[src/trunk]: src/sys/sys Add a comment.

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

details:   https://anonhg.NetBSD.org/src/rev/d1f8158c287a
branches:  trunk
changeset: 461323:d1f8158c287a
user:      ad <ad%NetBSD.org@localhost>
date:      Fri Nov 22 23:38:15 2019 +0000

description:
Add a comment.

diffstat:

 sys/sys/userret.h |  8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diffs (22 lines):

diff -r bdef8b446388 -r d1f8158c287a sys/sys/userret.h
--- a/sys/sys/userret.h Fri Nov 22 23:36:25 2019 +0000
+++ b/sys/sys/userret.h Fri Nov 22 23:38:15 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: userret.h,v 1.29 2019/11/21 19:24:02 ad Exp $  */
+/*     $NetBSD: userret.h,v 1.30 2019/11/22 23:38:15 ad Exp $  */
 
 /*-
  * Copyright (c) 1998, 2000, 2003, 2006, 2008, 2019 The NetBSD Foundation, Inc.
@@ -101,6 +101,12 @@
                ci = l->l_cpu;
        }
        l->l_kpriority = false;
+       /*
+        * lwp_eprio() is too involved to use here unlocked.  At this point
+        * it only matters for PTHREAD_PRIO_PROTECT; setting a too low value
+        * is OK because the scheduler will find out the true value if we
+        * end up in mi_switch().
+        */
        ci->ci_schedstate.spc_curpriority = l->l_priority;
        KPREEMPT_ENABLE(l);