runtime: convert p.statsSeq to internal atomic type

For #53821.

Change-Id: I1cab3671a29c218b8a927aba9064e63b65900173
Reviewed-on: https://go-review.googlesource.com/c/go/+/425416
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Michael Pratt <mpratt@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Run-TryBot: hopehook <hopehook@qq.com>

src/runtime/mstats.go

@@ -759,7 +759,7 @@ type consistentHeapStats struct {
 //go:nosplit
 func (m *consistentHeapStats) acquire() *heapStatsDelta {
 	if pp := getg().m.p.ptr(); pp != nil {
-		seq := atomic.Xadd(&pp.statsSeq, 1)
+		seq := pp.statsSeq.Add(1)
 		if seq%2 == 0 {
 			// Should have been incremented to odd.
 			print("runtime: seq=", seq, "\n")
@@ -788,7 +788,7 @@ func (m *consistentHeapStats) acquire() *heapStatsDelta {
 //go:nosplit
 func (m *consistentHeapStats) release() {
 	if pp := getg().m.p.ptr(); pp != nil {
-		seq := atomic.Xadd(&pp.statsSeq, 1)
+		seq := pp.statsSeq.Add(1)
 		if seq%2 != 0 {
 			// Should have been incremented to even.
 			print("runtime: seq=", seq, "\n")
@@ -862,7 +862,7 @@ func (m *consistentHeapStats) read(out *heapStatsDelta) {
 
 	for _, p := range allp {
 		// Spin until there are no more writers.
-		for atomic.Load(&p.statsSeq)%2 != 0 {
+		for p.statsSeq.Load()%2 != 0 {
 		}
 	}
 

src/runtime/runtime2.go

@@ -708,7 +708,7 @@ type p struct {
 
 	// statsSeq is a counter indicating whether this P is currently
 	// writing any stats. Its value is even when not, odd when it is.
-	statsSeq uint32
+	statsSeq atomic.Uint32
 
 	// Lock for timers. We normally access the timers while running
 	// on this P, but the scheduler can also do it from a different P.