From: Dmitriy Vyukov <dvyukov@google.com>
Date: Thu, 9 Oct 2014 13:05:38 +0000 (+0400)
Subject: runtime: add comment to mgc0.h
X-Git-Tag: go1.4beta1~146
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=f1c0899e6f1219921200d66f56c22807156096c1;p=gostls13.git

runtime: add comment to mgc0.h
Missed that comment in CL 153990043.

LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/156010043
---

diff --git a/src/runtime/mgc0.h b/src/runtime/mgc0.h
index 10f24d009f..64f8189143 100644
--- a/src/runtime/mgc0.h
+++ b/src/runtime/mgc0.h
@@ -42,6 +42,8 @@ enum {
 	BitsMask	= (1<<BitsPerPointer)-1,
 	PointersPerByte	= 8/BitsPerPointer,
 
+	// If you change these, also change scanblock.
+	// scanblock does "if(bits == BitsScalar || bits == BitsDead)" as "if(bits <= BitsScalar)".
 	BitsDead	= 0,
 	BitsScalar	= 1,
 	BitsPointer	= 2,