reduce impact of linux on the previous kevent changes

Signed-off-by: Daniel A. Steffen <dsteffen@apple.com>

Author: frankeh

configure.ac

@@ -139,10 +139,6 @@ AC_SEARCH_LIBS(pthread_create, pthread)
 AC_CHECK_HEADER(sys/event.h, [],
   [PKG_CHECK_MODULES(KQUEUE, libkqueue)]
 )
-AC_SEARCH_LIBS(kevent, kqueue)
-AC_SEARCH_LIBS(kevent64, kqueue,
-               [AC_DEFINE(HAVE_KEVENT64, 1, [Define if kevent64 is present])],
-               [AC_DEFINE(HAVE_KEVENT64, 0, [Define if kevent64 is present])])
 
 #
 # Checks for header files.

os/linux_base.h

@@ -78,7 +78,7 @@ struct voucher_offsets_s {
  * Stub out defines for other missing types
  */
 
-#if !HAVE_KEVENT64
+#if __linux__
 // we fall back to use kevent
 #define kevent64_s kevent
 #define kevent64(kq,cl,nc,el,ne,f,to)  kevent(kq,cl,nc,el,ne,to)

src/shims/linux_stubs.c

@@ -77,105 +77,6 @@ int sysctlbyname(const char *name, void *oldp, size_t *oldlenp,
   LINUX_PORT_ERROR();
 }
 
-#if 0
-
-// this code remains here purely for debugging purposes
-// ultimately it can be deleted
-
-DISPATCH_NOINLINE
-static const char *
-_evfiltstr(short filt)
-{
-        switch (filt) {
-#define _evfilt2(f) case (f): return #f
-        _evfilt2(EVFILT_READ);
-        _evfilt2(EVFILT_WRITE);
-        _evfilt2(EVFILT_AIO);
-        _evfilt2(EVFILT_VNODE);
-        _evfilt2(EVFILT_PROC);
-        _evfilt2(EVFILT_SIGNAL);
-        _evfilt2(EVFILT_TIMER);
-#if HAVE_MACH
-        _evfilt2(EVFILT_MACHPORT);
-        _evfilt2(DISPATCH_EVFILT_MACH_NOTIFICATION);
-#endif
-        _evfilt2(EVFILT_FS);
-        _evfilt2(EVFILT_USER);
-#ifdef EVFILT_VM
-        _evfilt2(EVFILT_VM);
-#endif
-#ifdef EVFILT_SOCK
-        _evfilt2(EVFILT_SOCK);
-#endif
-#ifdef EVFILT_MEMORYSTATUS
-        _evfilt2(EVFILT_MEMORYSTATUS);
-#endif
-
-        _evfilt2(DISPATCH_EVFILT_TIMER);
-        _evfilt2(DISPATCH_EVFILT_CUSTOM_ADD);
-        _evfilt2(DISPATCH_EVFILT_CUSTOM_OR);
-        default:
-                return "EVFILT_missing";
-        }
-}
-
-#if 0
-#define dbg_kevent64(fmt...)               do { printf(fmt); } while(0)
-#define dbg_cond_kevent64(cond,fmt...)     do { if (cond) printf(fmt); } while(0)
-#else
-#define dbg_kevent64(fmt...)     	   do { } while(0)
-#define dbg_cond_kevent64(cond,fmt...)     do { } while(0)
-#endif
-
-
-int kevent64(int kq, const struct kevent64_s *changelist_c, int nchanges, struct kevent64_s *eventlist,
-             int nevents, unsigned int flags, const struct timespec *timeout) 
-{
-     // Documentation is not really clear. Instrument the code to make sure
-     // we can do type conversions right now between kevent64 <-> kevent, where as 
-     // kevent64 uses the ext[2] extension. So far we only see these used in the EVFILT_TIMER.
-     // right now we do this in the way into kevent, we also have to assert that 
-     // no more than 1 change or one event is passed until we get a better handle of the
-     // usage pattern of this.  (Hubertus Franke)
-
-     struct kevent64_s *changelist = (struct kevent64_s*) changelist_c; // so we can modify it
-
-#if 1 
-     // lets put some checks in here to make sure we do it all correct
-     // we can only convert kevent64_s -> kevent for a single entry since kevent64_s has ext[0:1] extension
-     if ((nchanges > 1) || (nevents > 1)) 
- 	 LINUX_PORT_ERROR();
-     if (nchanges) { 
-	 dbg_kevent64("kevent64(%s,%x,%x): cl.ext[0,1]=%lx:%ld %lx:%ld cl.data=%lx:%ld\n", 
-	              _evfiltstr(changelist->filter), changelist->flags, changelist->fflags,
-		      changelist->ext[0], changelist->ext[0], 
-                      changelist->ext[1], changelist->ext[1],
-                      changelist->data, changelist->data);
-         if ((changelist->filter == EVFILT_TIMER) && (changelist->fflags & NOTE_ABSOLUTE)) {
-             // NOTE_ABSOLUTE is not recognized by the current kevent we need to convert this
-	     // into a relative. Consider fiddling with creating relative events instead (didn't work 
-	     // on first attempt). We also ignore the LEEWAY. Finally we must convert from 
-             // NSECS to MSECS (might have to expand to deal with OTHER NOTE_xSECS flags
-
-             //changelist->data -= _dispatch_get_nanoseconds();
-             //changelist->data -= time(NULL) * NSEC_PER_SEC;
-             dbg_kevent64("kevent64(%s,%x) data=%lx:%ld\n",
-                          _evfiltstr(changelist->filter),changelist->fflags,
-			  changelist->data,changelist->data);
-	     //changelist->data /= 1000000UL;
-	     //if ((int64_t)(changelist->data) <= 0) changelist->data = 1; // for some reason time turns negative
-         }
-     }
-#endif
-     // eventlist can not return more than 1 event type coersion doesn't work
-     int rc = kevent(kq,(struct kevent*) changelist,nchanges,(struct kevent*) eventlist,nevents,timeout);
-     if (rc > 1) 
-         LINUX_PORT_ERROR();
-     return rc;
-}
-
-#endif
-
 /*
  * Stubbed out static data
  */

src/source.c

@@ -1859,17 +1859,40 @@ _dispatch_timers_get_delay(uint64_t nows[], struct dispatch_timer_s timer[],
 }
 
 
-#if HAVE_KEVENT64
-#	define kevent_set_ext1(ke,val)  (ke)->ext[1] = (val)
-#	define adjust_delay(delay,at)   (delay) += (at)
+#ifdef __linux__ 
+// in linux we map the _dispatch_kevent_qos_s  to struct kevent instead of struct kevent64.
+// we loose the kevent.ext[] members and the time out is based on relavite msec based time
+// vs. absolute nsec based time. For now we make the adjustments right here until the solution
+// to either extend libkqueue with a proper kevent64 API or removing kevent all together 
+// and move to a lower API (e.g. epoll or kernel_module. Also leeway is ignored.
+
+static void 
+kevent_set_delay(_dispatch_kevent_qos_s *ke, uint64_t delay,uint64_t leeway, uint64_t nows[]) 
+{
+	_dispatch_source_timer_now(nows, DISPATCH_TIMER_KIND_WALL); // called to return nows[]
+	
+	delay /= 1000000L;
+        if ((int64_t)(delay) <= 0) 
+		delay = 1; /* if he value is negative or 0 then the dispatch will stop */
+	ke->data = (int64_t)delay;
+}
+
 #else
-#	define kevent_set_ext1(ke,val)  do { } while (0)
-#	define adjust_delay(delay,at)                                                              \
-              do {                                                                                 \	
-		  delay /= 1000000L;                                                               \
-                  if ((int64_t)(delay) <= 0) delay = 1; /* for some reason time turns negative */  \
-              } while (0)
 
+static void 
+kevent_set_delay(_dispatch_kevent_qos_s *ke, uint64_t delay,uint64_t leeway, uint64_t nows[]) 
+{
+
+	delay += _dispatch_source_timer_now(nows, DISPATCH_TIMER_KIND_WALL);
+	
+	if (slowpath(_dispatch_timers_force_max_leeway)) {
+		ke->data = (int64_t)(delay + leeway);
+		ke->ext[1] = 0;
+	} else {
+		ke->data = (int64_t)delay;
+		ke->ext[1] = leeway;
+	}
+}
 #endif
 
 static bool
@@ -1878,7 +1901,7 @@ _dispatch_timers_program2(uint64_t nows[], _dispatch_kevent_qos_s *ke,
 {
 	unsigned int tidx;
 	bool poll;
-	uint64_t delay, leeway, nowtime;
+	uint64_t delay, leeway;
 
 	tidx = _dispatch_timers_get_delay(nows, _dispatch_timer, &delay, &leeway,
 			(int)qos);
@@ -1895,19 +1918,12 @@ _dispatch_timers_program2(uint64_t nows[], _dispatch_kevent_qos_s *ke,
 		_dispatch_trace_next_timer_set(
 				TAILQ_FIRST(&_dispatch_kevent_timer[tidx].dk_sources), qos);
 		_dispatch_trace_next_timer_program(delay, qos);
-	        nowtime =_dispatch_source_timer_now(nows, DISPATCH_TIMER_KIND_WALL);
-	        adjust_delay(delay,nowtime);
 
-		if (slowpath(_dispatch_timers_force_max_leeway)) {
-			ke->data = (int64_t)(delay + leeway);
-	                kevent_set_ext1(ke,0);
-		} else {
-			ke->data = (int64_t)delay;
-	                kevent_set_ext1(ke,leeway);
-		}
-		ke->flags |= EV_ADD|EV_ENABLE;
-		ke->flags &= ~EV_DELETE;
+                kevent_set_delay(ke,delay,leeway,nows);
 	}
+ 
+	ke->flags |= EV_ADD|EV_ENABLE;
+	ke->flags &= ~EV_DELETE;
 	_dispatch_kq_update(ke);
 	return poll;
 }