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Unix: Rework of select-loop to poll-loop

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This should lift the limit of FD_SETSIZE and allow more than 1024 fd's.
FD_SETSIZE limit doesn't matter now when creating new sockets.
This commit is contained in:
Jan Moskyto Matejka 2016-03-09 12:12:02 +01:00
parent ce95af7a5f
commit e1c13a5a7b
1 changed files with 47 additions and 54 deletions
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101
sysdep/unix/io.c
View file

@ -19,6 +19,7 @@
#include <sys/socket.h>
#include <sys/uio.h>
#include <sys/un.h>
#include <poll.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
@ -41,12 +42,12 @@
#include "lib/sysio.h"
/* Maximum number of calls of tx handler for one socket in one
* select iteration. Should be small enough to not monopolize CPU by
* poll iteration. Should be small enough to not monopolize CPU by
* one protocol instance.
*/
#define MAX_STEPS 4
/* Maximum number of calls of rx handler for all sockets in one select
/* Maximum number of calls of rx handler for all sockets in one poll
iteration. RX callbacks are often much more costly so we limit
this to gen small latencies */
#define MAX_RX_STEPS 4
@ -1022,7 +1023,6 @@ sk_log_error(sock *s, const char *p)
static list sock_list;
static struct birdsock *current_sock;
static struct birdsock *stored_sock;
static int sock_recalc_fdsets_p;
static inline sock *
sk_next(sock *s)
@ -1078,7 +1078,6 @@ sk_free(resource *r)
if (s == stored_sock)
stored_sock = sk_next(s);
rem_node(&s->n);
sock_recalc_fdsets_p = 1;
}
}
@ -1276,7 +1275,6 @@ static void
sk_insert(sock *s)
{
add_tail(&sock_list, &s->n);
sock_recalc_fdsets_p = 1;
}
static void
@ -1328,18 +1326,6 @@ sk_passive_connected(sock *s, int type)
log(L_WARN "SOCK: Cannot get remote IP address for TCP<");
}
if (fd >= FD_SETSIZE)
{
/* FIXME: Call err_hook instead ? */
log(L_ERR "SOCK: Incoming connection from %I%J (port %d) %s",
t->daddr, ipa_is_link_local(t->daddr) ? t->iface : NULL,
t->dport, "rejected due to FD_SETSIZE limit");
close(fd);
t->fd = -1;
rfree(t);
return 1;
}
if (sk_setup(t) < 0)
{
/* FIXME: Call err_hook instead ? */
@ -1416,9 +1402,6 @@ sk_open(sock *s)
if (fd < 0)
ERR("socket");
if (fd >= FD_SETSIZE)
ERR2("FD_SETSIZE limit reached");
s->af = af;
s->fd = fd;
@ -2062,15 +2045,15 @@ static int short_loops = 0;
void
io_loop(void)
{
fd_set rd, wr;
struct timeval timo;
int poll_tout;
time_t tout;
int hi, events;
int nfds, events;
sock *s;
node *n;
int fdmax = 256;
struct pollfd *pfd = xmalloc(fdmax * sizeof(struct pollfd));
watchdog_start1();
sock_recalc_fdsets_p = 1;
for(;;)
{
events = ev_run_list(&global_event_list);
@ -2081,43 +2064,43 @@ io_loop(void)
tm_shot();
continue;
}
timo.tv_sec = events ? 0 : MIN(tout - now, 3);
timo.tv_usec = 0;
poll_tout = (events ? 0 : MIN(tout - now, 3)) * 1000; /* Time in milliseconds */
io_close_event();
if (sock_recalc_fdsets_p)
{
sock_recalc_fdsets_p = 0;
FD_ZERO(&rd);
FD_ZERO(&wr);
}
hi = 0;
nfds = 0;
WALK_LIST(n, sock_list)
{
pfd[nfds] = (struct pollfd) { .fd = -1 }; /* everything other set to 0 by this */
s = SKIP_BACK(sock, n, n);
if (s->rx_hook)
{
FD_SET(s->fd, &rd);
if (s->fd > hi)
hi = s->fd;
pfd[nfds].fd = s->fd;
pfd[nfds].events |= POLLIN;
}
else
FD_CLR(s->fd, &rd);
if (s->tx_hook && s->ttx != s->tpos)
{
FD_SET(s->fd, &wr);
if (s->fd > hi)
hi = s->fd;
pfd[nfds].fd = s->fd;
pfd[nfds].events |= POLLOUT;
}
if (pfd[nfds].fd != -1)
{
s->index = nfds;
nfds++;
}
else
FD_CLR(s->fd, &wr);
s->index = -1;
if (nfds >= fdmax)
{
fdmax *= 2;
pfd = xrealloc(pfd, fdmax * sizeof(struct pollfd));
}
}
/*
* Yes, this is racy. But even if the signal comes before this test
* and entering select(), it gets caught on the next timer tick.
* and entering poll(), it gets caught on the next timer tick.
*/
if (async_config_flag)
@ -2142,18 +2125,18 @@ io_loop(void)
continue;
}
/* And finally enter select() to find active sockets */
/* And finally enter poll() to find active sockets */
watchdog_stop();
hi = select(hi+1, &rd, &wr, NULL, &timo);
events = poll(pfd, nfds, poll_tout);
watchdog_start();
if (hi < 0)
if (events < 0)
{
if (errno == EINTR || errno == EAGAIN)
continue;
die("select: %m");
die("poll: %m");
}
if (hi)
if (events)
{
/* guaranteed to be non-empty */
current_sock = SKIP_BACK(sock, n, HEAD(sock_list));
@ -2161,11 +2144,17 @@ io_loop(void)
while (current_sock)
{
sock *s = current_sock;
if (s->index == -1)
{
current_sock = sk_next(s);
goto next;
}
int e;
int steps;
steps = MAX_STEPS;
if ((s->type >= SK_MAGIC) && FD_ISSET(s->fd, &rd) && s->rx_hook)
if ((s->type >= SK_MAGIC) && (pfd[s->index].revents & (POLLIN | POLLHUP | POLLERR)) && s->rx_hook)
do
{
steps--;
@ -2177,7 +2166,7 @@ io_loop(void)
while (e && s->rx_hook && steps);
steps = MAX_STEPS;
if (FD_ISSET(s->fd, &wr))
if (pfd[s->index].revents & POLLOUT)
do
{
steps--;
@ -2204,13 +2193,17 @@ io_loop(void)
while (current_sock && count < MAX_RX_STEPS)
{
sock *s = current_sock;
int e UNUSED;
if (s->index == -1)
{
current_sock = sk_next(s);
goto next2;
}
if ((s->type < SK_MAGIC) && FD_ISSET(s->fd, &rd) && s->rx_hook)
if ((s->type < SK_MAGIC) && (pfd[s->index].revents & (POLLIN | POLLHUP | POLLERR)) && s->rx_hook)
{
count++;
io_log_event(s->rx_hook, s->data);
e = sk_read(s);
sk_read(s);
if (s != current_sock)
goto next2;
}