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poll-loop: Make poll loop data structures per-thread.

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Signed-off-by: Ben Pfaff <blp@nicira.com>
This commit is contained in:
Ben Pfaff
2013-07-10 10:54:41 -07:00
parent 8f6c3ad72f
commit 2c06a96604
2 changed files with 78 additions and 44 deletions
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108
lib/poll-loop.c
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@@ -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. */
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(), 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. */
};
/* All active poll waiters. */
static struct poll_waiter *waiters;
static struct pollfd *pollfds;
static size_t n_waiters, allocated_waiters;
/* 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;
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;
@@ -211,45 +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 a new poll_waiter for 'fd' and 'events', recording 'where' as the
* location where the event was registered. */
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;
}