2 * Copyright (c) 2008, 2009, 2010, 2011, 2013 Nicira, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 /* High-level wrapper around the "poll" system call.
19 * The intended usage is for each thread's main loop to go about its business
20 * servicing whatever events it needs to. Then, when it runs out of immediate
21 * tasks, it calls each subordinate module's "wait" function, which in turn
22 * calls one (or more) of the functions poll_fd_wait(), poll_immediate_wake(),
23 * and poll_timer_wait() to register to be awakened when the appropriate event
24 * occurs. Then the main loop calls poll_block(), which blocks until one of
25 * the registered events happens.
31 * The poll set is per-thread, so all functions in this module are thread-safe.
44 /* Schedule events to wake up the following poll_block().
46 * The poll_loop logs the 'where' argument to each function at "debug" level
47 * when an event causes a wakeup. Ordinarily, it is automatically filled in
48 * with the location in the source of the call, and the caller should therefore
49 * omit it. But, if the function you are implementing is very generic, so that
50 * its location in the source would not be very helpful for debugging, you can
51 * avoid the macro expansion and pass a different argument, e.g.:
52 * (poll_fd_wait)(fd, events, where);
53 * See timer_wait() for an example.
55 void poll_fd_wait(int fd, short int events, const char *where);
56 #define poll_fd_wait(fd, events) poll_fd_wait(fd, events, SOURCE_LOCATOR)
58 void poll_timer_wait(long long int msec, const char *where);
59 #define poll_timer_wait(msec) poll_timer_wait(msec, SOURCE_LOCATOR)
61 void poll_timer_wait_until(long long int msec, const char *where);
62 #define poll_timer_wait_until(msec) poll_timer_wait_until(msec, SOURCE_LOCATOR)
64 void poll_immediate_wake(const char *where);
65 #define poll_immediate_wake() poll_immediate_wake(SOURCE_LOCATOR)
67 /* Wait until an event occurs. */
68 void poll_block(void);
74 #endif /* poll-loop.h */