[ecf6b46] | 1 | // |
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| 2 | // Cforall Version 1.0.0 Copyright (C) 2020 University of Waterloo |
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| 3 | // |
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| 4 | // The contents of this file are covered under the licence agreement in the |
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| 5 | // file "LICENCE" distributed with Cforall. |
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| 6 | // |
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| 7 | // io.cfa -- |
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| 8 | // |
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| 9 | // Author : Thierry Delisle |
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| 10 | // Created On : Thu Apr 23 17:31:00 2020 |
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| 11 | // Last Modified By : |
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| 12 | // Last Modified On : |
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| 13 | // Update Count : |
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| 14 | // |
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| 15 | |
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[3e2b9c9] | 16 | #define __cforall_thread__ |
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| 17 | |
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[20ab637] | 18 | #if defined(__CFA_DEBUG__) |
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| 19 | // #define __CFA_DEBUG_PRINT_IO__ |
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[e660761] | 20 | // #define __CFA_DEBUG_PRINT_IO_CORE__ |
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[20ab637] | 21 | #endif |
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[4069faad] | 22 | |
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[f6660520] | 23 | |
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[3e2b9c9] | 24 | #if defined(CFA_HAVE_LINUX_IO_URING_H) |
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[31bb2e1] | 25 | #define _GNU_SOURCE /* See feature_test_macros(7) */ |
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| 26 | #include <errno.h> |
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[3e2b9c9] | 27 | #include <signal.h> |
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[31bb2e1] | 28 | #include <stdint.h> |
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| 29 | #include <string.h> |
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| 30 | #include <unistd.h> |
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| 31 | |
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[92976d9] | 32 | extern "C" { |
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[f00b26d4] | 33 | #include <sys/epoll.h> |
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[92976d9] | 34 | #include <sys/syscall.h> |
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| 35 | |
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| 36 | #include <linux/io_uring.h> |
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| 37 | } |
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| 38 | |
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[3e2b9c9] | 39 | #include "stats.hfa" |
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| 40 | #include "kernel.hfa" |
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| 41 | #include "kernel/fwd.hfa" |
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| 42 | #include "io/types.hfa" |
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[185efe6] | 43 | |
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[92976d9] | 44 | //============================================================================================= |
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[3e2b9c9] | 45 | // I/O Syscall |
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[92976d9] | 46 | //============================================================================================= |
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[3e2b9c9] | 47 | static int __io_uring_enter( struct __io_data & ring, unsigned to_submit, bool get ) { |
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[20ab637] | 48 | bool need_sys_to_submit = false; |
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| 49 | bool need_sys_to_complete = false; |
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| 50 | unsigned flags = 0; |
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| 51 | |
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| 52 | TO_SUBMIT: |
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| 53 | if( to_submit > 0 ) { |
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| 54 | if( !(ring.ring_flags & IORING_SETUP_SQPOLL) ) { |
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| 55 | need_sys_to_submit = true; |
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| 56 | break TO_SUBMIT; |
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| 57 | } |
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| 58 | if( (*ring.submit_q.flags) & IORING_SQ_NEED_WAKEUP ) { |
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| 59 | need_sys_to_submit = true; |
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| 60 | flags |= IORING_ENTER_SQ_WAKEUP; |
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| 61 | } |
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| 62 | } |
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| 63 | |
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| 64 | if( get && !(ring.ring_flags & IORING_SETUP_SQPOLL) ) { |
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| 65 | flags |= IORING_ENTER_GETEVENTS; |
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| 66 | if( (ring.ring_flags & IORING_SETUP_IOPOLL) ) { |
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| 67 | need_sys_to_complete = true; |
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| 68 | } |
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| 69 | } |
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| 70 | |
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| 71 | int ret = 0; |
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| 72 | if( need_sys_to_submit || need_sys_to_complete ) { |
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[f00b26d4] | 73 | ret = syscall( __NR_io_uring_enter, ring.fd, to_submit, 0, flags, 0p, _NSIG / 8); |
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[20ab637] | 74 | if( ret < 0 ) { |
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| 75 | switch((int)errno) { |
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| 76 | case EAGAIN: |
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| 77 | case EINTR: |
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| 78 | ret = -1; |
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| 79 | break; |
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| 80 | default: |
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| 81 | abort( "KERNEL ERROR: IO_URING SYSCALL - (%d) %s\n", (int)errno, strerror(errno) ); |
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| 82 | } |
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| 83 | } |
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| 84 | } |
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| 85 | |
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| 86 | // Memory barrier |
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| 87 | __atomic_thread_fence( __ATOMIC_SEQ_CST ); |
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| 88 | return ret; |
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| 89 | } |
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| 90 | |
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[92976d9] | 91 | //============================================================================================= |
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| 92 | // I/O Polling |
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| 93 | //============================================================================================= |
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[1d5e4711] | 94 | static unsigned __collect_submitions( struct __io_data & ring ); |
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[34b61882] | 95 | static uint32_t __release_consumed_submission( struct __io_data & ring ); |
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[1d5e4711] | 96 | |
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[f00b26d4] | 97 | static inline void process(struct io_uring_cqe & cqe ) { |
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[5751a56] | 98 | struct __io_user_data_t * data = (struct __io_user_data_t *)(uintptr_t)cqe.user_data; |
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| 99 | __cfadbg_print_safe( io, "Kernel I/O : Syscall completed : cqe %p, result %d for %p\n", data, cqe.res, data->thrd ); |
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| 100 | |
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| 101 | data->result = cqe.res; |
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[f00b26d4] | 102 | unpark( data->thrd __cfaabi_dbg_ctx2 ); |
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[5751a56] | 103 | } |
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| 104 | |
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[92976d9] | 105 | // Process a single completion message from the io_uring |
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| 106 | // This is NOT thread-safe |
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[f00b26d4] | 107 | static [int, bool] __drain_io( & struct __io_data ring ) { |
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[e46c753] | 108 | /* paranoid */ verify( !kernelTLS.preemption_state.enabled ); |
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| 109 | |
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[5dadc9b] | 110 | unsigned to_submit = 0; |
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[f00b26d4] | 111 | if( ring.poller_submits ) { |
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[5dadc9b] | 112 | // If the poller thread also submits, then we need to aggregate the submissions which are ready |
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[e46c753] | 113 | to_submit = __collect_submitions( ring ); |
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[5dadc9b] | 114 | } |
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| 115 | |
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[f00b26d4] | 116 | int ret = __io_uring_enter(ring, to_submit, true); |
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[20ab637] | 117 | if( ret < 0 ) { |
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| 118 | return [0, true]; |
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| 119 | } |
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[1d5e4711] | 120 | |
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[20ab637] | 121 | // update statistics |
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| 122 | if (to_submit > 0) { |
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[1d5e4711] | 123 | __STATS__( true, |
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| 124 | if( to_submit > 0 ) { |
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| 125 | io.submit_q.submit_avg.rdy += to_submit; |
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| 126 | io.submit_q.submit_avg.csm += ret; |
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| 127 | io.submit_q.submit_avg.cnt += 1; |
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| 128 | } |
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| 129 | ) |
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[6f121b8] | 130 | } |
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| 131 | |
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[20ab637] | 132 | // Release the consumed SQEs |
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| 133 | __release_consumed_submission( ring ); |
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[6f121b8] | 134 | |
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[d384787] | 135 | // Drain the queue |
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[92976d9] | 136 | unsigned head = *ring.completion_q.head; |
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[6f121b8] | 137 | unsigned tail = *ring.completion_q.tail; |
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| 138 | const uint32_t mask = *ring.completion_q.mask; |
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| 139 | |
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[d384787] | 140 | // Nothing was new return 0 |
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| 141 | if (head == tail) { |
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[e46c753] | 142 | return [0, to_submit > 0]; |
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[d384787] | 143 | } |
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[92976d9] | 144 | |
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[d384787] | 145 | uint32_t count = tail - head; |
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[1d5e4711] | 146 | /* paranoid */ verify( count != 0 ); |
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[d384787] | 147 | for(i; count) { |
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[6f121b8] | 148 | unsigned idx = (head + i) & mask; |
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[d384787] | 149 | struct io_uring_cqe & cqe = ring.completion_q.cqes[idx]; |
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[92976d9] | 150 | |
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[d384787] | 151 | /* paranoid */ verify(&cqe); |
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[92976d9] | 152 | |
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[f00b26d4] | 153 | process( cqe ); |
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[d384787] | 154 | } |
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[2d8f7b0] | 155 | |
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[92976d9] | 156 | // Mark to the kernel that the cqe has been seen |
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| 157 | // Ensure that the kernel only sees the new value of the head index after the CQEs have been read. |
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[6f121b8] | 158 | __atomic_thread_fence( __ATOMIC_SEQ_CST ); |
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[d384787] | 159 | __atomic_fetch_add( ring.completion_q.head, count, __ATOMIC_RELAXED ); |
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[92976d9] | 160 | |
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[5dadc9b] | 161 | return [count, count > 0 || to_submit > 0]; |
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[92976d9] | 162 | } |
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| 163 | |
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[f00b26d4] | 164 | void main( $io_ctx_thread & this ) { |
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| 165 | epoll_event ev; |
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[3e2b9c9] | 166 | __ioctx_register( this, ev ); |
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[1539bbd] | 167 | |
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[f00b26d4] | 168 | __cfadbg_print_safe(io_core, "Kernel I/O : IO poller %p for ring %p ready\n", &this, &this.ring); |
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[1539bbd] | 169 | |
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[4e74466] | 170 | int reset = 0; |
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[61dd73d] | 171 | // Then loop until we need to start |
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[f00b26d4] | 172 | while(!__atomic_load_n(&this.done, __ATOMIC_SEQ_CST)) { |
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[61dd73d] | 173 | // Drain the io |
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[5dadc9b] | 174 | int count; |
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| 175 | bool again; |
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[13c5e19] | 176 | disable_interrupts(); |
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[f00b26d4] | 177 | [count, again] = __drain_io( *this.ring ); |
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[5dadc9b] | 178 | |
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[13c5e19] | 179 | if(!again) reset++; |
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[3c039b0] | 180 | |
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[13c5e19] | 181 | // Update statistics |
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[47746a2] | 182 | __STATS__( true, |
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| 183 | io.complete_q.completed_avg.val += count; |
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| 184 | io.complete_q.completed_avg.fast_cnt += 1; |
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| 185 | ) |
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[13c5e19] | 186 | enable_interrupts( __cfaabi_dbg_ctx ); |
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[3c039b0] | 187 | |
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[5dadc9b] | 188 | // If we got something, just yield and check again |
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[4e74466] | 189 | if(reset < 5) { |
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[61dd73d] | 190 | yield(); |
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| 191 | } |
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[5dadc9b] | 192 | // We didn't get anything baton pass to the slow poller |
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[61dd73d] | 193 | else { |
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[f00b26d4] | 194 | __cfadbg_print_safe(io_core, "Kernel I/O : Parking io poller %p\n", &this.self); |
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[5dadc9b] | 195 | reset = 0; |
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| 196 | |
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[3e2b9c9] | 197 | // block this thread |
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| 198 | __ioctx_prepare_block( this, ev ); |
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[f00b26d4] | 199 | wait( this.sem ); |
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[f6660520] | 200 | } |
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| 201 | } |
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[61dd73d] | 202 | |
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| 203 | __cfadbg_print_safe(io_core, "Kernel I/O : Fast poller for ring %p stopping\n", &this.ring); |
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| 204 | } |
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[f6660520] | 205 | |
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[92976d9] | 206 | //============================================================================================= |
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| 207 | // I/O Submissions |
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| 208 | //============================================================================================= |
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| 209 | |
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[2d8f7b0] | 210 | // Submition steps : |
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[e46c753] | 211 | // 1 - Allocate a queue entry. The ring already has memory for all entries but only the ones |
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[2d8f7b0] | 212 | // listed in sq.array are visible by the kernel. For those not listed, the kernel does not |
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| 213 | // offer any assurance that an entry is not being filled by multiple flags. Therefore, we |
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| 214 | // need to write an allocator that allows allocating concurrently. |
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| 215 | // |
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[e46c753] | 216 | // 2 - Actually fill the submit entry, this is the only simple and straightforward step. |
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[2d8f7b0] | 217 | // |
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[e46c753] | 218 | // 3 - Append the entry index to the array and adjust the tail accordingly. This operation |
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[2d8f7b0] | 219 | // needs to arrive to two concensus at the same time: |
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| 220 | // A - The order in which entries are listed in the array: no two threads must pick the |
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| 221 | // same index for their entries |
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| 222 | // B - When can the tail be update for the kernel. EVERY entries in the array between |
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| 223 | // head and tail must be fully filled and shouldn't ever be touched again. |
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| 224 | // |
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| 225 | |
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[31bb2e1] | 226 | [* struct io_uring_sqe, uint32_t] __submit_alloc( struct __io_data & ring, uint64_t data ) { |
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[e46c753] | 227 | /* paranoid */ verify( data != 0 ); |
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[13c5e19] | 228 | |
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[6f121b8] | 229 | // Prepare the data we need |
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| 230 | __attribute((unused)) int len = 0; |
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| 231 | __attribute((unused)) int block = 0; |
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| 232 | uint32_t cnt = *ring.submit_q.num; |
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| 233 | uint32_t mask = *ring.submit_q.mask; |
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[8ae4165] | 234 | |
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| 235 | disable_interrupts(); |
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| 236 | uint32_t off = __tls_rand(); |
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| 237 | enable_interrupts( __cfaabi_dbg_ctx ); |
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[6f121b8] | 238 | |
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| 239 | // Loop around looking for an available spot |
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[13c5e19] | 240 | for() { |
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[6f121b8] | 241 | // Look through the list starting at some offset |
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| 242 | for(i; cnt) { |
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| 243 | uint64_t expected = 0; |
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| 244 | uint32_t idx = (i + off) & mask; |
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| 245 | struct io_uring_sqe * sqe = &ring.submit_q.sqes[idx]; |
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[eafec07] | 246 | volatile uint64_t * udata = (volatile uint64_t *)&sqe->user_data; |
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[6f121b8] | 247 | |
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| 248 | if( *udata == expected && |
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| 249 | __atomic_compare_exchange_n( udata, &expected, data, true, __ATOMIC_SEQ_CST, __ATOMIC_RELAXED ) ) |
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| 250 | { |
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| 251 | // update statistics |
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[47746a2] | 252 | __STATS__( false, |
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| 253 | io.submit_q.alloc_avg.val += len; |
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| 254 | io.submit_q.alloc_avg.block += block; |
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| 255 | io.submit_q.alloc_avg.cnt += 1; |
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| 256 | ) |
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[6f121b8] | 257 | |
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[13c5e19] | 258 | |
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[6f121b8] | 259 | // Success return the data |
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| 260 | return [sqe, idx]; |
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| 261 | } |
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| 262 | verify(expected != data); |
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[2489d31] | 263 | |
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[6f121b8] | 264 | len ++; |
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| 265 | } |
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[2489d31] | 266 | |
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[6f121b8] | 267 | block++; |
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| 268 | yield(); |
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| 269 | } |
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[2489d31] | 270 | } |
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| 271 | |
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[df40a56] | 272 | static inline uint32_t __submit_to_ready_array( struct __io_data & ring, uint32_t idx, const uint32_t mask ) { |
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| 273 | /* paranoid */ verify( idx <= mask ); |
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| 274 | /* paranoid */ verify( idx != -1ul32 ); |
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| 275 | |
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| 276 | // We need to find a spot in the ready array |
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| 277 | __attribute((unused)) int len = 0; |
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| 278 | __attribute((unused)) int block = 0; |
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| 279 | uint32_t ready_mask = ring.submit_q.ready_cnt - 1; |
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| 280 | |
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| 281 | disable_interrupts(); |
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| 282 | uint32_t off = __tls_rand(); |
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| 283 | enable_interrupts( __cfaabi_dbg_ctx ); |
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| 284 | |
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| 285 | uint32_t picked; |
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| 286 | LOOKING: for() { |
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| 287 | for(i; ring.submit_q.ready_cnt) { |
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| 288 | picked = (i + off) & ready_mask; |
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| 289 | uint32_t expected = -1ul32; |
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| 290 | if( __atomic_compare_exchange_n( &ring.submit_q.ready[picked], &expected, idx, true, __ATOMIC_SEQ_CST, __ATOMIC_RELAXED ) ) { |
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| 291 | break LOOKING; |
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| 292 | } |
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| 293 | verify(expected != idx); |
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| 294 | |
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| 295 | len ++; |
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| 296 | } |
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| 297 | |
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| 298 | block++; |
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[34b61882] | 299 | if( try_lock(ring.submit_q.lock __cfaabi_dbg_ctx2) ) { |
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| 300 | __release_consumed_submission( ring ); |
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| 301 | unlock( ring.submit_q.lock ); |
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| 302 | } |
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| 303 | else { |
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| 304 | yield(); |
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| 305 | } |
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[df40a56] | 306 | } |
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| 307 | |
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| 308 | // update statistics |
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[47746a2] | 309 | __STATS__( false, |
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| 310 | io.submit_q.look_avg.val += len; |
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| 311 | io.submit_q.look_avg.block += block; |
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| 312 | io.submit_q.look_avg.cnt += 1; |
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| 313 | ) |
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[df40a56] | 314 | |
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| 315 | return picked; |
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| 316 | } |
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| 317 | |
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[f00b26d4] | 318 | void __submit( struct io_context * ctx, uint32_t idx ) __attribute__((nonnull (1))) { |
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| 319 | __io_data & ring = *ctx->thrd.ring; |
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[5dadc9b] | 320 | // Get now the data we definetely need |
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[eafec07] | 321 | volatile uint32_t * const tail = ring.submit_q.tail; |
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[f00b26d4] | 322 | const uint32_t mask = *ring.submit_q.mask; |
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[2489d31] | 323 | |
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[5dadc9b] | 324 | // There are 2 submission schemes, check which one we are using |
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[f00b26d4] | 325 | if( ring.poller_submits ) { |
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[5dadc9b] | 326 | // If the poller thread submits, then we just need to add this to the ready array |
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[df40a56] | 327 | __submit_to_ready_array( ring, idx, mask ); |
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[5dadc9b] | 328 | |
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[f00b26d4] | 329 | post( ctx->thrd.sem ); |
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[5dadc9b] | 330 | |
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[dd4e2d7] | 331 | __cfadbg_print_safe( io, "Kernel I/O : Added %u to ready for %p\n", idx, active_thread() ); |
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[2d8f7b0] | 332 | } |
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[f00b26d4] | 333 | else if( ring.eager_submits ) { |
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[e46c753] | 334 | uint32_t picked = __submit_to_ready_array( ring, idx, mask ); |
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| 335 | |
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| 336 | for() { |
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| 337 | yield(); |
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| 338 | |
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| 339 | // If some one else collected our index, we are done |
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[8bb239d] | 340 | #warning ABA problem |
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[e46c753] | 341 | if( ring.submit_q.ready[picked] != idx ) { |
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[47746a2] | 342 | __STATS__( false, |
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| 343 | io.submit_q.helped += 1; |
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| 344 | ) |
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[e46c753] | 345 | return; |
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| 346 | } |
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| 347 | |
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| 348 | if( try_lock(ring.submit_q.lock __cfaabi_dbg_ctx2) ) { |
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[47746a2] | 349 | __STATS__( false, |
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| 350 | io.submit_q.leader += 1; |
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| 351 | ) |
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[e46c753] | 352 | break; |
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| 353 | } |
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[8bb239d] | 354 | |
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[47746a2] | 355 | __STATS__( false, |
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| 356 | io.submit_q.busy += 1; |
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| 357 | ) |
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[e46c753] | 358 | } |
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| 359 | |
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| 360 | // We got the lock |
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[be36ec3] | 361 | // Collect the submissions |
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[e46c753] | 362 | unsigned to_submit = __collect_submitions( ring ); |
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| 363 | |
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[be36ec3] | 364 | // Release the lock now so syscalls can overlap |
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| 365 | unlock(ring.submit_q.lock); |
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| 366 | |
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| 367 | // Actually submit |
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| 368 | int ret = __io_uring_enter( ring, to_submit, false ); |
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| 369 | if( ret < 0 ) return; |
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[e46c753] | 370 | |
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| 371 | // Release the consumed SQEs |
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[34b61882] | 372 | __release_consumed_submission( ring ); |
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[e46c753] | 373 | |
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| 374 | // update statistics |
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[be36ec3] | 375 | __STATS__( false, |
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[47746a2] | 376 | io.submit_q.submit_avg.rdy += to_submit; |
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| 377 | io.submit_q.submit_avg.csm += ret; |
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| 378 | io.submit_q.submit_avg.cnt += 1; |
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| 379 | ) |
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[e46c753] | 380 | } |
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[5dadc9b] | 381 | else { |
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| 382 | // get mutual exclusion |
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| 383 | lock(ring.submit_q.lock __cfaabi_dbg_ctx2); |
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[2489d31] | 384 | |
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[20ab637] | 385 | /* paranoid */ verifyf( ring.submit_q.sqes[ idx ].user_data != 0, |
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| 386 | /* paranoid */ "index %u already reclaimed\n" |
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| 387 | /* paranoid */ "head %u, prev %u, tail %u\n" |
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| 388 | /* paranoid */ "[-0: %u,-1: %u,-2: %u,-3: %u]\n", |
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| 389 | /* paranoid */ idx, |
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| 390 | /* paranoid */ *ring.submit_q.head, ring.submit_q.prev_head, *tail |
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| 391 | /* paranoid */ ,ring.submit_q.array[ ((*ring.submit_q.head) - 0) & (*ring.submit_q.mask) ] |
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| 392 | /* paranoid */ ,ring.submit_q.array[ ((*ring.submit_q.head) - 1) & (*ring.submit_q.mask) ] |
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| 393 | /* paranoid */ ,ring.submit_q.array[ ((*ring.submit_q.head) - 2) & (*ring.submit_q.mask) ] |
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| 394 | /* paranoid */ ,ring.submit_q.array[ ((*ring.submit_q.head) - 3) & (*ring.submit_q.mask) ] |
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| 395 | /* paranoid */ ); |
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| 396 | |
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[5dadc9b] | 397 | // Append to the list of ready entries |
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| 398 | |
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| 399 | /* paranoid */ verify( idx <= mask ); |
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[20ab637] | 400 | ring.submit_q.array[ (*tail) & mask ] = idx; |
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[5dadc9b] | 401 | __atomic_fetch_add(tail, 1ul32, __ATOMIC_SEQ_CST); |
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[d384787] | 402 | |
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[5dadc9b] | 403 | // Submit however, many entries need to be submitted |
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[f00b26d4] | 404 | int ret = __io_uring_enter( ring, 1, false ); |
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[5dadc9b] | 405 | if( ret < 0 ) { |
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| 406 | switch((int)errno) { |
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| 407 | default: |
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| 408 | abort( "KERNEL ERROR: IO_URING SUBMIT - %s\n", strerror(errno) ); |
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| 409 | } |
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| 410 | } |
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[d384787] | 411 | |
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[5dadc9b] | 412 | // update statistics |
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[47746a2] | 413 | __STATS__( false, |
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| 414 | io.submit_q.submit_avg.csm += 1; |
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| 415 | io.submit_q.submit_avg.cnt += 1; |
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| 416 | ) |
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[5dadc9b] | 417 | |
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[34b61882] | 418 | // Release the consumed SQEs |
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| 419 | __release_consumed_submission( ring ); |
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[7bfc849] | 420 | |
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[5dadc9b] | 421 | unlock(ring.submit_q.lock); |
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[dd4e2d7] | 422 | |
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| 423 | __cfadbg_print_safe( io, "Kernel I/O : Performed io_submit for %p, returned %d\n", active_thread(), ret ); |
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[5dadc9b] | 424 | } |
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[2489d31] | 425 | } |
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[e46c753] | 426 | |
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| 427 | static unsigned __collect_submitions( struct __io_data & ring ) { |
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| 428 | /* paranoid */ verify( ring.submit_q.ready != 0p ); |
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| 429 | /* paranoid */ verify( ring.submit_q.ready_cnt > 0 ); |
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| 430 | |
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| 431 | unsigned to_submit = 0; |
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| 432 | uint32_t tail = *ring.submit_q.tail; |
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| 433 | const uint32_t mask = *ring.submit_q.mask; |
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| 434 | |
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| 435 | // Go through the list of ready submissions |
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| 436 | for( i; ring.submit_q.ready_cnt ) { |
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| 437 | // replace any submission with the sentinel, to consume it. |
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| 438 | uint32_t idx = __atomic_exchange_n( &ring.submit_q.ready[i], -1ul32, __ATOMIC_RELAXED); |
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| 439 | |
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| 440 | // If it was already the sentinel, then we are done |
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| 441 | if( idx == -1ul32 ) continue; |
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| 442 | |
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| 443 | // If we got a real submission, append it to the list |
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| 444 | ring.submit_q.array[ (tail + to_submit) & mask ] = idx & mask; |
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| 445 | to_submit++; |
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| 446 | } |
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| 447 | |
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| 448 | // Increment the tail based on how many we are ready to submit |
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| 449 | __atomic_fetch_add(ring.submit_q.tail, to_submit, __ATOMIC_SEQ_CST); |
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| 450 | |
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| 451 | return to_submit; |
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| 452 | } |
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[34b61882] | 453 | |
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| 454 | static uint32_t __release_consumed_submission( struct __io_data & ring ) { |
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| 455 | const uint32_t smask = *ring.submit_q.mask; |
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[732b406] | 456 | |
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| 457 | if( !try_lock(ring.submit_q.release_lock __cfaabi_dbg_ctx2) ) return 0; |
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[34b61882] | 458 | uint32_t chead = *ring.submit_q.head; |
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| 459 | uint32_t phead = ring.submit_q.prev_head; |
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| 460 | ring.submit_q.prev_head = chead; |
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[732b406] | 461 | unlock(ring.submit_q.release_lock); |
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| 462 | |
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[34b61882] | 463 | uint32_t count = chead - phead; |
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| 464 | for( i; count ) { |
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| 465 | uint32_t idx = ring.submit_q.array[ (phead + i) & smask ]; |
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| 466 | ring.submit_q.sqes[ idx ].user_data = 0; |
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| 467 | } |
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| 468 | return count; |
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| 469 | } |
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[47746a2] | 470 | #endif |
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