summaryrefslogtreecommitdiffstats
path: root/src/ev_poll.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/ev_poll.c')
-rw-r--r--src/ev_poll.c348
1 files changed, 348 insertions, 0 deletions
diff --git a/src/ev_poll.c b/src/ev_poll.c
new file mode 100644
index 0000000..e98630c
--- /dev/null
+++ b/src/ev_poll.c
@@ -0,0 +1,348 @@
+/*
+ * FD polling functions for generic poll()
+ *
+ * Copyright 2000-2014 Willy Tarreau <w@1wt.eu>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+#define _GNU_SOURCE // for POLLRDHUP on Linux
+
+#include <unistd.h>
+#include <poll.h>
+#include <sys/time.h>
+#include <sys/types.h>
+
+#include <haproxy/activity.h>
+#include <haproxy/api.h>
+#include <haproxy/clock.h>
+#include <haproxy/fd.h>
+#include <haproxy/global.h>
+#include <haproxy/signal.h>
+#include <haproxy/task.h>
+#include <haproxy/ticks.h>
+
+
+#ifndef POLLRDHUP
+/* POLLRDHUP was defined late in libc, and it appeared in kernel 2.6.17 */
+#define POLLRDHUP 0
+#endif
+
+static int maxfd; /* # of the highest fd + 1 */
+static unsigned int *fd_evts[2];
+
+/* private data */
+static THREAD_LOCAL int nbfd = 0;
+static THREAD_LOCAL struct pollfd *poll_events = NULL;
+
+static void __fd_clo(int fd)
+{
+ hap_fd_clr(fd, fd_evts[DIR_RD]);
+ hap_fd_clr(fd, fd_evts[DIR_WR]);
+}
+
+static void _update_fd(int fd, int *max_add_fd)
+{
+ int en;
+ ulong pr, ps;
+
+ en = fdtab[fd].state;
+ pr = _HA_ATOMIC_LOAD(&polled_mask[fd].poll_recv);
+ ps = _HA_ATOMIC_LOAD(&polled_mask[fd].poll_send);
+
+ /* we have a single state for all threads, which is why we
+ * don't check the tid_bit. First thread to see the update
+ * takes it for every other one.
+ */
+ if (!(en & FD_EV_ACTIVE_RW)) {
+ if (!(pr | ps)) {
+ /* fd was not watched, it's still not */
+ return;
+ }
+ /* fd totally removed from poll list */
+ hap_fd_clr(fd, fd_evts[DIR_RD]);
+ hap_fd_clr(fd, fd_evts[DIR_WR]);
+ _HA_ATOMIC_AND(&polled_mask[fd].poll_recv, 0);
+ _HA_ATOMIC_AND(&polled_mask[fd].poll_send, 0);
+ }
+ else {
+ /* OK fd has to be monitored, it was either added or changed */
+ if (!(en & FD_EV_ACTIVE_R)) {
+ hap_fd_clr(fd, fd_evts[DIR_RD]);
+ if (pr & ti->ltid_bit)
+ _HA_ATOMIC_AND(&polled_mask[fd].poll_recv, ~ti->ltid_bit);
+ } else {
+ hap_fd_set(fd, fd_evts[DIR_RD]);
+ if (!(pr & ti->ltid_bit))
+ _HA_ATOMIC_OR(&polled_mask[fd].poll_recv, ti->ltid_bit);
+ }
+
+ if (!(en & FD_EV_ACTIVE_W)) {
+ hap_fd_clr(fd, fd_evts[DIR_WR]);
+ if (ps & ti->ltid_bit)
+ _HA_ATOMIC_AND(&polled_mask[fd].poll_send, ~ti->ltid_bit);
+ } else {
+ hap_fd_set(fd, fd_evts[DIR_WR]);
+ if (!(ps & ti->ltid_bit))
+ _HA_ATOMIC_OR(&polled_mask[fd].poll_send, ti->ltid_bit);
+ }
+
+ if (fd > *max_add_fd)
+ *max_add_fd = fd;
+ }
+}
+
+/*
+ * Poll() poller
+ */
+static void _do_poll(struct poller *p, int exp, int wake)
+{
+ int status;
+ int fd;
+ int wait_time;
+ int updt_idx;
+ int fds, count;
+ int sr, sw;
+ int old_maxfd, new_maxfd, max_add_fd;
+ unsigned rn, wn; /* read new, write new */
+ int old_fd;
+
+ max_add_fd = -1;
+
+ /* first, scan the update list to find changes */
+ for (updt_idx = 0; updt_idx < fd_nbupdt; updt_idx++) {
+ fd = fd_updt[updt_idx];
+
+ _HA_ATOMIC_AND(&fdtab[fd].update_mask, ~ti->ltid_bit);
+ if (!fdtab[fd].owner) {
+ activity[tid].poll_drop_fd++;
+ continue;
+ }
+ _update_fd(fd, &max_add_fd);
+ }
+
+ /* Now scan the global update list */
+ for (old_fd = fd = update_list[tgid - 1].first; fd != -1; fd = fdtab[fd].update.next) {
+ if (fd == -2) {
+ fd = old_fd;
+ continue;
+ }
+ else if (fd <= -3)
+ fd = -fd -4;
+ if (fd == -1)
+ break;
+ if (fdtab[fd].update_mask & ti->ltid_bit) {
+ /* Cheat a bit, as the state is global to all pollers
+ * we don't need every thread to take care of the
+ * update.
+ */
+ _HA_ATOMIC_AND(&fdtab[fd].update_mask, ~tg->threads_enabled);
+ done_update_polling(fd);
+ } else
+ continue;
+ if (!fdtab[fd].owner)
+ continue;
+ _update_fd(fd, &max_add_fd);
+ }
+
+ /* maybe we added at least one fd larger than maxfd */
+ for (old_maxfd = maxfd; old_maxfd <= max_add_fd; ) {
+ if (_HA_ATOMIC_CAS(&maxfd, &old_maxfd, max_add_fd + 1))
+ break;
+ }
+
+ /* maxfd doesn't need to be precise but it needs to cover *all* active
+ * FDs. Thus we only shrink it if we have such an opportunity. The algo
+ * is simple : look for the previous used place, try to update maxfd to
+ * point to it, abort if maxfd changed in the mean time.
+ */
+ old_maxfd = maxfd;
+ do {
+ new_maxfd = old_maxfd;
+ while (new_maxfd - 1 >= 0 && !fdtab[new_maxfd - 1].owner)
+ new_maxfd--;
+ if (new_maxfd >= old_maxfd)
+ break;
+ } while (!_HA_ATOMIC_CAS(&maxfd, &old_maxfd, new_maxfd));
+
+ thread_idle_now();
+ thread_harmless_now();
+
+ fd_nbupdt = 0;
+
+ nbfd = 0;
+ for (fds = 0; (fds * 8*sizeof(**fd_evts)) < maxfd; fds++) {
+ rn = fd_evts[DIR_RD][fds];
+ wn = fd_evts[DIR_WR][fds];
+
+ if (!(rn|wn))
+ continue;
+
+ for (count = 0, fd = fds * 8*sizeof(**fd_evts); count < 8*sizeof(**fd_evts) && fd < maxfd; count++, fd++) {
+ sr = (rn >> count) & 1;
+ sw = (wn >> count) & 1;
+ if ((sr|sw)) {
+ if (!fdtab[fd].owner) {
+ /* should normally not happen here except
+ * due to rare thread concurrency
+ */
+ continue;
+ }
+
+ if (!(fdtab[fd].thread_mask & ti->ltid_bit)) {
+ continue;
+ }
+
+ poll_events[nbfd].fd = fd;
+ poll_events[nbfd].events = (sr ? (POLLIN | POLLRDHUP) : 0) | (sw ? POLLOUT : 0);
+ nbfd++;
+ }
+ }
+ }
+
+ /* Now let's wait for polled events. */
+ wait_time = wake ? 0 : compute_poll_timeout(exp);
+ clock_entering_poll();
+ status = poll(poll_events, nbfd, wait_time);
+ clock_update_date(wait_time, status);
+
+ fd_leaving_poll(wait_time, status);
+
+ if (status > 0)
+ activity[tid].poll_io++;
+
+ for (count = 0; status > 0 && count < nbfd; count++) {
+ unsigned int n;
+ int e = poll_events[count].revents;
+
+ fd = poll_events[count].fd;
+
+ if ((e & POLLRDHUP) && !(cur_poller.flags & HAP_POLL_F_RDHUP))
+ _HA_ATOMIC_OR(&cur_poller.flags, HAP_POLL_F_RDHUP);
+
+#ifdef DEBUG_FD
+ _HA_ATOMIC_INC(&fdtab[fd].event_count);
+#endif
+ if (!(e & ( POLLOUT | POLLIN | POLLERR | POLLHUP | POLLRDHUP )))
+ continue;
+
+ /* ok, we found one active fd */
+ status--;
+
+ n = ((e & POLLIN) ? FD_EV_READY_R : 0) |
+ ((e & POLLOUT) ? FD_EV_READY_W : 0) |
+ ((e & POLLRDHUP) ? FD_EV_SHUT_R : 0) |
+ ((e & POLLHUP) ? FD_EV_SHUT_RW : 0) |
+ ((e & POLLERR) ? FD_EV_ERR_RW : 0);
+
+ fd_update_events(fd, n);
+ }
+}
+
+
+static int init_poll_per_thread()
+{
+ poll_events = calloc(1, sizeof(struct pollfd) * global.maxsock);
+ if (poll_events == NULL)
+ return 0;
+ return 1;
+}
+
+static void deinit_poll_per_thread()
+{
+ ha_free(&poll_events);
+}
+
+/*
+ * Initialization of the poll() poller.
+ * Returns 0 in case of failure, non-zero in case of success. If it fails, it
+ * disables the poller by setting its pref to 0.
+ */
+static int _do_init(struct poller *p)
+{
+ __label__ fail_swevt, fail_srevt;
+ int fd_evts_bytes;
+
+ p->private = NULL;
+
+ /* this old poller uses a process-wide FD list that cannot work with
+ * groups.
+ */
+ if (global.nbtgroups > 1)
+ goto fail_srevt;
+
+ fd_evts_bytes = (global.maxsock + sizeof(**fd_evts) * 8 - 1) / (sizeof(**fd_evts) * 8) * sizeof(**fd_evts);
+
+ if ((fd_evts[DIR_RD] = calloc(1, fd_evts_bytes)) == NULL)
+ goto fail_srevt;
+ if ((fd_evts[DIR_WR] = calloc(1, fd_evts_bytes)) == NULL)
+ goto fail_swevt;
+
+ hap_register_per_thread_init(init_poll_per_thread);
+ hap_register_per_thread_deinit(deinit_poll_per_thread);
+
+ return 1;
+
+ fail_swevt:
+ free(fd_evts[DIR_RD]);
+ fail_srevt:
+ p->pref = 0;
+ return 0;
+}
+
+/*
+ * Termination of the poll() poller.
+ * Memory is released and the poller is marked as unselectable.
+ */
+static void _do_term(struct poller *p)
+{
+ free(fd_evts[DIR_WR]);
+ free(fd_evts[DIR_RD]);
+ p->private = NULL;
+ p->pref = 0;
+}
+
+/*
+ * Check that the poller works.
+ * Returns 1 if OK, otherwise 0.
+ */
+static int _do_test(struct poller *p)
+{
+ return 1;
+}
+
+/*
+ * Registers the poller.
+ */
+static void _do_register(void)
+{
+ struct poller *p;
+
+ if (nbpollers >= MAX_POLLERS)
+ return;
+ p = &pollers[nbpollers++];
+
+ p->name = "poll";
+ p->pref = 200;
+ p->flags = HAP_POLL_F_ERRHUP;
+ p->private = NULL;
+
+ p->clo = __fd_clo;
+ p->test = _do_test;
+ p->init = _do_init;
+ p->term = _do_term;
+ p->poll = _do_poll;
+}
+
+INITCALL0(STG_REGISTER, _do_register);
+
+/*
+ * Local variables:
+ * c-indent-level: 8
+ * c-basic-offset: 8
+ * End:
+ */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-12 10:36:50 +0000