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2021-03-18io_uring: remove structures from include/linux/io_uring.hStefan Metzmacher
Link: https://lore.kernel.org/r/8c1d14f3748105f4caeda01716d47af2fa41d11c.1615809009.git.metze@samba.org Signed-off-by: Stefan Metzmacher <metze@samba.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-06io-wq: always track creds for async issueJens Axboe
If we go async with a request, grab the creds that the task currently has assigned and make sure that the async side switches to them. This is handled in the same way that we do for registered personalities. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-05io_uring: move to using create_io_thread()Jens Axboe
This allows us to do task creation and setup without needing to use completions to try and synchronize with the starting thread. Get rid of the old io_wq_fork_thread() wrapper, and the 'wq' and 'worker' startup completion events - we can now do setup before the task is running. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-04io_uring: move cred assignment into io_issue_sqe()Jens Axboe
If we move it in there, then we no longer have to care about it in io-wq. This means we can drop the cred handling in io-wq, and we can drop the REQ_F_WORK_INITIALIZED flag and async init functions as that was the last user of it since we moved to the new workers. Then we can also drop io_wq_work->creds, and just hold the personality u16 in there instead. Suggested-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-04io-wq: provide an io_wq_put_and_exit() helperJens Axboe
If we put the io-wq from io_uring, we really want it to exit. Provide a helper that does that for us. Couple that with not having the manager hold a reference to the 'wq' and the normal SQPOLL exit will tear down the io-wq context appropriate. On the io-wq side, our wq context is per task, so only the task itself is manipulating ->manager and hence it's safe to check and clear without any extra locking. We just need to ensure that the manager task stays around, in case it exits. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-25io-wq: improve manager/worker handling over execJens Axboe
exec will cancel any threads, including the ones that io-wq is using. This isn't a problem, in fact we'd prefer it to be that way since it means we know that any async work cancels naturally without having to handle it proactively. But it does mean that we need to setup a new manager, as the manager and workers are gone. Handle this at queue time, and cancel work if we fail. Since the manager can go away without us noticing, ensure that the manager itself holds a reference to the 'wq' as well. Rename io_wq_destroy() to io_wq_put() to reflect that. In the future we can now simplify exec cancelation handling, for now just leave it the same. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-25io-wq: make buffered file write hashed work map per-ctxJens Axboe
Before the io-wq thread change, we maintained a hash work map and lock per-node per-ring. That wasn't ideal, as we really wanted it to be per ring. But now that we have per-task workers, the hash map ends up being just per-task. That'll work just fine for the normal case of having one task use a ring, but if you share the ring between tasks, then it's considerably worse than it was before. Make the hash map per ctx instead, which provides full per-ctx buffered write serialization on hashed writes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-23io-wq: remove nr_process accountingJens Axboe
We're now just using fork like we would from userspace, so there's no need to try and impose extra restrictions or accounting on the user side of things. That's already being done for us. That also means we don't have to pass in the user_struct anymore, that's correctly inherited through ->creds on fork. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-21io-wq: make io_wq_fork_thread() available to other usersJens Axboe
We want to use this in io_uring proper as well, for the SQPOLL thread. Rename it from fork_thread() to io_wq_fork_thread(), and make it available through the io-wq.h header. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-21io_uring: remove io_identityJens Axboe
We are no longer grabbing state, so no need to maintain an IO identity that we COW if there are changes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-21io_uring: remove any grabbing of contextJens Axboe
The async workers are siblings of the task itself, so by definition we have all the state that we need. Remove any of the state grabbing that we have, and requests flagging what they need. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-21io-wq: fork worker threads from original taskJens Axboe
Instead of using regular kthread kernel threads, create kernel threads that are like a real thread that the task would create. This ensures that we get all the context that we need, without having to carry that state around. This greatly reduces the code complexity, and the risk of missing state for a given request type. With the move away from kthread, we can also dump everything related to assigned state to the new threads. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-21io-wq: get rid of wq->use_refsJens Axboe
We don't support attach anymore, so doesn't make sense to carry the use_refs reference count. Get rid of it. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-21io_uring: remove the need for relying on an io-wq fallback workerJens Axboe
We hit this case when the task is exiting, and we need somewhere to do background cleanup of requests. Instead of relying on the io-wq task manager to do this work for us, just stuff it somewhere where we can safely run it ourselves directly. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: provide FIFO ordering for task_workJens Axboe
task_work is a LIFO list, due to how it's implemented as a lockless list. For long chains of task_work, this can be problematic as the first entry added is the last one processed. Similarly, we'd waste a lot of CPU cycles reversing this list. Wrap the task_work so we have a single task_work entry per task per ctx, and use that to run it in the right order. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-04io_uring/io-wq: return 2-step work swap schemePavel Begunkov
Saving one lock/unlock for io-wq is not super important, but adds some ugliness in the code. More important, atomic decs not turning it to zero for some archs won't give the right ordering/barriers so the io_steal_work() may pretty easily get subtly and completely broken. Return back 2-step io-wq work exchange and clean it up. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-01io_uring/io-wq: kill off now unused IO_WQ_WORK_NO_CANCELJens Axboe
It's no longer used as IORING_OP_CLOSE got rid for the need of flagging it as uncancelable, kill it of. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-20io-wq: kill now unused io_wq_cancel_all()Jens Axboe
io_uring no longer issues full cancelations on the io-wq, so remove any remnants of this code and the IO_WQ_BIT_CANCEL flag. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-18io_uring: fix io_wqe->work_list corruptionXiaoguang Wang
For the first time a req punted to io-wq, we'll initialize io_wq_work's list to be NULL, then insert req to io_wqe->work_list. If this req is not inserted into tail of io_wqe->work_list, this req's io_wq_work list will point to another req's io_wq_work. For splitted bio case, this req maybe inserted to io_wqe->work_list repeatedly, once we insert it to tail of io_wqe->work_list for the second time, now io_wq_work->list->next will be invalid pointer, which then result in many strang error, panic, kernel soft-lockup, rcu stall, etc. In my vm, kernel doest not have commit cc29e1bf0d63f7 ("block: disable iopoll for split bio"), below fio job can reproduce this bug steadily: [global] name=iouring-sqpoll-iopoll-1 ioengine=io_uring iodepth=128 numjobs=1 thread rw=randread direct=1 registerfiles=1 hipri=1 bs=4m size=100M runtime=120 time_based group_reporting randrepeat=0 [device] directory=/home/feiman.wxg/mntpoint/ # an ext4 mount point If we have commit cc29e1bf0d63f7 ("block: disable iopoll for split bio"), there will no splitted bio case for polled io, but I think we still to need to fix this list corruption, it also should maybe go to stable branchs. To fix this corruption, if a req is inserted into tail of io_wqe->work_list, initialize req->io_wq_work->list->next to bu NULL. Cc: stable@vger.kernel.org Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09io_uring: always batch cancel in *cancel_files()Pavel Begunkov
Instead of iterating over each request and cancelling it individually in io_uring_cancel_files(), try to cancel all matching requests and use ->inflight_list only to check if there anything left. In many cases it should be faster, and we can reuse a lot of code from task cancellation. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-20io_uring: unify fsize with def->work_flagsJens Axboe
This one was missed in the earlier conversion, should be included like any of the other IO identity flags. Make sure we restore to RLIM_INIFITY when dropping the personality again. Fixes: 98447d65b4a7 ("io_uring: move io identity items into separate struct") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17io_uring: move io identity items into separate structJens Axboe
io-wq contains a pointer to the identity, which we just hold in io_kiocb for now. This is in preparation for putting this outside io_kiocb. The only exception is struct files_struct, which we'll need different rules for to avoid a circular dependency. No functional changes in this patch. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17io_uring: pass required context in as flagsJens Axboe
We have a number of bits that decide what context to inherit. Set up io-wq flags for these instead. This is in preparation for always having the various members set, but not always needing them for all requests. No intended functional changes in this patch. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30io_uring: add blkcg accounting to offloaded operationsDennis Zhou
There are a few operations that are offloaded to the worker threads. In this case, we lose process context and end up in kthread context. This results in ios to be not accounted to the issuing cgroup and consequently end up as issued by root. Just like others, adopt the personality of the blkcg too when issuing via the workqueues. For the SQPOLL thread, it will live and attach in the inited cgroup's context. Signed-off-by: Dennis Zhou <dennis@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30io_uring: reference ->nsproxy for file table commandsJens Axboe
If we don't get and assign the namespace for the async work, then certain paths just don't work properly (like /dev/stdin, /proc/mounts, etc). Anything that references the current namespace of the given task should be assigned for async work on behalf of that task. Cc: stable@vger.kernel.org # v5.5+ Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-24io_uring/io-wq: move RLIMIT_FSIZE to io-wqPavel Begunkov
RLIMIT_SIZE in needed only for execution from an io-wq context, hence move all preparations from hot path to io-wq work setup. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-26io-wq: return next work from ->do_work() directlyPavel Begunkov
It's easier to return next work from ->do_work() than having an in-out argument. Looks nicer and easier to compile. Also, merge io_wq_assign_next() into its only user. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-26io-wq: compact io-wq flags numbersPavel Begunkov
Renumerate IO_WQ flags, so they take adjacent bits Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-15io_uring: cancel by ->task not pidPavel Begunkov
For an exiting process it tries to cancel all its inflight requests. Use req->task to match such instead of work.pid. We always have req->task set, and it will be valid because we're matching only current exiting task. Also, remove work.pid and everything related, it's useless now. Reported-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-15io_uring: cancel all task's requests on exitPavel Begunkov
If a process is going away, io_uring_flush() will cancel only 1 request with a matching pid. Cancel all of them Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-15io-wq: add an option to cancel all matched reqsPavel Begunkov
This adds support for cancelling all io-wq works matching a predicate. It isn't used yet, so no change in observable behaviour. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-10io_uring: avoid whole io_wq_work copy for requests completed inlineXiaoguang Wang
If requests can be submitted and completed inline, we don't need to initialize whole io_wq_work in io_init_req(), which is an expensive operation, add a new 'REQ_F_WORK_INITIALIZED' to determine whether io_wq_work is initialized and add a helper io_req_init_async(), users must call io_req_init_async() for the first time touching any members of io_wq_work. I use /dev/nullb0 to evaluate performance improvement in my physical machine: modprobe null_blk nr_devices=1 completion_nsec=0 sudo taskset -c 60 fio -name=fiotest -filename=/dev/nullb0 -iodepth=128 -thread -rw=read -ioengine=io_uring -direct=1 -bs=4k -size=100G -numjobs=1 -time_based -runtime=120 before this patch: Run status group 0 (all jobs): READ: bw=724MiB/s (759MB/s), 724MiB/s-724MiB/s (759MB/s-759MB/s), io=84.8GiB (91.1GB), run=120001-120001msec With this patch: Run status group 0 (all jobs): READ: bw=761MiB/s (798MB/s), 761MiB/s-761MiB/s (798MB/s-798MB/s), io=89.2GiB (95.8GB), run=120001-120001msec About 5% improvement. Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-08io_wq: add per-wq work handler instead of per workPavel Begunkov
io_uring is the only user of io-wq, and now it uses only io-wq callback for all its requests, namely io_wq_submit_work(). Instead of storing work->runner callback in each instance of io_wq_work, keep it in io-wq itself. pros: - reduces io_wq_work size - more robust -- ->func won't be invalidated with mem{cpy,set}(req) - helps other work Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-03io_uring: use io-wq manager as backup task if task is exitingJens Axboe
If the original task is (or has) exited, then the task work will not get queued properly. Allow for using the io-wq manager task to queue this work for execution, and ensure that the io-wq manager notices and runs this work if woken up (or exiting). Reported-by: Dan Melnic <dmm@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-23io-wq: handle hashed writes in chainsPavel Begunkov
We always punt async buffered writes to an io-wq helper, as the core kernel does not have IOCB_NOWAIT support for that. Most buffered async writes complete very quickly, as it's just a copy operation. This means that doing multiple locking roundtrips on the shared wqe lock for each buffered write is wasteful. Additionally, buffered writes are hashed work items, which means that any buffered write to a given file is serialized. Keep identicaly hashed work items contiguously in @wqe->work_list, and track a tail for each hash bucket. On dequeue of a hashed item, splice all of the same hash in one go using the tracked tail. Until the batch is done, the caller doesn't have to synchronize with the wqe or worker locks again. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-22io_uring: Fix ->data corruption on re-enqueuePavel Begunkov
work->data and work->list are shared in union. io_wq_assign_next() sets ->data if a req having a linked_timeout, but then io-wq may want to use work->list, e.g. to do re-enqueue of a request, so corrupting ->data. ->data is not necessary, just remove it and extract linked_timeout through @link_list. Fixes: 60cf46ae6054 ("io-wq: hash dependent work") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-14io-wq: split hashing and enqueueingPavel Begunkov
It's a preparation patch removing io_wq_enqueue_hashed(), which now should be done by io_wq_hash_work() + io_wq_enqueue(). Also, set hash value for dependant works, and do it as late as possible, because req->file can be unavailable before. This hash will be ignored by io-wq. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-04io_uring/io-wq: forward submission ref to asyncPavel Begunkov
First it changes io-wq interfaces. It replaces {get,put}_work() with free_work(), which guaranteed to be called exactly once. It also enforces free_work() callback to be non-NULL. io_uring follows the changes and instead of putting a submission reference in io_put_req_async_completion(), it will be done in io_free_work(). As removes io_get_work() with corresponding refcount_inc(), the ref balance is maintained. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02io_uring: remove IO_WQ_WORK_CBPavel Begunkov
IO_WQ_WORK_CB is used only for linked timeouts, which will be armed before the work setup (i.e. mm, override creds, etc). The setup shouldn't take long, so it's ok to arm it a bit later and get rid of IO_WQ_WORK_CB. Make io-wq call work->func() only once, callbacks will handle the rest. i.e. the linked timeout handler will do the actual issue. And as a bonus, it removes an extra indirect call. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02io-wq: remove unused IO_WQ_WORK_HAS_MMPavel Begunkov
IO_WQ_WORK_HAS_MM is set but never used, remove it. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02io-wq: remove io_wq_flush and IO_WQ_WORK_INTERNALPavel Begunkov
io_wq_flush() is buggy, during cancelation of a flush, the associated work may be passed to the caller's (i.e. io_uring) @match callback. That callback is expecting it to be embedded in struct io_kiocb. Cancelation of internal work probably doesn't make a lot of sense to begin with. As the flush helper is no longer used, just delete it and the associated work flag. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-25io-wq: ensure work->task_pid is cleared on initJens Axboe
We use ->task_pid for exit cancellation, but we need to ensure it's cleared to zero for io_req_work_grab_env() to do the right thing. Take a suggestion from Bart and clear the whole thing, just setting the function passed in. This makes it more future proof as well. Fixes: 36282881a795 ("io-wq: add io_wq_cancel_pid() to cancel based on a specific pid") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-09io-wq: add io_wq_cancel_pid() to cancel based on a specific pidJens Axboe
Add a helper that allows the caller to cancel work based on what mm it belongs to. This allows io_uring to cancel work from a given task or thread when it exits. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08io-wq: add support for inheriting ->fsJens Axboe
Some work items need this for relative path lookup, make it available like the other inherited credentials/mm/etc. Cc: stable@vger.kernel.org # 5.3+ Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-29io_uring: fix linked command file table usageJens Axboe
We're not consistent in how the file table is grabbed and assigned if we have a command linked that requires the use of it. Add ->file_table to the io_op_defs[] array, and use that to determine when to grab the table instead of having the handlers set it if they need to defer. This also means we can kill the IO_WQ_WORK_NEEDS_FILES flag. We always initialize work->files, so io-wq can just check for that. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-28io-wq: allow grabbing existing io-wqPavel Begunkov
Export a helper to attach to an existing io-wq, rather than setting up a new one. This is doable now that we have reference counted io_wq's. Reported-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-28io_uring/io-wq: don't use static creds/mm assignmentsJens Axboe
We currently setup the io_wq with a static set of mm and creds. Even for a single-use io-wq per io_uring, this is suboptimal as we have may have multiple enters of the ring. For sharing the io-wq backend, it doesn't work at all. Switch to passing in the creds and mm when the work item is setup. This means that async work is no longer deferred to the io_uring mm and creds, it is done with the current mm and creds. Flag this behavior with IORING_FEAT_CUR_PERSONALITY, so applications know they can rely on the current personality (mm and creds) being the same for direct issue and async issue. Reviewed-by: Stefan Metzmacher <metze@samba.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-20io-wq: support concurrent non-blocking workJens Axboe
io-wq assumes that work will complete fast (and not block), so it doesn't create a new worker when work is enqueued, if we already have at least one worker running. This is done on the assumption that if work is running, then it will complete fast. Add an option to force io-wq to fork a new worker for work queued. This is signaled by setting IO_WQ_WORK_CONCURRENT on the work item. For that case, io-wq will create a new worker, even though workers are already running. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-20io-wq: add support for uncancellable workJens Axboe
Not all work can be cancelled, some of it we may need to guarantee that it runs to completion. Allow the caller to set IO_WQ_WORK_NO_CANCEL on work that must not be cancelled. Note that the caller work function must also check for IO_WQ_WORK_NO_CANCEL on work that is marked IO_WQ_WORK_CANCEL. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-12-17io-wq: re-add io_wq_current_is_worker()Jens Axboe
This reverts commit 8cdda87a4414, we now have several use csaes for this helper. Reinstate it. Signed-off-by: Jens Axboe <axboe@kernel.dk>