runtime: convert g.parkingOnChan to atomic type

Updates #53821

Change-Id: I54de39b984984fb3c160aba5afacb90131fd47c4
Reviewed-on: https://go-review.googlesource.com/c/go/+/424394
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>

diff --git a/src/runtime/chan.go b/src/runtime/chan.go
index ca516ad9e8b8489086a879d8285c3d5c2d30860f..853a300ab52bf352f37c3bf91e09852ee2f108d7 100644 (file)
--- a/src/runtime/chan.go
+++ b/src/runtime/chan.go
@@ -255,7 +255,7 @@ func chansend(c *hchan, ep unsafe.Pointer, block bool, callerpc uintptr) bool {
        // to park on a channel. The window between when this G's status
        // changes and when we set gp.activeStackChans is not safe for
        // stack shrinking.
-       atomic.Store8(&gp.parkingOnChan, 1)
+       gp.parkingOnChan.Store(true)
        gopark(chanparkcommit, unsafe.Pointer(&c.lock), waitReasonChanSend, traceEvGoBlockSend, 2)
        // Ensure the value being sent is kept alive until the
        // receiver copies it out. The sudog has a pointer to the
@@ -579,7 +579,7 @@ func chanrecv(c *hchan, ep unsafe.Pointer, block bool) (selected, received bool)
        // to park on a channel. The window between when this G's status
        // changes and when we set gp.activeStackChans is not safe for
        // stack shrinking.
-       atomic.Store8(&gp.parkingOnChan, 1)
+       gp.parkingOnChan.Store(true)
        gopark(chanparkcommit, unsafe.Pointer(&c.lock), waitReasonChanReceive, traceEvGoBlockRecv, 2)
 
        // someone woke us up
@@ -664,7 +664,7 @@ func chanparkcommit(gp *g, chanLock unsafe.Pointer) bool {
        // Mark that it's safe for stack shrinking to occur now,
        // because any thread acquiring this G's stack for shrinking
        // is guaranteed to observe activeStackChans after this store.
-       atomic.Store8(&gp.parkingOnChan, 0)
+       gp.parkingOnChan.Store(false)
        // Make sure we unlock after setting activeStackChans and
        // unsetting parkingOnChan. The moment we unlock chanLock
        // we risk gp getting readied by a channel operation and

diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go
index 32ad34ccdf1dc9d0bc3bb634789f90a10f5295d2..2fbb1d1744d0d99c85c72e7157c667ded68ab68d 100644 (file)
--- a/src/runtime/runtime2.go
+++ b/src/runtime/runtime2.go
@@ -461,8 +461,8 @@ type g struct {
        activeStackChans bool
        // parkingOnChan indicates that the goroutine is about to
        // park on a chansend or chanrecv. Used to signal an unsafe point
-       // for stack shrinking. It's a boolean value, but is updated atomically.
-       parkingOnChan uint8
+       // for stack shrinking.
+       parkingOnChan atomic.Bool
 
        raceignore     int8     // ignore race detection events
        sysblocktraced bool     // StartTrace has emitted EvGoInSyscall about this goroutine

diff --git a/src/runtime/select.go b/src/runtime/select.go
index e18b2f14c08cc1b3b5bf838dca6899a3975cea00..2dd6333fa7ab86ccbbacd7a4c1593db3c4c9c960 100644 (file)
--- a/src/runtime/select.go
+++ b/src/runtime/select.go
@@ -8,7 +8,6 @@ package runtime
 
 import (
        "internal/abi"
-       "runtime/internal/atomic"
        "unsafe"
 )
 
@@ -70,7 +69,7 @@ func selparkcommit(gp *g, _ unsafe.Pointer) bool {
        // Mark that it's safe for stack shrinking to occur now,
        // because any thread acquiring this G's stack for shrinking
        // is guaranteed to observe activeStackChans after this store.
-       atomic.Store8(&gp.parkingOnChan, 0)
+       gp.parkingOnChan.Store(false)
        // Make sure we unlock after setting activeStackChans and
        // unsetting parkingOnChan. The moment we unlock any of the
        // channel locks we risk gp getting readied by a channel operation
@@ -324,7 +323,7 @@ func selectgo(cas0 *scase, order0 *uint16, pc0 *uintptr, nsends, nrecvs int, blo
        // to park on a channel. The window between when this G's status
        // changes and when we set gp.activeStackChans is not safe for
        // stack shrinking.
-       atomic.Store8(&gp.parkingOnChan, 1)
+       gp.parkingOnChan.Store(true)
        gopark(selparkcommit, nil, waitReasonSelect, traceEvGoBlockSelect, 1)
        gp.activeStackChans = false
 

diff --git a/src/runtime/stack.go b/src/runtime/stack.go
index 2a7f0bd1c3f6cdc1169b12b16091e772c7df22c1..0bfa9320e0a4ea806c45d91219d5b8a0e1607102 100644 (file)
--- a/src/runtime/stack.go
+++ b/src/runtime/stack.go
@@ -886,7 +886,7 @@ func copystack(gp *g, newsize uintptr) {
        // Adjust sudogs, synchronizing with channel ops if necessary.
        ncopy := used
        if !gp.activeStackChans {
-               if newsize < old.hi-old.lo && atomic.Load8(&gp.parkingOnChan) != 0 {
+               if newsize < old.hi-old.lo && gp.parkingOnChan.Load() {
                        // It's not safe for someone to shrink this stack while we're actively
                        // parking on a channel, but it is safe to grow since we do that
                        // ourselves and explicitly don't want to synchronize with channels
@@ -1150,7 +1150,7 @@ func isShrinkStackSafe(gp *g) bool {
        // We also can't *shrink* the stack in the window between the
        // goroutine calling gopark to park on a channel and
        // gp.activeStackChans being set.
-       return gp.syscallsp == 0 && !gp.asyncSafePoint && atomic.Load8(&gp.parkingOnChan) == 0
+       return gp.syscallsp == 0 && !gp.asyncSafePoint && !gp.parkingOnChan.Load()
 }
 
 // Maybe shrink the stack being used by gp.