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Comparing libev/ev_epoll.c (file contents):
Revision 1.56 by root, Wed Jan 5 04:25:12 2011 UTC vs.
Revision 1.67 by root, Wed Jun 20 12:39:53 2012 UTC

… …
4 * Copyright (c) 2007,2008,2009,2010,2011 Marc Alexander Lehmann <libev@schmorp.de> 4 * Copyright (c) 2007,2008,2009,2010,2011 Marc Alexander Lehmann <libev@schmorp.de>
5 * All rights reserved. 5 * All rights reserved.
6 * 6 *
7 * Redistribution and use in source and binary forms, with or without modifica- 7 * Redistribution and use in source and binary forms, with or without modifica-
8 * tion, are permitted provided that the following conditions are met: 8 * tion, are permitted provided that the following conditions are met:
9 * 9 *
10 * 1. Redistributions of source code must retain the above copyright notice, 10 * 1. Redistributions of source code must retain the above copyright notice,
11 * this list of conditions and the following disclaimer. 11 * this list of conditions and the following disclaimer.
12 * 12 *
13 * 2. Redistributions in binary form must reproduce the above copyright 13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the 14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution. 15 * documentation and/or other materials provided with the distribution.
16 * 16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER- 18 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
19 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO 19 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
20 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE- 20 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
21 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 21 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
… …
115 if (!epoll_ctl (backend_fd, EPOLL_CTL_MOD, fd, &ev)) 115 if (!epoll_ctl (backend_fd, EPOLL_CTL_MOD, fd, &ev))
116 return; 116 return;
117 } 117 }
118 else if (expect_true (errno == EPERM)) 118 else if (expect_true (errno == EPERM))
119 { 119 {
120 /* EPERM means the fd is always ready, but epoll is too snobbish */
121 /* to handle it, unlike select or poll. */
120 anfds [fd].emask = EV_EMASK_EPERM; 122 anfds [fd].emask = EV_EMASK_EPERM;
121 123
122 /* add fd to epoll_eperms, if not already inside */ 124 /* add fd to epoll_eperms, if not already inside */
123 if (!(oldmask & EV_EMASK_EPERM)) 125 if (!(oldmask & EV_EMASK_EPERM))
124 { 126 {
… …
139static void 141static void
140epoll_poll (EV_P_ ev_tstamp timeout) 142epoll_poll (EV_P_ ev_tstamp timeout)
141{ 143{
142 int i; 144 int i;
143 int eventcnt; 145 int eventcnt;
144 146
147 if (expect_false (epoll_epermcnt))
148 timeout = 0.;
149
145 /* epoll wait times cannot be larger than (LONG_MAX - 999UL) / HZ msecs, which is below */ 150 /* epoll wait times cannot be larger than (LONG_MAX - 999UL) / HZ msecs, which is below */
146 /* the default libev max wait time, however. */ 151 /* the default libev max wait time, however. */
147 EV_RELEASE_CB; 152 EV_RELEASE_CB;
148 eventcnt = epoll_wait (backend_fd, epoll_events, epoll_eventmax, (int)ceil (timeout * 1000.)); 153 eventcnt = epoll_wait (backend_fd, epoll_events, epoll_eventmax, timeout * 1e3);
149 EV_ACQUIRE_CB; 154 EV_ACQUIRE_CB;
150 155
151 if (expect_false (eventcnt < 0)) 156 if (expect_false (eventcnt < 0))
152 { 157 {
153 if (errno != EINTR) 158 if (errno != EINTR)
… …
163 int fd = (uint32_t)ev->data.u64; /* mask out the lower 32 bits */ 168 int fd = (uint32_t)ev->data.u64; /* mask out the lower 32 bits */
164 int want = anfds [fd].events; 169 int want = anfds [fd].events;
165 int got = (ev->events & (EPOLLOUT | EPOLLERR | EPOLLHUP) ? EV_WRITE : 0) 170 int got = (ev->events & (EPOLLOUT | EPOLLERR | EPOLLHUP) ? EV_WRITE : 0)
166 | (ev->events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0); 171 | (ev->events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0);
167 172
173 /*
168 /* check for spurious notification */ 174 * check for spurious notification.
175 * this only finds spurious notifications on egen updates
176 * other spurious notifications will be found by epoll_ctl, below
169 /* we assume that fd is always in range, as we never shrink the anfds array */ 177 * we assume that fd is always in range, as we never shrink the anfds array
178 */
170 if (expect_false ((uint32_t)anfds [fd].egen != (uint32_t)(ev->data.u64 >> 32))) 179 if (expect_false ((uint32_t)anfds [fd].egen != (uint32_t)(ev->data.u64 >> 32)))
171 { 180 {
172 /* recreate kernel state */ 181 /* recreate kernel state */
173 postfork = 1; 182 postfork = 1;
174 continue; 183 continue;
… …
176 185
177 if (expect_false (got & ~want)) 186 if (expect_false (got & ~want))
178 { 187 {
179 anfds [fd].emask = want; 188 anfds [fd].emask = want;
180 189
190 /*
181 /* we received an event but are not interested in it, try mod or del */ 191 * we received an event but are not interested in it, try mod or del
182 /* I don't think we ever need MOD, but let's handle it anyways */ 192 * this often happens because we optimistically do not unregister fds
193 * when we are no longer interested in them, but also when we get spurious
194 * notifications for fds from another process. this is partially handled
195 * above with the gencounter check (== our fd is not the event fd), and
196 * partially here, when epoll_ctl returns an error (== a child has the fd
197 * but we closed it).
198 */
183 ev->events = (want & EV_READ ? EPOLLIN : 0) 199 ev->events = (want & EV_READ ? EPOLLIN : 0)
184 | (want & EV_WRITE ? EPOLLOUT : 0); 200 | (want & EV_WRITE ? EPOLLOUT : 0);
185 201
186 /* pre-2.6.9 kernels require a non-null pointer with EPOLL_CTL_DEL, */ 202 /* pre-2.6.9 kernels require a non-null pointer with EPOLL_CTL_DEL, */
187 /* which is fortunately easy to do for us. */ 203 /* which is fortunately easy to do for us. */
… …
220epoll_init (EV_P_ int flags) 236epoll_init (EV_P_ int flags)
221{ 237{
222#ifdef EPOLL_CLOEXEC 238#ifdef EPOLL_CLOEXEC
223 backend_fd = epoll_create1 (EPOLL_CLOEXEC); 239 backend_fd = epoll_create1 (EPOLL_CLOEXEC);
224 240
225 if (backend_fd <= 0) 241 if (backend_fd < 0 && (errno == EINVAL || errno == ENOSYS))
226#endif 242#endif
227 backend_fd = epoll_create (256); 243 backend_fd = epoll_create (256);
228 244
229 if (backend_fd < 0) 245 if (backend_fd < 0)
230 return 0; 246 return 0;
231 247
232 fcntl (backend_fd, F_SETFD, FD_CLOEXEC); 248 fcntl (backend_fd, F_SETFD, FD_CLOEXEC);
233 249
234 backend_fudge = 0.; /* kernel sources seem to indicate this to be zero */ 250 backend_mintime = 1e-3; /* epoll does sometimes return early, this is just to avoid the worst */
235 backend_modify = epoll_modify; 251 backend_modify = epoll_modify;
236 backend_poll = epoll_poll; 252 backend_poll = epoll_poll;
237 253
238 epoll_eventmax = 64; /* initial number of events receivable per poll */ 254 epoll_eventmax = 64; /* initial number of events receivable per poll */
239 epoll_events = (struct epoll_event *)ev_malloc (sizeof (struct epoll_event) * epoll_eventmax); 255 epoll_events = (struct epoll_event *)ev_malloc (sizeof (struct epoll_event) * epoll_eventmax);
240 256
241 return EVBACKEND_EPOLL; 257 return EVBACKEND_EPOLL;

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