/*
- * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include <config.h>
#include "poll-loop.h"
-#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <poll.h>
/* All active poll waiters. */
static struct list waiters = LIST_INITIALIZER(&waiters);
-/* Number of elements in the waiters list. */
-static size_t n_waiters;
-
-/* Max time to wait in next call to poll_block(), in milliseconds, or -1 to
+/* Time at which to wake up the next call to poll_block(), in milliseconds as
+ * returned by time_msec(), LLONG_MIN to wake up immediately, or LLONG_MAX to
* wait forever. */
-static int timeout = -1;
+static long long int timeout_when = LLONG_MAX;
/* Location where waiter created. */
static const char *timeout_where;
return new_waiter(fd, events, where);
}
-/* The caller must ensure that 'msec' is not negative. */
-static void
-poll_timer_wait__(int msec, const char *where)
-{
- if (timeout < 0 || msec < timeout) {
- timeout = msec;
- timeout_where = where;
- }
-}
-
/* Causes the following call to poll_block() to block for no more than 'msec'
* milliseconds. If 'msec' is nonpositive, the following call to poll_block()
* will not block at all.
void
poll_timer_wait(long long int msec, const char *where)
{
- poll_timer_wait__((msec < 0 ? 0
- : msec > INT_MAX ? INT_MAX
- : msec),
- where);
+ long long int now = time_msec();
+ long long int when;
+
+ if (msec <= 0) {
+ /* Wake up immediately. */
+ when = LLONG_MIN;
+ } else if ((unsigned long long int) now + msec <= LLONG_MAX) {
+ /* Normal case. */
+ when = now + msec;
+ } else {
+ /* now + msec would overflow. */
+ when = LLONG_MAX;
+ }
+
+ poll_timer_wait_until(when, where);
}
/* Causes the following call to poll_block() to wake up when the current time,
- * as returned by time_msec(), reaches 'msec' or later. If 'msec' is earlier
+ * as returned by time_msec(), reaches 'when' or later. If 'when' is earlier
* than the current time, the following call to poll_block() will not block at
* all.
*
* Ordinarily the 'where' argument is supplied automatically; see poll-loop.h
* for more information. */
void
-poll_timer_wait_until(long long int msec, const char *where)
+poll_timer_wait_until(long long int when, const char *where)
{
- long long int now = time_msec();
- poll_timer_wait__((msec <= now ? 0
- : msec < now + INT_MAX ? msec - now
- : INT_MAX),
- where);
+ if (when < timeout_when) {
+ timeout_when = when;
+ timeout_where = where;
+ }
}
/* Causes the following call to poll_block() to wake up immediately, without
poll_timer_wait(0, where);
}
-static void PRINTF_FORMAT(2, 3)
-log_wakeup(const char *where, const char *format, ...)
+/* Logs, if appropriate, that the poll loop was awakened by an event
+ * registered at 'where' (typically a source file and line number). The other
+ * arguments have two possible interpretations:
+ *
+ * - If 'pollfd' is nonnull then it should be the "struct pollfd" that caused
+ * the wakeup. 'timeout' is ignored.
+ *
+ * - If 'pollfd' is NULL then 'timeout' is the number of milliseconds after
+ * which the poll loop woke up.
+ */
+static void
+log_wakeup(const char *where, const struct pollfd *pollfd, int timeout)
{
- struct ds ds;
- va_list args;
+ static struct vlog_rate_limit trace_rl = VLOG_RATE_LIMIT_INIT(1, 1);
+ static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 10);
+ enum vlog_level level;
+ int cpu_usage;
+ struct ds s;
- ds_init(&ds);
- va_start(args, format);
- ds_put_format_valist(&ds, format, args);
- va_end(args);
+ cpu_usage = get_cpu_usage();
+ if (VLOG_IS_DBG_ENABLED()) {
+ level = VLL_DBG;
+ } else if (cpu_usage > 50 && !VLOG_DROP_INFO(&rl)) {
+ level = VLL_INFO;
+ } else {
+ return;
+ }
+ ds_init(&s);
+ ds_put_cstr(&s, "wakeup due to ");
+ if (pollfd) {
+ char *description = describe_fd(pollfd->fd);
+ if (pollfd->revents & POLLIN) {
+ ds_put_cstr(&s, "[POLLIN]");
+ }
+ if (pollfd->revents & POLLOUT) {
+ ds_put_cstr(&s, "[POLLOUT]");
+ }
+ if (pollfd->revents & POLLERR) {
+ ds_put_cstr(&s, "[POLLERR]");
+ }
+ if (pollfd->revents & POLLHUP) {
+ ds_put_cstr(&s, "[POLLHUP]");
+ }
+ if (pollfd->revents & POLLNVAL) {
+ ds_put_cstr(&s, "[POLLNVAL]");
+ }
+ ds_put_format(&s, " on fd %d (%s)", pollfd->fd, description);
+ free(description);
+ } else {
+ ds_put_format(&s, "%d-ms timeout", timeout);
+ }
if (where) {
- ds_put_format(&ds, " at %s", where);
+ ds_put_format(&s, " at %s", where);
}
+ if (cpu_usage >= 0) {
+ ds_put_format(&s, " (%d%% CPU usage)", cpu_usage);
- VLOG_DBG("%s", ds_cstr(&ds));
- ds_destroy(&ds);
+ if (!vlog_should_drop(THIS_MODULE, level, &trace_rl)) {
+ ds_put_char(&s, '\n');
+ format_backtraces(&s, 2);
+ }
+ }
+ VLOG(level, "%s", ds_cstr(&s));
+ ds_destroy(&s);
}
/* Blocks until one or more of the events registered with poll_fd_wait()
static size_t max_pollfds;
struct poll_waiter *pw, *next;
- int n_pollfds;
+ int n_waiters, n_pollfds;
+ int elapsed;
int retval;
/* Register fatal signal events before actually doing any real work for
* poll_block. */
fatal_signal_wait();
+ n_waiters = list_size(&waiters);
if (max_pollfds < n_waiters) {
max_pollfds = n_waiters;
pollfds = xrealloc(pollfds, max_pollfds * sizeof *pollfds);
n_pollfds++;
}
- if (!timeout) {
+ if (timeout_when == LLONG_MIN) {
COVERAGE_INC(poll_zero_timeout);
}
- retval = time_poll(pollfds, n_pollfds, timeout);
+ retval = time_poll(pollfds, n_pollfds, timeout_when, &elapsed);
if (retval < 0) {
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
- VLOG_ERR_RL(&rl, "poll: %s", strerror(-retval));
- } else if (!retval && VLOG_IS_DBG_ENABLED()) {
- log_wakeup(timeout_where, "%d-ms timeout", timeout);
+ VLOG_ERR_RL(&rl, "poll: %s", ovs_strerror(-retval));
+ } else if (!retval) {
+ log_wakeup(timeout_where, NULL, elapsed);
}
LIST_FOR_EACH_SAFE (pw, next, node, &waiters) {
- if (pw->pollfd->revents && VLOG_IS_DBG_ENABLED()) {
- char *description = describe_fd(pw->fd);
- log_wakeup(pw->where, "%s%s%s%s%s on fd %d (%s)",
- pw->pollfd->revents & POLLIN ? "[POLLIN]" : "",
- pw->pollfd->revents & POLLOUT ? "[POLLOUT]" : "",
- pw->pollfd->revents & POLLERR ? "[POLLERR]" : "",
- pw->pollfd->revents & POLLHUP ? "[POLLHUP]" : "",
- pw->pollfd->revents & POLLNVAL ? "[POLLNVAL]" : "",
- pw->fd, description);
- free(description);
+ if (pw->pollfd->revents) {
+ log_wakeup(pw->where, pw->pollfd, 0);
}
poll_cancel(pw);
}
- timeout = -1;
+ timeout_when = LLONG_MAX;
timeout_where = NULL;
/* Handle any pending signals before doing anything else. */
if (pw) {
list_remove(&pw->node);
free(pw);
- n_waiters--;
}
}
\f
new_waiter(int fd, short int events, const char *where)
{
struct poll_waiter *waiter = xzalloc(sizeof *waiter);
- assert(fd >= 0);
+ ovs_assert(fd >= 0);
waiter->fd = fd;
waiter->events = events;
waiter->where = where;
list_push_back(&waiters, &waiter->node);
- n_waiters++;
return waiter;
}
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