/*
- * Copyright (c) 2008, 2009 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>
#include <stdlib.h>
#include <string.h>
-#include "backtrace.h"
#include "coverage.h"
#include "dynamic-string.h"
#include "fatal-signal.h"
#include "list.h"
+#include "socket-util.h"
#include "timeval.h"
-
-#define THIS_MODULE VLM_poll_loop
#include "vlog.h"
+#undef poll_fd_wait
+#undef poll_timer_wait
+#undef poll_timer_wait_until
+#undef poll_immediate_wake
+
+VLOG_DEFINE_THIS_MODULE(poll_loop);
+
+COVERAGE_DEFINE(poll_fd_wait);
+COVERAGE_DEFINE(poll_zero_timeout);
+
/* An event that will wake the following call to poll_block(). */
struct poll_waiter {
/* Set when the waiter is created. */
struct list node; /* Element in global waiters list. */
int fd; /* File descriptor. */
short int events; /* Events to wait for (POLLIN, POLLOUT). */
- poll_fd_func *function; /* Callback function, if any, or null. */
- void *aux; /* Argument to callback function. */
- struct backtrace *backtrace; /* Optionally, event that created waiter. */
+ const char *where; /* Where the waiter was created. */
/* Set only when poll_block() is called. */
- struct pollfd *pollfd; /* Pointer to element of the pollfds array
- (null if added from a callback). */
+ struct pollfd *pollfd; /* Pointer to element of the pollfds array. */
};
/* 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;
-
-/* Backtrace of 'timeout''s registration, if debugging is enabled. */
-static struct backtrace timeout_backtrace;
+static long long int timeout_when = LLONG_MAX;
-/* Callback currently running, to allow verifying that poll_cancel() is not
- * being called on a running callback. */
-#ifndef NDEBUG
-static struct poll_waiter *running_cb;
-#endif
+/* Location where waiter created. */
+static const char *timeout_where;
-static struct poll_waiter *new_waiter(int fd, short int events);
+static struct poll_waiter *new_waiter(int fd, short int events,
+ const char *where);
/* Registers 'fd' as waiting for the specified 'events' (which should be POLLIN
* or POLLOUT or POLLIN | POLLOUT). The following call to poll_block() will
*
* The event registration is one-shot: only the following call to poll_block()
* is affected. The event will need to be re-registered after poll_block() is
- * called if it is to persist. */
+ * called if it is to persist.
+ *
+ * Ordinarily the 'where' argument is supplied automatically; see poll-loop.h
+ * for more information. */
struct poll_waiter *
-poll_fd_wait(int fd, short int events)
+poll_fd_wait(int fd, short int events, const char *where)
{
COVERAGE_INC(poll_fd_wait);
- return new_waiter(fd, events);
+ return new_waiter(fd, events, where);
}
/* Causes the following call to poll_block() to block for no more than 'msec'
*
* The timer registration is one-shot: only the following call to poll_block()
* is affected. The timer will need to be re-registered after poll_block() is
- * called if it is to persist. */
+ * called if it is to persist.
+ *
+ * Ordinarily the 'where' argument is supplied automatically; see poll-loop.h
+ * for more information. */
void
-poll_timer_wait(int msec)
+poll_timer_wait(long long int msec, const char *where)
{
- if (timeout < 0 || msec < timeout) {
- timeout = MAX(0, msec);
- if (VLOG_IS_DBG_ENABLED()) {
- backtrace_capture(&timeout_backtrace);
- }
+ 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 'when' or later. If 'when' is earlier
+ * than the current time, the following call to poll_block() will not block at
+ * all.
+ *
+ * The timer registration is one-shot: only the following call to poll_block()
+ * is affected. The timer will need to be re-registered after poll_block() is
+ * called if it is to persist.
+ *
+ * Ordinarily the 'where' argument is supplied automatically; see poll-loop.h
+ * for more information. */
+void
+poll_timer_wait_until(long long int when, const char *where)
+{
+ if (when < timeout_when) {
+ timeout_when = when;
+ timeout_where = where;
}
}
/* Causes the following call to poll_block() to wake up immediately, without
- * blocking. */
+ * blocking.
+ *
+ * Ordinarily the 'where' argument is supplied automatically; see poll-loop.h
+ * for more information. */
void
-poll_immediate_wake(void)
+poll_immediate_wake(const char *where)
{
- poll_timer_wait(0);
+ poll_timer_wait(0, where);
}
-static void PRINTF_FORMAT(2, 3)
-log_wakeup(const struct backtrace *backtrace, 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;
+ }
- if (backtrace) {
- int i;
+ 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(&s, " at %s", where);
+ }
+ if (cpu_usage >= 0) {
+ ds_put_format(&s, " (%d%% CPU usage)", cpu_usage);
- ds_put_char(&ds, ':');
- for (i = 0; i < backtrace->n_frames; i++) {
- ds_put_format(&ds, " 0x%"PRIxPTR, backtrace->frames[i]);
+ if (!vlog_should_drop(THIS_MODULE, level, &trace_rl)) {
+ ds_put_char(&s, '\n');
+ format_backtraces(&s, 2);
}
}
- VLOG_DBG("%s", ds_cstr(&ds));
- ds_destroy(&ds);
+ VLOG(level, "%s", ds_cstr(&s));
+ ds_destroy(&s);
}
/* Blocks until one or more of the events registered with poll_fd_wait()
* occurs, or until the minimum duration registered with poll_timer_wait()
- * elapses, or not at all if poll_immediate_wake() has been called.
- *
- * Also executes any autonomous subroutines registered with poll_fd_callback(),
- * if their file descriptors have become ready. */
+ * elapses, or not at all if poll_immediate_wake() has been called. */
void
poll_block(void)
{
static struct pollfd *pollfds;
static size_t max_pollfds;
- struct poll_waiter *pw;
- struct list *node;
- int n_pollfds;
+ struct poll_waiter *pw, *next;
+ 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();
- assert(!running_cb);
+ n_waiters = list_size(&waiters);
if (max_pollfds < n_waiters) {
max_pollfds = n_waiters;
pollfds = xrealloc(pollfds, max_pollfds * sizeof *pollfds);
}
n_pollfds = 0;
- LIST_FOR_EACH (pw, struct poll_waiter, node, &waiters) {
+ LIST_FOR_EACH (pw, node, &waiters) {
pw->pollfd = &pollfds[n_pollfds];
pollfds[n_pollfds].fd = pw->fd;
pollfds[n_pollfds].events = pw->events;
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_backtrace, "%d-ms timeout", timeout);
+ VLOG_ERR_RL(&rl, "poll: %s", ovs_strerror(-retval));
+ } else if (!retval) {
+ log_wakeup(timeout_where, NULL, elapsed);
}
- for (node = waiters.next; node != &waiters; ) {
- pw = CONTAINER_OF(node, struct poll_waiter, node);
- if (!pw->pollfd || !pw->pollfd->revents) {
- if (pw->function) {
- node = node->next;
- continue;
- }
- } else {
- if (VLOG_IS_DBG_ENABLED()) {
- log_wakeup(pw->backtrace, "%s%s%s%s%s on fd %d",
- 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);
- }
-
- if (pw->function) {
-#ifndef NDEBUG
- running_cb = pw;
-#endif
- pw->function(pw->fd, pw->pollfd->revents, pw->aux);
-#ifndef NDEBUG
- running_cb = NULL;
-#endif
- }
+ LIST_FOR_EACH_SAFE (pw, next, node, &waiters) {
+ if (pw->pollfd->revents) {
+ log_wakeup(pw->where, pw->pollfd, 0);
}
- node = node->next;
poll_cancel(pw);
}
- timeout = -1;
- timeout_backtrace.n_frames = 0;
+ timeout_when = LLONG_MAX;
+ timeout_where = NULL;
/* Handle any pending signals before doing anything else. */
fatal_signal_run();
}
-/* Registers 'function' to be called with argument 'aux' by poll_block() when
- * 'fd' becomes ready for one of the events in 'events', which should be POLLIN
- * or POLLOUT or POLLIN | POLLOUT.
- *
- * The callback registration persists until the event actually occurs. At that
- * point, it is automatically de-registered. The callback function must
- * re-register the event by calling poll_fd_callback() again within the
- * callback, if it wants to be called back again later. */
-struct poll_waiter *
-poll_fd_callback(int fd, short int events, poll_fd_func *function, void *aux)
-{
- struct poll_waiter *pw = new_waiter(fd, events);
- pw->function = function;
- pw->aux = aux;
- return pw;
-}
-
-/* Cancels the file descriptor event registered with poll_fd_wait() or
- * poll_fd_callback(). 'pw' must be the struct poll_waiter returned by one of
- * those functions.
+/* Cancels the file descriptor event registered with poll_fd_wait() using 'pw',
+ * the struct poll_waiter returned by that function.
*
* An event registered with poll_fd_wait() may be canceled from its time of
* registration until the next call to poll_block(). At that point, the event
- * is automatically canceled by the system and its poll_waiter is freed.
- *
- * An event registered with poll_fd_callback() may be canceled from its time of
- * registration until its callback is actually called. At that point, the
- * event is automatically canceled by the system and its poll_waiter is
- * freed. */
+ * is automatically canceled by the system and its poll_waiter is freed. */
void
poll_cancel(struct poll_waiter *pw)
{
if (pw) {
- assert(pw != running_cb);
list_remove(&pw->node);
- free(pw->backtrace);
free(pw);
- n_waiters--;
}
}
\f
/* Creates and returns a new poll_waiter for 'fd' and 'events'. */
static struct poll_waiter *
-new_waiter(int fd, short int events)
+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;
- if (VLOG_IS_DBG_ENABLED()) {
- waiter->backtrace = xmalloc(sizeof *waiter->backtrace);
- backtrace_capture(waiter->backtrace);
- }
+ waiter->where = where;
list_push_back(&waiters, &waiter->node);
- n_waiters++;
return waiter;
}
git://git.onelab.eu / sliver-openvswitch.git / blobdiff