Revert "runtime: make NumGoroutine and Stack agree not to include system goroutines"

This reverts commit c5bafc82.

Change-Id: Ie7030c978c6263b9e996d5aa0e490086796df26d
Reviewed-on: https://go-review.googlesource.com/18431Reviewed-by: Russ Cox <rsc@golang.org>

src/runtime/mprof.go

@@ -576,17 +576,12 @@ func Stack(buf []byte, all bool) int {
 		pc := getcallerpc(unsafe.Pointer(&buf))
 		systemstack(func() {
 			g0 := getg()
-			// Force traceback=1 to override GOTRACEBACK setting,
-			// so that Stack's results are consistent.
-			// GOTRACEBACK is only about crash dumps.
-			g0.m.traceback = 1
 			g0.writebuf = buf[0:0:len(buf)]
 			goroutineheader(gp)
 			traceback(pc, sp, 0, gp)
 			if all {
 				tracebackothers(gp)
 			}
-			g0.m.traceback = 0
 			n = len(g0.writebuf)
 			g0.writebuf = nil
 		})

src/runtime/proc.go

@@ -2162,9 +2162,6 @@ func goexit0(gp *g) {
 	_g_ := getg()
 
 	casgstatus(gp, _Grunning, _Gdead)
-	if isSystemGoroutine(gp) {
-		atomic.Xadd(&sched.ngsys, -1)
-	}
 	gp.m = nil
 	gp.lockedm = nil
 	_g_.m.lockedg = nil
@@ -2696,9 +2693,6 @@ func newproc1(fn *funcval, argp *uint8, narg int32, nret int32, callerpc uintptr
 	gostartcallfn(&newg.sched, fn)
 	newg.gopc = callerpc
 	newg.startpc = fn.fn
-	if isSystemGoroutine(newg) {
-		atomic.Xadd(&sched.ngsys, +1)
-	}
 	casgstatus(newg, _Gdead, _Grunnable)
 
 	if _p_.goidcache == _p_.goidcacheend {
@@ -2891,7 +2885,7 @@ func badunlockosthread() {
 }
 
 func gcount() int32 {
-	n := int32(allglen) - sched.ngfree - int32(atomic.Load(&sched.ngsys))
+	n := int32(allglen) - sched.ngfree
 	for i := 0; ; i++ {
 		_p_ := allp[i]
 		if _p_ == nil {

src/runtime/proc_test.go

@@ -9,7 +9,6 @@ import (
 	"net"
 	"runtime"
 	"runtime/debug"
-	"strings"
 	"sync"
 	"sync/atomic"
 	"syscall"
@@ -337,23 +336,6 @@ func TestGCFairness(t *testing.T) {
 	}
 }
 
-func TestNumGoroutine(t *testing.T) {
-	output := runTestProg(t, "testprog", "NumGoroutine")
-	want := "1\n"
-	if output != want {
-		t.Fatalf("want %q, got %q", want, output)
-	}
-
-	buf := make([]byte, 1<<20)
-	buf = buf[:runtime.Stack(buf, true)]
-
-	n := runtime.NumGoroutine()
-
-	if nstk := strings.Count(string(buf), "goroutine "); n != nstk {
-		t.Fatalf("NumGoroutine=%d, but found %d goroutines in stack dump", n, nstk)
-	}
-}
-
 func TestPingPongHog(t *testing.T) {
 	if testing.Short() {
 		t.Skip("skipping in -short mode")

src/runtime/runtime2.go

@@ -418,8 +418,6 @@ type schedt struct {
 	mcount       int32    // number of m's that have been created
 	maxmcount    int32    // maximum number of m's allowed (or die)
 
-	ngsys uint32 // number of system goroutines; updated atomically
-
 	pidle      puintptr // idle p's
 	npidle     uint32
 	nmspinning uint32 // See "Worker thread parking/unparking" comment in proc.go.

src/runtime/testdata/testprog/misc.go

-// Copyright 2016 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 main
-
-import "runtime"
-
-func init() {
-	register("NumGoroutine", NumGoroutine)
-}
-
-func NumGoroutine() {
-	println(runtime.NumGoroutine())
-}