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116 | unsigned header_length; /* size of aio_ring */ |
116 | unsigned header_length; /* size of aio_ring */ |
117 | |
117 | |
118 | struct io_event io_events[0]; |
118 | struct io_event io_events[0]; |
119 | }; |
119 | }; |
120 | |
120 | |
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121 | /* |
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122 | * define some syscall wrappers for common architectures |
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123 | * this is mostly for nice looks during debugging, not performance. |
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124 | * our syscalls return < 0, not == -1, on error. which is good |
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125 | * enough for linux aio. |
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126 | * TODO: arm is also common nowadays, maybe even mips and x86 |
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127 | * TODO: after implementing this, it suddenly looks like overkill, but its hard to remove... |
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128 | */ |
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129 | #if __GNUC__ && __linux && ECB_AMD64 && !defined __OPTIMIZE_SIZE__ |
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130 | /* the costly errno access probably kills this for size optimisation */ |
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131 | |
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132 | #define ev_syscall(nr,narg,arg1,arg2,arg3,arg4,arg5) \ |
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133 | ({ \ |
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134 | long res; \ |
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135 | register unsigned long r5 __asm__ ("r8" ); \ |
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136 | register unsigned long r4 __asm__ ("r10"); \ |
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137 | register unsigned long r3 __asm__ ("rdx"); \ |
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138 | register unsigned long r2 __asm__ ("rsi"); \ |
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139 | register unsigned long r1 __asm__ ("rdi"); \ |
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140 | if (narg >= 5) r5 = (unsigned long)(arg5); \ |
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141 | if (narg >= 4) r4 = (unsigned long)(arg4); \ |
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142 | if (narg >= 3) r3 = (unsigned long)(arg3); \ |
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143 | if (narg >= 2) r2 = (unsigned long)(arg2); \ |
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144 | if (narg >= 1) r1 = (unsigned long)(arg1); \ |
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145 | __asm__ __volatile__ ( \ |
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146 | "syscall\n\t" \ |
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147 | : "=a" (res) \ |
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148 | : "0" (nr), "r" (r1), "r" (r2), "r" (r3), "r" (r4), "r" (r5) \ |
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149 | : "cc", "r11", "cx", "memory"); \ |
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150 | errno = -res; \ |
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151 | res; \ |
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152 | }) |
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153 | |
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154 | #endif |
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155 | |
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156 | #ifdef ev_syscall |
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157 | #define ev_syscall0(nr) ev_syscall (nr, 0, 0, 0, 0, 0, 0 |
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158 | #define ev_syscall1(nr,arg1) ev_syscall (nr, 1, arg1, 0, 0, 0, 0) |
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159 | #define ev_syscall2(nr,arg1,arg2) ev_syscall (nr, 2, arg1, arg2, 0, 0, 0) |
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160 | #define ev_syscall3(nr,arg1,arg2,arg3) ev_syscall (nr, 3, arg1, arg2, arg3, 0, 0) |
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161 | #define ev_syscall4(nr,arg1,arg2,arg3,arg4) ev_syscall (nr, 3, arg1, arg2, arg3, arg4, 0) |
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162 | #define ev_syscall5(nr,arg1,arg2,arg3,arg4,arg5) ev_syscall (nr, 5, arg1, arg2, arg3, arg4, arg5) |
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163 | #else |
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164 | #define ev_syscall0(nr) syscall (nr) |
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165 | #define ev_syscall1(nr,arg1) syscall (nr, arg1) |
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166 | #define ev_syscall2(nr,arg1,arg2) syscall (nr, arg1, arg2) |
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167 | #define ev_syscall3(nr,arg1,arg2,arg3) syscall (nr, arg1, arg2, arg3) |
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168 | #define ev_syscall4(nr,arg1,arg2,arg3,arg4) syscall (nr, arg1, arg2, arg3, arg4) |
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169 | #define ev_syscall5(nr,arg1,arg2,arg3,arg4,arg5) syscall (nr, arg1, arg2, arg3, arg4, arg5) |
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170 | #endif |
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171 | |
121 | inline_size |
172 | inline_size |
122 | int |
173 | int |
123 | evsys_io_setup (unsigned nr_events, aio_context_t *ctx_idp) |
174 | evsys_io_setup (unsigned nr_events, aio_context_t *ctx_idp) |
124 | { |
175 | { |
125 | return syscall (SYS_io_setup, nr_events, ctx_idp); |
176 | return ev_syscall2 (SYS_io_setup, nr_events, ctx_idp); |
126 | } |
177 | } |
127 | |
178 | |
128 | inline_size |
179 | inline_size |
129 | int |
180 | int |
130 | evsys_io_destroy (aio_context_t ctx_id) |
181 | evsys_io_destroy (aio_context_t ctx_id) |
131 | { |
182 | { |
132 | return syscall (SYS_io_destroy, ctx_id); |
183 | return ev_syscall1 (SYS_io_destroy, ctx_id); |
133 | } |
184 | } |
134 | |
185 | |
135 | inline_size |
186 | inline_size |
136 | int |
187 | int |
137 | evsys_io_submit (aio_context_t ctx_id, long nr, struct iocb *cbp[]) |
188 | evsys_io_submit (aio_context_t ctx_id, long nr, struct iocb *cbp[]) |
138 | { |
189 | { |
139 | return syscall (SYS_io_submit, ctx_id, nr, cbp); |
190 | return ev_syscall3 (SYS_io_submit, ctx_id, nr, cbp); |
140 | } |
191 | } |
141 | |
192 | |
142 | inline_size |
193 | inline_size |
143 | int |
194 | int |
144 | evsys_io_cancel (aio_context_t ctx_id, struct iocb *cbp, struct io_event *result) |
195 | evsys_io_cancel (aio_context_t ctx_id, struct iocb *cbp, struct io_event *result) |
145 | { |
196 | { |
146 | return syscall (SYS_io_cancel, ctx_id, cbp, result); |
197 | return ev_syscall3 (SYS_io_cancel, ctx_id, cbp, result); |
147 | } |
198 | } |
148 | |
199 | |
149 | inline_size |
200 | inline_size |
150 | int |
201 | int |
151 | evsys_io_getevents (aio_context_t ctx_id, long min_nr, long nr, struct io_event *events, struct timespec *timeout) |
202 | evsys_io_getevents (aio_context_t ctx_id, long min_nr, long nr, struct io_event *events, struct timespec *timeout) |
152 | { |
203 | { |
153 | return syscall (SYS_io_getevents, ctx_id, min_nr, nr, events, timeout); |
204 | return ev_syscall5 (SYS_io_getevents, ctx_id, min_nr, nr, events, timeout); |
154 | } |
205 | } |
155 | |
206 | |
156 | /*****************************************************************************/ |
207 | /*****************************************************************************/ |
157 | /* actual backed implementation */ |
208 | /* actual backed implementation */ |
158 | |
209 | |
… | |
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240 | if (iocb->io.aio_reqprio < 0) |
291 | if (iocb->io.aio_reqprio < 0) |
241 | { |
292 | { |
242 | /* we handed this fd over to epoll, so undo this first */ |
293 | /* we handed this fd over to epoll, so undo this first */ |
243 | /* we do it manually because the optimisations on epoll_modfy won't do us any good */ |
294 | /* we do it manually because the optimisations on epoll_modfy won't do us any good */ |
244 | epoll_ctl (backend_fd, EPOLL_CTL_DEL, fd, 0); |
295 | epoll_ctl (backend_fd, EPOLL_CTL_DEL, fd, 0); |
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296 | anfds [fd].emask = 0; |
245 | iocb->io.aio_reqprio = 0; |
297 | iocb->io.aio_reqprio = 0; |
246 | } |
298 | } |
247 | |
299 | |
248 | if (iocb->io.aio_buf) |
300 | if (iocb->io.aio_buf) |
249 | /* io_cancel always returns some error on relevant kernels, but works */ |
301 | /* io_cancel always returns some error on relevant kernels, but works */ |
… | |
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334 | { |
386 | { |
335 | linuxaio_parse_events (EV_A_ ring->io_events + head, ring->nr - head); |
387 | linuxaio_parse_events (EV_A_ ring->io_events + head, ring->nr - head); |
336 | linuxaio_parse_events (EV_A_ ring->io_events, tail); |
388 | linuxaio_parse_events (EV_A_ ring->io_events, tail); |
337 | } |
389 | } |
338 | |
390 | |
339 | ECB_MEMORY_FENCE_RELAXED; |
391 | ECB_MEMORY_FENCE_RELEASE; |
340 | /* as an extension to C, we hope that the volatile will make this atomic and once-only */ |
392 | /* as an extension to C, we hope that the volatile will make this atomic and once-only */ |
341 | *(volatile unsigned *)&ring->head = tail; |
393 | *(volatile unsigned *)&ring->head = tail; |
342 | /* make sure kernel can see our new head value - probably not required */ |
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343 | ECB_MEMORY_FENCE_RELEASE; |
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344 | |
394 | |
345 | return 1; |
395 | return 1; |
346 | } |
396 | } |
347 | |
397 | |
348 | /* read at least one event from kernel, or timeout */ |
398 | /* read at least one event from kernel, or timeout */ |
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375 | /* ignored */; |
425 | /* ignored */; |
376 | else |
426 | else |
377 | ev_syserr ("(libev) linuxaio io_getevents"); |
427 | ev_syserr ("(libev) linuxaio io_getevents"); |
378 | else if (res) |
428 | else if (res) |
379 | { |
429 | { |
380 | /* at least one event received, handle it and any remaining ones in the ring buffer */ |
430 | /* at least one event available, handle it and any remaining ones in the ring buffer */ |
381 | linuxaio_parse_events (EV_A_ ioev, res); |
431 | linuxaio_parse_events (EV_A_ ioev, res); |
382 | linuxaio_get_events_from_ring (EV_A); |
432 | linuxaio_get_events_from_ring (EV_A); |
383 | } |
433 | } |
384 | } |
434 | } |
385 | |
435 | |
386 | static int |
436 | inline_size |
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437 | int |
387 | linuxaio_io_setup (EV_P) |
438 | linuxaio_io_setup (EV_P) |
388 | { |
439 | { |
389 | linuxaio_ctx = 0; |
440 | linuxaio_ctx = 0; |
390 | return evsys_io_setup (linuxaio_nr_events (EV_A), &linuxaio_ctx); |
441 | return evsys_io_setup (linuxaio_nr_events (EV_A), &linuxaio_ctx); |
391 | } |
442 | } |