runtime: fix out of date comments

The transition from mark 1 to mark 2 no longer enqueues new root
marking jobs, but some of the comments still refer to this. Fix these
comments.

Change-Id: I3f98628dba32c5afe30495ab495da42b32291e9e
Reviewed-on: https://go-review.googlesource.com/24965
Reviewed-by: Rick Hudson <rlh@golang.org>

diff --git a/src/runtime/mgc.go b/src/runtime/mgc.go
index 1efbace63caf7dd2d03f45be9ed2afc12b6db09f..cd5ddadd49734707da1ded7d8a3505d1bfefbf08 100644 (file)
--- a/src/runtime/mgc.go
+++ b/src/runtime/mgc.go
@@ -1073,9 +1073,8 @@ top:
                // Transition from mark 1 to mark 2.
                //
                // The global work list is empty, but there can still be work
-               // sitting in the per-P work caches and there can be more
-               // objects reachable from global roots since they don't have write
-               // barriers. Rescan some roots and flush work caches.
+               // sitting in the per-P work caches.
+               // Flush and disable work caches.
 
                gcMarkRootCheck()
 
@@ -1095,8 +1094,7 @@ top:
                        // ensure all Ps see gcBlackenPromptly. This
                        // also blocks until any remaining mark 1
                        // workers have exited their loop so we can
-                       // start new mark 2 workers that will observe
-                       // the new root marking jobs.
+                       // start new mark 2 workers.
                        forEachP(func(_p_ *p) {
                                _p_.gcw.dispose()
                        })