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mirror of https://gitlab.nic.cz/labs/bird.git synced 2024-11-10 13:18:42 +00:00
bird/sysdep/unix/io-loop.c
Maria Matejka 84c298465f Decoupling loops from threads to allow fixed thread count
On large configurations, too many threads would spawn with one thread
per loop. Therefore, threads may now run multiple loops at once. The
thread count is configurable and may be changed during run. All threads
are spawned on startup.

This change helps with memory bloating. BIRD filters need large
temporary memory blocks to store their stack and also memory management
keeps its hot page storage per-thread.

Known bugs:
* Thread autobalancing is not yet implemented.
* Low latency loops are executed together with standard loops.
2023-01-19 11:13:50 +01:00

1016 lines
22 KiB
C

/*
* BIRD -- I/O and event loop
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <pthread.h>
#include <time.h>
#include <sys/time.h>
#include "nest/bird.h"
#include "lib/buffer.h"
#include "lib/lists.h"
#include "lib/locking.h"
#include "lib/resource.h"
#include "lib/event.h"
#include "lib/timer.h"
#include "lib/socket.h"
#include "lib/io-loop.h"
#include "sysdep/unix/io-loop.h"
#include "conf/conf.h"
#include "nest/cli.h"
#define THREAD_STACK_SIZE 65536 /* To be lowered in near future */
/*
* Nanosecond time for accounting purposes
*
* A fixed point on startup is set as zero, all other values are relative to that.
* Caution: this overflows after like 500 years or so. If you plan to run
* BIRD for such a long time, please implement some means of overflow prevention.
*/
static struct timespec ns_begin;
static void ns_init(void)
{
if (clock_gettime(CLOCK_MONOTONIC, &ns_begin))
bug("clock_gettime: %m");
}
static u64 ns_now(void)
{
struct timespec ts;
if (clock_gettime(CLOCK_MONOTONIC, &ts))
bug("clock_gettime: %m");
return (u64) (ts.tv_sec - ns_begin.tv_sec) * 1000000000 + ts.tv_nsec - ns_begin.tv_nsec;
}
/*
* Current thread context
*/
_Thread_local struct birdloop *birdloop_current;
static _Thread_local struct birdloop *birdloop_wakeup_masked;
static _Thread_local uint birdloop_wakeup_masked_count;
event_list *
birdloop_event_list(struct birdloop *loop)
{
return &loop->event_list;
}
struct timeloop *
birdloop_time_loop(struct birdloop *loop)
{
return &loop->time;
}
_Bool
birdloop_inside(struct birdloop *loop)
{
for (struct birdloop *c = birdloop_current; c; c = c->prev_loop)
if (loop == c)
return 1;
return 0;
}
_Bool
birdloop_in_this_thread(struct birdloop *loop)
{
return pthread_equal(pthread_self(), loop->thread->thread_id);
}
void
birdloop_flag(struct birdloop *loop, u32 flag)
{
atomic_fetch_or_explicit(&loop->flags, flag, memory_order_acq_rel);
birdloop_ping(loop);
}
void
birdloop_flag_set_handler(struct birdloop *loop, struct birdloop_flag_handler *fh)
{
ASSERT_DIE(birdloop_inside(loop));
loop->flag_handler = fh;
}
static int
birdloop_process_flags(struct birdloop *loop)
{
if (!loop->flag_handler)
return 0;
u32 flags = atomic_exchange_explicit(&loop->flags, 0, memory_order_acq_rel);
if (!flags)
return 0;
loop->flag_handler->hook(loop->flag_handler, flags);
return 1;
}
/*
* Wakeup code for birdloop
*/
void
pipe_new(struct pipe *p)
{
int rv = pipe(p->fd);
if (rv < 0)
die("pipe: %m");
if (fcntl(p->fd[0], F_SETFL, O_NONBLOCK) < 0)
die("fcntl(O_NONBLOCK): %m");
if (fcntl(p->fd[1], F_SETFL, O_NONBLOCK) < 0)
die("fcntl(O_NONBLOCK): %m");
}
void
pipe_drain(struct pipe *p)
{
while (1) {
char buf[64];
int rv = read(p->fd[0], buf, sizeof(buf));
if ((rv < 0) && (errno == EAGAIN))
return;
if (rv == 0)
bug("wakeup read eof");
if ((rv < 0) && (errno != EINTR))
bug("wakeup read: %m");
}
}
int
pipe_read_one(struct pipe *p)
{
while (1) {
char v;
int rv = read(p->fd[0], &v, sizeof(v));
if (rv == 1)
return 1;
if ((rv < 0) && (errno == EAGAIN))
return 0;
if (rv > 1)
bug("wakeup read more bytes than expected: %d", rv);
if (rv == 0)
bug("wakeup read eof");
if (errno != EINTR)
bug("wakeup read: %m");
}
}
void
pipe_kick(struct pipe *p)
{
char v = 1;
int rv;
while (1) {
rv = write(p->fd[1], &v, sizeof(v));
if ((rv >= 0) || (errno == EAGAIN))
return;
if (errno != EINTR)
bug("wakeup write: %m");
}
}
void
pipe_pollin(struct pipe *p, struct pollfd *pfd)
{
pfd->fd = p->fd[0];
pfd->events = POLLIN;
pfd->revents = 0;
}
static inline void
wakeup_init(struct bird_thread *loop)
{
pipe_new(&loop->wakeup);
}
static inline void
wakeup_drain(struct bird_thread *loop)
{
pipe_drain(&loop->wakeup);
}
static inline void
wakeup_do_kick(struct bird_thread *loop)
{
pipe_kick(&loop->wakeup);
}
static inline void
birdloop_do_ping(struct birdloop *loop)
{
if (!loop->thread)
return;
if (atomic_fetch_add_explicit(&loop->thread->ping_sent, 1, memory_order_acq_rel))
return;
if (loop == birdloop_wakeup_masked)
birdloop_wakeup_masked_count++;
else
wakeup_do_kick(loop->thread);
}
void
birdloop_ping(struct birdloop *loop)
{
if (birdloop_inside(loop) && !loop->ping_pending)
loop->ping_pending++;
else
birdloop_do_ping(loop);
}
/*
* Sockets
*/
static void
sockets_init(struct birdloop *loop)
{
init_list(&loop->sock_list);
loop->sock_num = 0;
}
static void
sockets_add(struct birdloop *loop, sock *s)
{
add_tail(&loop->sock_list, &s->n);
loop->sock_num++;
s->index = -1;
if (loop->thread)
atomic_store_explicit(&loop->thread->poll_changed, 1, memory_order_release);
birdloop_ping(loop);
}
void
sk_start(sock *s)
{
ASSERT_DIE(birdloop_current != &main_birdloop);
sockets_add(birdloop_current, s);
}
static void
sockets_remove(struct birdloop *loop, sock *s)
{
if (!enlisted(&s->n))
return;
/* Decouple the socket from the loop at all. */
rem_node(&s->n);
loop->sock_num--;
if (loop->thread)
atomic_store_explicit(&loop->thread->poll_changed, 1, memory_order_release);
s->index = -1;
/* Close the filedescriptor. If it ever gets into the poll(), it just returns
* POLLNVAL for this fd which then is ignored because nobody checks for
* that result. Or some other routine opens another fd, getting this number,
* yet also in this case poll() at worst spuriously returns and nobody checks
* for the result in this fd. No further precaution is needed. */
close(s->fd);
}
void
sk_stop(sock *s)
{
sockets_remove(birdloop_current, s);
}
static inline uint sk_want_events(sock *s)
{ return (s->rx_hook ? POLLIN : 0) | ((s->ttx != s->tpos) ? POLLOUT : 0); }
static struct pollfd *
sockets_prepare(struct birdloop *loop, struct pollfd *pfd, struct pollfd *end)
{
node *n;
loop->pfd = pfd;
WALK_LIST(n, loop->sock_list)
{
sock *s = SKIP_BACK(sock, n, n);
/* Out of space for pfds. Force reallocation. */
if (pfd >= end)
return NULL;
s->index = pfd - loop->pfd;
pfd->fd = s->fd;
pfd->events = sk_want_events(s);
pfd->revents = 0;
pfd++;
}
return pfd;
}
int sk_read(sock *s, int revents);
int sk_write(sock *s);
static void
sockets_fire(struct birdloop *loop)
{
struct pollfd *pfd = loop->pfd;
times_update();
sock *s; node *n, *nxt;
WALK_LIST2_DELSAFE(s, n, nxt, loop->sock_list, n)
{
if (s->index < 0)
continue;
int rev = pfd[s->index].revents;
if (!rev)
continue;
if (rev & POLLNVAL)
bug("poll: invalid fd %d", s->fd);
int e = 1;
if (rev & POLLIN)
while (e && s->rx_hook)
e = sk_read(s, rev);
if (rev & POLLOUT)
{
atomic_store_explicit(&loop->thread->poll_changed, 1, memory_order_release);
while (e = sk_write(s))
;
}
}
}
/*
* Threads
*/
DEFINE_DOMAIN(resource);
static DOMAIN(resource) birdloop_domain;
static list birdloop_pickup;
static list bird_thread_pickup;
static _Thread_local struct bird_thread *this_thread;
static void *
bird_thread_main(void *arg)
{
struct bird_thread *thr = this_thread = arg;
rcu_thread_start(&thr->rcu);
synchronize_rcu();
tmp_init(thr->pool);
init_list(&thr->loops);
u32 refresh_sockets = 1;
struct pollfd *pfd, *end;
while (1)
{
/* Wakeup at least once a minute. */
int timeout = 60000;
/* Pickup new loops */
LOCK_DOMAIN(resource, birdloop_domain);
if (!EMPTY_LIST(birdloop_pickup))
{
struct birdloop *loop = SKIP_BACK(struct birdloop, n, HEAD(birdloop_pickup));
rem_node(&loop->n);
UNLOCK_DOMAIN(resource, birdloop_domain);
add_tail(&thr->loops, &loop->n);
birdloop_enter(loop);
loop->thread = thr;
if (!EMPTY_LIST(loop->sock_list))
refresh_sockets = 1;
birdloop_leave(loop);
/* If there are more loops to be picked up, wakeup the next thread */
LOCK_DOMAIN(resource, birdloop_domain);
rem_node(&thr->n);
add_tail(&bird_thread_pickup, &thr->n);
if (!EMPTY_LIST(birdloop_pickup))
wakeup_do_kick(SKIP_BACK(struct bird_thread, n, HEAD(bird_thread_pickup)));
}
UNLOCK_DOMAIN(resource, birdloop_domain);
struct birdloop *loop; node *nn;
WALK_LIST2(loop, nn, thr->loops, n)
{
birdloop_enter(loop);
u64 after_enter = ns_now();
timer *t;
times_update();
timers_fire(&loop->time, 0);
int again = birdloop_process_flags(loop) + ev_run_list(&loop->event_list);
#if 0
if (loop->n.next->next)
__builtin_prefetch(SKIP_BACK(struct birdloop, n, loop->n.next)->time.domain);
#endif
if (again)
timeout = MIN(0, timeout);
else if (t = timers_first(&loop->time))
timeout = MIN(((tm_remains(t) TO_MS) + 1), timeout);
u64 before_leave = ns_now();
loop->total_time_spent_ns += (before_leave - after_enter);
birdloop_leave(loop);
ev_run_list(&thr->priority_events);
}
refresh_sockets += atomic_exchange_explicit(&thr->poll_changed, 0, memory_order_acq_rel);
if (!refresh_sockets && ((timeout < 0) || (timeout > 5000)))
flush_local_pages();
while (refresh_sockets)
{
sock_retry:;
end = (pfd = thr->pfd) + thr->pfd_max;
/* Add internal wakeup fd */
pipe_pollin(&thr->wakeup, pfd);
pfd++;
WALK_LIST2(loop, nn, thr->loops, n)
{
birdloop_enter(loop);
pfd = sockets_prepare(loop, pfd, end);
birdloop_leave(loop);
if (!pfd)
{
mb_free(thr->pfd);
thr->pfd = mb_alloc(thr->pool, sizeof(struct pollfd) * (thr->pfd_max *= 2));
goto sock_retry;
}
}
refresh_sockets = 0;
}
poll_retry:;
int rv = poll(thr->pfd, pfd - thr->pfd, timeout);
if (rv < 0)
{
if (errno == EINTR || errno == EAGAIN)
goto poll_retry;
bug("poll in %p: %m", thr);
}
/* Drain wakeup fd */
if (thr->pfd[0].revents & POLLIN)
{
ASSERT_DIE(rv > 0);
rv--;
wakeup_drain(thr);
}
atomic_exchange_explicit(&thr->ping_sent, 0, memory_order_acq_rel);
if (!rv && !atomic_exchange_explicit(&thr->run_cleanup, 0, memory_order_acq_rel))
continue;
/* Process stops and regular sockets */
node *nxt;
WALK_LIST2_DELSAFE(loop, nn, nxt, thr->loops, n)
{
birdloop_enter(loop);
if (loop->stopped)
{
/* Flush remaining events */
ASSERT_DIE(!ev_run_list(&loop->event_list));
/* Drop timers */
timer *t;
while (t = timers_first(&loop->time))
tm_stop(t);
/* No sockets allowed */
ASSERT_DIE(EMPTY_LIST(loop->sock_list));
/* Declare loop stopped */
rem_node(&loop->n);
birdloop_leave(loop);
loop->stopped(loop->stop_data);
/* Birdloop already left */
continue;
}
else if (rv)
sockets_fire(loop);
birdloop_leave(loop);
}
}
}
static void
bird_thread_cleanup(void *_thr)
{
struct bird_thread *thr = _thr;
ASSERT_DIE(birdloop_inside(&main_birdloop));
/* Thread attributes no longer needed */
pthread_attr_destroy(&thr->thread_attr);
/* Free all remaining memory */
rfree(thr->pool);
}
static struct bird_thread *
bird_thread_start(void)
{
ASSERT_DIE(birdloop_inside(&main_birdloop));
pool *p = rp_new(&root_pool, "Thread");
struct bird_thread *thr = mb_allocz(p, sizeof(*thr));
thr->pool = p;
thr->pfd = mb_alloc(p, sizeof(struct pollfd) * (thr->pfd_max = 16));
thr->cleanup_event = (event) { .hook = bird_thread_cleanup, .data = thr, };
atomic_store_explicit(&thr->ping_sent, 0, memory_order_relaxed);
wakeup_init(thr);
ev_init_list(&thr->priority_events, NULL, "Thread direct event list");
LOCK_DOMAIN(resource, birdloop_domain);
add_tail(&bird_thread_pickup, &thr->n);
UNLOCK_DOMAIN(resource, birdloop_domain);
int e = 0;
if (e = pthread_attr_init(&thr->thread_attr))
die("pthread_attr_init() failed: %M", e);
/* We don't have to worry about thread stack size so much.
if (e = pthread_attr_setstacksize(&thr->thread_attr, THREAD_STACK_SIZE))
die("pthread_attr_setstacksize(%u) failed: %M", THREAD_STACK_SIZE, e);
*/
if (e = pthread_attr_setdetachstate(&thr->thread_attr, PTHREAD_CREATE_DETACHED))
die("pthread_attr_setdetachstate(PTHREAD_CREATE_DETACHED) failed: %M", e);
if (e = pthread_create(&thr->thread_id, &thr->thread_attr, bird_thread_main, thr))
die("pthread_create() failed: %M", e);
return thr;
}
static struct birdloop *thread_dropper;
static event *thread_dropper_event;
static uint thread_dropper_goal;
static void
bird_thread_shutdown(void * _ UNUSED)
{
LOCK_DOMAIN(resource, birdloop_domain);
int dif = list_length(&bird_thread_pickup) - thread_dropper_goal;
struct birdloop *tdl_stop = NULL;
if (dif > 0)
ev_send_loop(thread_dropper, thread_dropper_event);
else
{
tdl_stop = thread_dropper;
thread_dropper = NULL;
}
UNLOCK_DOMAIN(resource, birdloop_domain);
log(L_INFO "Thread pickup size differs from dropper goal by %d%s", dif, tdl_stop ? ", stopping" : "");
if (tdl_stop)
{
birdloop_stop_self(tdl_stop, NULL, NULL);
return;
}
struct bird_thread *thr = this_thread;
/* Leave the thread-picker list to get no more loops */
LOCK_DOMAIN(resource, birdloop_domain);
rem_node(&thr->n);
/* Drop loops including the thread dropper itself */
while (!EMPTY_LIST(thr->loops))
{
/* Remove loop from this thread's list */
struct birdloop *loop = HEAD(thr->loops);
rem_node(&loop->n);
UNLOCK_DOMAIN(resource, birdloop_domain);
/* Unset loop's thread */
if (birdloop_inside(loop))
loop->thread = NULL;
else
{
birdloop_enter(loop);
loop->thread = NULL;
birdloop_leave(loop);
}
/* Put loop into pickup list */
LOCK_DOMAIN(resource, birdloop_domain);
add_tail(&birdloop_pickup, &loop->n);
}
/* Let others know about new loops */
if (!EMPTY_LIST(birdloop_pickup))
wakeup_do_kick(SKIP_BACK(struct bird_thread, n, HEAD(bird_thread_pickup)));
UNLOCK_DOMAIN(resource, birdloop_domain);
/* Leave the thread-dropper loop as we aren't going to return. */
birdloop_leave(thread_dropper);
/* Local pages not needed anymore */
flush_local_pages();
/* Unregister from RCU */
rcu_thread_stop(&thr->rcu);
/* Request thread cleanup from main loop */
ev_send_loop(&main_birdloop, &thr->cleanup_event);
/* Exit! */
pthread_exit(NULL);
}
void
bird_thread_commit(struct config *new, struct config *old UNUSED)
{
ASSERT_DIE(birdloop_inside(&main_birdloop));
if (new->shutdown)
return;
if (!new->thread_count)
new->thread_count = 1;
while (1)
{
LOCK_DOMAIN(resource, birdloop_domain);
int dif = list_length(&bird_thread_pickup) - (thread_dropper_goal = new->thread_count);
_Bool thread_dropper_running = !!thread_dropper;
UNLOCK_DOMAIN(resource, birdloop_domain);
if (dif < 0)
{
bird_thread_start();
continue;
}
if ((dif > 0) && !thread_dropper_running)
{
struct birdloop *tdl = birdloop_new(&root_pool, DOMAIN_ORDER(control), "Thread dropper");
event *tde = ev_new_init(tdl->pool, bird_thread_shutdown, NULL);
LOCK_DOMAIN(resource, birdloop_domain);
thread_dropper = tdl;
thread_dropper_event = tde;
UNLOCK_DOMAIN(resource, birdloop_domain);
ev_send_loop(thread_dropper, thread_dropper_event);
}
return;
}
}
DEFINE_DOMAIN(control);
struct bird_thread_show_data {
cli *cli;
pool *pool;
DOMAIN(control) lock;
uint total;
uint done;
u8 show_loops;
};
static void
bird_thread_show_cli_cont(struct cli *c UNUSED)
{
/* Explicitly do nothing to prevent CLI from trying to parse another command. */
}
static int
bird_thread_show_cli_cleanup(struct cli *c UNUSED)
{
return 1; /* Defer the cleanup until the writeout is finished. */
}
static void
bird_thread_show(void *data)
{
struct bird_thread_show_data *tsd = data;
LOCK_DOMAIN(control, tsd->lock);
if (tsd->show_loops)
cli_printf(tsd->cli, -1026, "Thread %p", this_thread);
u64 total_time_ns = 0;
struct birdloop *loop;
WALK_LIST(loop, this_thread->loops)
{
if (tsd->show_loops)
cli_printf(tsd->cli, -1026, " Loop %s time: %t", domain_name(loop->time.domain), loop->total_time_spent_ns NS);
total_time_ns += loop->total_time_spent_ns;
}
tsd->done++;
int last = (tsd->done == tsd->total);
if (last)
{
tsd->cli->cont = NULL;
tsd->cli->cleanup = NULL;
}
if (tsd->show_loops)
cli_printf(tsd->cli, (last ? 1 : -1) * 1026, " Total time: %t", total_time_ns NS);
else
cli_printf(tsd->cli, (last ? 1 : -1) * 1026, "Thread %p time %t", this_thread, total_time_ns NS);
UNLOCK_DOMAIN(control, tsd->lock);
if (last)
{
the_bird_lock();
LOCK_DOMAIN(resource, birdloop_domain);
if (!EMPTY_LIST(birdloop_pickup))
if (tsd->show_loops)
{
cli_printf(tsd->cli, -1026, "Unassigned loops");
WALK_LIST(loop, birdloop_pickup)
cli_printf(tsd->cli, -1026, " Loop %s time: %t", domain_name(loop->time.domain), loop->total_time_spent_ns NS);
}
else
{
uint count = 0;
u64 total_time_ns = 0;
WALK_LIST(loop, birdloop_pickup)
{
count++;
total_time_ns += loop->total_time_spent_ns;
}
cli_printf(tsd->cli, -1026, "Unassigned loops: %d, total time %t", count, total_time_ns NS);
}
UNLOCK_DOMAIN(resource, birdloop_domain);
cli_write_trigger(tsd->cli);
DOMAIN_FREE(control, tsd->lock);
rfree(tsd->pool);
the_bird_unlock();
}
}
void
cmd_show_threads(int show_loops)
{
pool *p = rp_new(&root_pool, "Show Threads");
struct bird_thread_show_data *tsd = mb_allocz(p, sizeof(struct bird_thread_show_data));
tsd->lock = DOMAIN_NEW(control, "Show Threads");
tsd->cli = this_cli;
tsd->pool = p;
tsd->show_loops = show_loops;
this_cli->cont = bird_thread_show_cli_cont;
this_cli->cleanup = bird_thread_show_cli_cleanup;
LOCK_DOMAIN(control, tsd->lock);
LOCK_DOMAIN(resource, birdloop_domain);
struct bird_thread *thr;
WALK_LIST(thr, bird_thread_pickup)
{
tsd->total++;
ev_send(&thr->priority_events, ev_new_init(p, bird_thread_show, tsd));
wakeup_do_kick(thr);
}
UNLOCK_DOMAIN(resource, birdloop_domain);
UNLOCK_DOMAIN(control, tsd->lock);
}
/*
* Birdloop
*/
static struct bird_thread main_thread;
struct birdloop main_birdloop = { .thread = &main_thread, };
static void birdloop_enter_locked(struct birdloop *loop);
void
birdloop_init(void)
{
ns_init();
birdloop_domain = DOMAIN_NEW(resource, "Loop Pickup");
init_list(&birdloop_pickup);
init_list(&bird_thread_pickup);
wakeup_init(main_birdloop.thread);
main_birdloop.time.domain = the_bird_domain.the_bird;
main_birdloop.time.loop = &main_birdloop;
times_update();
timers_init(&main_birdloop.time, &root_pool);
birdloop_enter_locked(&main_birdloop);
}
struct birdloop *
birdloop_new(pool *pp, uint order, const char *name)
{
struct domain_generic *dg = domain_new(name, order);
pool *p = rp_new(pp, name);
struct birdloop *loop = mb_allocz(p, sizeof(struct birdloop));
loop->pool = p;
loop->time.domain = dg;
loop->time.loop = loop;
birdloop_enter(loop);
ev_init_list(&loop->event_list, loop, name);
timers_init(&loop->time, p);
sockets_init(loop);
LOCK_DOMAIN(resource, birdloop_domain);
add_tail(&birdloop_pickup, &loop->n);
wakeup_do_kick(SKIP_BACK(struct bird_thread, n, HEAD(bird_thread_pickup)));
UNLOCK_DOMAIN(resource, birdloop_domain);
birdloop_leave(loop);
return loop;
}
static void
birdloop_do_stop(struct birdloop *loop, void (*stopped)(void *data), void *data)
{
loop->stopped = stopped;
loop->stop_data = data;
if (loop->thread)
{
atomic_store_explicit(&loop->thread->run_cleanup, 1, memory_order_release);
wakeup_do_kick(loop->thread);
}
}
void
birdloop_stop(struct birdloop *loop, void (*stopped)(void *data), void *data)
{
DG_LOCK(loop->time.domain);
birdloop_do_stop(loop, stopped, data);
DG_UNLOCK(loop->time.domain);
}
void
birdloop_stop_self(struct birdloop *loop, void (*stopped)(void *data), void *data)
{
ASSERT_DIE(loop == birdloop_current);
ASSERT_DIE(DG_IS_LOCKED(loop->time.domain));
birdloop_do_stop(loop, stopped, data);
}
void
birdloop_free(struct birdloop *loop)
{
ASSERT_DIE(loop->links == 0);
ASSERT_DIE(birdloop_in_this_thread(loop));
domain_free(loop->time.domain);
rfree(loop->pool);
}
static void
birdloop_enter_locked(struct birdloop *loop)
{
ASSERT_DIE(DG_IS_LOCKED(loop->time.domain));
ASSERT_DIE(!birdloop_inside(loop));
/* Store the old context */
loop->prev_loop = birdloop_current;
/* Put the new context */
birdloop_current = loop;
}
void
birdloop_enter(struct birdloop *loop)
{
DG_LOCK(loop->time.domain);
return birdloop_enter_locked(loop);
}
static void
birdloop_leave_locked(struct birdloop *loop)
{
/* Check the current context */
ASSERT_DIE(birdloop_current == loop);
/* Send pending pings */
if (loop->ping_pending)
{
loop->ping_pending = 0;
birdloop_do_ping(loop);
}
/* Restore the old context */
birdloop_current = loop->prev_loop;
}
void
birdloop_leave(struct birdloop *loop)
{
birdloop_leave_locked(loop);
DG_UNLOCK(loop->time.domain);
}
void
birdloop_mask_wakeups(struct birdloop *loop)
{
ASSERT_DIE(birdloop_wakeup_masked == NULL);
birdloop_wakeup_masked = loop;
}
void
birdloop_unmask_wakeups(struct birdloop *loop)
{
ASSERT_DIE(birdloop_wakeup_masked == loop);
birdloop_wakeup_masked = NULL;
if (birdloop_wakeup_masked_count)
wakeup_do_kick(loop->thread);
birdloop_wakeup_masked_count = 0;
}
void
birdloop_link(struct birdloop *loop)
{
ASSERT_DIE(birdloop_inside(loop));
loop->links++;
}
void
birdloop_unlink(struct birdloop *loop)
{
ASSERT_DIE(birdloop_inside(loop));
loop->links--;
}
void
birdloop_yield(void)
{
usleep(100);
}