Non-perfect epoll patch
Shachar Shemesh
wine-devel at shemesh.biz
Tue Aug 24 16:36:39 CDT 2004
Hi all,
Attached is a non-perfect patch for review. This is a migration of the
wineserver to use epoll instead of poll (if it's available).
current known issue with this patch:
1. Will not compile if HAVE_SYS_EPOLL_H is not 1 (i.e. - won't compile
if epoll not available at compile time)
2. Segfaults on wine exit.
3. Lots of debug asserts.
Comments welcome.
Shachar
--
Shachar Shemesh
Lingnu Open Source Consulting ltd.
http://www.lingnu.com/
-------------- next part --------------
Index: configure
===================================================================
RCS file: /home/sun/sources/cvs/wine/configure,v
retrieving revision 1.573
diff -u -r1.573 configure
--- configure 17 Jul 2004 00:52:37 -0000 1.573
+++ configure 24 Aug 2004 12:03:32 -0000
@@ -6727,6 +6727,79 @@
fi
+echo "$as_me:$LINENO: checking for epoll_create in -lepoll" >&5
+echo $ECHO_N "checking for epoll_create in -lepoll... $ECHO_C" >&6
+if test "${ac_cv_lib_epoll_epoll_create+set}" = set; then
+ echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+ ac_check_lib_save_LIBS=$LIBS
+LIBS="-lepoll $LIBS"
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h. */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h. */
+
+/* Override any gcc2 internal prototype to avoid an error. */
+#ifdef __cplusplus
+extern "C"
+#endif
+/* We use char because int might match the return type of a gcc2
+ builtin and then its argument prototype would still apply. */
+char epoll_create ();
+int
+main ()
+{
+epoll_create ();
+ ;
+ return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
+ (eval $ac_link) 2>conftest.er1
+ ac_status=$?
+ grep -v '^ *+' conftest.er1 >conftest.err
+ rm -f conftest.er1
+ cat conftest.err >&5
+ echo "$as_me:$LINENO: \$? = $ac_status" >&5
+ (exit $ac_status); } &&
+ { ac_try='test -z "$ac_c_werror_flag" || test ! -s conftest.err'
+ { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+ (eval $ac_try) 2>&5
+ ac_status=$?
+ echo "$as_me:$LINENO: \$? = $ac_status" >&5
+ (exit $ac_status); }; } &&
+ { ac_try='test -s conftest$ac_exeext'
+ { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+ (eval $ac_try) 2>&5
+ ac_status=$?
+ echo "$as_me:$LINENO: \$? = $ac_status" >&5
+ (exit $ac_status); }; }; then
+ ac_cv_lib_epoll_epoll_create=yes
+else
+ echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+ac_cv_lib_epoll_epoll_create=no
+fi
+rm -f conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+echo "$as_me:$LINENO: result: $ac_cv_lib_epoll_epoll_create" >&5
+echo "${ECHO_T}$ac_cv_lib_epoll_epoll_create" >&6
+if test $ac_cv_lib_epoll_epoll_create = yes; then
+ cat >>confdefs.h <<_ACEOF
+#define HAVE_LIBEPOLL 1
+_ACEOF
+
+ LIBS="-lepoll $LIBS"
+
+fi
+
+
echo "$as_me:$LINENO: checking for res_9_init in -lresolv" >&5
echo $ECHO_N "checking for res_9_init in -lresolv... $ECHO_C" >&6
if test "${ac_cv_lib_resolv_res_9_init+set}" = set; then
@@ -16190,6 +16263,7 @@
+
for ac_func in \
_lwp_create \
_lwp_self \
@@ -16202,6 +16276,7 @@
_vsnprintf \
chsize \
clone \
+ epoll_create \
finite \
fpclass \
fstatfs \
@@ -16435,6 +16510,7 @@
+
for ac_header in \
arpa/inet.h \
arpa/nameser.h \
@@ -16495,6 +16571,7 @@
sys/msg.h \
sys/param.h \
sys/poll.h \
+ sys/epoll.h \
sys/ptrace.h \
sys/reg.h \
sys/scsiio.h \
Index: configure.ac
===================================================================
RCS file: /home/sun/sources/cvs/wine/configure.ac,v
retrieving revision 1.285
diff -u -r1.285 configure.ac
--- configure.ac 6 Jul 2004 21:01:19 -0000 1.285
+++ configure.ac 24 Aug 2004 12:01:22 -0000
@@ -140,6 +140,8 @@
AC_CHECK_LIB(xpg4,_xpg4_setrunelocale)
dnl Check for -lpoll for Mac OS X/Darwin
AC_CHECK_LIB(poll,poll)
+dnl Check for -lepoll
+AC_CHECK_LIB(epoll,epoll_create)
dnl Check for -lresolv for Mac OS X/Darwin
AC_CHECK_LIB(resolv,res_9_init)
dnl Check for -lpthread
@@ -1036,6 +1038,7 @@
_vsnprintf \
chsize \
clone \
+ epoll_create \
finite \
fpclass \
fstatfs \
@@ -1146,6 +1149,7 @@
sys/msg.h \
sys/param.h \
sys/poll.h \
+ sys/epoll.h \
sys/ptrace.h \
sys/reg.h \
sys/scsiio.h \
Index: include/config.h.in
===================================================================
RCS file: /home/sun/sources/cvs/wine/include/config.h.in,v
retrieving revision 1.190
diff -u -r1.190 config.h.in
--- include/config.h.in 18 Jun 2004 19:36:26 -0000 1.190
+++ include/config.h.in 24 Aug 2004 12:05:42 -0000
@@ -80,6 +80,9 @@
/* Define to 1 if you have the <elf.h> header file. */
#undef HAVE_ELF_H
+/* Define to 1 if you have the `epoll_create' function. */
+#undef HAVE_EPOLL_CREATE
+
/* Define to 1 if you have the `finite' function. */
#undef HAVE_FINITE
@@ -248,6 +251,9 @@
/* Define if you have the curses library (-lcurses) */
#undef HAVE_LIBCURSES
+/* Define to 1 if you have the `epoll' library (-lepoll). */
+#undef HAVE_LIBEPOLL
+
/* Define if you have libgif/libungif including devel headers */
#undef HAVE_LIBGIF
@@ -608,6 +614,9 @@
/* Define to 1 if you have the <sys/elf32.h> header file. */
#undef HAVE_SYS_ELF32_H
+/* Define to 1 if you have the <sys/epoll.h> header file. */
+#undef HAVE_SYS_EPOLL_H
+
/* Define to 1 if you have the <sys/errno.h> header file. */
#undef HAVE_SYS_ERRNO_H
Index: server/fd.c
===================================================================
RCS file: /home/sun/sources/cvs/wine/server/fd.c,v
retrieving revision 1.21
diff -u -r1.21 fd.c
--- server/fd.c 22 May 2004 03:15:04 -0000 1.21
+++ server/fd.c 24 Aug 2004 21:20:53 -0000
@@ -33,6 +33,12 @@
#ifdef HAVE_SYS_POLL_H
#include <sys/poll.h>
#endif
+#ifdef HAVE_SYS_EPOLL_H
+#include <sys/epoll.h>
+#endif
+#ifdef HAVE_SYS_SYSCALL_H
+#include <sys/syscall.h>
+#endif
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
@@ -48,6 +54,9 @@
#include "winreg.h"
#include "winternl.h"
+#undef NDEBUG
+#include <assert.h>
+
/* Because of the stupid Posix locking semantics, we need to keep
* track of all file descriptors referencing a given file, and not
* close a single one until all the locks are gone (sigh).
@@ -255,51 +264,107 @@
/****************************************************************/
-/* poll support */
+/* poll and epoll support */
+
+/* Vars used by both */
+static int active_users; /* current number of active users */
+/* Vars used by poll */
static struct fd **poll_users; /* users array */
static struct pollfd *pollfd; /* poll fd array */
static int nb_users; /* count of array entries actually in use */
-static int active_users; /* current number of active users */
static int allocated_users; /* count of allocated entries in the array */
static struct fd **freelist; /* list of free entries in the array */
+/* Vars used by epoll */
+static int epoll_fd=-1; /* File descriptor for the epoll */
+static const int EPOLL_SIZE=1024; /* "Maximal size" passed to epoll_create. This is an optimization, not a real maximum */
+static struct epoll_event *epoll_revents; /* Array for event results */
+static int epoll_revents_size; /* Number of elements in epoll_revents */
+
+#if defined(HAVE_EPOLL_CREATE) && defined(HAVE_SYS_SYSCALL_H)
+/* To prevent wine from not loading on non-epoll supporting platforms,
+ * we need to dynamically call the epoll functions */
+static inline int _epoll_create( int size )
+{
+ return syscall(__NR_epoll_create, size);
+}
+
+static inline int _epoll_ctl(int epfd, int op, int fd, struct epoll_event *event)
+{
+ return syscall(__NR_epoll_ctl, epfd, op, fd, event);
+}
+
+static inline int _epoll_wait(int epfd, struct epoll_event *events, int maxevents, int timeout)
+{
+ return syscall(__NR_epoll_wait, epfd, events, maxevents, timeout);
+}
+#else
+static inline int _epoll_create( int size )
+{
+ errno=ENOSYS;
+ return -1;
+}
+
+static inline int _epoll_ctl(int epfd, int op, int fd, struct epoll_event *event)
+{
+ errno=ENOSYS;
+ return -1;
+}
+
+static inline int _epoll_wait(int epfd, struct epoll_event *events, int maxevents, int timeout)
+{
+ errno=ENOSYS;
+ return -1;
+}
+#endif
+
+
/* add a user in the poll array and return its index, or -1 on failure */
static int add_poll_user( struct fd *fd )
{
int ret;
- if (freelist)
+ if( epoll_fd>=0 ) /* We are using the epoll interface */
{
- ret = freelist - poll_users;
- freelist = (struct fd **)poll_users[ret];
+ /* No poll array when using epoll - always return 1 */
+ ret=1;
}
else
- {
- if (nb_users == allocated_users)
+ { /* We are using the poll interface */
+ if (freelist)
{
- struct fd **newusers;
- struct pollfd *newpoll;
- int new_count = allocated_users ? (allocated_users + allocated_users / 2) : 16;
- if (!(newusers = realloc( poll_users, new_count * sizeof(*poll_users) ))) return -1;
- if (!(newpoll = realloc( pollfd, new_count * sizeof(*pollfd) )))
+ ret = freelist - poll_users;
+ freelist = (struct fd **)poll_users[ret];
+ }
+ else
+ {
+ if (nb_users == allocated_users)
{
- if (allocated_users)
- poll_users = newusers;
- else
- free( newusers );
- return -1;
+ struct fd **newusers;
+ struct pollfd *newpoll;
+ int new_count = allocated_users ? (allocated_users + allocated_users / 2) : 16;
+ if (!(newusers = realloc( poll_users, new_count * sizeof(*poll_users) ))) return -1;
+ if (!(newpoll = realloc( pollfd, new_count * sizeof(*pollfd) )))
+ {
+ if (allocated_users)
+ poll_users = newusers;
+ else
+ free( newusers );
+ return -1;
+ }
+ poll_users = newusers;
+ pollfd = newpoll;
+ allocated_users = new_count;
}
- poll_users = newusers;
- pollfd = newpoll;
- allocated_users = new_count;
- }
- ret = nb_users++;
- }
- pollfd[ret].fd = -1;
- pollfd[ret].events = 0;
- pollfd[ret].revents = 0;
- poll_users[ret] = fd;
+ ret = nb_users++;
+ }
+ pollfd[ret].fd = -1;
+ pollfd[ret].events = 0;
+ pollfd[ret].revents = 0;
+ poll_users[ret] = fd;
+ }
active_users++;
+
return ret;
}
@@ -307,15 +372,37 @@
static void remove_poll_user( struct fd *fd, int user )
{
assert( user >= 0 );
- assert( poll_users[user] == fd );
- pollfd[user].fd = -1;
- pollfd[user].events = 0;
- pollfd[user].revents = 0;
- poll_users[user] = (struct fd *)freelist;
- freelist = &poll_users[user];
+ if( epoll_fd>=0 )
+ {
+ if( fd->unix_fd!=-1 )
+ {
+ struct epoll_event event; /* This struct needn't actually contain anything meaningful, as we are merely calling DEL */
+ if(!(_epoll_ctl(epoll_fd, EPOLL_CTL_DEL, fd->unix_fd, &event)==0 || errno==ENOENT))
+ {
+ int err;
+ err=errno;
+ }
+ }
+ }
+ else
+ {
+ assert( poll_users[user] == fd );
+ pollfd[user].fd = -1;
+ pollfd[user].events = 0;
+ pollfd[user].revents = 0;
+ poll_users[user] = (struct fd *)freelist;
+ freelist = &poll_users[user];
+ }
active_users--;
}
+/* initialize the fd related state */
+void init_fd()
+{
+ /* If this function fails, epoll_fd will be -1, which will signal
+ * the rest of the functions to use poll instead */
+ epoll_fd=_epoll_create(EPOLL_SIZE);
+}
/* server main poll() loop */
void main_loop(void)
@@ -341,16 +428,44 @@
}
if (!active_users) break; /* last user removed by a timeout */
}
- ret = poll( pollfd, nb_users, diff );
- if (ret > 0)
+ if( epoll_fd>=0 )
{
- int i;
- for (i = 0; i < nb_users; i++)
+ /* if the event handlers added a lot of new events, we may want to increase the returned
+ * events space */
+ if( epoll_revents_size<active_users )
{
- if (pollfd[i].revents)
+ /* If epoll_revents_size is below active_users, there is a (very slim) potential for starvation.
+ * It is not, strictly speaking, an error though. As such, if the allocation fails, we just go on
+ * with the smaller array size. */
+ struct epoll_event *new_revents=malloc(sizeof(struct epoll_event)*active_users);
+ if( new_revents!=NULL )
{
- fd_poll_event( poll_users[i], pollfd[i].revents );
- if (!--ret) break;
+ free(epoll_revents);
+ epoll_revents=new_revents;
+ epoll_revents_size=active_users;
+ }
+ }
+
+ ret = epoll_wait(epoll_fd, epoll_revents, epoll_revents_size, diff );
+ while( (ret--)>0 )
+ {
+ fd_poll_event((struct fd *)epoll_revents[ret].data.ptr, epoll_revents[ret].events);
+ }
+ }
+ else
+ {
+ /* No epoll support - use poll */
+ ret = poll( pollfd, nb_users, diff );
+ if (ret > 0)
+ {
+ int i;
+ for (i = 0; i < nb_users; i++)
+ {
+ if (pollfd[i].revents)
+ {
+ fd_poll_event( poll_users[i], pollfd[i].revents );
+ if (!--ret) break;
+ }
}
}
}
@@ -835,18 +950,46 @@
/* set the events that select waits for on this fd */
void set_fd_events( struct fd *fd, int events )
{
- int user = fd->poll_index;
- assert( poll_users[user] == fd );
- if (events == -1) /* stop waiting on this fd completely */
+ if( epoll_fd>=0 )
{
- pollfd[user].fd = -1;
- pollfd[user].events = POLLERR;
- pollfd[user].revents = 0;
+ struct epoll_event event;
+ event.events=events;
+ event.data.ptr=fd;
+
+ assert(fd->unix_fd>=0);
+
+ if( events != -1 )
+ {
+ int epoll_res;
+ if( (epoll_res=_epoll_ctl(epoll_fd, EPOLL_CTL_MOD, fd->unix_fd, &event )!=0) && errno==ENOENT )
+ {
+ /* For one reason or another this file descriptor isn't being watched at the moment. Just add it */
+ assert(_epoll_ctl(epoll_fd, EPOLL_CTL_ADD, fd->unix_fd, &event )==0);
+ }
+ else
+ assert(epoll_res==0);
+ }
+ else
+ {
+ /* Stop waiting on this fd completely */
+ assert(_epoll_ctl(epoll_fd, EPOLL_CTL_DEL, fd->unix_fd, &event )==0);
+ }
}
- else if (pollfd[user].fd != -1 || !pollfd[user].events)
+ else
{
- pollfd[user].fd = fd->unix_fd;
- pollfd[user].events = events;
+ int user = fd->poll_index;
+ assert( poll_users[user] == fd );
+ if (events == -1) /* stop waiting on this fd completely */
+ {
+ pollfd[user].fd = -1;
+ pollfd[user].events = POLLERR;
+ pollfd[user].revents = 0;
+ }
+ else if (pollfd[user].fd != -1 || !pollfd[user].events)
+ {
+ pollfd[user].fd = fd->unix_fd;
+ pollfd[user].events = events;
+ }
}
}
Index: server/file.h
===================================================================
RCS file: /home/sun/sources/cvs/wine/server/file.h,v
retrieving revision 1.16
diff -u -r1.16 file.h
--- server/file.h 16 Apr 2004 04:31:35 -0000 1.16
+++ server/file.h 24 Aug 2004 13:34:21 -0000
@@ -44,6 +44,7 @@
/* file descriptor functions */
+extern void init_fd();
extern struct fd *alloc_fd( const struct fd_ops *fd_user_ops, struct object *user );
extern struct fd *open_fd( struct fd *fd, const char *name, int flags, mode_t *mode,
unsigned int access, unsigned int sharing, unsigned int options );
Index: server/main.c
===================================================================
RCS file: /home/sun/sources/cvs/wine/server/main.c,v
retrieving revision 1.31
diff -u -r1.31 main.c
--- server/main.c 26 Mar 2003 01:32:18 -0000 1.31
+++ server/main.c 24 Aug 2004 15:49:33 -0000
@@ -122,6 +122,7 @@
signal( SIGTERM, sigterm_handler );
signal( SIGABRT, sigterm_handler );
+ init_fd();
sock_init();
open_master_socket();
sync_namespace = create_namespace( 37, TRUE );
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