eb42cebb2c io_uring: add zc notification infrastructure
Add internal part of send zerocopy notifications. There are two main
structures, the first one is struct io_notif, which carries inside
struct ubuf_info and maps 1:1 to it. io_uring will be binding a number
of zerocopy send requests to it and ask to complete (aka flush) it. When
flushed and all attached requests and skbs complete, it'll generate one
and only one CQE. There are intended to be passed into the network layer
as struct msghdr::msg_ubuf.

The second concept is notification slots. The userspace will be able to
register an array of slots and subsequently addressing them by the index
in the array. Slots are independent of each other. Each slot can have
only one notifier at a time (called active notifier) but many notifiers
during the lifetime. When active, a notifier not going to post any
completion but the userspace can attach requests to it by specifying
the corresponding slot while issueing send zc requests. Eventually, the
userspace will want to "flush" the notifier losing any way to attach
new requests to it, however it can use the next atomatically added
notifier of this slot or of any other slot.

When the network layer is done with all enqueued skbs attached to a
notifier and doesn't need the specified in them user data, the flushed
notifier will post a CQE.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/3ecf54c31a85762bf679b0a432c9f43ecf7e61cc.1657643355.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:41:06 -06:00