runtime: rewrite a comment in malloc.go

This commit changes the wording of a comment in malloc.go that describes
how span objects are zeroed to make it more clear.

Change-Id: I07722df1e101af3cbf8680ad07437d4a230b0168
GitHub-Last-Rev: 0e909898c709a9119cea7dbd80c25d9d7a73e22b
GitHub-Pull-Request: golang/go#37008
Reviewed-on: https://go-review.googlesource.com/c/go/+/217618
Reviewed-by: Austin Clements <austin@google.com>

diff --git a/src/runtime/malloc.go b/src/runtime/malloc.go
index de363408e7de0f278e7b681b86918705925df9ab..5f92e7480ee0485911f197c75c9d5257e5545dd9 100644 (file)
--- a/src/runtime/malloc.go
+++ b/src/runtime/malloc.go
@@ -62,9 +62,10 @@
 // Allocating and freeing a large object uses the mheap
 // directly, bypassing the mcache and mcentral.
 //
-// Free object slots in an mspan are zeroed only if mspan.needzero is
-// false. If needzero is true, objects are zeroed as they are
-// allocated. There are various benefits to delaying zeroing this way:
+// If mspan.needzero is false, then free object slots in the mspan are
+// already zeroed. Otherwise if needzero is true, objects are zeroed as
+// they are allocated. There are various benefits to delaying zeroing
+// this way:
 //
 //     1. Stack frame allocation can avoid zeroing altogether.
 //