runtime: convert Gosched to Go

LGTM=rlh, khr
R=golang-codereviews, rlh, bradfitz, khr
CC=golang-codereviews, rsc
https://golang.org/cl/127490043

src/pkg/runtime/extern.go

@@ -73,10 +73,6 @@ of the run-time system.
 */
 package runtime
 
-// Gosched yields the processor, allowing other goroutines to run.  It does not
-// suspend the current goroutine, so execution resumes automatically.
-func Gosched()
-
 // Goexit terminates the goroutine that calls it.  No other goroutine is affected.
 // Goexit runs all deferred calls before terminating the goroutine.
 //

src/pkg/runtime/proc.c

@@ -1449,15 +1449,15 @@ park0(G *gp)
 void
 runtime·gosched(void)
 {
-	if(g->status != Grunning)
+	runtime·mcall(runtime·gosched_m);
-		runtime·throw("bad g status");
-	runtime·mcall(runtime·gosched0);
 }
 
 // runtime·gosched continuation on g0.
 void
-runtime·gosched0(G *gp)
+runtime·gosched_m(G *gp)
 {
+	if(gp->status != Grunning)
+		runtime·throw("bad g status");
 	gp->status = Grunnable;
 	dropg();
 	runtime·lock(&runtime·sched.lock);
@@ -2055,12 +2055,6 @@ runtime·Breakpoint(void)
 	runtime·breakpoint();
 }
 
-void
-runtime·Gosched(void)
-{
-	runtime·gosched();
-}
-
 // Implementation of runtime.GOMAXPROCS.
 // delete when scheduler is even stronger
 int32

src/pkg/runtime/proc.go

@@ -0,0 +1,11 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package runtime
+
+// Gosched yields the processor, allowing other goroutines to run.  It does not
+// suspend the current goroutine, so execution resumes automatically.
+func Gosched() {
+	mcall(&gosched_m)
+}

src/pkg/runtime/runtime.h

@@ -919,7 +919,7 @@ void	runtime·newextram(void);
 void	runtime·exit(int32);
 void	runtime·breakpoint(void);
 void	runtime·gosched(void);
-void	runtime·gosched0(G*);
+void	runtime·gosched_m(G*);
 void	runtime·schedtrace(bool);
 void	runtime·park(bool(*)(G*, void*), void*, int8*);
 void	runtime·parkunlock(Lock*, int8*);

src/pkg/runtime/stack.c

@@ -903,7 +903,7 @@ runtime·newstack(void)
 		}
 		// Act like goroutine called runtime.Gosched.
 		gp->status = oldstatus;
-		runtime·gosched0(gp);	// never return
+		runtime·gosched_m(gp);	// never return
 	}
 
 	// If every frame on the top segment is copyable, allocate a bigger segment

src/pkg/runtime/stubs.go

@@ -68,7 +68,8 @@ var (
 	setFinalizer_m,
 	markallocated_m,
 	unrollgcprog_m,
-	unrollgcproginplace_m mFunction
+	unrollgcproginplace_m,
+	gosched_m mFunction
 )
 
 // memclr clears n bytes starting at ptr.