[dev.power64] runtime: switch back to old initial stack size, and disable...

[dev.power64] runtime: switch back to old initial stack size, and disable debugging messages for rewindmorestack

LGTM=rsc
R=rsc, iant
CC=golang-codereviews
https://golang.org/cl/129850044

src/pkg/runtime/stack.h

@@ -76,7 +76,7 @@ enum {
 	// The minimum stack segment size to allocate.
 	// If the amount needed for the splitting frame + StackExtra
 	// is less than this number, the stack will have this size instead.
-	StackMin = 65536,
+	StackMin = 8192,
 	StackSystemRounded = StackSystem + (-StackSystem & (StackMin-1)),
 	FixedStack = StackMin + StackSystemRounded,
 

src/pkg/runtime/sys_power64x.c

@@ -28,7 +28,7 @@ runtime·rewindmorestack(Gobuf *gobuf)
 
 	inst = *(uint32*)gobuf->pc;
 	if((gobuf->pc&3) == 0 && (inst>>24) == 0x4b && (inst&3) == 0) {
-		runtime·printf("runtime: rewind pc=%p to pc=%p\n", gobuf->pc, gobuf->pc + ((int32)(inst<<8)>>8));
+		//runtime·printf("runtime: rewind pc=%p to pc=%p\n", gobuf->pc, gobuf->pc + ((int32)(inst<<8)>>8));
 		gobuf->pc += (int32)(inst<<8)>>8;
 		return;
 	}