Merge pull request apple#8 from dgrove-oss/linux-port-hdd-timers2

Linux port hdd timers2

Author: MadCoder

os/linux_base.h

@@ -20,6 +20,7 @@
 #define __OS_LINUX_BASE__
 
 // #include <sys/event.h>
+#include <sys/user.h>
 
 // marker for hacks we have made to make progress
 #define __LINUX_PORT_HDD__ 1 
@@ -76,34 +77,41 @@ struct voucher_offsets_s {
 };
 
 
+// Print a warning when an unported code path executes.
+#define LINUX_PORT_ERROR()  do { printf("LINUX_PORT_ERROR_CALLED %s:%d: %s\n",__FILE__,__LINE__,__FUNCTION__); } while (0)
+
 /*
  * Stub out defines for other missing types
  */
 
-// Pulled from OS X man page for kevent
-struct kevent64_s {
-    uint64_t        ident;          /* identifier for this event */
-    int16_t         filter;         /* filter for event */
-    uint16_t        flags;          /* general flags */
-    uint32_t        fflags;         /* filter-specific flags */
-    int64_t         data;           /* filter-specific data */
-    uint64_t        udata;          /* opaque user data identifier */
-    uint64_t        ext[2];         /* filter-specific extensions */
-};
-
+#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)
+#endif
 
-// PAGE_SIZE and SIZE_T_MAX should not be hardcoded like this here.
-#define PAGE_SIZE (4096)
+// SIZE_T_MAX should not be hardcoded like this here.
 #define SIZE_T_MAX (0x7fffffff)
 
 // Define to 0 the NOTE_ values that are not present on Linux.
 // Revisit this...would it be better to ifdef out the uses instead??
-#define NOTE_VM_PRESSURE 0
-#define NOTE_ABSOLUTE 0
-#define NOTE_NSECONDS 0
-#define NOTE_LEEWAY 0
-#define NOTE_CRITICAL 0
-#define NOTE_BACKGROUND 0
+
+// The following values are passed as part of the EVFILT_TIMER requests
+
+#define IGNORE_KEVENT64_EXT   /* will force the kevent64_s.ext[] to not be used -> leeway ignored */
+
+#define NOTE_SECONDS	0x01
+#define NOTE_USECONDS 	0x02
+#define NOTE_NSECONDS	0x04
+#define NOTE_ABSOLUTE	0x08
+#define NOTE_CRITICAL	0x10
+#define NOTE_BACKGROUND	0x20
+#define NOTE_LEEWAY	0x40
+
+// need to catch the following usage if it happens .. 
+// we simply return '0' as a value probably not correct 
+
+#define NOTE_VM_PRESSURE ({LINUX_PORT_ERROR(); 0;})
 
 /*
  * Stub out misc linking and compilation attributes
@@ -135,8 +143,5 @@ struct kevent64_s {
 #define __OSX_AVAILABLE_BUT_DEPRECATED_MSG(a,b,c,d,msg) // 
 
 
-// Print a warning when an unported code path executes.
-#define LINUX_PORT_ERROR()  do { printf("LINUX_PORT_ERROR_CALLED %s:%d: %s\n",__FILE__,__LINE__,__FUNCTION__); } while (0)
-
 
 #endif /* __OS_LINUX_BASE__ */

src/shims/linux_stubs.c

@@ -84,11 +84,6 @@ int sysctlbyname(const char *name, void *oldp, size_t *oldlenp,
   LINUX_PORT_ERROR();
 }
 
-int kevent64(int kq, const struct kevent *changelist, int nchanges, struct kevent *eventlist, int nevents,unsigned int flags, const struct timespec *timeout)
-{
-     return kevent(kq,changelist,nchanges,eventlist,nevents,timeout);
-}
-
 /*
  * Stubbed out static data
  */

src/source.c

@@ -1858,6 +1858,47 @@ _dispatch_timers_get_delay(uint64_t nows[], struct dispatch_timer_s timer[],
 	return ridx;
 }
 
+
+#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 
+_dispatch_kevent_timer_set_delay(_dispatch_kevent_qos_s *ke, uint64_t delay,
+		uint64_t leeway, uint64_t nows[]) 
+{
+	// call to return nows[]
+	_dispatch_source_timer_now(nows, DISPATCH_TIMER_KIND_WALL); 
+	// adjust nsec based delay to msec based and ignore leeway	
+	delay /= 1000000L;
+	if ((int64_t)(delay) <= 0) {
+		delay = 1; // if value <= 0 the dispatch will stop
+	}
+	ke->data = (int64_t)delay;
+}
+
+#else
+
+static void 
+_dispatch_kevent_timer_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
 _dispatch_timers_program2(uint64_t nows[], _dispatch_kevent_qos_s *ke,
 		unsigned int qos)
@@ -1881,14 +1922,7 @@ _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);
-		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;
-		}
+		_dispatch_kevent_timer_set_delay(ke, delay, leeway, nows);
 		ke->flags |= EV_ADD|EV_ENABLE;
 		ke->flags &= ~EV_DELETE;
 	}