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Comparing libev/ev_epoll.c (file contents):
Revision 1.36 by root, Mon Oct 27 11:08:29 2008 UTC vs.
Revision 1.42 by root, Wed Oct 29 10:24:23 2008 UTC

… …
50 * limits the applicability over poll, so this is not a generic 50 * limits the applicability over poll, so this is not a generic
51 * poll replacement. 51 * poll replacement.
52 * 52 *
53 * lots of "weird code" and complication handling in this file is due 53 * lots of "weird code" and complication handling in this file is due
54 * to these design problems with epoll, as we try very hard to avoid 54 * to these design problems with epoll, as we try very hard to avoid
55 * epoll_ctl syscalls for common usage patterns. 55 * epoll_ctl syscalls for common usage patterns and handle the breakage
56 * ensuing from receiving events for closed and otherwise long gone
57 * file descriptors.
56 */ 58 */
57 59
58#include <sys/epoll.h> 60#include <sys/epoll.h>
59
60void inline_size
61unsigned_char_init (unsigned char *base, int count)
62{
63 /* memset might be overkill */
64 while (count--)
65 *base++ = 0;
66}
67 61
68static void 62static void
69epoll_modify (EV_P_ int fd, int oev, int nev) 63epoll_modify (EV_P_ int fd, int oev, int nev)
70{ 64{
71 struct epoll_event ev; 65 struct epoll_event ev;
… …
83 return; 77 return;
84 78
85 oldmask = anfds [fd].emask; 79 oldmask = anfds [fd].emask;
86 anfds [fd].emask = nev; 80 anfds [fd].emask = nev;
87 81
88 /* store the generation counter in the upper 32 bits */ 82 /* store the generation counter in the upper 32 bits, the fd in the lower 32 bits */
89 ev.data.u64 = fd | ((uint64_t)++anfds [fd].egen << 32); 83 ev.data.u64 = (uint64_t)(uint32_t)fd
84 | ((uint64_t)(uint32_t)++anfds [fd].egen << 32);
90 ev.events = (nev & EV_READ ? EPOLLIN : 0) 85 ev.events = (nev & EV_READ ? EPOLLIN : 0)
91 | (nev & EV_WRITE ? EPOLLOUT : 0); 86 | (nev & EV_WRITE ? EPOLLOUT : 0);
92 87
93 if (expect_true (!epoll_ctl (backend_fd, oev ? EPOLL_CTL_MOD : EPOLL_CTL_ADD, fd, &ev))) 88 if (expect_true (!epoll_ctl (backend_fd, oev ? EPOLL_CTL_MOD : EPOLL_CTL_ADD, fd, &ev)))
94 return; 89 return;
… …
127 int eventcnt = epoll_wait (backend_fd, epoll_events, epoll_eventmax, (int)ceil (timeout * 1000.)); 122 int eventcnt = epoll_wait (backend_fd, epoll_events, epoll_eventmax, (int)ceil (timeout * 1000.));
128 123
129 if (expect_false (eventcnt < 0)) 124 if (expect_false (eventcnt < 0))
130 { 125 {
131 if (errno != EINTR) 126 if (errno != EINTR)
132 syserr ("(libev) epoll_wait"); 127 ev_syserr ("(libev) epoll_wait");
133 128
134 return; 129 return;
135 } 130 }
136 131
137 for (i = 0; i < eventcnt; ++i) 132 for (i = 0; i < eventcnt; ++i)
138 { 133 {
139 struct epoll_event *ev = epoll_events + i; 134 struct epoll_event *ev = epoll_events + i;
140 135
141 int fd = (uint32_t)ev->data.u64; /* mask out the lower 32 bits */ 136 int fd = (uint32_t)ev->data.u64; /* mask out the lower 32 bits */
137 int want = anfds [fd].events;
142 int got = (ev->events & (EPOLLOUT | EPOLLERR | EPOLLHUP) ? EV_WRITE : 0) 138 int got = (ev->events & (EPOLLOUT | EPOLLERR | EPOLLHUP) ? EV_WRITE : 0)
143 | (ev->events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0); 139 | (ev->events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0);
144 int want = anfds [fd].events;
145 140
146 if (anfds [fd].egen != (unsigned char)(ev->data.u64 >> 32)) 141 /* check for spurious notification */
147 /*fprintf (stderr, "spurious notification fd %d, %d vs %d\n", fd, (int)(ev->data.u64 >> 32), anfds [fd].egen);*/ 142 if (expect_false ((uint32_t)anfds [fd].egen != (uint32_t)(ev->data.u64 >> 32)))
143 {
144 /* recreate kernel state */
145 postfork = 1;
148 continue; 146 continue;
147 }
149 148
150 if (expect_false (got & ~want)) 149 if (expect_false (got & ~want))
151 { 150 {
152 anfds [fd].emask = want; 151 anfds [fd].emask = want;
153 152
154 /* we received an event but are not interested in it, try mod or del */ 153 /* we received an event but are not interested in it, try mod or del */
155 /* I don't think we ever need MOD, but let's handle it anyways */ 154 /* I don't think we ever need MOD, but let's handle it anyways */
156 ev->events = (want & EV_READ ? EPOLLIN : 0) 155 ev->events = (want & EV_READ ? EPOLLIN : 0)
157 | (want & EV_WRITE ? EPOLLOUT : 0); 156 | (want & EV_WRITE ? EPOLLOUT : 0);
158 157
159 epoll_ctl (backend_fd, want ? EPOLL_CTL_MOD : EPOLL_CTL_DEL, fd, ev); 158 if (epoll_ctl (backend_fd, want ? EPOLL_CTL_MOD : EPOLL_CTL_DEL, fd, ev))
159 {
160 postfork = 1; /* an error occured, recreate kernel state */
161 continue;
162 }
160 } 163 }
161 164
162 fd_event (EV_A_ fd, got); 165 fd_event (EV_A_ fd, got);
163 } 166 }
164 167
… …
183 186
184 backend_fudge = 0.; /* kernel sources seem to indicate this to be zero */ 187 backend_fudge = 0.; /* kernel sources seem to indicate this to be zero */
185 backend_modify = epoll_modify; 188 backend_modify = epoll_modify;
186 backend_poll = epoll_poll; 189 backend_poll = epoll_poll;
187 190
188 epoll_eventmax = 64; /* intiial number of events receivable per poll */ 191 epoll_eventmax = 64; /* initial number of events receivable per poll */
189 epoll_events = (struct epoll_event *)ev_malloc (sizeof (struct epoll_event) * epoll_eventmax); 192 epoll_events = (struct epoll_event *)ev_malloc (sizeof (struct epoll_event) * epoll_eventmax);
190 193
191 return EVBACKEND_EPOLL; 194 return EVBACKEND_EPOLL;
192} 195}
193 196
… …
201epoll_fork (EV_P) 204epoll_fork (EV_P)
202{ 205{
203 close (backend_fd); 206 close (backend_fd);
204 207
205 while ((backend_fd = epoll_create (256)) < 0) 208 while ((backend_fd = epoll_create (256)) < 0)
206 syserr ("(libev) epoll_create"); 209 ev_syserr ("(libev) epoll_create");
207 210
208 fcntl (backend_fd, F_SETFD, FD_CLOEXEC); 211 fcntl (backend_fd, F_SETFD, FD_CLOEXEC);
209 212
210 fd_rearm_all (EV_A); 213 fd_rearm_all (EV_A);
211} 214}

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