*** empty log message ***

6 files changed, 120 insertions, 26 deletions

diff --git a/Changes b/Changes
index a698546..544a113 100644
--- a/Changes
+++ b/Changes
@@ -1,5 +1,9 @@
 Revision history for libev, a high-performance and full-featured event loop.
 
+	- added linux eventfd support.
+        - try to autodetect epoll and inotify support
+          by libc header version if not using autoconf.
+
 3.2  Wed Apr  2 17:11:19 CEST 2008
 	- fix a 64 bit overflow issue in the select backend,
           by using fd_mask instead of int for the mask.
diff --git a/ev.c b/ev.c
index 4475386..3c4d5b4 100644
--- a/ev.c
+++ b/ev.c
@@ -41,6 +41,7 @@
 extern "C" {
 #endif
 
+/* this big block deduces configuration from config.h */
 #ifndef EV_STANDALONE
 # ifdef EV_CONFIG_H
 #  include EV_CONFIG_H
@@ -120,6 +121,14 @@ extern "C" {
 #  endif
 # endif
 
+# ifndef EV_USE_EVENTFD
+#  if HAVE_EVENTFD
+#   define EV_USE_EVENTFD 1
+#  else
+#   define EV_USE_EVENTFD 0
+#  endif
+# endif
+   
 #endif
 
 #include <math.h>
@@ -154,7 +163,7 @@ extern "C" {
 # endif
 #endif
 
-/**/
+/* this block tries to deduce configuration from header-defined symbols and defaults */
 
 #ifndef EV_USE_MONOTONIC
 # define EV_USE_MONOTONIC 0
@@ -181,7 +190,11 @@ extern "C" {
 #endif
 
 #ifndef EV_USE_EPOLL
-# define EV_USE_EPOLL 0
+# if __linux && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 4))
+#  define EV_USE_EPOLL 1
+# else
+#  define EV_USE_EPOLL 0
+# endif
 #endif
 
 #ifndef EV_USE_KQUEUE
@@ -193,7 +206,11 @@ extern "C" {
 #endif
 
 #ifndef EV_USE_INOTIFY
-# define EV_USE_INOTIFY 0
+# if __linux && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 4))
+#  define EV_USE_INOTIFY 1
+# else
+#  define EV_USE_INOTIFY 0
+# endif
 #endif
 
 #ifndef EV_PID_HASHSIZE
@@ -212,7 +229,15 @@ extern "C" {
 # endif
 #endif
 
-/**/
+#ifndef EV_USE_EVENTFD
+# if __linux && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 7))
+#  define EV_USE_EVENTFD 1
+# else
+#  define EV_USE_EVENTFD 0
+# endif
+#endif
+
+/* this block fixes any misconfiguration where we know we run into trouble otherwise */
 
 #ifndef CLOCK_MONOTONIC
 # undef EV_USE_MONOTONIC
@@ -243,6 +268,11 @@ extern "C" {
 # include <winsock.h>
 #endif
 
+#if EV_USE_EVENTFD
+/* our minimum requirement is glibc 2.7 which has the stub, but not the header */
+int eventfd (unsigned int initval, int flags);
+#endif
+
 /**/
 
 /*
@@ -804,13 +834,24 @@ evpipe_init (EV_P)
 {
   if (!ev_is_active (&pipeev))
     {
-      while (pipe (evpipe))
-        syserr ("(libev) error creating signal/async pipe");
+#if EV_USE_EVENTFD
+      if ((evfd = eventfd (0, 0)) >= 0)
+        {
+          evpipe [0] = -1;
+          fd_intern (evfd);
+          ev_io_set (&pipeev, evfd, EV_READ);
+        }
+      else
+#endif
+        {
+          while (pipe (evpipe))
+            syserr ("(libev) error creating signal/async pipe");
 
-      fd_intern (evpipe [0]);
-      fd_intern (evpipe [1]);
+          fd_intern (evpipe [0]);
+          fd_intern (evpipe [1]);
+          ev_io_set (&pipeev, evpipe [0], EV_READ);
+        }
 
-      ev_io_set (&pipeev, evpipe [0], EV_READ);
       ev_io_start (EV_A_ &pipeev);
       ev_unref (EV_A); /* watcher should not keep loop alive */
     }
@@ -824,7 +865,16 @@ evpipe_write (EV_P_ EV_ATOMIC_T *flag)
       int old_errno = errno; /* save errno because write might clobber it */
 
       *flag = 1;
-      write (evpipe [1], &old_errno, 1);
+
+#if EV_USE_EVENTFD
+      if (evfd >= 0)
+        {
+          uint64_t counter = 1;
+          write (evfd, &counter, sizeof (uint64_t));
+        }
+      else
+#endif
+        write (evpipe [1], &old_errno, 1);
 
       errno = old_errno;
     }
@@ -833,10 +883,18 @@ evpipe_write (EV_P_ EV_ATOMIC_T *flag)
 static void
 pipecb (EV_P_ ev_io *iow, int revents)
 {
-  {
-    int dummy;
-    read (evpipe [0], &dummy, 1);
-  }
+#if EV_USE_EVENTFD
+  if (evfd >= 0)
+    {
+      uint64_t counter = 1;
+      read (evfd, &counter, sizeof (uint64_t));
+    }
+  else
+#endif
+    {
+      char dummy;
+      read (evpipe [0], &dummy, 1);
+    }
 
   if (gotsig && ev_is_default_loop (EV_A))
     {    
@@ -1141,8 +1199,16 @@ loop_destroy (EV_P)
       ev_ref (EV_A); /* signal watcher */
       ev_io_stop (EV_A_ &pipeev);
 
-      close (evpipe [0]); evpipe [0] = 0;
-      close (evpipe [1]); evpipe [1] = 0;
+#if EV_USE_EVENTFD
+      if (evfd >= 0)
+        close (evfd);
+#endif
+
+      if (evpipe [0] >= 0)
+        {
+          close (evpipe [0]);
+          close (evpipe [1]);
+        }
     }
 
 #if EV_USE_INOTIFY
@@ -1226,8 +1292,17 @@ loop_fork (EV_P)
 
       ev_ref (EV_A);
       ev_io_stop (EV_A_ &pipeev);
-      close (evpipe [0]);
-      close (evpipe [1]);
+
+#if EV_USE_EVENTFD
+      if (evfd >= 0)
+        close (evfd);
+#endif
+
+      if (evpipe [0] >= 0)
+        {
+          close (evpipe [0]);
+          close (evpipe [1]);
+        }
 
       evpipe_init (EV_A);
       /* now iterate over everything, in case we missed something */
diff --git a/ev.pod b/ev.pod
index 4fe808a..72cf388 100644
--- a/ev.pod
+++ b/ev.pod
@@ -2739,9 +2739,9 @@ For this of course you need the m4 file:
 
 =head2 PREPROCESSOR SYMBOLS/MACROS
 
-Libev can be configured via a variety of preprocessor symbols you have to define
-before including any of its files. The default is not to build for multiplicity
-and only include the select backend.
+Libev can be configured via a variety of preprocessor symbols you have to
+define before including any of its files. The default in the absense of
+autoconf is noted for every option.
 
 =over 4
 
@@ -2777,6 +2777,14 @@ note about libraries in the description of C<EV_USE_MONOTONIC>, though.
 If defined to be C<1>, libev will assume that C<nanosleep ()> is available
 and will use it for delays. Otherwise it will use C<select ()>.
 
+=item EV_USE_EVENTFD
+
+If defined to be C<1>, then libev will assume that C<eventfd ()> is
+available and will probe for kernel support at runtime. This will improve
+C<ev_signal> and C<ev_async> performance and reduce resource consumption.
+If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc
+2.7 or newer, otherwise disabled.
+
 =item EV_USE_SELECT
 
 If undefined or defined to be C<1>, libev will compile in support for the
@@ -2822,8 +2830,9 @@ takes precedence over select.
 
 If defined to be C<1>, libev will compile in support for the Linux
 C<epoll>(7) backend. Its availability will be detected at runtime,
-otherwise another method will be used as fallback. This is the
-preferred backend for GNU/Linux systems.
+otherwise another method will be used as fallback. This is the preferred
+backend for GNU/Linux systems. If undefined, it will be enabled if the
+headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled.
 
 =item EV_USE_KQUEUE
 
@@ -2852,7 +2861,8 @@ reserved for future expansion, works like the USE symbols above.
 
 If defined to be C<1>, libev will compile in support for the Linux inotify
 interface to speed up C<ev_stat> watchers. Its actual availability will
-be detected at runtime.
+be detected at runtime. If undefined, it will be enabled if the headers
+indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled.
 
 =item EV_ATOMIC_T
 
diff --git a/ev_vars.h b/ev_vars.h
index 249aa2f..dbd3aac 100644
--- a/ev_vars.h
+++ b/ev_vars.h
@@ -55,6 +55,9 @@ VARx(ev_tstamp, backend_fudge) /* assumed typical timer resolution */
 VAR (backend_modify, void (*backend_modify)(EV_P_ int fd, int oev, int nev))
 VAR (backend_poll  , void (*backend_poll)(EV_P_ ev_tstamp timeout))
 
+#if EV_USE_EVENTFD || EV_GENWRAP
+VARx(int, evfd)
+#endif
 VAR (evpipe, int evpipe [2])
 VARx(ev_io, pipeev)
 
diff --git a/ev_wrap.h b/ev_wrap.h
index fbfc802..2124af6 100644
--- a/ev_wrap.h
+++ b/ev_wrap.h
@@ -13,6 +13,7 @@
 #define backend_fudge ((loop)->backend_fudge)
 #define backend_modify ((loop)->backend_modify)
 #define backend_poll ((loop)->backend_poll)
+#define evfd ((loop)->evfd)
 #define evpipe ((loop)->evpipe)
 #define pipeev ((loop)->pipeev)
 #define curpid ((loop)->curpid)
@@ -84,6 +85,7 @@
 #undef backend_fudge
 #undef backend_modify
 #undef backend_poll
+#undef evfd
 #undef evpipe
 #undef pipeev
 #undef curpid
diff --git a/libev.m4 b/libev.m4
index 5db99fb..393835e 100644
--- a/libev.m4
+++ b/libev.m4
@@ -2,9 +2,9 @@ dnl this file is part of libev, do not make local modifications
 dnl http://software.schmorp.de/pkg/libev
 
 dnl libev support 
-AC_CHECK_HEADERS(sys/inotify.h sys/epoll.h sys/event.h sys/queue.h port.h poll.h sys/select.h) 
+AC_CHECK_HEADERS(sys/inotify.h sys/epoll.h sys/event.h sys/queue.h port.h poll.h sys/select.h sys/eventfd.h) 
  
-AC_CHECK_FUNCS(inotify_init epoll_ctl kqueue port_create poll select)
+AC_CHECK_FUNCS(inotify_init epoll_ctl kqueue port_create poll select eventfd)
  
 AC_CHECK_FUNC(clock_gettime, [], [ 
    if test -z "$LIBEV_M4_AVOID_LIBRT"; then