[src/trunk]: src/sys/kern Patch from Nick Hudson to clean up a couple of case...

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

details:   https://anonhg.NetBSD.org/src/rev/823177e9f60c
branches:  trunk
changeset: 546248:823177e9f60c
user:      nathanw <nathanw%NetBSD.org@localhost>
date:      Wed Apr 23 21:32:10 2003 +0000

description:
Patch from Nick Hudson to clean up a couple of cases in proc_unstop(),
as well as improving the comments a bit. Addresses PR kern/20159.

diffstat:

 sys/kern/kern_sig.c |  27 ++++++++++++++++++---------
 1 files changed, 18 insertions(+), 9 deletions(-)

diffs (62 lines):

diff -r 96edddd785ba -r 823177e9f60c sys/kern/kern_sig.c
--- a/sys/kern/kern_sig.c       Wed Apr 23 19:36:12 2003 +0000
+++ b/sys/kern/kern_sig.c       Wed Apr 23 21:32:10 2003 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_sig.c,v 1.139 2003/04/15 12:11:25 skrll Exp $     */
+/*     $NetBSD: kern_sig.c,v 1.140 2003/04/23 21:32:10 nathanw Exp $   */
 
 /*
  * Copyright (c) 1982, 1986, 1989, 1991, 1993
@@ -41,7 +41,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.139 2003/04/15 12:11:25 skrll Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.140 2003/04/23 21:32:10 nathanw Exp $");
 
 #include "opt_ktrace.h"
 #include "opt_compat_sunos.h"
@@ -1396,18 +1396,27 @@
        SCHED_ASSERT_LOCKED();
 
        /*
-        * Our caller will want to invoke setrunnable() on whatever we return,
-        * provided that it isn't NULL.
+        * Our caller wants to be informed if there are only sleeping
+        * and interruptable LWPs left after we have run so that it
+        * can invoke setrunnable() if required - return one of the
+        * interruptable LWPs if this is the case.
         */
 
        p->p_stat = SACTIVE;
        if (p->p_flag & P_SA) {
-               lr = p->p_sa->sa_idle; /* OK if this is NULL. */
-               cantake = 1;
+               /*
+                * Preferentially select the idle LWP as the interruptable
+                * LWP to return if it exists.
+                */
+               lr = p->p_sa->sa_idle;
+               if (lr != NULL)
+                       cantake = 1;
        }
        LIST_FOREACH(l, &p->p_lwps, l_sibling) {
-               if (l->l_stat == LSRUN)
+               if (l->l_stat == LSRUN) {
+                       lr = NULL;
                        cantake = 1;
+               }
                if (l->l_stat != LSSTOP)
                        continue;
 
@@ -1418,8 +1427,8 @@
                                cantake = 1;
                        }
                } else {
-                       if (l != lr)
-                               setrunnable(l);
+                       setrunnable(l);
+                       lr = NULL;
                        cantake = 1;
                }
        }