Unix: Rework of select-loop to poll-loop (e1c13a5a) · Commits · 戴 / Bird

sysdep/unix/io.c

+47 −54

Original line number	Diff line number	Diff line
		@@ -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;
		}

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