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iovecs that are turned into registered buffers are imported in a special
way with an offset, so that later we can do an in place translation. Add
a helper function taking care of it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/7de2ecb9ed5efc3c5cf320232236966da5ad4ccc.1741457480.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Add io_import_reg_vec(), which will be responsible for importing
vectored registered buffers. The function might reallocate the vector,
but it'd try to do the conversion in place first, which is why it's
required of the user to pad the iovec to the right border of the cache.
Overlapping also depends on struct iovec being larger than bvec, which
is not the case on e.g. 32 bit architectures. Don't try to complicate
this case and make sure vectors never overlap, it'll be improved later.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/60bd246b1249476a6996407c1dbc38ef6febad14.1741362889.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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I need a convenient way to pass around and work with iovec+size pair,
put them into a structure and makes use of it in rw.c
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d39fadafc9e9047b0a292e5be6db3cf2f48bb1f7.1741362889.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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* for-6.15/io_uring-rx-zc: (80 commits)
io_uring/zcrx: add selftest case for recvzc with read limit
io_uring/zcrx: add a read limit to recvzc requests
io_uring: add missing IORING_MAP_OFF_ZCRX_REGION in io_uring_mmap
io_uring: Rename KConfig to Kconfig
io_uring/zcrx: fix leaks on failed registration
io_uring/zcrx: recheck ifq on shutdown
io_uring/zcrx: add selftest
net: add documentation for io_uring zcrx
io_uring/zcrx: add copy fallback
io_uring/zcrx: throttle receive requests
io_uring/zcrx: set pp memory provider for an rx queue
io_uring/zcrx: add io_recvzc request
io_uring/zcrx: dma-map area for the device
io_uring/zcrx: implement zerocopy receive pp memory provider
io_uring/zcrx: grab a net device
io_uring/zcrx: add io_zcrx_area
io_uring/zcrx: add interface queue and refill queue
net: add helpers for setting a memory provider on an rx queue
net: page_pool: add memory provider helpers
net: prepare for non devmem TCP memory providers
...
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Add a helper function io_cache_free() that returns an allocation to a
io_alloc_cache, falling back on kfree() if the io_alloc_cache is full.
This is the inverse of io_cache_alloc(), which takes an allocation from
an io_alloc_cache and falls back on kmalloc() if the cache is empty.
Convert 4 callers to use the helper.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Suggested-by: Li Zetao <lizetao1@huawei.com>
Link: https://lore.kernel.org/r/20250304194814.2346705-1-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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io_rsrc_node's of type IORING_RSRC_FILE always have a file attached
immediately after they are allocated. IORING_RSRC_BUFFER nodes won't be
returned from io_sqe_buffer_register()/io_buffer_register_bvec() until
they have a io_mapped_ubuf attached.
So remove the checks for a NULL file/buffer in io_free_rsrc_node().
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Link: https://lore.kernel.org/r/20250228235916.670437-5-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The done: label is only reachable if node is non-NULL. So don't bother
checking, just call io_free_node().
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Link: https://lore.kernel.org/r/20250228235916.670437-4-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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io_sqe_buffer_register() currently calls io_put_rsrc_node() if it fails
to fully set up the io_rsrc_node. io_put_rsrc_node() is more involved
than necessary, since we already know the reference count will reach 0
and no io_mapped_ubuf has been attached to the node yet.
So just call io_free_node() to release the node's memory. This also
avoids the need to temporarily set the node's buf pointer to NULL.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Link: https://lore.kernel.org/r/20250228235916.670437-3-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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io_rsrc_node_alloc() calls io_cache_alloc(), which uses kmalloc() to
allocate the node. So it can be freed with kfree() instead of kvfree().
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Link: https://lore.kernel.org/r/20250228235916.670437-2-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Split the freeing of the io_rsrc_node from io_free_rsrc_node(), for use
with nodes that haven't been fully initialized.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Link: https://lore.kernel.org/r/20250228235916.670437-1-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Declare io_find_buf_node() in io_uring/rsrc.h so it can be called from
other files.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Link: https://lore.kernel.org/r/20250301001610.678223-1-csander@purestorage.com
[axboe: keep the inline for local hot path usage]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Indicate to userspace applications if a UBLK_IO_UNREGISTER_IO_BUF
command specifies an invalid buffer index by returning an error code.
Return -EINVAL if no buffer is registered with the given index, and
-EBUSY if the registered buffer is not a kernel bvec.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Link: https://lore.kernel.org/r/20250228231432.642417-1-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The macro rq_data_dir() already computes a request's data direction.
Use it in place of the if-else to set imu->dir.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Link: https://lore.kernel.org/r/20250228223057.615284-1-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Frequent alloc/free cycles on these is pretty costly. Use an io cache to
more efficiently reuse these buffers.
Signed-off-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20250227223916.143006-7-kbusch@meta.com
[axboe: fix imu leak]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Provide an interface for the kernel to leverage the existing
pre-registered buffers that io_uring provides. User space can reference
these later to achieve zero-copy IO.
User space must register an empty fixed buffer table with io_uring in
order for the kernel to make use of it.
Signed-off-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20250227223916.143006-5-kbusch@meta.com
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Registered buffer are currently imported in two steps, first we lookup
a rsrc node and then use it to set up the iterator. The first part is
usually done at the prep stage, and import happens whenever it's needed.
As we want to defer binding to a node so that it works with linked
requests, combine both steps into a single helper.
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250224213116.3509093-6-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The only caller to io_buffer_unmap already checks if the node's buf is
not null, so no need to check again.
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250224213116.3509093-2-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Add io_zcrx_area that represents a region of userspace memory that is
used for zero copy. During ifq registration, userspace passes in the
uaddr and len of userspace memory, which is then pinned by the kernel.
Each net_iov is mapped to one of these pages.
The freelist is a spinlock protected list that keeps track of all the
net_iovs/pages that aren't used.
For now, there is only one area per ifq and area registration happens
implicitly as part of ifq registration. There is no API for
adding/removing areas yet. The struct for area registration is there for
future extensibility once we support multiple areas and TCP devmem.
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: David Wei <dw@davidwei.uk>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20250215000947.789731-3-dw@davidwei.uk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Checking for lockdep_assert_held(&ctx->uring_lock) in io_free_rsrc_node()
means that the assertion is only checked when the resource drops to zero
references.
Move the lockdep assertion up into the caller io_put_rsrc_node() so that it
instead happens on every reference count decrement.
Signed-off-by: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/r/20250120-uring-lockdep-assert-earlier-v1-1-68d8e071a4bb@google.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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io_uring_ctx parameter for io_rsrc_node_alloc() is unused for now.
This patch removes the parameter and fixes the callers accordingly.
Signed-off-by: Sidong Yang <sidong.yang@furiosa.ai>
Link: https://lore.kernel.org/r/20250115142033.658599-1-sidong.yang@furiosa.ai
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Make it always reference the returned file. It's safer, especially with
unregistrations happening under it. And it makes the api cleaner with no
conditional clean ups by the caller.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0d0b13a63e8edd6b5d360fc821dcdb035cb6b7e0.1736995897.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The locking in the buffer cloning code is somewhat complex because it goes
back and forth between locking the source ring and the destination ring.
Make it easier to reason about by locking both rings at the same time.
To avoid ABBA deadlocks, lock the rings in ascending kernel address order,
just like in lock_two_nondirectories().
Signed-off-by: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/r/20250115-uring-clone-refactor-v2-1-7289ba50776d@google.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Pull io_uring updates from Jens Axboe:
"Not a lot in terms of features this time around, mostly just cleanups
and code consolidation:
- Support for PI meta data read/write via io_uring, with NVMe and
SCSI covered
- Cleanup the per-op structure caching, making it consistent across
various command types
- Consolidate the various user mapped features into a concept called
regions, making the various users of that consistent
- Various cleanups and fixes"
* tag 'for-6.14/io_uring-20250119' of git://git.kernel.dk/linux: (56 commits)
io_uring/fdinfo: fix io_uring_show_fdinfo() misuse of ->d_iname
io_uring: reuse io_should_terminate_tw() for cmds
io_uring: Factor out a function to parse restrictions
io_uring/rsrc: require cloned buffers to share accounting contexts
io_uring: simplify the SQPOLL thread check when cancelling requests
io_uring: expose read/write attribute capability
io_uring/rw: don't gate retry on completion context
io_uring/rw: handle -EAGAIN retry at IO completion time
io_uring/rw: use io_rw_recycle() from cleanup path
io_uring/rsrc: simplify the bvec iter count calculation
io_uring: ensure io_queue_deferred() is out-of-line
io_uring/rw: always clear ->bytes_done on io_async_rw setup
io_uring/rw: use NULL for rw->free_iovec assigment
io_uring/rw: don't mask in f_iocb_flags
io_uring/msg_ring: Drop custom destructor
io_uring: Move old async data allocation helper to header
io_uring/rw: Allocate async data through helper
io_uring/net: Allocate msghdr async data through helper
io_uring/uring_cmd: Allocate async data through generic helper
io_uring/poll: Allocate apoll with generic alloc_cache helper
...
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When IORING_REGISTER_CLONE_BUFFERS is used to clone buffers from uring
instance A to uring instance B, where A and B use different MMs for
accounting, the accounting can go wrong:
If uring instance A is closed before uring instance B, the pinned memory
counters for uring instance B will be decremented, even though the pinned
memory was originally accounted through uring instance A; so the MM of
uring instance B can end up with negative locked memory.
Cc: stable@vger.kernel.org
Closes: https://lore.kernel.org/r/CAG48ez1zez4bdhmeGLEFxtbFADY4Czn3CV0u9d_TMcbvRA01bg@mail.gmail.com
Fixes: 7cc2a6eadcd7 ("io_uring: add IORING_REGISTER_COPY_BUFFERS method")
Signed-off-by: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/r/20250114-uring-check-accounting-v1-1-42e4145aa743@google.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Jann reports he can trigger a UAF if the target ring unregisters
buffers before the clone operation is fully done. And additionally
also an issue related to node allocation failures. Both of those
stemp from the fact that the cleanup logic puts the buffers manually,
rather than just relying on io_rsrc_data_free() doing it. Hence kill
the manual cleanup code and just let io_rsrc_data_free() handle it,
it'll put the nodes appropriately.
Reported-by: Jann Horn <jannh@google.com>
Fixes: 3597f2786b68 ("io_uring/rsrc: unify file and buffer resource tables")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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As we don't use iov_iter_advance() but our own logic in io_import_fixed(),
we can remove the logic that over-sets the iter's count to len + offset
then adjusts it later to len. This helps to make the code cleaner.
Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
Link: https://lore.kernel.org/r/20250103150412.12549-1-minhquangbui99@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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When io_check_coalesce_buffer() meets a single page buffer it bails out
and tells that it can be coalesced. That's fine for registered buffers
as io_coalesce_buffer() wouldn't change anything, but the region code
now uses the function to decided on whether to vmap the buffer or not.
Report that a single page buffer is trivially coalescable and let
io_sqe_buffer_register() to filter them.
Fixes: c4d0ac1c1567 ("io_uring/memmap: optimise single folio regions")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/cb83e053f318857068447d40c95becebcd8aeced.1733689833.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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io_try_coalesce_buffer() is a useful helper collecting useful info about
a set of pages, I want to reuse it for analysing ring/etc. mappings. I
don't need the entire thing and only interested if it can be coalesced
into a single page, but that's better than duplicating the parsing.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/353b447953cd5d34c454a7d909bb6024c391d6e2.1732886067.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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If cloning of buffers fail and we have to put the ones already grabbed,
check for NULL buffers and skip those. They used to be dummy ubufs, but
now they are just NULL and that should be checked before reaping them.
Reported-by: chase xd <sl1589472800@gmail.com>
Link: https://lore.kernel.org/io-uring/CADZouDQ7TcKn8gz8_efnyAEp1JvU1ktRk8PWz-tO0FXUoh8VGQ@mail.gmail.com/
Fixes: d50f94d761a5 ("io_uring/rsrc: get rid of the empty node and dummy_ubuf")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Remove '->ctx_ptr' of 'struct io_rsrc_node', and add 'type' field,
meantime remove io_rsrc_node_type().
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20241107110149.890530-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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`io_rsrc_node` instance won't be shared among different io_uring ctxs,
and its allocation 'ctx' is always same with the user's 'ctx', so it is
safe to pass user 'ctx' reference to rsrc helpers. Even in io_clone_buffers(),
`io_rsrc_node` instance is allocated actually for destination io_uring_ctx.
Then io_rsrc_node_ctx() can be removed, and the 8 bytes `ctx` pointer will be
removed from `io_rsrc_node` in the following patch.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20241107110149.890530-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Rather than keep the type field separate rom ctx, use the fact that we
can encode up to 4 types of nodes in the LSB of the ctx pointer. Doesn't
reclaim any space right now on 64-bit archs, but it leaves a full int
for future use.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Currently cloning a buffer table will fail if the destination already has
a table. But it should be possible to use it to replace existing elements.
Add a IORING_REGISTER_DST_REPLACE cloning flag, which if set, will allow
the destination to already having a buffer table. If that is the case,
then entries designated by offset + nr buffers will be replaced if they
already exist.
Note that it's allowed to use IORING_REGISTER_DST_REPLACE and not have
an existing table, in which case it'll work just like not having the
flag set and an empty table - it'll just assign the newly created table
for that case.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Right now buffer cloning is an all-or-nothing kind of thing - either the
whole table is cloned from a source to a destination ring, or nothing at
all.
However, it's not always desired to clone the whole thing. Allow for
the application to specify a source and destination offset, and a
number of buffers to clone. If the destination offset is non-zero, then
allocate sparse nodes upfront.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The empty node was used as a placeholder for a sparse entry, but it
didn't really solve any issues. The caller still has to check for
whether it's the empty node or not, it may as well just check for a NULL
return instead.
The dummy_ubuf was used for a sparse buffer entry, but NULL will serve
the same purpose there of ensuring an -EFAULT on attempted import.
Just use NULL for a sparse node, regardless of whether or not it's a
file or buffer resource.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Puts and reset an existing node in a slot, if one exists. Returns true
if a node was there, false if not. This helps cleanup some of the code
that does a lookup just to clear an existing node.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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There are lots of spots open-coding this functionality, add a generic
helper that does the node lookup in a speculation safe way.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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For files, there's nr_user_files/file_table/file_data, and buffers have
nr_user_bufs/user_bufs/buf_data. There's no reason why file_table and
file_data can't be the same thing, and ditto for the buffer side. That
gets rid of more io_ring_ctx state that's in two spots rather than just
being in one spot, as it should be. Put all the registered file data in
one locations, and ditto on the buffer front.
This also avoids having both io_rsrc_data->nodes being an allocated
array, and ->user_bufs[] or ->file_table.nodes. There's no reason to
have this information duplicated. Keep it in one spot, io_rsrc_data,
along with how many resources are available.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Rather than allocate an io_rsrc_node for an empty/sparse buffer entry,
add a const entry that can be used for that. This just needs checking
for writing the tag, and the put check needs to check for that sparse
node rather than NULL for validity.
This avoids allocating rsrc nodes for sparse buffer entries.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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It's not going to be needed in the fast path going forward, so kill it
off.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Work in progress, but get rid of the per-ring serialization of resource
nodes, like registered buffers and files. Main issue here is that one
node can otherwise hold up a bunch of other nodes from getting freed,
which is especially a problem for file resource nodes and networked
workloads where some descriptors may not see activity in a long time.
As an example, instantiate an io_uring ring fd and create a sparse
registered file table. Even 2 will do. Then create a socket and register
it as fixed file 0, F0. The number of open files in the app is now 5,
with 0/1/2 being the usual stdin/out/err, 3 being the ring fd, and 4
being the socket. Register this socket (eg "the listener") in slot 0 of
the registered file table. Now add an operation on the socket that uses
slot 0. Finally, loop N times, where each loop creates a new socket,
registers said socket as a file, then unregisters the socket, and
finally closes the socket. This is roughly similar to what a basic
accept loop would look like.
At the end of this loop, it's not unreasonable to expect that there
would still be 5 open files. Each socket created and registered in the
loop is also unregistered and closed. But since the listener socket
registered first still has references to its resource node due to still
being active, each subsequent socket unregistration is stuck behind it
for reclaim. Hence 5 + N files are still open at that point, where N is
awaiting the final put held up by the listener socket.
Rewrite the io_rsrc_node handling to NOT rely on serialization. Struct
io_kiocb now gets explicit resource nodes assigned, with each holding a
reference to the parent node. A parent node is either of type FILE or
BUFFER, which are the two types of nodes that exist. A request can have
two nodes assigned, if it's using both registered files and buffers.
Since request issue and task_work completion is both under the ring
private lock, no atomics are needed to handle these references. It's a
simple unlocked inc/dec. As before, the registered buffer or file table
each hold a reference as well to the registered nodes. Final put of the
node will remove the node and free the underlying resource, eg unmap the
buffer or put the file.
Outside of removing the stall in resource reclaim described above, it
has the following advantages:
1) It's a lot simpler than the previous scheme, and easier to follow.
No need to specific quiesce handling anymore.
2) There are no resource node allocations in the fast path, all of that
happens at resource registration time.
3) The structs related to resource handling can all get simplified
quite a bit, like io_rsrc_node and io_rsrc_data. io_rsrc_put can
go away completely.
4) Handling of resource tags is much simpler, and doesn't require
persistent storage as it can simply get assigned up front at
registration time. Just copy them in one-by-one at registration time
and assign to the resource node.
The only real downside is that a request is now explicitly limited to
pinning 2 resources, one file and one buffer, where before just
assigning a resource node to a request would pin all of them. The upside
is that it's easier to follow now, as an individual resource is
explicitly referenced and assigned to the request.
With this in place, the above mentioned example will be using exactly 5
files at the end of the loop, not N.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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iter->bvec is already set to imu->bvec - remove the one dead assignment
and turn the other one into an addition instead.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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For placeholder buffers, &dummy_ubuf is assigned which is a static
value. When buffers are attempted cloned, don't attempt to grab a
reference to it, as we both don't need it and it'll actively fail as
dummy_ubuf doesn't have a valid reference count setup.
Link: https://lore.kernel.org/io-uring/Zw8dkUzsxQ5LgAJL@ly-workstation/
Reported-by: Lai, Yi <yi1.lai@linux.intel.com>
Fixes: 7cc2a6eadcd7 ("io_uring: add IORING_REGISTER_COPY_BUFFERS method")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Pull more io_uring updates from Jens Axboe:
"Mostly just a set of fixes in here, or little changes that didn't get
included in the initial pull request. This contains:
- Move the SQPOLL napi polling outside the submission lock (Olivier)
- Rename of the "copy buffers" API that got added in the 6.12 merge
window. There's really no copying going on, it's just referencing
the buffers. After a bit of consideration, decided that it was
better to simply rename this to avoid potential confusion (me)
- Shrink struct io_mapped_ubuf from 48 to 32 bytes, by changing it to
start + len tracking rather than having start / end in there, and
by removing the caching of folio_mask when we can just calculate it
from folio_shift when we need it (me)
- Fixes for the SQPOLL affinity checking (me, Felix)
- Fix for how cqring waiting checks for the presence of task_work.
Just check it directly rather than check for a specific
notification mechanism (me)
- Tweak to how request linking is represented in tracing (me)
- Fix a syzbot report that deliberately sets up a huge list of
overflow entries, and then hits rcu stalls when flushing this list.
Just check for the need to preempt, and drop/reacquire locks in the
loop. There's no state maintained over the loop itself, and each
entry is yanked from head-of-list (me)"
* tag 'for-6.12/io_uring-20240922' of git://git.kernel.dk/linux:
io_uring: check if we need to reschedule during overflow flush
io_uring: improve request linking trace
io_uring: check for presence of task_work rather than TIF_NOTIFY_SIGNAL
io_uring/sqpoll: do the napi busy poll outside the submission block
io_uring: clean up a type in io_uring_register_get_file()
io_uring/sqpoll: do not put cpumask on stack
io_uring/sqpoll: retain test for whether the CPU is valid
io_uring/rsrc: change ubuf->ubuf_end to length tracking
io_uring/rsrc: get rid of io_mapped_ubuf->folio_mask
io_uring: rename "copy buffers" to "clone buffers"
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Pull io_uring updates from Jens Axboe:
- NAPI fixes and cleanups (Pavel, Olivier)
- Add support for absolute timeouts (Pavel)
- Fixes for io-wq/sqpoll affinities (Felix)
- Efficiency improvements for dealing with huge pages (Chenliang)
- Support for a minwait mode, where the application essentially has two
timouts - one smaller one that defines the batch timeout, and the
overall large one similar to what we had before. This enables
efficient use of batching based on count + timeout, while still
working well with periods of less intensive workloads
- Use ITER_UBUF for single segment sends
- Add support for incremental buffer consumption. Right now each
operation will always consume a full buffer. With incremental
consumption, a recv/read operation only consumes the part of the
buffer that it needs to satisfy the operation
- Add support for GCOV for io_uring, to help retain a high coverage of
test to code ratio
- Fix regression with ocfs2, where an odd -EOPNOTSUPP wasn't correctly
converted to a blocking retry
- Add support for cloning registered buffers from one ring to another
- Misc cleanups (Anuj, me)
* tag 'for-6.12/io_uring-20240913' of git://git.kernel.dk/linux: (35 commits)
io_uring: add IORING_REGISTER_COPY_BUFFERS method
io_uring/register: provide helper to get io_ring_ctx from 'fd'
io_uring/rsrc: add reference count to struct io_mapped_ubuf
io_uring/rsrc: clear 'slot' entry upfront
io_uring/io-wq: inherit cpuset of cgroup in io worker
io_uring/io-wq: do not allow pinning outside of cpuset
io_uring/rw: drop -EOPNOTSUPP check in __io_complete_rw_common()
io_uring/rw: treat -EOPNOTSUPP for IOCB_NOWAIT like -EAGAIN
io_uring/sqpoll: do not allow pinning outside of cpuset
io_uring/eventfd: move refs to refcount_t
io_uring: remove unused rsrc_put_fn
io_uring: add new line after variable declaration
io_uring: add GCOV_PROFILE_URING Kconfig option
io_uring/kbuf: add support for incremental buffer consumption
io_uring/kbuf: pass in 'len' argument for buffer commit
Revert "io_uring: Require zeroed sqe->len on provided-buffers send"
io_uring/kbuf: move io_ring_head_to_buf() to kbuf.h
io_uring/kbuf: add io_kbuf_commit() helper
io_uring/kbuf: shrink nr_iovs/mode in struct buf_sel_arg
io_uring: wire up min batch wake timeout
...
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If we change it to tracking ubuf->start + ubuf->len, then we can reduce
the size of struct io_mapped_ubuf by another 4 bytes, effectively 8
bytes, as a hole is eliminated too.
This shrinks io_mapped_ubuf to 32 bytes.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We don't really need to cache this, let's reclaim 8 bytes from struct
io_mapped_ubuf and just calculate it when we need it. The only hot path
here is io_import_fixed().
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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A recent commit added support for copying registered buffers from one
ring to another. But that term is a bit confusing, as no copying of
buffer data is done here. What is being done is simply cloning the
buffer registrations from one ring to another.
Rename it while we still can, so that it's more descriptive. No
functional changes in this patch.
Fixes: 7cc2a6eadcd7 ("io_uring: add IORING_REGISTER_COPY_BUFFERS method")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Buffers can get registered with io_uring, which allows to skip the
repeated pin_pages, unpin/unref pages for each O_DIRECT operation. This
reduces the overhead of O_DIRECT IO.
However, registrering buffers can take some time. Normally this isn't an
issue as it's done at initialization time (and hence less critical), but
for cases where rings can be created and destroyed as part of an IO
thread pool, registering the same buffers for multiple rings become a
more time sensitive proposition. As an example, let's say an application
has an IO memory pool of 500G. Initial registration takes:
Got 500 huge pages (each 1024MB)
Registered 500 pages in 409 msec
or about 0.4 seconds. If we go higher to 900 1GB huge pages being
registered:
Registered 900 pages in 738 msec
which is, as expected, a fully linear scaling.
Rather than have each ring pin/map/register the same buffer pool,
provide an io_uring_register(2) opcode to simply duplicate the buffers
that are registered with another ring. Adding the same 900GB of
registered buffers to the target ring can then be accomplished in:
Copied 900 pages in 17 usec
While timing differs a bit, this provides around a 25,000-40,000x
speedup for this use case.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Currently there's a single ring owner of a mapped buffer, and hence the
reference count will always be 1 when it's torn down and freed. However,
in preparation for being able to link io_mapped_ubuf to different spots,
add a reference count to manage the lifetime of it.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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