[src/trunk]: src/sys/sys Mention caution changing the defaults.

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/cbd980e89f0e
branches:  trunk
changeset: 984722:cbd980e89f0e
user:      christos <christos%NetBSD.org@localhost>
date:      Mon Jul 19 19:13:33 2021 +0000

description:
Mention caution changing the defaults.

diffstat:

 sys/sys/param.h |  10 ++++++++--
 1 files changed, 8 insertions(+), 2 deletions(-)

diffs (30 lines):

diff -r afb326e846f1 -r cbd980e89f0e sys/sys/param.h
--- a/sys/sys/param.h   Mon Jul 19 16:31:19 2021 +0000
+++ b/sys/sys/param.h   Mon Jul 19 19:13:33 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: param.h,v 1.697 2021/06/29 21:03:37 pgoyette Exp $     */
+/*     $NetBSD: param.h,v 1.698 2021/07/19 19:13:33 christos Exp $     */
 
 /*-
  * Copyright (c) 1982, 1986, 1989, 1993
@@ -200,13 +200,19 @@
 #define        dbtob(x)        ((x) << DEV_BSHIFT)
 #define        btodb(x)        ((x) >> DEV_BSHIFT)
 
-/* Coherency unit: assumed cache line size.  See also MIN_LWP_ALIGNMENT. */
+/*
+ * Coherency unit: assumed cache line size.  See also MIN_LWP_ALIGNMENT.
+ * The MD code depends on the current values of these constants. Don't
+ * change them without coordinating.
+ */
 #ifndef COHERENCY_UNIT
 #define        COHERENCY_UNIT          64
 #endif
 #ifndef CACHE_LINE_SIZE
 #define        CACHE_LINE_SIZE         64
 #endif
+
+
 #ifndef MAXCPUS
 #define        MAXCPUS                 32
 #endif