[src/trunk]: src/sys/kern Comments.

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

details:   https://anonhg.NetBSD.org/src/rev/48363e2ec18c
branches:  trunk
changeset: 948235:48363e2ec18c
user:      ad <ad%NetBSD.org@localhost>
date:      Tue Dec 22 01:57:29 2020 +0000

description:
Comments.

diffstat:

 sys/kern/kern_lock.c  |   8 ++------
 sys/kern/subr_xcall.c |  18 +++++++++---------
 2 files changed, 11 insertions(+), 15 deletions(-)

diffs (77 lines):

diff -r af9fb909ea28 -r 48363e2ec18c sys/kern/kern_lock.c
--- a/sys/kern/kern_lock.c      Tue Dec 22 01:07:23 2020 +0000
+++ b/sys/kern/kern_lock.c      Tue Dec 22 01:57:29 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_lock.c,v 1.171 2020/05/02 09:13:40 martin Exp $   */
+/*     $NetBSD: kern_lock.c,v 1.172 2020/12/22 01:57:29 ad Exp $       */
 
 /*-
  * Copyright (c) 2002, 2006, 2007, 2008, 2009, 2020 The NetBSD Foundation, Inc.
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_lock.c,v 1.171 2020/05/02 09:13:40 martin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_lock.c,v 1.172 2020/12/22 01:57:29 ad Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_lockdebug.h"
@@ -215,10 +215,6 @@
         * is required to ensure that the result of any mutex_exit()
         * by the current LWP becomes visible on the bus before the set
         * of ci->ci_biglock_wanted becomes visible.
-        *
-        * However, we won't set ci_biglock_wanted until we've spun for
-        * a bit, as we don't want to make any lock waiters in rw_oncpu()
-        * or mutex_oncpu() block prematurely.
         */
        membar_producer();
        owant = ci->ci_biglock_wanted;
diff -r af9fb909ea28 -r 48363e2ec18c sys/kern/subr_xcall.c
--- a/sys/kern/subr_xcall.c     Tue Dec 22 01:07:23 2020 +0000
+++ b/sys/kern/subr_xcall.c     Tue Dec 22 01:57:29 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: subr_xcall.c,v 1.33 2019/12/19 10:51:54 thorpej Exp $  */
+/*     $NetBSD: subr_xcall.c,v 1.34 2020/12/22 01:57:29 ad Exp $       */
 
 /*-
  * Copyright (c) 2007-2010, 2019 The NetBSD Foundation, Inc.
@@ -48,12 +48,12 @@
  *     prohibitive, another way must be found.
  *
  *     Cross calls help to solve these types of problem by allowing
- *     any CPU in the system to request that an arbitrary function be
- *     executed on any other CPU.
+ *     any LWP in the system to request that an arbitrary function be
+ *     executed on a specific CPU.
  *
  * Implementation
  *
- *     A slow mechanism for making 'low priority' cross calls is
+ *     A slow mechanism for making low priority cross calls is
  *     provided.  The function to be executed runs on the remote CPU
  *     within a bound kthread.  No queueing is provided, and the
  *     implementation uses global state.  The function being called may
@@ -64,17 +64,17 @@
  *     CPU, and so has exclusive access to the CPU.  Since this facility
  *     is heavyweight, it's expected that it will not be used often.
  *
- *     Cross calls must not allocate memory, as the pagedaemon uses
- *     them (and memory allocation may need to wait on the pagedaemon).
+ *     Cross calls must not allocate memory, as the pagedaemon uses cross
+ *     calls (and memory allocation may need to wait on the pagedaemon).
  *
  *     A low-overhead mechanism for high priority calls (XC_HIGHPRI) is
- *     also provided.  The function to be executed runs on a software
- *     interrupt context, at IPL_SOFTSERIAL level, and is expected to
+ *     also provided.  The function to be executed runs in software
+ *     interrupt context at IPL_SOFTSERIAL level, and is expected to
  *     be very lightweight, e.g. avoid blocking.
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_xcall.c,v 1.33 2019/12/19 10:51:54 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_xcall.c,v 1.34 2020/12/22 01:57:29 ad Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>