runtime: convert g.atomicstatus to internal atomic type

Note that this changes some unsynchronized operations of g.atomicstatus to synchronized operations.

Updates #53821

Change-Id: If249d62420ea09fbec39b570942f96c63669c333
Reviewed-on: https://go-review.googlesource.com/c/go/+/425363
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>

src/runtime/export_debug_test.go

@@ -109,7 +109,7 @@ func (h *debugCallHandler) inject(info *siginfo, ctxt *sigctxt, gp2 *g) bool {
 	// a signal handler. Add the go:nowritebarrierrec annotation and restructure
 	// this to avoid write barriers.
 
-	switch h.gp.atomicstatus {
+	switch h.gp.atomicstatus.Load() {
 	case _Grunning:
 		if getg().m != h.mp {
 			println("trap on wrong M", getg().m, h.mp)

src/runtime/proc.go

@@ -899,7 +899,7 @@ func freezetheworld() {
 //
 //go:nosplit
 func readgstatus(gp *g) uint32 {
-	return atomic.Load(&gp.atomicstatus)
+	return gp.atomicstatus.Load()
 }
 
 // The Gscanstatuses are acting like locks and this releases them.
@@ -921,7 +921,7 @@ func casfrom_Gscanstatus(gp *g, oldval, newval uint32) {
 		_Gscansyscall,
 		_Gscanpreempted:
 		if newval == oldval&^_Gscan {
-			success = atomic.Cas(&gp.atomicstatus, oldval, newval)
+			success = gp.atomicstatus.CompareAndSwap(oldval, newval)
 		}
 	}
 	if !success {
@@ -941,7 +941,7 @@ func castogscanstatus(gp *g, oldval, newval uint32) bool {
 		_Gwaiting,
 		_Gsyscall:
 		if newval == oldval|_Gscan {
-			r := atomic.Cas(&gp.atomicstatus, oldval, newval)
+			r := gp.atomicstatus.CompareAndSwap(oldval, newval)
 			if r {
 				acquireLockRank(lockRankGscan)
 			}
@@ -977,15 +977,15 @@ func casgstatus(gp *g, oldval, newval uint32) {
 
 	// loop if gp->atomicstatus is in a scan state giving
 	// GC time to finish and change the state to oldval.
-	for i := 0; !atomic.Cas(&gp.atomicstatus, oldval, newval); i++ {
-		if oldval == _Gwaiting && gp.atomicstatus == _Grunnable {
+	for i := 0; !gp.atomicstatus.CompareAndSwap(oldval, newval); i++ {
+		if oldval == _Gwaiting && gp.atomicstatus.Load() == _Grunnable {
 			throw("casgstatus: waiting for Gwaiting but is Grunnable")
 		}
 		if i == 0 {
 			nextYield = nanotime() + yieldDelay
 		}
 		if nanotime() < nextYield {
-			for x := 0; x < 10 && gp.atomicstatus != oldval; x++ {
+			for x := 0; x < 10 && gp.atomicstatus.Load() != oldval; x++ {
 				procyield(1)
 			}
 		} else {
@@ -1040,7 +1040,7 @@ func casgcopystack(gp *g) uint32 {
 		if oldstatus != _Gwaiting && oldstatus != _Grunnable {
 			throw("copystack: bad status, not Gwaiting or Grunnable")
 		}
-		if atomic.Cas(&gp.atomicstatus, oldstatus, _Gcopystack) {
+		if gp.atomicstatus.CompareAndSwap(oldstatus, _Gcopystack) {
 			return oldstatus
 		}
 	}
@@ -1055,7 +1055,7 @@ func casGToPreemptScan(gp *g, old, new uint32) {
 		throw("bad g transition")
 	}
 	acquireLockRank(lockRankGscan)
-	for !atomic.Cas(&gp.atomicstatus, _Grunning, _Gscan|_Gpreempted) {
+	for !gp.atomicstatus.CompareAndSwap(_Grunning, _Gscan|_Gpreempted) {
 	}
 }
 
@@ -1066,7 +1066,7 @@ func casGFromPreempted(gp *g, old, new uint32) bool {
 	if old != _Gpreempted || new != _Gwaiting {
 		throw("bad g transition")
 	}
-	return atomic.Cas(&gp.atomicstatus, _Gpreempted, _Gwaiting)
+	return gp.atomicstatus.CompareAndSwap(_Gpreempted, _Gwaiting)
 }
 
 // stopTheWorld stops all P's from executing goroutines, interrupting

src/runtime/runtime-gdb.py

@@ -447,7 +447,7 @@ class GoroutinesCmd(gdb.Command):
 		# args = gdb.string_to_argv(arg)
 		vp = gdb.lookup_type('void').pointer()
 		for ptr in SliceValue(gdb.parse_and_eval("'runtime.allgs'")):
-			if ptr['atomicstatus'] == G_DEAD:
+			if ptr['atomicstatus']['value'] == G_DEAD:
 				continue
 			s = ' '
 			if ptr['m']:
@@ -455,7 +455,7 @@ class GoroutinesCmd(gdb.Command):
 			pc = ptr['sched']['pc'].cast(vp)
 			pc = pc_to_int(pc)
 			blk = gdb.block_for_pc(pc)
-			status = int(ptr['atomicstatus'])
+			status = int(ptr['atomicstatus']['value'])
 			st = sts.get(status, "unknown(%d)" % status)
 			print(s, ptr['goid'], "{0:8s}".format(st), blk.function)
 
@@ -472,7 +472,7 @@ def find_goroutine(goid):
 	"""
 	vp = gdb.lookup_type('void').pointer()
 	for ptr in SliceValue(gdb.parse_and_eval("'runtime.allgs'")):
-		if ptr['atomicstatus'] == G_DEAD:
+		if ptr['atomicstatus']['value'] == G_DEAD:
 			continue
 		if ptr['goid'] == goid:
 			break
@@ -480,7 +480,7 @@ def find_goroutine(goid):
 		return None, None
 	# Get the goroutine's saved state.
 	pc, sp = ptr['sched']['pc'], ptr['sched']['sp']
-	status = ptr['atomicstatus']&~G_SCAN
+	status = ptr['atomicstatus']['value']&~G_SCAN
 	# Goroutine is not running nor in syscall, so use the info in goroutine
 	if status != G_RUNNING and status != G_SYSCALL:
 		return pc.cast(vp), sp.cast(vp)

src/runtime/runtime2.go

@@ -435,7 +435,7 @@ type g struct {
 	// 3. By debugCallWrap to pass parameters to a new goroutine because allocating a
 	//    closure in the runtime is forbidden.
 	param        unsafe.Pointer
-	atomicstatus uint32
+	atomicstatus atomic.Uint32
 	stackLock    uint32 // sigprof/scang lock; TODO: fold in to atomicstatus
 	goid         uint64
 	schedlink    guintptr