Give applications a way to tell if the kernel supports sane linked files,
as in files being assigned at the right time to be able to reliably
do <open file direct into slot X><read file from slot X> while using
IOSQE_IO_LINK to order them.
Not really a bug fix, but flag it as such so that it gets pulled in with
backports of the deferred file assignment.
Fixes: 6bf9c47a39 ("io_uring: defer file assignment")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This was introduced with the message ring opcode, but isn't strictly
required for the request itself. The sender can encode what is needed
in user_data, which is passed to the receiver. It's unclear if having
a separate flag that essentially says "This CQE did not originate from
an SQE on this ring" provides any real utility to applications. While
we can always re-introduce a flag to provide this information, we cannot
take it away at a later point in time.
Remove the flag while we still can, before it's in a released kernel.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
By default, io_uring will stop submitting a batch of requests if we run
into an error submitting a request. This isn't strictly necessary, as
the error result is passed out-of-band via a CQE anyway. And it can be
a bit confusing for some applications.
Provide a way to setup a ring that will continue submitting on error,
when the error CQE has been posted.
There's still one case that will break out of submission. If we fail
allocating a request, then we'll still return -ENOMEM. We could in theory
post a CQE for that condition too even if we never got a request. Leave
that for a potential followup.
Reported-by: Dylan Yudaken <dylany@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This adds support for IORING_OP_MSG_RING, which allows an SQE to signal
another ring. That allows either waking up someone waiting on the ring,
or even passing a 64-bit value via the user_data field in the CQE.
sqe->fd must contain the fd of a ring that should receive the CQE.
sqe->off will be propagated to the cqe->user_data on the target ring,
and sqe->len will be propagated to cqe->res. The results CQE will have
IORING_CQE_F_MSG set in its flags, to indicate that this CQE was generated
from a messaging request rather than a SQE issued locally on that ring.
This effectively allows passing a 64-bit and a 32-bit quantify between
the two rings.
This request type has the following request specific error cases:
- -EBADFD. Set if the sqe->fd doesn't point to a file descriptor that is
of the io_uring type.
- -EOVERFLOW. Set if we were not able to deliver a request to the target
ring.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Lots of workloads use multiple threads, in which case the file table is
shared between them. This makes getting and putting the ring file
descriptor for each io_uring_enter(2) system call more expensive, as it
involves an atomic get and put for each call.
Similarly to how we allow registering normal file descriptors to avoid
this overhead, add support for an io_uring_register(2) API that allows
to register the ring fds themselves:
1) IORING_REGISTER_RING_FDS - takes an array of io_uring_rsrc_update
structs, and registers them with the task.
2) IORING_UNREGISTER_RING_FDS - takes an array of io_uring_src_update
structs, and unregisters them.
When a ring fd is registered, it is internally represented by an offset.
This offset is returned to the application, and the application then
uses this offset and sets IORING_ENTER_REGISTERED_RING for the
io_uring_enter(2) system call. This works just like using a registered
file descriptor, rather than a real one, in an SQE, where
IOSQE_FIXED_FILE gets set to tell io_uring that we're using an internal
offset/descriptor rather than a real file descriptor.
In initial testing, this provides a nice bump in performance for
threaded applications in real world cases where the batch count (eg
number of requests submitted per io_uring_enter(2) invocation) is low.
In a microbenchmark, submitting NOP requests, we see the following
increases in performance:
Requests per syscall Baseline Registered Increase
----------------------------------------------------------------
1 ~7030K ~8080K +15%
2 ~13120K ~14800K +13%
4 ~22740K ~25300K +11%
Co-developed-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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>
For some reason non-off IORING_OP_TIMEOUT always fails links, it's
pretty inconvenient and unnecessary limits chaining after it to hard
linking, which is far from ideal, e.g. doesn't pair well with timeout
cancellation. Add a flag forcing it to not fail links on -ETIME.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/17c7ec0fb7a6113cc6be8cdaedcada0ba836ac0e.1633199723.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The items passed in the array pointed by the arg parameter
of IORING_REGISTER_IOWQ_MAX_WORKERS io_uring_register operation
carry certain semantics: they refer to different io-wq worker categories;
provide IO_WQ_* constants in the UAPI, so these categories can be referenced
in the user space code.
Suggested-by: Jens Axboe <axboe@kernel.dk>
Complements: 2e480058dd ("io-wq: provide a way to limit max number of workers")
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
Link: https://lore.kernel.org/r/20210913154415.GA12890@asgard.redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
-----BEGIN PGP SIGNATURE-----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=T7Zv
-----END PGP SIGNATURE-----
Merge tag 'for-5.15/io_uring-vfs-2021-08-30' of git://git.kernel.dk/linux-block
Pull io_uring mkdirat/symlinkat/linkat support from Jens Axboe:
"This adds io_uring support for mkdirat, symlinkat, and linkat"
* tag 'for-5.15/io_uring-vfs-2021-08-30' of git://git.kernel.dk/linux-block:
io_uring: add support for IORING_OP_LINKAT
io_uring: add support for IORING_OP_SYMLINKAT
io_uring: add support for IORING_OP_MKDIRAT
namei: update do_*() helpers to return ints
namei: make do_linkat() take struct filename
namei: add getname_uflags()
namei: make do_symlinkat() take struct filename
namei: make do_mknodat() take struct filename
namei: make do_mkdirat() take struct filename
namei: change filename_parentat() calling conventions
namei: ignore ERR/NULL names in putname()
We allow updating normal timeouts, add support for adjusting timings of
linked timeouts as well.
Reported-by: Victor Stewart <v@nametag.social>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Certain use cases want to use CLOCK_BOOTTIME or CLOCK_REALTIME rather than
CLOCK_MONOTONIC, instead of the default CLOCK_MONOTONIC.
Add an IORING_TIMEOUT_BOOTTIME and IORING_TIMEOUT_REALTIME flag that
allows timeouts and linked timeouts to use the selected clock source.
Only one clock source may be selected, and we -EINVAL the request if more
than one is given. If neither BOOTIME nor REALTIME are selected, the
previous default of MONOTONIC is used.
Link: https://github.com/axboe/liburing/issues/369
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io-wq divides work into two categories:
1) Work that completes in a bounded time, like reading from a regular file
or a block device. This type of work is limited based on the size of
the SQ ring.
2) Work that may never complete, we call this unbounded work. The amount
of workers here is just limited by RLIMIT_NPROC.
For various uses cases, it's handy to have the kernel limit the maximum
amount of pending workers for both categories. Provide a way to do with
with a new IORING_REGISTER_IOWQ_MAX_WORKERS operation.
IORING_REGISTER_IOWQ_MAX_WORKERS takes an array of two integers and sets
the max worker count to what is being passed in for each category. The
old values are returned into that same array. If 0 is being passed in for
either category, it simply returns the current value.
The value is capped at RLIMIT_NPROC. This actually isn't that important
as it's more of a hint, if we're exceeding the value then our attempt
to fork a new worker will fail. This happens naturally already if more
than one node is in the system, as these values are per-node internally
for io-wq.
Reported-by: Johannes Lundberg <johalun0@gmail.com>
Link: https://github.com/axboe/liburing/issues/420
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of opening a file into a process's file table as usual and then
registering the fd within io_uring, some users may want to skip the
first step and place it directly into io_uring's fixed file table.
This patch adds such a capability for IORING_OP_OPENAT and
IORING_OP_OPENAT2.
The behaviour is controlled by setting sqe->file_index, where 0 implies
the old behaviour using normal file tables. If non-zero value is
specified, then it will behave as described and place the file into a
fixed file slot sqe->file_index - 1. A file table should be already
created, the slot should be valid and empty, otherwise the operation
will fail.
Keep the error codes consistent with IORING_OP_FILES_UPDATE, ENXIO and
EINVAL on inappropriate fixed tables, and return EBADF on collision with
already registered file.
Note: IOSQE_FIXED_FILE can't be used to switch between modes, because
accept takes a file, and it already uses the flag with a different
meaning.
Suggested-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/e9b33d1163286f51ea707f87d95bd596dada1e65.1629888991.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
IORING_OP_LINKAT behaves like linkat(2) and takes the same flags and
arguments.
In some internal places 'hardlink' is used instead of 'link' to avoid
confusion with the SQE links. Name 'link' conflicts with the existing
'link' member of io_kiocb.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/io-uring/20210514145259.wtl4xcsp52woi6ab@wittgenstein/
Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20210708063447.3556403-12-dkadashev@gmail.com
[axboe: add splice_fd_in check]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io-wq defaults to per-node masks for IO workers. This works fine by
default, but isn't particularly handy for workloads that prefer more
specific affinities, for either performance or isolation reasons.
This adds IORING_REGISTER_IOWQ_AFF that allows the user to pass in a CPU
mask that is then applied to IO thread workers, and an
IORING_UNREGISTER_IOWQ_AFF that simply resets the masks back to the
default of per-node.
Note that no care is given to existing IO threads, they will need to go
through a reschedule before the affinity is correct if they are already
running or sleeping.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add IORING_FEAT_RSRC_TAGS indicating that io_uring supports a bunch of
new IORING_REGISTER operations, in particular
IORING_REGISTER_[FILES[,UPDATE]2,BUFFERS[2,UPDATE]] that support rsrc
tagging, and also indicating implemented dynamic fixed buffer updates.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9b995d4045b6c6b4ab7510ca124fd25ac2203af7.1623339162.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There are ABI moments about recently added rsrc registration/update and
tagging that might become a nuisance in the future. First,
IORING_REGISTER_RSRC[_UPD] hide different types of resources under it,
so breaks fine control over them by restrictions. It works for now, but
once those are wanted under restrictions it would require a rework.
It was also inconvenient trying to fit a new resource not supporting
all the features (e.g. dynamic update) into the interface, so better
to return to IORING_REGISTER_* top level dispatching.
Second, register/update were considered to accept a type of resource,
however that's not a good idea because there might be several ways of
registration of a single resource type, e.g. we may want to add
non-contig buffers or anything more exquisite as dma mapped memory.
So, remove IORING_RSRC_[FILE,BUFFER] out of the ABI, and place them
internally for now to limit changes.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9b554897a7c17ad6e3becc48dfed2f7af9f423d5.1623339162.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a new io_uring_register() opcode for rsrc registeration. Instead of
accepting a pointer to resources, fds or iovecs, it @arg is now pointing
to a struct io_uring_rsrc_register, and the second argument tells how
large that struct is to make it easily extendible by adding new fields.
All that is done mainly to be able to pass in a pointer with tags. Pass
it in and enable CQE posting for file resources. Doesn't support setting
tags on update yet.
A design choice made here is to not post CQEs on rsrc de-registration,
but only when we updated-removed it by rsrc dynamic update.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/c498aaec32a4bb277b2406b9069662c02cdda98c.1619356238.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This adds two new POLL_ADD flags, IORING_POLL_UPDATE_EVENTS and
IORING_POLL_UPDATE_USER_DATA. As with the other POLL_ADD flag, these are
masked into sqe->len. If set, the POLL_ADD will have the following
behavior:
- sqe->addr must contain the the user_data of the poll request that
needs to be modified. This field is otherwise invalid for a POLL_ADD
command.
- If IORING_POLL_UPDATE_EVENTS is set, sqe->poll_events must contain the
new mask for the existing poll request. There are no checks for whether
these are identical or not, if a matching poll request is found, then it
is re-armed with the new mask.
- If IORING_POLL_UPDATE_USER_DATA is set, sqe->off must contain the new
user_data for the existing poll request.
A POLL_ADD with any of these flags set may complete with any of the
following results:
1) 0, which means that we successfully found the existing poll request
specified, and performed the re-arm procedure. Any error from that
re-arm will be exposed as a completion event for that original poll
request, not for the update request.
2) -ENOENT, if no existing poll request was found with the given
user_data.
3) -EALREADY, if the existing poll request was already in the process of
being removed/canceled/completing.
4) -EACCES, if an attempt was made to modify an internal poll request
(eg not one originally issued ass IORING_OP_POLL_ADD).
The usual -EINVAL cases apply as well, if any invalid fields are set
in the sqe for this command type.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The default io_uring poll mode is one-shot, where once the event triggers,
the poll command is completed and won't trigger any further events. If
we're doing repeated polling on the same file or socket, then it can be
more efficient to do multishot, where we keep triggering whenever the
event becomes true.
This deviates from the usual norm of having one CQE per SQE submitted. Add
a CQE flag, IORING_CQE_F_MORE, which tells the application to expect
further completion events from the submitted SQE. Right now the only user
of this is POLL_ADD in multishot mode.
Since sqe->poll_events is using the space that we normally use for adding
flags to commands, use sqe->len for the flag space for POLL_ADD. Multishot
mode is selected by setting IORING_POLL_ADD_MULTI in sqe->len. An
application should expect more CQEs for the specificed SQE if the CQE is
flagged with IORING_CQE_F_MORE. In multishot mode, only cancelation or an
error will terminate the poll request, in which case the flag will be
cleared.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A few reasons to do this:
- The naming of the manager and worker have changed. That's a user visible
change, so makes sense to flag it.
- Opening certain files that use ->signal (like /proc/self or /dev/tty)
now works, and the flag tells the application upfront that this is the
case.
- Related to the above, using signalfd will now work as well.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This patch adds support for skipping a file descriptor when using
IORING_REGISTER_FILES_UPDATE. __io_sqe_files_update will skip fds set
to IORING_REGISTER_FILES_SKIP. IORING_REGISTER_FILES_SKIP is inturn
added as a #define in io_uring.h
Signed-off-by: noah <goldstein.w.n@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This is a prep rename patch for subsequent patches to generalize file
registration.
[io_uring_rsrc_update:: rename fds -> data]
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
[leave io_uring_files_update as struct]
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Support timeout updates through IORING_OP_TIMEOUT_REMOVE with passed in
IORING_TIMEOUT_UPDATE. Updates doesn't support offset timeout mode.
Oirignal timeout.off will be ignored as well.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: remove now unused 'ret' variable]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now users who want to get woken when waiting for events should submit a
timeout command first. It is not safe for applications that split SQ and
CQ handling between two threads, such as mysql. Users should synchronize
the two threads explicitly to protect SQ and that will impact the
performance.
This patch adds support for timeout to existing io_uring_enter(). To
avoid overloading arguments, it introduces a new parameter structure
which contains sigmask and timeout.
I have tested the workloads with one thread submiting nop requests
while the other reaping the cqe with timeout. It shows 1.8~2x faster
when the iodepth is 16.
Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com>
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
[axboe: various cleanups/fixes, and name change to SIG_IS_DATA]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The restriction of needing fixed files for SQPOLL is problematic, and
prevents/inhibits several valid uses cases. With the referenced
files_struct that we have now, it's trivially supportable.
Treat ->files like we do the mm for the SQPOLL thread - grab a reference
to it (and assign it), and drop it when we're done.
This feature is exposed as IORING_FEAT_SQPOLL_NONFIXED.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This adds support for the shutdown(2) system call, which is useful for
dealing with sockets.
shutdown(2) may block, so we have to punt it to async context.
Suggested-by: Norman Maurer <norman.maurer@googlemail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When using SQPOLL, applications can run into the issue of running out of
SQ ring entries because the thread hasn't consumed them yet. The only
option for dealing with that is checking later, or busy checking for the
condition.
Provide IORING_ENTER_SQ_WAIT if applications want to wait on this
condition.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This patch adds a new IORING_SETUP_R_DISABLED flag to start the
rings disabled, allowing the user to register restrictions,
buffers, files, before to start processing SQEs.
When IORING_SETUP_R_DISABLED is set, SQE are not processed and
SQPOLL kthread is not started.
The restrictions registration are allowed only when the rings
are disable to prevent concurrency issue while processing SQEs.
The rings can be enabled using IORING_REGISTER_ENABLE_RINGS
opcode with io_uring_register(2).
Suggested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The new io_uring_register(2) IOURING_REGISTER_RESTRICTIONS opcode
permanently installs a feature allowlist on an io_ring_ctx.
The io_ring_ctx can then be passed to untrusted code with the
knowledge that only operations present in the allowlist can be
executed.
The allowlist approach ensures that new features added to io_uring
do not accidentally become available when an existing application
is launched on a newer kernel version.
Currently is it possible to restrict sqe opcodes, sqe flags, and
register opcodes.
IOURING_REGISTER_RESTRICTIONS can only be made once. Afterwards
it is not possible to change restrictions anymore.
This prevents untrusted code from removing restrictions.
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The enumeration allows us to keep track of the last
io_uring_register(2) opcode available.
Behaviour and opcodes names don't change.
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Merge in io_uring-5.8 fixes, as changes/cleanups to how we do locked
mem accounting require a fixup, and only one of the spots are noticed
by git as the other merges cleanly. The flags fix from io_uring-5.8
also causes a merge conflict, the leak fix for recvmsg, the double poll
fix, and the link failure locking fix.
* io_uring-5.8:
io_uring: fix lockup in io_fail_links()
io_uring: fix ->work corruption with poll_add
io_uring: missed req_init_async() for IOSQE_ASYNC
io_uring: always allow drain/link/hardlink/async sqe flags
io_uring: ensure double poll additions work with both request types
io_uring: fix recvmsg memory leak with buffer selection
io_uring: fix not initialised work->flags
io_uring: fix missing msg_name assignment
io_uring: account user memory freed when exit has been queued
io_uring: fix memleak in io_sqe_files_register()
io_uring: fix memleak in __io_sqe_files_update()
io_uring: export cq overflow status to userspace
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For those applications which are not willing to use io_uring_enter()
to reap and handle cqes, they may completely rely on liburing's
io_uring_peek_cqe(), but if cq ring has overflowed, currently because
io_uring_peek_cqe() is not aware of this overflow, it won't enter
kernel to flush cqes, below test program can reveal this bug:
static void test_cq_overflow(struct io_uring *ring)
{
struct io_uring_cqe *cqe;
struct io_uring_sqe *sqe;
int issued = 0;
int ret = 0;
do {
sqe = io_uring_get_sqe(ring);
if (!sqe) {
fprintf(stderr, "get sqe failed\n");
break;;
}
ret = io_uring_submit(ring);
if (ret <= 0) {
if (ret != -EBUSY)
fprintf(stderr, "sqe submit failed: %d\n", ret);
break;
}
issued++;
} while (ret > 0);
assert(ret == -EBUSY);
printf("issued requests: %d\n", issued);
while (issued) {
ret = io_uring_peek_cqe(ring, &cqe);
if (ret) {
if (ret != -EAGAIN) {
fprintf(stderr, "peek completion failed: %s\n",
strerror(ret));
break;
}
printf("left requets: %d\n", issued);
continue;
}
io_uring_cqe_seen(ring, cqe);
issued--;
printf("left requets: %d\n", issued);
}
}
int main(int argc, char *argv[])
{
int ret;
struct io_uring ring;
ret = io_uring_queue_init(16, &ring, 0);
if (ret) {
fprintf(stderr, "ring setup failed: %d\n", ret);
return 1;
}
test_cq_overflow(&ring);
return 0;
}
To fix this issue, export cq overflow status to userspace by adding new
IORING_SQ_CQ_OVERFLOW flag, then helper functions() in liburing, such as
io_uring_peek_cqe, can be aware of this cq overflow and do flush accordingly.
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
poll events should be 32-bits to cover EPOLLEXCLUSIVE.
Explicit word-swap the poll32_events for big endian to make sure the ABI
is not changed. We call this feature IORING_FEAT_POLL_32BITS,
applications who want to use EPOLLEXCLUSIVE should check the feature bit
first.
Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add IORING_OP_TEE implementing tee(2) support. Almost identical to
splice bits, but without offsets.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This new flag should be set/clear from the application to
disable/enable eventfd notifications when a request is completed
and queued to the CQ ring.
Before this patch, notifications were always sent if an eventfd is
registered, so IORING_CQ_EVENTFD_DISABLED is not set during the
initialization.
It will be up to the application to set the flag after initialization
if no notifications are required at the beginning.
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This patch adds the new 'cq_flags' field that should be written by
the application and read by the kernel.
This new field is available to the userspace application through
'cq_off.flags'.
We are using 4-bytes previously reserved and set to zero. This means
that if the application finds this field to zero, then the new
functionality is not supported.
In the next patch we will introduce the first flag available.
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This just syncs the header it with the liburing version, so there's no
confusion on the license of the header parts.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We have IORING_OP_PROVIDE_BUFFERS, but the only way to remove buffers
is to trigger IO on them. The usual case of shrinking a buffer pool
would be to just not replenish the buffers when IO completes, and
instead just free it. But it may be nice to have a way to manually
remove a number of buffers from a given group, and
IORING_OP_REMOVE_BUFFERS provides that functionality.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If a server process has tons of pending socket connections, generally
it uses epoll to wait for activity. When the socket is ready for reading
(or writing), the task can select a buffer and issue a recv/send on the
given fd.
Now that we have fast (non-async thread) support, a task can have tons
of pending reads or writes pending. But that means they need buffers to
back that data, and if the number of connections is high enough, having
them preallocated for all possible connections is unfeasible.
With IORING_OP_PROVIDE_BUFFERS, an application can register buffers to
use for any request. The request then sets IOSQE_BUFFER_SELECT in the
sqe, and a given group ID in sqe->buf_group. When the fd becomes ready,
a free buffer from the specified group is selected. If none are
available, the request is terminated with -ENOBUFS. If successful, the
CQE on completion will contain the buffer ID chosen in the cqe->flags
member, encoded as:
(buffer_id << IORING_CQE_BUFFER_SHIFT) | IORING_CQE_F_BUFFER;
Once a buffer has been consumed by a request, it is no longer available
and must be registered again with IORING_OP_PROVIDE_BUFFERS.
Requests need to support this feature. For now, IORING_OP_READ and
IORING_OP_RECV support it. This is checked on SQE submission, a CQE with
res == -EOPNOTSUPP will be posted if attempted on unsupported requests.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
IORING_OP_PROVIDE_BUFFERS uses the buffer registration infrastructure to
support passing in an addr/len that is associated with a buffer ID and
buffer group ID. The group ID is used to index and lookup the buffers,
while the buffer ID can be used to notify the application which buffer
in the group was used. The addr passed in is the starting buffer address,
and length is each buffer length. A number of buffers to add with can be
specified, in which case addr is incremented by length for each addition,
and each buffer increments the buffer ID specified.
No validation is done of the buffer ID. If the application provides
buffers within the same group with identical buffer IDs, then it'll have
a hard time telling which buffer ID was used. The only restriction is
that the buffer ID can be a max of 16-bits in size, so USHRT_MAX is the
maximum ID that can be used.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
