[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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[d60d30e] | 19 | // #define __CFA_DEBUG_PRINT_IO__ |
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| 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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| 33 | #include <sys/syscall.h> |
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[dddb3dd0] | 34 | #include <sys/eventfd.h> |
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[92976d9] | 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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[2fab24e3] | 44 | __attribute__((unused)) static const char * opcodes[] = { |
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[426f60c] | 45 | "OP_NOP", |
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| 46 | "OP_READV", |
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| 47 | "OP_WRITEV", |
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| 48 | "OP_FSYNC", |
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| 49 | "OP_READ_FIXED", |
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| 50 | "OP_WRITE_FIXED", |
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| 51 | "OP_POLL_ADD", |
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| 52 | "OP_POLL_REMOVE", |
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| 53 | "OP_SYNC_FILE_RANGE", |
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| 54 | "OP_SENDMSG", |
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| 55 | "OP_RECVMSG", |
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| 56 | "OP_TIMEOUT", |
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| 57 | "OP_TIMEOUT_REMOVE", |
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| 58 | "OP_ACCEPT", |
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| 59 | "OP_ASYNC_CANCEL", |
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| 60 | "OP_LINK_TIMEOUT", |
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| 61 | "OP_CONNECT", |
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| 62 | "OP_FALLOCATE", |
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| 63 | "OP_OPENAT", |
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| 64 | "OP_CLOSE", |
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| 65 | "OP_FILES_UPDATE", |
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| 66 | "OP_STATX", |
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| 67 | "OP_READ", |
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| 68 | "OP_WRITE", |
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| 69 | "OP_FADVISE", |
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| 70 | "OP_MADVISE", |
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| 71 | "OP_SEND", |
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| 72 | "OP_RECV", |
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| 73 | "OP_OPENAT2", |
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| 74 | "OP_EPOLL_CTL", |
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| 75 | "OP_SPLICE", |
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| 76 | "OP_PROVIDE_BUFFERS", |
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| 77 | "OP_REMOVE_BUFFERS", |
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| 78 | "OP_TEE", |
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| 79 | "INVALID_OP" |
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| 80 | }; |
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| 81 | |
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[dddb3dd0] | 82 | static $io_context * __ioarbiter_allocate( $io_arbiter & mutex this, processor *, __u32 idxs[], __u32 want ); |
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| 83 | static void __ioarbiter_submit( $io_arbiter & mutex this, $io_context * , __u32 idxs[], __u32 have, bool lazy ); |
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| 84 | static void __ioarbiter_flush ( $io_arbiter & mutex this, $io_context * ); |
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| 85 | static inline void __ioarbiter_notify( $io_context & ctx ); |
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[92976d9] | 86 | //============================================================================================= |
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| 87 | // I/O Polling |
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| 88 | //============================================================================================= |
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[78da4ab] | 89 | static inline unsigned __flush( struct $io_context & ); |
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| 90 | static inline __u32 __release_sqes( struct $io_context & ); |
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[1d5e4711] | 91 | |
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[dddb3dd0] | 92 | void __cfa_io_drain( processor * proc ) { |
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| 93 | /* paranoid */ verify( ! __preemption_enabled() ); |
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| 94 | /* paranoid */ verify( proc ); |
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| 95 | /* paranoid */ verify( proc->io.ctx ); |
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[6f121b8] | 96 | |
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[d384787] | 97 | // Drain the queue |
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[dddb3dd0] | 98 | $io_context * ctx = proc->io.ctx; |
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| 99 | unsigned head = *ctx->cq.head; |
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| 100 | unsigned tail = *ctx->cq.tail; |
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| 101 | const __u32 mask = *ctx->cq.mask; |
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[92976d9] | 102 | |
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[4998155] | 103 | __u32 count = tail - head; |
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[dddb3dd0] | 104 | __STATS__( false, io.calls.drain++; io.calls.completed += count; ) |
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[d60d30e] | 105 | |
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[d384787] | 106 | for(i; count) { |
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[6f121b8] | 107 | unsigned idx = (head + i) & mask; |
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[dddb3dd0] | 108 | volatile struct io_uring_cqe & cqe = ctx->cq.cqes[idx]; |
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[92976d9] | 109 | |
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[d384787] | 110 | /* paranoid */ verify(&cqe); |
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[92976d9] | 111 | |
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[78da4ab] | 112 | struct io_future_t * future = (struct io_future_t *)(uintptr_t)cqe.user_data; |
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| 113 | __cfadbg_print_safe( io, "Kernel I/O : Syscall completed : cqe %p, result %d for %p\n", &cqe, cqe.res, future ); |
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| 114 | |
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| 115 | fulfil( *future, cqe.res ); |
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| 116 | } |
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| 117 | |
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[dddb3dd0] | 118 | __cfadbg_print_safe(io, "Kernel I/O : %u completed\n", count); |
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[2d8f7b0] | 119 | |
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[92976d9] | 120 | // Mark to the kernel that the cqe has been seen |
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| 121 | // Ensure that the kernel only sees the new value of the head index after the CQEs have been read. |
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[dddb3dd0] | 122 | __atomic_store_n( ctx->cq.head, head + count, __ATOMIC_SEQ_CST ); |
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[92976d9] | 123 | |
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[dddb3dd0] | 124 | /* paranoid */ verify( ! __preemption_enabled() ); |
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| 125 | |
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| 126 | return; |
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[92976d9] | 127 | } |
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| 128 | |
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[dddb3dd0] | 129 | void __cfa_io_flush( processor * proc ) { |
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| 130 | /* paranoid */ verify( ! __preemption_enabled() ); |
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| 131 | /* paranoid */ verify( proc ); |
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| 132 | /* paranoid */ verify( proc->io.ctx ); |
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[1539bbd] | 133 | |
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[dddb3dd0] | 134 | $io_context & ctx = *proc->io.ctx; |
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[78da4ab] | 135 | |
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[dddb3dd0] | 136 | if(!ctx.ext_sq.empty) { |
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| 137 | __ioarbiter_flush( *ctx.arbiter, &ctx ); |
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| 138 | } |
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[3c039b0] | 139 | |
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[dddb3dd0] | 140 | __STATS__( true, io.calls.flush++; ) |
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| 141 | int ret = syscall( __NR_io_uring_enter, ctx.fd, ctx.sq.to_submit, 0, 0, (sigset_t *)0p, _NSIG / 8); |
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| 142 | if( ret < 0 ) { |
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| 143 | switch((int)errno) { |
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| 144 | case EAGAIN: |
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| 145 | case EINTR: |
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| 146 | case EBUSY: |
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| 147 | // Update statistics |
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| 148 | __STATS__( false, io.calls.errors.busy ++; ) |
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| 149 | return; |
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| 150 | default: |
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| 151 | abort( "KERNEL ERROR: IO_URING SYSCALL - (%d) %s\n", (int)errno, strerror(errno) ); |
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[61dd73d] | 152 | } |
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[dddb3dd0] | 153 | } |
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[ece0e80] | 154 | |
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[dddb3dd0] | 155 | __cfadbg_print_safe(io, "Kernel I/O : %u submitted to io_uring %d\n", ret, ctx.fd); |
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| 156 | __STATS__( true, io.calls.submitted += ret; ) |
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| 157 | /* paranoid */ verify( ctx.sq.to_submit <= *ctx.sq.num ); |
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| 158 | /* paranoid */ verify( ctx.sq.to_submit >= ret ); |
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| 159 | |
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| 160 | ctx.sq.to_submit -= ret; |
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[ece0e80] | 161 | |
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[dddb3dd0] | 162 | /* paranoid */ verify( ctx.sq.to_submit <= *ctx.sq.num ); |
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[5dadc9b] | 163 | |
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[dddb3dd0] | 164 | // Release the consumed SQEs |
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| 165 | __release_sqes( ctx ); |
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[ece0e80] | 166 | |
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[dddb3dd0] | 167 | /* paranoid */ verify( ! __preemption_enabled() ); |
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[61dd73d] | 168 | |
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[dddb3dd0] | 169 | ctx.proc->io.pending = false; |
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[61dd73d] | 170 | } |
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[f6660520] | 171 | |
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[92976d9] | 172 | //============================================================================================= |
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| 173 | // I/O Submissions |
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| 174 | //============================================================================================= |
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| 175 | |
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[2d8f7b0] | 176 | // Submition steps : |
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[e46c753] | 177 | // 1 - Allocate a queue entry. The ring already has memory for all entries but only the ones |
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[2d8f7b0] | 178 | // listed in sq.array are visible by the kernel. For those not listed, the kernel does not |
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| 179 | // offer any assurance that an entry is not being filled by multiple flags. Therefore, we |
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| 180 | // need to write an allocator that allows allocating concurrently. |
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| 181 | // |
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[e46c753] | 182 | // 2 - Actually fill the submit entry, this is the only simple and straightforward step. |
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[2d8f7b0] | 183 | // |
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[e46c753] | 184 | // 3 - Append the entry index to the array and adjust the tail accordingly. This operation |
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[2d8f7b0] | 185 | // needs to arrive to two concensus at the same time: |
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| 186 | // A - The order in which entries are listed in the array: no two threads must pick the |
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| 187 | // same index for their entries |
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| 188 | // B - When can the tail be update for the kernel. EVERY entries in the array between |
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| 189 | // head and tail must be fully filled and shouldn't ever be touched again. |
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| 190 | // |
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[78da4ab] | 191 | //============================================================================================= |
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| 192 | // Allocation |
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| 193 | // for user's convenience fill the sqes from the indexes |
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| 194 | static inline void __fill(struct io_uring_sqe * out_sqes[], __u32 want, __u32 idxs[], struct $io_context * ctx) { |
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| 195 | struct io_uring_sqe * sqes = ctx->sq.sqes; |
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| 196 | for(i; want) { |
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[dddb3dd0] | 197 | __cfadbg_print_safe(io, "Kernel I/O : filling loop\n"); |
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[78da4ab] | 198 | out_sqes[i] = &sqes[idxs[i]]; |
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| 199 | } |
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| 200 | } |
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[2489d31] | 201 | |
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[78da4ab] | 202 | // Try to directly allocate from the a given context |
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| 203 | // Not thread-safe |
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| 204 | static inline bool __alloc(struct $io_context * ctx, __u32 idxs[], __u32 want) { |
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| 205 | __sub_ring_t & sq = ctx->sq; |
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| 206 | const __u32 mask = *sq.mask; |
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| 207 | __u32 fhead = sq.free_ring.head; // get the current head of the queue |
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| 208 | __u32 ftail = sq.free_ring.tail; // get the current tail of the queue |
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[2489d31] | 209 | |
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[78da4ab] | 210 | // If we don't have enough sqes, fail |
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| 211 | if((ftail - fhead) < want) { return false; } |
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[426f60c] | 212 | |
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[78da4ab] | 213 | // copy all the indexes we want from the available list |
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| 214 | for(i; want) { |
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[dddb3dd0] | 215 | __cfadbg_print_safe(io, "Kernel I/O : allocating loop\n"); |
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[78da4ab] | 216 | idxs[i] = sq.free_ring.array[(fhead + i) & mask]; |
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[6f121b8] | 217 | } |
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[2489d31] | 218 | |
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[78da4ab] | 219 | // Advance the head to mark the indexes as consumed |
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| 220 | __atomic_store_n(&sq.free_ring.head, fhead + want, __ATOMIC_RELEASE); |
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[df40a56] | 221 | |
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[78da4ab] | 222 | // return success |
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| 223 | return true; |
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| 224 | } |
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[df40a56] | 225 | |
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[78da4ab] | 226 | // Allocate an submit queue entry. |
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| 227 | // The kernel cannot see these entries until they are submitted, but other threads must be |
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| 228 | // able to see which entries can be used and which are already un used by an other thread |
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| 229 | // for convenience, return both the index and the pointer to the sqe |
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| 230 | // sqe == &sqes[idx] |
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| 231 | struct $io_context * cfa_io_allocate(struct io_uring_sqe * sqes[], __u32 idxs[], __u32 want) { |
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| 232 | __cfadbg_print_safe(io, "Kernel I/O : attempting to allocate %u\n", want); |
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[df40a56] | 233 | |
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[78da4ab] | 234 | disable_interrupts(); |
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| 235 | processor * proc = __cfaabi_tls.this_processor; |
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[dddb3dd0] | 236 | $io_context * ctx = proc->io.ctx; |
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[78da4ab] | 237 | /* paranoid */ verify( __cfaabi_tls.this_processor ); |
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[dddb3dd0] | 238 | /* paranoid */ verify( ctx ); |
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[78da4ab] | 239 | |
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[dddb3dd0] | 240 | __cfadbg_print_safe(io, "Kernel I/O : attempting to fast allocation\n"); |
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[78da4ab] | 241 | |
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[dddb3dd0] | 242 | // We can proceed to the fast path |
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| 243 | if( __alloc(ctx, idxs, want) ) { |
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| 244 | // Allocation was successful |
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| 245 | __STATS__( true, io.alloc.fast += 1; ) |
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| 246 | enable_interrupts( __cfaabi_dbg_ctx ); |
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[df40a56] | 247 | |
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[dddb3dd0] | 248 | __cfadbg_print_safe(io, "Kernel I/O : fast allocation successful from ring %d\n", ctx->fd); |
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[2fafe7e] | 249 | |
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[dddb3dd0] | 250 | __fill( sqes, want, idxs, ctx ); |
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| 251 | return ctx; |
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[df40a56] | 252 | } |
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[dddb3dd0] | 253 | // The fast path failed, fallback |
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| 254 | __STATS__( true, io.alloc.fail += 1; ) |
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[df40a56] | 255 | |
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[78da4ab] | 256 | // Fast path failed, fallback on arbitration |
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[d60d30e] | 257 | __STATS__( true, io.alloc.slow += 1; ) |
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[78da4ab] | 258 | enable_interrupts( __cfaabi_dbg_ctx ); |
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| 259 | |
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[dddb3dd0] | 260 | $io_arbiter * ioarb = proc->cltr->io.arbiter; |
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| 261 | /* paranoid */ verify( ioarb ); |
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| 262 | |
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[78da4ab] | 263 | __cfadbg_print_safe(io, "Kernel I/O : falling back on arbiter for allocation\n"); |
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| 264 | |
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| 265 | struct $io_context * ret = __ioarbiter_allocate(*ioarb, proc, idxs, want); |
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| 266 | |
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[dddb3dd0] | 267 | __cfadbg_print_safe(io, "Kernel I/O : slow allocation completed from ring %d\n", ret->fd); |
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[df40a56] | 268 | |
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[78da4ab] | 269 | __fill( sqes, want, idxs,ret ); |
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| 270 | return ret; |
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[df40a56] | 271 | } |
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| 272 | |
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[426f60c] | 273 | |
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[78da4ab] | 274 | //============================================================================================= |
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| 275 | // submission |
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[dddb3dd0] | 276 | static inline void __submit( struct $io_context * ctx, __u32 idxs[], __u32 have, bool lazy) { |
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[78da4ab] | 277 | // We can proceed to the fast path |
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| 278 | // Get the right objects |
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| 279 | __sub_ring_t & sq = ctx->sq; |
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| 280 | const __u32 mask = *sq.mask; |
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[dddb3dd0] | 281 | __u32 tail = *sq.kring.tail; |
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[78da4ab] | 282 | |
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| 283 | // Add the sqes to the array |
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| 284 | for( i; have ) { |
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[dddb3dd0] | 285 | __cfadbg_print_safe(io, "Kernel I/O : __submit loop\n"); |
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[78da4ab] | 286 | sq.kring.array[ (tail + i) & mask ] = idxs[i]; |
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[426f60c] | 287 | } |
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| 288 | |
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[78da4ab] | 289 | // Make the sqes visible to the submitter |
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[dddb3dd0] | 290 | __atomic_store_n(sq.kring.tail, tail + have, __ATOMIC_RELEASE); |
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| 291 | sq.to_submit++; |
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[426f60c] | 292 | |
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[dddb3dd0] | 293 | ctx->proc->io.pending = true; |
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| 294 | ctx->proc->io.dirty = true; |
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| 295 | if(sq.to_submit > 30 || !lazy) { |
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| 296 | __cfa_io_flush( ctx->proc ); |
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| 297 | } |
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[78da4ab] | 298 | } |
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[2489d31] | 299 | |
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[dddb3dd0] | 300 | void cfa_io_submit( struct $io_context * inctx, __u32 idxs[], __u32 have, bool lazy ) __attribute__((nonnull (1))) { |
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| 301 | __cfadbg_print_safe(io, "Kernel I/O : attempting to submit %u (%s)\n", have, lazy ? "lazy" : "eager"); |
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[5dadc9b] | 302 | |
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[78da4ab] | 303 | disable_interrupts(); |
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| 304 | processor * proc = __cfaabi_tls.this_processor; |
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| 305 | $io_context * ctx = proc->io.ctx; |
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[dddb3dd0] | 306 | /* paranoid */ verify( __cfaabi_tls.this_processor ); |
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| 307 | /* paranoid */ verify( ctx ); |
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[e46c753] | 308 | |
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[78da4ab] | 309 | // Can we proceed to the fast path |
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[dddb3dd0] | 310 | if( ctx == inctx ) // We have the right instance? |
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[78da4ab] | 311 | { |
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[dddb3dd0] | 312 | __submit(ctx, idxs, have, lazy); |
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[e46c753] | 313 | |
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[78da4ab] | 314 | // Mark the instance as no longer in-use, re-enable interrupts and return |
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[d60d30e] | 315 | __STATS__( true, io.submit.fast += 1; ) |
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[78da4ab] | 316 | enable_interrupts( __cfaabi_dbg_ctx ); |
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[ece0e80] | 317 | |
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[78da4ab] | 318 | __cfadbg_print_safe(io, "Kernel I/O : submitted on fast path\n"); |
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| 319 | return; |
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[e46c753] | 320 | } |
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[d384787] | 321 | |
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[78da4ab] | 322 | // Fast path failed, fallback on arbitration |
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[d60d30e] | 323 | __STATS__( true, io.submit.slow += 1; ) |
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[78da4ab] | 324 | enable_interrupts( __cfaabi_dbg_ctx ); |
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[5dadc9b] | 325 | |
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[78da4ab] | 326 | __cfadbg_print_safe(io, "Kernel I/O : falling back on arbiter for submission\n"); |
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[426f60c] | 327 | |
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[dddb3dd0] | 328 | __ioarbiter_submit(*inctx->arbiter, inctx, idxs, have, lazy); |
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[78da4ab] | 329 | } |
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[2fab24e3] | 330 | |
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[78da4ab] | 331 | //============================================================================================= |
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| 332 | // Flushing |
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[426f60c] | 333 | // Go through the ring's submit queue and release everything that has already been consumed |
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| 334 | // by io_uring |
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[78da4ab] | 335 | // This cannot be done by multiple threads |
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| 336 | static __u32 __release_sqes( struct $io_context & ctx ) { |
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| 337 | const __u32 mask = *ctx.sq.mask; |
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[732b406] | 338 | |
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[426f60c] | 339 | __attribute__((unused)) |
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[78da4ab] | 340 | __u32 ctail = *ctx.sq.kring.tail; // get the current tail of the queue |
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| 341 | __u32 chead = *ctx.sq.kring.head; // get the current head of the queue |
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| 342 | __u32 phead = ctx.sq.kring.released; // get the head the last time we were here |
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| 343 | |
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| 344 | __u32 ftail = ctx.sq.free_ring.tail; // get the current tail of the queue |
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[732b406] | 345 | |
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[426f60c] | 346 | // the 3 fields are organized like this diagram |
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| 347 | // except it's are ring |
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| 348 | // ---+--------+--------+---- |
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| 349 | // ---+--------+--------+---- |
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| 350 | // ^ ^ ^ |
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| 351 | // phead chead ctail |
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| 352 | |
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| 353 | // make sure ctail doesn't wrap around and reach phead |
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| 354 | /* paranoid */ verify( |
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| 355 | (ctail >= chead && chead >= phead) |
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| 356 | || (chead >= phead && phead >= ctail) |
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| 357 | || (phead >= ctail && ctail >= chead) |
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| 358 | ); |
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| 359 | |
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| 360 | // find the range we need to clear |
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[4998155] | 361 | __u32 count = chead - phead; |
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[426f60c] | 362 | |
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[78da4ab] | 363 | if(count == 0) { |
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| 364 | return 0; |
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| 365 | } |
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| 366 | |
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[426f60c] | 367 | // We acquired an previous-head/current-head range |
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| 368 | // go through the range and release the sqes |
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[34b61882] | 369 | for( i; count ) { |
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[dddb3dd0] | 370 | __cfadbg_print_safe(io, "Kernel I/O : release loop\n"); |
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[78da4ab] | 371 | __u32 idx = ctx.sq.kring.array[ (phead + i) & mask ]; |
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| 372 | ctx.sq.free_ring.array[ (ftail + i) & mask ] = idx; |
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[34b61882] | 373 | } |
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[78da4ab] | 374 | |
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| 375 | ctx.sq.kring.released = chead; // note up to were we processed |
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| 376 | __atomic_store_n(&ctx.sq.free_ring.tail, ftail + count, __ATOMIC_SEQ_CST); |
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| 377 | |
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| 378 | __ioarbiter_notify(ctx); |
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| 379 | |
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[34b61882] | 380 | return count; |
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| 381 | } |
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[35285fd] | 382 | |
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[78da4ab] | 383 | //============================================================================================= |
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| 384 | // I/O Arbiter |
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| 385 | //============================================================================================= |
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| 386 | static $io_context * __ioarbiter_allocate( $io_arbiter & mutex this, processor * proc, __u32 idxs[], __u32 want ) { |
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| 387 | __cfadbg_print_safe(io, "Kernel I/O : arbiter allocating\n"); |
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| 388 | |
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[d60d30e] | 389 | __STATS__( false, io.alloc.block += 1; ) |
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| 390 | |
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[78da4ab] | 391 | // No one has any resources left, wait for something to finish |
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| 392 | // Mark as pending |
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| 393 | __atomic_store_n( &this.pending.flag, true, __ATOMIC_SEQ_CST ); |
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| 394 | |
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| 395 | // Wait for our turn to submit |
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| 396 | wait( this.pending.blocked, want ); |
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| 397 | |
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| 398 | __attribute((unused)) bool ret = |
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| 399 | __alloc( this.pending.ctx, idxs, want); |
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| 400 | /* paranoid */ verify( ret ); |
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| 401 | |
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| 402 | return this.pending.ctx; |
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[dddb3dd0] | 403 | |
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[78da4ab] | 404 | } |
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| 405 | |
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| 406 | static void __ioarbiter_notify( $io_arbiter & mutex this, $io_context * ctx ) { |
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| 407 | /* paranoid */ verify( !is_empty(this.pending.blocked) ); |
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| 408 | this.pending.ctx = ctx; |
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| 409 | |
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| 410 | while( !is_empty(this.pending.blocked) ) { |
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[dddb3dd0] | 411 | __cfadbg_print_safe(io, "Kernel I/O : notifying\n"); |
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[78da4ab] | 412 | __u32 have = ctx->sq.free_ring.tail - ctx->sq.free_ring.head; |
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| 413 | __u32 want = front( this.pending.blocked ); |
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| 414 | |
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| 415 | if( have > want ) return; |
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| 416 | |
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| 417 | signal_block( this.pending.blocked ); |
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| 418 | } |
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| 419 | |
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| 420 | this.pending.flag = false; |
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| 421 | } |
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| 422 | |
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| 423 | static void __ioarbiter_notify( $io_context & ctx ) { |
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| 424 | if(__atomic_load_n( &ctx.arbiter->pending.flag, __ATOMIC_SEQ_CST)) { |
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| 425 | __ioarbiter_notify( *ctx.arbiter, &ctx ); |
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| 426 | } |
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| 427 | } |
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| 428 | |
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| 429 | // Simply append to the pending |
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[dddb3dd0] | 430 | static void __ioarbiter_submit( $io_arbiter & mutex this, $io_context * ctx, __u32 idxs[], __u32 have, bool lazy ) { |
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[78da4ab] | 431 | __cfadbg_print_safe(io, "Kernel I/O : submitting %u from the arbiter to context %u\n", have, ctx->fd); |
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| 432 | |
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| 433 | /* paranoid */ verify( &this == ctx->arbiter ); |
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| 434 | |
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| 435 | // Mark as pending |
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| 436 | __atomic_store_n( &ctx->ext_sq.empty, false, __ATOMIC_SEQ_CST ); |
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| 437 | |
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| 438 | __cfadbg_print_safe(io, "Kernel I/O : waiting to submit %u\n", have); |
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| 439 | |
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| 440 | // Wait for our turn to submit |
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| 441 | wait( ctx->ext_sq.blocked ); |
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| 442 | |
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| 443 | // Submit our indexes |
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[dddb3dd0] | 444 | __submit(ctx, idxs, have, lazy); |
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[78da4ab] | 445 | |
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| 446 | __cfadbg_print_safe(io, "Kernel I/O : %u submitted from arbiter\n", have); |
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| 447 | } |
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| 448 | |
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| 449 | static void __ioarbiter_flush( $io_arbiter & mutex this, $io_context * ctx ) { |
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| 450 | /* paranoid */ verify( &this == ctx->arbiter ); |
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| 451 | |
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[d60d30e] | 452 | __STATS__( false, io.flush.external += 1; ) |
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| 453 | |
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[78da4ab] | 454 | __cfadbg_print_safe(io, "Kernel I/O : arbiter flushing\n"); |
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| 455 | |
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| 456 | condition & blcked = ctx->ext_sq.blocked; |
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| 457 | /* paranoid */ verify( ctx->ext_sq.empty == is_empty( blcked ) ); |
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| 458 | while(!is_empty( blcked )) { |
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| 459 | signal_block( blcked ); |
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| 460 | } |
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| 461 | |
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| 462 | ctx->ext_sq.empty = true; |
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| 463 | } |
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[47746a2] | 464 | #endif |
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