runtime: fix LastGC comment

I have no idea what "absolute time" means.

LGTM=dvyukov, r
R=r, dvyukov
CC=golang-codereviews
https://golang.org/cl/144320043

diff --git a/src/runtime/mem.go b/src/runtime/mem.go
index b3c216f18ec60994c785f3b2fc519fb424de9b06..438f22ec09fc0aee7828a742d54b50cd16b3d699 100644 (file)
--- a/src/runtime/mem.go
+++ b/src/runtime/mem.go
@@ -41,8 +41,8 @@ type MemStats struct {
        OtherSys    uint64 // other system allocations
 
        // Garbage collector statistics.
-       NextGC       uint64 // next run in HeapAlloc time (bytes)
-       LastGC       uint64 // last run in absolute time (ns)
+       NextGC       uint64 // next collection will happen when HeapAlloc ≥ this amount
+       LastGC       uint64 // end time of last collection (nanoseconds since 1970)
        PauseTotalNs uint64
        PauseNs      [256]uint64 // circular buffer of recent GC pause times, most recent at [(NumGC+255)%256]
        NumGC        uint32