runtime: document that GC blocks the whole program

No code changes. Just make it clear that runtime.GC is not concurrent.

Change-Id: I00a99ebd26402817c665c9a128978cef19f037be
Reviewed-on: https://go-review.googlesource.com/12345
Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

diff --git a/src/runtime/mgc.go b/src/runtime/mgc.go
index 4eff8fc59b6ab3510f03e073214107e4ad34bf4c..5bd624293250c342d5be982d1267f3789bd4af18 100644 (file)
--- a/src/runtime/mgc.go
+++ b/src/runtime/mgc.go
@@ -770,7 +770,7 @@ var work struct {
        initialHeapLive uint64
 }
 
-// GC runs a garbage collection and blocks until the garbage
+// GC runs a garbage collection and blocks the entire program until the
 // collection is complete.
 func GC() {
        startGC(gcForceBlockMode)