On Fri, Jul 12, 2013 at 2:54 PM, Ben Pfaff <[email protected]> wrote:
> Signed-off-by: Ben Pfaff <[email protected]>
>
Looks good to me.
> ---
> lib/poll-loop.c | 107
> +++++++++++++++++++++++++++++++++++--------------------
> lib/poll-loop.h | 14 +++++--
> 2 files changed, 78 insertions(+), 43 deletions(-)
>
> diff --git a/lib/poll-loop.c b/lib/poll-loop.c
> index 567c19f..97fc806 100644
> --- a/lib/poll-loop.c
> +++ b/lib/poll-loop.c
> @@ -25,6 +25,7 @@
> #include "dynamic-string.h"
> #include "fatal-signal.h"
> #include "list.h"
> +#include "ovs-thread.h"
> #include "socket-util.h"
> #include "timeval.h"
> #include "vlog.h"
> @@ -39,25 +40,20 @@ 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 {
> - const char *where; /* Where the waiter was created. */
> -};
> -
> -/* All active poll waiters. */
> -static struct poll_waiter *waiters;
> -static struct pollfd *pollfds;
> -static size_t n_waiters, allocated_waiters;
> +struct poll_loop {
> + /* All active poll waiters. */
> + struct pollfd *pollfds; /* Events to pass to poll(). */
> + const char **where; /* Where each pollfd was created. */
> + size_t n_waiters; /* Number of elems in 'where' and
> 'pollfds'. */
> + size_t allocated_waiters; /* Allocated elems in 'where' and
> 'pollfds'. */
>
> -/* 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 long long int timeout_when = LLONG_MAX;
> -
> -/* Location where waiter created. */
> -static const char *timeout_where;
> + /* Time at which to wake up the next call to poll_block(), LLONG_MIN
> to
> + * wake up immediately, or LLONG_MAX to wait forever. */
> + long long int timeout_when; /* In msecs as returned by time_msec(). */
> + const char *timeout_where; /* Where 'timeout_when' was set. */
> +};
>
> -static void new_waiter(int fd, short int events, const char *where);
> +static struct poll_loop *poll_loop(void);
>
> /* Registers 'fd' as waiting for the specified 'events' (which should be
> POLLIN
> * or POLLOUT or POLLIN | POLLOUT). The following call to poll_block()
> will
> @@ -72,8 +68,21 @@ static void new_waiter(int fd, short int events, const
> char *where);
> void
> poll_fd_wait(int fd, short int events, const char *where)
> {
> + struct poll_loop *loop = poll_loop();
> +
> COVERAGE_INC(poll_fd_wait);
> - new_waiter(fd, events, where);
> + if (loop->n_waiters >= loop->allocated_waiters) {
> + loop->where = x2nrealloc(loop->where, &loop->allocated_waiters,
> + sizeof *loop->where);
> + loop->pollfds = xrealloc(loop->pollfds,
> + (loop->allocated_waiters
> + * sizeof *loop->pollfds));
> + }
> +
> + loop->where[loop->n_waiters] = where;
> + loop->pollfds[loop->n_waiters].fd = fd;
> + loop->pollfds[loop->n_waiters].events = events;
> + loop->n_waiters++;
> }
>
> /* Causes the following call to poll_block() to block for no more than
> 'msec'
> @@ -120,9 +129,10 @@ poll_timer_wait(long long int msec, const char *where)
> void
> poll_timer_wait_until(long long int when, const char *where)
> {
> - if (when < timeout_when) {
> - timeout_when = when;
> - timeout_where = where;
> + struct poll_loop *loop = poll_loop();
> + if (when < loop->timeout_when) {
> + loop->timeout_when = when;
> + loop->timeout_where = where;
> }
> }
>
> @@ -204,6 +214,7 @@ log_wakeup(const char *where, const struct pollfd
> *pollfd, int timeout)
> void
> poll_block(void)
> {
> + struct poll_loop *loop = poll_loop();
> int elapsed;
> int retval;
>
> @@ -211,44 +222,62 @@ poll_block(void)
> * poll_block. */
> fatal_signal_wait();
>
> - if (timeout_when == LLONG_MIN) {
> + if (loop->timeout_when == LLONG_MIN) {
> COVERAGE_INC(poll_zero_timeout);
> }
> - retval = time_poll(pollfds, n_waiters, timeout_when, &elapsed);
> +
> + retval = time_poll(loop->pollfds, loop->n_waiters,
> + loop->timeout_when, &elapsed);
> if (retval < 0) {
> static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
> VLOG_ERR_RL(&rl, "poll: %s", ovs_strerror(-retval));
> } else if (!retval) {
> - log_wakeup(timeout_where, NULL, elapsed);
> + log_wakeup(loop->timeout_where, NULL, elapsed);
> } else if (get_cpu_usage() > 50 || VLOG_IS_DBG_ENABLED()) {
> size_t i;
>
> - for (i = 0; i < n_waiters; i++) {
> - if (pollfds[i].revents) {
> - log_wakeup(waiters[i].where, &pollfds[i], 0);
> + for (i = 0; i < loop->n_waiters; i++) {
> + if (loop->pollfds[i].revents) {
> + log_wakeup(loop->where[i], &loop->pollfds[i], 0);
> }
> }
> }
>
> - timeout_when = LLONG_MAX;
> - timeout_where = NULL;
> - n_waiters = 0;
> + loop->timeout_when = LLONG_MAX;
> + loop->timeout_where = NULL;
> + loop->n_waiters = 0;
>
> /* Handle any pending signals before doing anything else. */
> fatal_signal_run();
> }
>
> -/* Creates and returns a new poll_waiter for 'fd' and 'events'. */
> static void
> -new_waiter(int fd, short int events, const char *where)
> +free_poll_loop(void *loop_)
> {
> - if (n_waiters >= allocated_waiters) {
> - waiters = x2nrealloc(waiters, &allocated_waiters, sizeof
> *waiters);
> - pollfds = xrealloc(pollfds, allocated_waiters * sizeof *pollfds);
> + struct poll_loop *loop = loop_;
> +
> + free(loop->pollfds);
> + free(loop->where);
> + free(loop);
> +}
> +
> +static struct poll_loop *
> +poll_loop(void)
> +{
> + static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
> + static pthread_key_t key;
> + struct poll_loop *loop;
> +
> + if (ovsthread_once_start(&once)) {
> + xpthread_key_create(&key, free_poll_loop);
> + ovsthread_once_done(&once);
> }
>
> - waiters[n_waiters].where = where;
> - pollfds[n_waiters].fd = fd;
> - pollfds[n_waiters].events = events;
> - n_waiters++;
> + loop = pthread_getspecific(key);
> + if (!loop) {
> + loop = xzalloc(sizeof *loop);
> + pthread_setspecific(key, loop);
> + }
> + return loop;
> }
> +
> diff --git a/lib/poll-loop.h b/lib/poll-loop.h
> index 6c78bbd..6614ebe 100644
> --- a/lib/poll-loop.h
> +++ b/lib/poll-loop.h
> @@ -1,5 +1,5 @@
> /*
> - * Copyright (c) 2008, 2009, 2010, 2011 Nicira, Inc.
> + * Copyright (c) 2008, 2009, 2010, 2011, 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.
> @@ -16,14 +16,20 @@
>
> /* High-level wrapper around the "poll" system call.
> *
> - * Intended usage is for the program's main loop to go about its business
> + * The intended usage is for each thread's main loop to go about its
> business
> * servicing whatever events it needs to. Then, when it runs out of
> immediate
> * tasks, it calls each subordinate module's "wait" function, which in
> turn
> * calls one (or more) of the functions poll_fd_wait(),
> poll_immediate_wake(),
> * and poll_timer_wait() to register to be awakened when the appropriate
> event
> * occurs. Then the main loop calls poll_block(), which blocks until one
> of
> - * the registered events happens. */
> -
> + * the registered events happens.
> + *
> + *
> + * Thread-safety
> + * =============
> + *
> + * The poll set is per-thread, so all functions in this module are
> thread-safe.
> + */
> #ifndef POLL_LOOP_H
> #define POLL_LOOP_H 1
>
> --
> 1.7.2.5
>
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> [email protected]
> http://openvswitch.org/mailman/listinfo/dev
>
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