Hi,
I'm writing a new polling module and I stumbled upon some strange code:
The following function is implemented in
openmpi-trunk/opal/mca/event/libevent2013/libevent/signal.c :
evsig_add(struct event_base *base, evutil_socket_t evsignal, short old,
short events, void *p)
- It appears the three last paramaters are not used at all!
It's a coincidence that I'm just trying to register ANY signal handler
to interrupt my ppoll syscall, so It may work out,
but I'm not sure how I'm supposed to use this function to set my own
handler, not what the other parameters are for.
I've attached my patch for OPAL so far... I'll appreciate any advice.
Alex
Index: mca/event/libevent2013/configure.m4
===================================================================
--- mca/event/libevent2013/configure.m4 (revision 26274)
+++ mca/event/libevent2013/configure.m4 (working copy)
@@ -52,6 +52,12 @@
if test "$enable_event_poll" = "no"; then
event_args="$event_args --disable-poll"
fi
+
+ AC_ARG_ENABLE(event-mosix-ppoll,
+ AC_HELP_STRING([--disable-event-mosix-ppoll], [disable MOSIX ppoll support]))
+ if test "$enable_event_mosix_ppoll" = "no"; then
+ event_args="$event_args --disable-mosix-ppoll"
+ fi
AC_ARG_ENABLE(event-devpoll,
AC_HELP_STRING([--disable-event-devpoll], [disable devpoll support]))
Index: mca/event/libevent2013/libevent2013_module.c
===================================================================
--- mca/event/libevent2013/libevent2013_module.c (revision 26274)
+++ mca/event/libevent2013/libevent2013_module.c (working copy)
@@ -65,6 +65,9 @@
#if defined(_EVENT_HAVE_SELECT) && _EVENT_HAVE_SELECT
extern const struct eventop selectops;
#endif
+#if defined(_EVENT_HAVE_MOSIX_PPOLL) && _EVENT_HAVE_MOSIX_PPOLL
+extern const struct eventop mosix_ppollops;
+#endif
#if defined(_EVENT_HAVE_POLL) && _EVENT_HAVE_POLL
extern const struct eventop pollops;
#endif
@@ -95,6 +98,9 @@
#if defined(_EVENT_HAVE_DEVPOLL) && _EVENT_HAVE_DEVPOLL
&devpollops,
#endif
+#if defined(_EVENT_HAVE_MOSIX_PPOLL) && _EVENT_HAVE_MOSIX_PPOLL
+ &mosix_ppollops,
+#endif
#if defined(_EVENT_HAVE_POLL) && _EVENT_HAVE_POLL
&pollops,
#endif
@@ -194,9 +200,13 @@
#ifdef __WINDOWS__
"win32",
#else
+#ifdef _EVENT_HAVE_MOSIX_PPOLL
+ "mosix_ppoll",
+#else
"poll",
#endif
#endif
+#endif
&event_module_include);
if (dumpit) {
Index: mca/event/libevent2013/libevent/configure.in
===================================================================
--- mca/event/libevent2013/libevent/configure.in (revision 26274)
+++ mca/event/libevent2013/libevent/configure.in (working copy)
@@ -453,9 +453,18 @@
needsignal=yes
fi
fi
-AM_CONDITIONAL(POLL_BACKEND, [test "x$havepoll" = "xyes" -a "$enable_poll" != "no"])
+
+AM_CONDITIONAL(MOSIX_PPOLL_BACKEND, [test "x$havepoll" = "xyes" -a "$enable_mosix_ppoll" != "no" && test -n "/proc/mosix/mosip"])
+AC_MSG_CHECKING([for mosix_ppoll support])
+AS_IF([test "$enable_mosix_ppoll" != "no" && test "x$havepoll" = "xyes"],
+ [AC_DEFINE(HAVE_MOSIX_PPOLL, 1, [Have MOSIX ppoll support])
+ AC_MSG_RESULT([yes])],
+ [AC_DEFINE(HAVE_MOSIX_PPOLL, 0, [No MOSIX ppoll support])
+ AC_MSG_RESULT([no])])
+
+AM_CONDITIONAL(POLL_BACKEND, [test "x$havepoll" = "xyes" -a "$enable_poll" != "no" -a "$enable_mosix_poll" == "no"])
AC_MSG_CHECKING([for poll support])
-AS_IF([test "$enable_poll" != "no" && test "x$havepoll" = "xyes"],
+AS_IF([test "$enable_poll" != "no" && test "$enable_mosix_poll" == "no" && test "x$havepoll" = "xyes"],
[AC_DEFINE(HAVE_POLL, 1, [Have poll support])
AC_MSG_RESULT([yes])],
[AC_DEFINE(HAVE_POLL, 0, [No poll support])
Index: mca/event/libevent2013/libevent/mosix_ppoll.c
===================================================================
--- mca/event/libevent2013/libevent/mosix_ppoll.c (revision 0)
+++ mca/event/libevent2013/libevent/mosix_ppoll.c (revision 0)
@@ -0,0 +1,384 @@
+/* $OpenBSD: mosix_ppoll.c,v 1.2 2002/06/25 15:50:15 mickey Exp $ */
+
+/*
+ * Copyright 2000-2007 Niels Provos <pro...@citi.umich.edu>
+ * Copyright 2007-2010 Niels Provos and Nick Mathewson
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include "event2/event-config.h"
+
+#include <sys/types.h>
+#ifdef _EVENT_HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+#ifdef _EVENT_HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#ifdef _EVENT_HAVE_FCNTL_H
+#include <fcntl.h>
+#endif
+#include <sys/queue.h>
+#include <poll.h>
+#include <signal.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include "event-internal.h"
+#include "evsignal-internal.h"
+#include "log-internal.h"
+#include "evmap-internal.h"
+#include "event2/thread.h"
+#include "evthread-internal.h"
+
+#define MOSIX_PPOLL_MBOX_FD_LOWER_LIMIT (1000000000)
+#define MOSIX_PPOLL_MBOX_DEFAULT_FLAGS (71)
+#define MOSIX_PPOLL_MBOX_SIGIO_FLAGS (71 | 16)
+#define MOSIX_PPOLL_MBOX_OPEN_FILE_PATH "/proc/mosix/mybox"
+
+struct pollidx {
+ int idxplus1;
+};
+
+struct mosix_ppollop {
+ int event_count; /* Highest number alloc */
+ int nfds; /* Highest number used */
+ int realloc_copy; /* True iff we must realloc
+ * event_set_copy */
+
+ struct pollfd *event_set;
+ struct pollfd *event_set_copy;
+
+ int mosix_fd; /* High FD of a MOSIX mailbox or 0. */
+ sigset_t sigio; /* SIGIO-only sigmask for ppoll interruption */
+};
+
+static void *mosix_ppoll_init(struct event_base *);
+static int mosix_ppoll_add(struct event_base *, int, short old, short events, void *_idx);
+static int mosix_ppoll_del(struct event_base *, int, short old, short events, void *_idx);
+static int mosix_ppoll_dispatch(struct event_base *, struct timeval *);
+static void mosix_ppoll_dealloc(struct event_base *);
+
+const struct eventop mosix_ppollops = {
+ "mosix_ppoll",
+ mosix_ppoll_init,
+ mosix_ppoll_add,
+ mosix_ppoll_del,
+ mosix_ppoll_dispatch,
+ mosix_ppoll_dealloc,
+ 0, /* doesn't need_reinit */
+ EV_FEATURE_FDS,
+ sizeof(struct pollidx),
+};
+
+/* This dummy handler is only used to allow SIGIO interrupt the poll() syscall */
+static void mosix_ppoll_dummy_sigio_handler() {}
+
+static void *
+mosix_ppoll_init(struct event_base *base)
+{
+ struct mosix_ppollop *mosix_ppollop;
+
+ if (!(mosix_ppollop = mm_calloc(1, sizeof(struct mosix_ppollop))))
+ return (NULL);
+
+ evsig_init(base);
+ /* TODO: Setup the sigid_t for ppoll */
+ //evsig_add(base, SIGIO, 0,0, NULL);
+
+ return (mosix_ppollop);
+}
+
+#ifdef CHECK_INVARIANTS
+static void
+mosix_ppoll_check_ok(struct mosix_ppollop *pop)
+{
+ int i, idx;
+ struct event *ev;
+
+ for (i = 0; i < pop->fd_count; ++i) {
+ idx = pop->idxplus1_by_fd[i]-1;
+ if (idx < 0)
+ continue;
+ EVUTIL_ASSERT(pop->event_set[idx].fd == i);
+ }
+ for (i = 0; i < pop->nfds; ++i) {
+ struct pollfd *pfd = &pop->event_set[i];
+ EVUTIL_ASSERT(pop->idxplus1_by_fd[pfd->fd] == i+1);
+ }
+}
+#else
+#define mosix_ppoll_check_ok(pop)
+#endif
+
+static void mosix_ppoll_check_mosix_dicom(struct event_base *base, int fd)
+{
+ if (read(((struct mosix_ppollop*)(base->evbase))->mosix_fd, NULL, -1)) {
+ evmap_io_active(base, fd, EV_READ);
+ }
+}
+
+static int
+mosix_ppoll_dispatch(struct event_base *base, struct timeval *tv)
+{
+ int res, i, j, nfds;
+ long msec = -1;
+ struct mosix_ppollop *pop = base->evbase;
+ struct pollfd *event_set;
+
+ mosix_ppoll_check_ok(pop);
+
+ nfds = pop->nfds;
+
+#ifndef _EVENT_DISABLE_THREAD_SUPPORT
+ if (base->th_base_lock) {
+ /* If we're using this backend in a multithreaded setting,
+ * then we need to work on a copy of event_set, so that we can
+ * let other threads modify the main event_set while we're
+ * polling. If we're not multithreaded, then we'll skip the
+ * copy step here to save memory and time. */
+ if (pop->realloc_copy) {
+ struct pollfd *tmp = mm_realloc(pop->event_set_copy,
+ pop->event_count * sizeof(struct pollfd));
+ if (tmp == NULL) {
+ event_warn("realloc");
+ return -1;
+ }
+ pop->event_set_copy = tmp;
+ pop->realloc_copy = 0;
+ }
+ memcpy(pop->event_set_copy, pop->event_set,
+ sizeof(struct pollfd)*nfds);
+ event_set = pop->event_set_copy;
+ } else {
+ event_set = pop->event_set;
+ }
+#else
+ event_set = pop->event_set;
+#endif
+
+ if (0 < pop->mosix_fd) {
+ mosix_ppoll_check_mosix_dicom(base, pop->mosix_fd);
+ pop->mosix_fd = open(MOSIX_PPOLL_MBOX_OPEN_FILE_PATH, O_CREAT,
+ MOSIX_PPOLL_MBOX_SIGIO_FLAGS);
+ }
+
+ /* TODO: remove */
+ if (tv != NULL) {
+ msec = evutil_tv_to_msec(tv);
+ if (msec < 0 || msec > INT_MAX)
+ msec = INT_MAX;
+ }
+
+ EVBASE_RELEASE_LOCK(base, th_base_lock);
+
+ printf("OUR PPOLL!\n");
+ res = poll(event_set, nfds, msec); /* TODO: tv, sigmap_t*/
+
+ EVBASE_ACQUIRE_LOCK(base, th_base_lock);
+ if (0 < pop->mosix_fd) {
+ pop->mosix_fd = open(MOSIX_PPOLL_MBOX_OPEN_FILE_PATH, O_CREAT,
+ MOSIX_PPOLL_MBOX_SIGIO_FLAGS);
+ }
+ if (res == -1) {
+ if (errno != EINTR) {
+ event_warn("poll");
+ return (-1);
+ }
+
+ if (0 < pop->mosix_fd) {
+ mosix_ppoll_check_mosix_dicom(base, pop->mosix_fd);
+ }
+ return (0);
+ }
+
+ event_debug(("%s: poll reports %d", __func__, res));
+
+ if (res == 0 || nfds == 0)
+ return (0);
+
+ i = random() % nfds;
+ for (j = 0; j < nfds; j++) {
+ int what;
+ if (++i == nfds)
+ i = 0;
+ what = event_set[i].revents;
+ if (!what)
+ continue;
+
+ res = 0;
+
+ /* If the file gets closed notify */
+ if (what & (POLLHUP|POLLERR))
+ what |= POLLIN|POLLOUT;
+ if (what & POLLIN)
+ res |= EV_READ;
+ if (what & POLLOUT)
+ res |= EV_WRITE;
+ if (res == 0)
+ continue;
+
+ evmap_io_active(base, event_set[i].fd, res);
+ }
+
+ return (0);
+}
+
+static int
+mosix_ppoll_add(struct event_base *base, int fd, short old, short events, void *_idx)
+{
+ struct mosix_ppollop *pop = base->evbase;
+ struct pollfd *pfd = NULL;
+ struct pollidx *idx = _idx;
+ int i;
+
+ EVUTIL_ASSERT((events & EV_SIGNAL) == 0);
+ if (!(events & (EV_READ|EV_WRITE)))
+ return (0);
+
+ if (MOSIX_PPOLL_MBOX_FD_LOWER_LIMIT < fd) {
+ pop->mosix_fd = fd;
+ return (0);
+ }
+
+ mosix_ppoll_check_ok(pop);
+ if (pop->nfds + 1 >= pop->event_count) {
+ struct pollfd *tmp_event_set;
+ int tmp_event_count;
+
+ if (pop->event_count < 32)
+ tmp_event_count = 32;
+ else
+ tmp_event_count = pop->event_count * 2;
+
+ /* We need more file descriptors */
+ tmp_event_set = mm_realloc(pop->event_set,
+ tmp_event_count * sizeof(struct pollfd));
+ if (tmp_event_set == NULL) {
+ event_warn("realloc");
+ return (-1);
+ }
+ pop->event_set = tmp_event_set;
+
+ pop->event_count = tmp_event_count;
+ pop->realloc_copy = 1;
+ }
+
+ i = idx->idxplus1 - 1;
+
+ if (i >= 0) {
+ pfd = &pop->event_set[i];
+ } else {
+ i = pop->nfds++;
+ pfd = &pop->event_set[i];
+ pfd->events = 0;
+ pfd->fd = fd;
+ idx->idxplus1 = i + 1;
+ }
+
+ pfd->revents = 0;
+ if (events & EV_WRITE)
+ pfd->events |= POLLOUT;
+ if (events & EV_READ)
+ pfd->events |= POLLIN;
+ mosix_ppoll_check_ok(pop);
+
+ return (0);
+}
+
+/*
+ * Nothing to be done here.
+ */
+
+static int
+mosix_ppoll_del(struct event_base *base, int fd, short old, short events, void *_idx)
+{
+ struct mosix_ppollop *pop = base->evbase;
+ struct pollfd *pfd = NULL;
+ struct pollidx *idx = _idx;
+ int i;
+
+ EVUTIL_ASSERT((events & EV_SIGNAL) == 0);
+ if (!(events & (EV_READ|EV_WRITE)))
+ return (0);
+
+ if (pop->mosix_fd == fd) {
+ pop->mosix_fd = 0;
+ return (0);
+ }
+
+ mosix_ppoll_check_ok(pop);
+ i = idx->idxplus1 - 1;
+ if (i < 0)
+ return (-1);
+
+ /* Do we still want to read or write? */
+ pfd = &pop->event_set[i];
+ if (events & EV_READ)
+ pfd->events &= ~POLLIN;
+ if (events & EV_WRITE)
+ pfd->events &= ~POLLOUT;
+ mosix_ppoll_check_ok(pop);
+ if (pfd->events)
+ /* Another event cares about that fd. */
+ return (0);
+
+ /* Okay, so we aren't interested in that fd anymore. */
+ idx->idxplus1 = 0;
+
+ --pop->nfds;
+ if (i != pop->nfds) {
+ /*
+ * Shift the last pollfd down into the now-unoccupied
+ * position.
+ */
+ memcpy(&pop->event_set[i], &pop->event_set[pop->nfds],
+ sizeof(struct pollfd));
+ idx = evmap_io_get_fdinfo(&base->io, pop->event_set[i].fd);
+ EVUTIL_ASSERT(idx);
+ EVUTIL_ASSERT(idx->idxplus1 == pop->nfds + 1);
+ idx->idxplus1 = i + 1;
+ }
+
+ mosix_ppoll_check_ok(pop);
+ return (0);
+}
+
+static void
+mosix_ppoll_dealloc(struct event_base *base)
+{
+ struct mosix_ppollop *pop = base->evbase;
+
+ evsig_dealloc(base);
+ if (pop->event_set)
+ mm_free(pop->event_set);
+ if (pop->event_set_copy)
+ mm_free(pop->event_set_copy);
+
+ memset(pop, 0, sizeof(struct mosix_ppollop));
+ mm_free(pop);
+}
Index: mca/event/libevent2013/libevent/event.c
===================================================================
--- mca/event/libevent2013/libevent/event.c (revision 26274)
+++ mca/event/libevent2013/libevent/event.c (working copy)
@@ -81,6 +81,9 @@
#if defined(_EVENT_HAVE_SELECT) && _EVENT_HAVE_SELECT
extern const struct eventop selectops;
#endif
+#if defined(_EVENT_HAVE_MOSIX_PPOLL) && _EVENT_HAVE_MOSIX_PPOLL
+extern const struct eventop mosix_ppollops;
+#endif
#if defined(_EVENT_HAVE_POLL) && _EVENT_HAVE_POLL
extern const struct eventop pollops;
#endif
@@ -111,6 +114,9 @@
#if defined(_EVENT_HAVE_DEVPOLL) && _EVENT_HAVE_DEVPOLL
&devpollops,
#endif
+#if defined(_EVENT_HAVE_MOSIX_PPOLL) && _EVENT_HAVE_MOSIX_PPOLL
+ &mosix_ppollops,
+#endif
#if defined(_EVENT_HAVE_POLL) && _EVENT_HAVE_POLL
&pollops,
#endif
Index: mca/event/libevent2013/libevent/Makefile.am
===================================================================
--- mca/event/libevent2013/libevent/Makefile.am (revision 26274)
+++ mca/event/libevent2013/libevent/Makefile.am (working copy)
@@ -137,6 +137,9 @@
if POLL_BACKEND
SYS_SRC += poll.c
endif
+if MOSIX_PPOLL_BACKEND
+SYS_SRC += mosix_ppoll.c
+endif
if DEVPOLL_BACKEND
SYS_SRC += devpoll.c
endif
