1 files changed, 21 insertions, 0 deletions
diff --git a/src/pkg/runtime/proc.go b/src/pkg/runtime/proc.go
index 32fe35e28c..6c295c7b18 100644
--- a/src/pkg/runtime/proc.go
+++ b/src/pkg/runtime/proc.go
@@ -29,6 +29,27 @@ const (
 
 var parkunlock_c byte
 
+// start forcegc helper goroutine
+func init() {
+	go func() {
+		forcegc.g = getg()
+		forcegc.g.issystem = true
+		for {
+			lock(&forcegc.lock)
+			if forcegc.idle != 0 {
+				gothrow("forcegc: phase error")
+			}
+			atomicstore(&forcegc.idle, 1)
+			goparkunlock(&forcegc.lock, "force gc (idle)")
+			// this goroutine is explicitly resumed by sysmon
+			if debug.gctrace > 0 {
+				println("GC forced")
+			}
+			gogc(1)
+		}
+	}()
+}
+
 // Gosched yields the processor, allowing other goroutines to run.  It does not
 // suspend the current goroutine, so execution resumes automatically.
 func Gosched() {