kernel/git/stable/linux.git/fs/io-wq.c, branch master

io_uring: move to separate directory

2022-07-25T00:39:10+00:00

In preparation for splitting io_uring up a bit, move it into its own top level directory. It didn't really belong in fs/ anyway, as it's not a file system only API. This adds io_uring/ and moves the core files in there, and updates the MAINTAINERS file for the new location. Signed-off-by: Jens Axboe

io-wq: use __set_notify_signal() to wake workers

2022-04-30T14:39:54+00:00

The only difference between set_notify_signal() and __set_notify_signal() is that the former checks if it needs to deliver an IPI to force a reschedule. As the io-wq workers never leave the kernel, and IPI is never needed, they simply need a wakeup. Reviewed-by: Pavel Begunkov Link: https://lore.kernel.org/r/20220426014904.60384-4-axboe@kernel.dk Signed-off-by: Jens Axboe

Merge tag 'ptrace-cleanups-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2022-03-29T00:29:53+00:00

Pull ptrace cleanups from Eric Biederman: "This set of changes removes tracehook.h, moves modification of all of the ptrace fields inside of siglock to remove races, adds a missing permission check to ptrace.c The removal of tracehook.h is quite significant as it has been a major source of confusion in recent years. Much of that confusion was around task_work and TIF_NOTIFY_SIGNAL (which I have now decoupled making the semantics clearer). For people who don't know tracehook.h is a vestiage of an attempt to implement uprobes like functionality that was never fully merged, and was later superseeded by uprobes when uprobes was merged. For many years now we have been removing what tracehook functionaly a little bit at a time. To the point where anything left in tracehook.h was some weird strange thing that was difficult to understand" * tag 'ptrace-cleanups-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: ptrace: Remove duplicated include in ptrace.c ptrace: Check PTRACE_O_SUSPEND_SECCOMP permission on PTRACE_SEIZE ptrace: Return the signal to continue with from ptrace_stop ptrace: Move setting/clearing ptrace_message into ptrace_stop tracehook: Remove tracehook.h resume_user_mode: Move to resume_user_mode.h resume_user_mode: Remove #ifdef TIF_NOTIFY_RESUME in set_notify_resume signal: Move set_notify_signal and clear_notify_signal into sched/signal.h task_work: Decouple TIF_NOTIFY_SIGNAL and task_work task_work: Call tracehook_notify_signal from get_signal on all architectures task_work: Introduce task_work_pending task_work: Remove unnecessary include from posix_timers.h ptrace: Remove tracehook_signal_handler ptrace: Remove arch_syscall_{enter,exit}_tracehook ptrace: Create ptrace_report_syscall_{entry,exit} in ptrace.h ptrace/arm: Rename tracehook_report_syscall report_syscall ptrace: Move ptrace_report_syscall into ptrace.h

tracehook: Remove tracehook.h

2022-03-10T22:51:51+00:00

Now that all of the definitions have moved out of tracehook.h into ptrace.h, sched/signal.h, resume_user_mode.h there is nothing left in tracehook.h so remove it. Update the few files that were depending upon tracehook.h to bring in definitions to use the headers they need directly. Reviewed-by: Kees Cook Link: https://lkml.kernel.org/r/20220309162454.123006-13-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman"

task_work: Decouple TIF_NOTIFY_SIGNAL and task_work

2022-03-10T22:51:50+00:00

There are a small handful of reasons besides pending signals that the kernel might want to break out of interruptible sleeps. The flag TIF_NOTIFY_SIGNAL and the helpers that set and clear TIF_NOTIFY_SIGNAL provide that the infrastructure for breaking out of interruptible sleeps and entering the return to user space slow path for those cases. Expand tracehook_notify_signal inline in it's callers and remove it, which makes clear that TIF_NOTIFY_SIGNAL and task_work are separate concepts. Update the comment on set_notify_signal to more accurately describe it's purpose. Reviewed-by: Kees Cook Link: https://lkml.kernel.org/r/20220309162454.123006-9-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman"

io-wq: use IO_WQ_ACCT_NR rather than hardcoded number

2022-03-10T13:32:49+00:00

It's better to use the defined enum stuff not the hardcoded number to define array. Signed-off-by: Hao Xu Link: https://lore.kernel.org/r/20220206095241.121485-4-haoxu@linux.alibaba.com Signed-off-by: Jens Axboe

io-wq: reduce acct->lock crossing functions lock/unlock

2022-03-10T13:32:49+00:00

reduce acct->lock lock and unlock in different functions to make the code clearer. Signed-off-by: Hao Xu Link: https://lore.kernel.org/r/20220206095241.121485-3-haoxu@linux.alibaba.com Signed-off-by: Jens Axboe

io-wq: decouple work_list protection from the big wqe->lock

2022-03-10T13:32:49+00:00

wqe->lock is abused, it now protects acct->work_list, hash stuff, nr_workers, wqe->free_list and so on. Lets first get the work_list out of the wqe-lock mess by introduce a specific lock for work list. This is the first step to solve the huge contension between work insertion and work consumption. good thing: - split locking for bound and unbound work list - reduce contension between work_list visit and (worker's)free_list. For the hash stuff, since there won't be a work with same file in both bound and unbound work list, thus they won't visit same hash entry. it works well to use the new lock to protect hash stuff. Results: set max_unbound_worker = 4, test with echo-server: nice -n -15 ./io_uring_echo_server -p 8081 -f -n 1000 -l 16 (-n connection, -l workload) before this patch: Samples: 2M of event 'cycles:ppp', Event count (approx.): 1239982111074 Overhead Command Shared Object Symbol 28.59% iou-wrk-10021 [kernel.vmlinux] [k] native_queued_spin_lock_slowpath 8.89% io_uring_echo_s [kernel.vmlinux] [k] native_queued_spin_lock_slowpath 6.20% iou-wrk-10021 [kernel.vmlinux] [k] _raw_spin_lock 2.45% io_uring_echo_s [kernel.vmlinux] [k] io_prep_async_work 2.36% iou-wrk-10021 [kernel.vmlinux] [k] _raw_spin_lock_irqsave 2.29% iou-wrk-10021 [kernel.vmlinux] [k] io_worker_handle_work 1.29% io_uring_echo_s [kernel.vmlinux] [k] io_wqe_enqueue 1.06% iou-wrk-10021 [kernel.vmlinux] [k] io_wqe_worker 1.06% io_uring_echo_s [kernel.vmlinux] [k] _raw_spin_lock 1.03% iou-wrk-10021 [kernel.vmlinux] [k] __schedule 0.99% iou-wrk-10021 [kernel.vmlinux] [k] tcp_sendmsg_locked with this patch: Samples: 1M of event 'cycles:ppp', Event count (approx.): 708446691943 Overhead Command Shared Object Symbol 16.86% iou-wrk-10893 [kernel.vmlinux] [k] native_queued_spin_lock_slowpat 9.10% iou-wrk-10893 [kernel.vmlinux] [k] _raw_spin_lock 4.53% io_uring_echo_s [kernel.vmlinux] [k] native_queued_spin_lock_slowpat 2.87% iou-wrk-10893 [kernel.vmlinux] [k] io_worker_handle_work 2.57% iou-wrk-10893 [kernel.vmlinux] [k] _raw_spin_lock_irqsave 2.56% io_uring_echo_s [kernel.vmlinux] [k] io_prep_async_work 1.82% io_uring_echo_s [kernel.vmlinux] [k] _raw_spin_lock 1.33% iou-wrk-10893 [kernel.vmlinux] [k] io_wqe_worker 1.26% io_uring_echo_s [kernel.vmlinux] [k] try_to_wake_up spin_lock failure from 25.59% + 8.89% = 34.48% to 16.86% + 4.53% = 21.39% TPS is similar, while cpu usage is from almost 400% to 350% Signed-off-by: Hao Xu Link: https://lore.kernel.org/r/20220206095241.121485-2-haoxu@linux.alibaba.com Signed-off-by: Jens Axboe

Merge tag 'io_uring-5.17-2022-01-21' of git://git.kernel.dk/linux-block

2022-01-21T14:07:21+00:00

Pull io_uring fixes from Jens Axboe: - Fix the io_uring POLLFREE handling, similarly to how it was done for aio (Pavel) - Remove (now) unused function (Jiapeng) - Small series fixing an issue with work cancelations. A window exists where work isn't locatable in the pending list, and isn't active in a worker yet either. (me) * tag 'io_uring-5.17-2022-01-21' of git://git.kernel.dk/linux-block: io-wq: delete dead lock shuffling code io_uring: perform poll removal even if async work removal is successful io-wq: add intermediate work step between pending list and active work io-wq: perform both unstarted and started work cancelations in one go io-wq: invoke work cancelation with wqe->lock held io-wq: make io_worker lock a raw spinlock io-wq: remove useless 'work' argument to __io_worker_busy() io_uring: fix UAF due to missing POLLFREE handling io_uring: Remove unused function req_ref_put

io-wq: delete dead lock shuffling code

2022-01-19T20:11:58+00:00

We used to have more code around the work loop, but now the goto and lock juggling just makes it less readable than it should. Get rid of it. Signed-off-by: Jens Axboe