ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/libev/ev_epoll.c
(Generate patch)

Comparing libev/ev_epoll.c (file contents):
Revision 1.36 by root, Mon Oct 27 11:08:29 2008 UTC vs.
Revision 1.47 by root, Sun Jul 19 04:11:27 2009 UTC

1/* 1/*
2 * libev epoll fd activity backend 2 * libev epoll fd activity backend
3 * 3 *
4 * Copyright (c) 2007,2008 Marc Alexander Lehmann <libev@schmorp.de> 4 * Copyright (c) 2007,2008,2009 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 *
… …
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;
… …
74 /* 68 /*
75 * we handle EPOLL_CTL_DEL by ignoring it here 69 * we handle EPOLL_CTL_DEL by ignoring it here
76 * on the assumption that the fd is gone anyways 70 * on the assumption that the fd is gone anyways
77 * if that is wrong, we have to handle the spurious 71 * if that is wrong, we have to handle the spurious
78 * event in epoll_poll. 72 * event in epoll_poll.
79 * the fd is later added, we try to ADD it, and, if that 73 * if the fd is added again, we try to ADD it, and, if that
80 * fails, we assume it still has the same eventmask. 74 * fails, we assume it still has the same eventmask.
81 */ 75 */
82 if (!nev) 76 if (!nev)
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;
… …
122 117
123static void 118static void
124epoll_poll (EV_P_ ev_tstamp timeout) 119epoll_poll (EV_P_ ev_tstamp timeout)
125{ 120{
126 int i; 121 int i;
122 int eventcnt;
123
124 EV_RELEASE_CB;
127 int eventcnt = epoll_wait (backend_fd, epoll_events, epoll_eventmax, (int)ceil (timeout * 1000.)); 125 eventcnt = epoll_wait (backend_fd, epoll_events, epoll_eventmax, (int)ceil (timeout * 1000.));
126 EV_ACQUIRE_CB;
128 127
129 if (expect_false (eventcnt < 0)) 128 if (expect_false (eventcnt < 0))
130 { 129 {
131 if (errno != EINTR) 130 if (errno != EINTR)
132 syserr ("(libev) epoll_wait"); 131 ev_syserr ("(libev) epoll_wait");
133 132
134 return; 133 return;
135 } 134 }
136 135
137 for (i = 0; i < eventcnt; ++i) 136 for (i = 0; i < eventcnt; ++i)
138 { 137 {
139 struct epoll_event *ev = epoll_events + i; 138 struct epoll_event *ev = epoll_events + i;
140 139
141 int fd = (uint32_t)ev->data.u64; /* mask out the lower 32 bits */ 140 int fd = (uint32_t)ev->data.u64; /* mask out the lower 32 bits */
141 int want = anfds [fd].events;
142 int got = (ev->events & (EPOLLOUT | EPOLLERR | EPOLLHUP) ? EV_WRITE : 0) 142 int got = (ev->events & (EPOLLOUT | EPOLLERR | EPOLLHUP) ? EV_WRITE : 0)
143 | (ev->events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0); 143 | (ev->events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0);
144 int want = anfds [fd].events;
145 144
146 if (anfds [fd].egen != (unsigned char)(ev->data.u64 >> 32)) 145 /* check for spurious notification */
147 /*fprintf (stderr, "spurious notification fd %d, %d vs %d\n", fd, (int)(ev->data.u64 >> 32), anfds [fd].egen);*/ 146 if (expect_false ((uint32_t)anfds [fd].egen != (uint32_t)(ev->data.u64 >> 32)))
147 {
148 /* recreate kernel state */
149 postfork = 1;
148 continue; 150 continue;
151 }
149 152
150 if (expect_false (got & ~want)) 153 if (expect_false (got & ~want))
151 { 154 {
152 anfds [fd].emask = want; 155 anfds [fd].emask = want;
153 156
154 /* we received an event but are not interested in it, try mod or del */ 157 /* 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 */ 158 /* I don't think we ever need MOD, but let's handle it anyways */
156 ev->events = (want & EV_READ ? EPOLLIN : 0) 159 ev->events = (want & EV_READ ? EPOLLIN : 0)
157 | (want & EV_WRITE ? EPOLLOUT : 0); 160 | (want & EV_WRITE ? EPOLLOUT : 0);
158 161
159 epoll_ctl (backend_fd, want ? EPOLL_CTL_MOD : EPOLL_CTL_DEL, fd, ev); 162 if (epoll_ctl (backend_fd, want ? EPOLL_CTL_MOD : EPOLL_CTL_DEL, fd, ev))
163 {
164 postfork = 1; /* an error occured, recreate kernel state */
165 continue;
166 }
160 } 167 }
161 168
162 fd_event (EV_A_ fd, got); 169 fd_event (EV_A_ fd, got);
163 } 170 }
164 171
… …
172} 179}
173 180
174int inline_size 181int inline_size
175epoll_init (EV_P_ int flags) 182epoll_init (EV_P_ int flags)
176{ 183{
184#ifdef EPOLL_CLOEXEC
185 backend_fd = epoll_create1 (EPOLL_CLOEXEC);
186
187 if (backend_fd <= 0)
188#endif
177 backend_fd = epoll_create (256); 189 backend_fd = epoll_create (256);
178 190
179 if (backend_fd < 0) 191 if (backend_fd < 0)
180 return 0; 192 return 0;
181 193
182 fcntl (backend_fd, F_SETFD, FD_CLOEXEC); 194 fcntl (backend_fd, F_SETFD, FD_CLOEXEC);
183 195
184 backend_fudge = 0.; /* kernel sources seem to indicate this to be zero */ 196 backend_fudge = 0.; /* kernel sources seem to indicate this to be zero */
185 backend_modify = epoll_modify; 197 backend_modify = epoll_modify;
186 backend_poll = epoll_poll; 198 backend_poll = epoll_poll;
187 199
188 epoll_eventmax = 64; /* intiial number of events receivable per poll */ 200 epoll_eventmax = 64; /* initial number of events receivable per poll */
189 epoll_events = (struct epoll_event *)ev_malloc (sizeof (struct epoll_event) * epoll_eventmax); 201 epoll_events = (struct epoll_event *)ev_malloc (sizeof (struct epoll_event) * epoll_eventmax);
190 202
191 return EVBACKEND_EPOLL; 203 return EVBACKEND_EPOLL;
192} 204}
193 205
… …
201epoll_fork (EV_P) 213epoll_fork (EV_P)
202{ 214{
203 close (backend_fd); 215 close (backend_fd);
204 216
205 while ((backend_fd = epoll_create (256)) < 0) 217 while ((backend_fd = epoll_create (256)) < 0)
206 syserr ("(libev) epoll_create"); 218 ev_syserr ("(libev) epoll_create");
207 219
208 fcntl (backend_fd, F_SETFD, FD_CLOEXEC); 220 fcntl (backend_fd, F_SETFD, FD_CLOEXEC);
209 221
210 fd_rearm_all (EV_A); 222 fd_rearm_all (EV_A);
211} 223}

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines