[src/nathanw_sa]: src/sys/kern In mi_switch(), pass up the return value from ...

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

details:   https://anonhg.NetBSD.org/src/rev/6f63765cb73a
branches:  nathanw_sa
changeset: 504608:6f63765cb73a
user:      nathanw <nathanw%NetBSD.org@localhost>
date:      Sun Apr 08 20:53:05 2001 +0000

description:
In mi_switch(), pass up the return value from cpu_switch().
In preempt(), make use of the return value of mi_switch() to determine
whether to send a PREEMPTED upcall.

diffstat:

 sys/kern/kern_synch.c |  23 +++++++++++++++--------
 1 files changed, 15 insertions(+), 8 deletions(-)

diffs (73 lines):

diff -r b46a868cbfb9 -r 6f63765cb73a sys/kern/kern_synch.c
--- a/sys/kern/kern_synch.c     Sun Apr 08 20:51:35 2001 +0000
+++ b/sys/kern/kern_synch.c     Sun Apr 08 20:53:05 2001 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_synch.c,v 1.101.2.1 2001/03/05 22:49:42 nathanw Exp $     */
+/*     $NetBSD: kern_synch.c,v 1.101.2.2 2001/04/08 20:53:05 nathanw Exp $     */
 
 /*-
  * Copyright (c) 1999, 2000 The NetBSD Foundation, Inc.
@@ -765,15 +765,15 @@
 preempt(struct lwp *newl)
 {
        struct lwp *l = curproc;
-       int s;
+       int r, s;
 
        SCHED_LOCK(s);
        l->l_priority = l->l_usrpri;
        l->l_stat = LSRUN;
        setrunqueue(l);
        l->l_proc->p_stats->p_ru.ru_nivcsw++;
-       mi_switch(l, newl);
-       if (l->l_flag & L_SA)
+       r = mi_switch(l, newl);
+       if (r && (l->l_flag & L_SA))
                sa_upcall(l, SA_UPCALL_PREEMPTED, l, NULL, 0, 0);
        SCHED_ASSERT_UNLOCKED();
        splx(s);
@@ -785,8 +785,10 @@
  * the sched_lock held.
  * Switch to "new" if non-NULL, otherwise let cpu_switch choose
  * the next lwp.
+ * 
+ * Returns 1 if another process was actually run.
  */
-void
+int
 mi_switch(struct lwp *l, struct lwp *new)
 {
        struct schedstate_percpu *spc;
@@ -797,6 +799,7 @@
        int hold_count;
 #endif
        struct proc *p = l->l_proc;
+       int retval;
 
        SCHED_ASSERT_LOCKED();
 
@@ -876,10 +879,12 @@
         * run again, we'll return back here.
         */
        uvmexp.swtch++;
-       if (new == NULL)
-               cpu_switch(l);
-       else
+       if (new == NULL) {
+               retval = cpu_switch(l);
+       } else {
                cpu_preempt(l, new);
+               retval = 0;
+       }
 
        /*
         * Make sure that MD code released the scheduler lock before
@@ -905,6 +910,8 @@
        if (p->p_flag & P_BIGLOCK)
                spinlock_acquire_count(&kernel_lock, hold_count);
 #endif
+
+       return retval;
 }
 
 /*