X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Fpoll-loop.c;h=9855306834cf47744d52ec2d8cc87abb59b1d4eb;hb=7431e17196fdb1c3189d67e3aeed4adeab4cf479;hp=c944477dcead6f3d461325980a7721418f405bce;hpb=b2fda3effc787f265b5ad5dfa967ac00627bd075;p=sliver-openvswitch.git diff --git a/lib/poll-loop.c b/lib/poll-loop.c index c944477dc..985530683 100644 --- a/lib/poll-loop.c +++ b/lib/poll-loop.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks. + * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -16,7 +16,6 @@ #include #include "poll-loop.h" -#include #include #include #include @@ -55,12 +54,10 @@ struct poll_waiter { /* 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; @@ -85,16 +82,6 @@ poll_fd_wait(int fd, short int events, const char *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. @@ -108,14 +95,25 @@ poll_timer_wait__(int msec, const char *where) 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. * @@ -126,13 +124,12 @@ poll_timer_wait(long long int msec, const char *where) * 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 @@ -146,23 +143,71 @@ poll_immediate_wake(const char *where) 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() @@ -175,13 +220,15 @@ poll_block(void) 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); @@ -196,33 +243,25 @@ poll_block(void) 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); + } 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. */ @@ -241,7 +280,6 @@ poll_cancel(struct poll_waiter *pw) if (pw) { list_remove(&pw->node); free(pw); - n_waiters--; } } @@ -250,11 +288,10 @@ static struct poll_waiter * 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; }