1 files changed, 5 insertions, 29 deletions

diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index e71ebcd7a7..11e1e21291 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -432,16 +432,6 @@ func allgadd(gp *g) {
 	lock(&allglock)
 	allgs = append(allgs, gp)
 	allglen = uintptr(len(allgs))
-
-	// Grow GC rescan list if necessary.
-	if len(allgs) > cap(work.rescan.list) {
-		lock(&work.rescan.lock)
-		l := work.rescan.list
-		// Let append do the heavy lifting, but keep the
-		// length the same.
-		work.rescan.list = append(l[:cap(l)], 0)[:len(l)]
-		unlock(&work.rescan.lock)
-	}
 	unlock(&allglock)
 }
 
@@ -795,9 +785,8 @@ func casgstatus(gp *g, oldval, newval uint32) {
 			nextYield = nanotime() + yieldDelay/2
 		}
 	}
-	if newval == _Grunning && gp.gcscanvalid {
-		// Run queueRescan on the system stack so it has more space.
-		systemstack(func() { queueRescan(gp) })
+	if newval == _Grunning {
+		gp.gcscanvalid = false
 	}
 }
 
@@ -1481,9 +1470,8 @@ func oneNewExtraM() {
 	gp.syscallpc = gp.sched.pc
 	gp.syscallsp = gp.sched.sp
 	gp.stktopsp = gp.sched.sp
-	gp.gcscanvalid = true // fresh G, so no dequeueRescan necessary
+	gp.gcscanvalid = true
 	gp.gcscandone = true
-	gp.gcRescan = -1
 	// malg returns status as Gidle, change to Gsyscall before adding to allg
 	// where GC will see it.
 	casgstatus(gp, _Gidle, _Gsyscall)
@@ -2346,8 +2334,7 @@ func goexit0(gp *g) {
 	gp.labels = nil
 
 	// Note that gp's stack scan is now "valid" because it has no
-	// stack. We could dequeueRescan, but that takes a lock and
-	// isn't really necessary.
+	// stack.
 	gp.gcscanvalid = true
 	dropg()
 
@@ -2875,7 +2862,6 @@ func newproc1(fn *funcval, argp *uint8, narg int32, nret int32, callerpc uintptr
 	if newg == nil {
 		newg = malg(_StackMin)
 		casgstatus(newg, _Gidle, _Gdead)
-		newg.gcRescan = -1
 		allgadd(newg) // publishes with a g->status of Gdead so GC scanner doesn't look at uninitialized stack.
 	}
 	if newg.stack.hi == 0 {
@@ -2927,17 +2913,7 @@ func newproc1(fn *funcval, argp *uint8, narg int32, nret int32, callerpc uintptr
 	if isSystemGoroutine(newg) {
 		atomic.Xadd(&sched.ngsys, +1)
 	}
-	// The stack is dirty from the argument frame, so queue it for
-	// scanning. Do this before setting it to runnable so we still
-	// own the G. If we're recycling a G, it may already be on the
-	// rescan list.
-	if newg.gcRescan == -1 {
-		queueRescan(newg)
-	} else {
-		// The recycled G is already on the rescan list. Just
-		// mark the stack dirty.
-		newg.gcscanvalid = false
-	}
+	newg.gcscanvalid = false
 	casgstatus(newg, _Gdead, _Grunnable)
 
 	if _p_.goidcache == _p_.goidcacheend {