[src/netbsd-1-5]: src/sys Pull up (approved by thorpej):

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

details:   https://anonhg.NetBSD.org/src/rev/8556cde5c748
branches:  netbsd-1-5
changeset: 489392:8556cde5c748
user:      bouyer <bouyer%NetBSD.org@localhost>
date:      Wed Sep 06 08:41:41 2000 +0000

description:
Pull up (approved by thorpej):
sys/proc.h 1.104 -> 1.105
sys/kern/kern_synch.c 1.93 -> 1.94 (via patch to remove SMPism)
sys/kern/vfs_subr.c 1.137 -> 1.138

Add a suspendsched() fuctions, which stops scheduling of users processes
(exept curproc) by putting all SRUN and SSLEEP non-P_SYSTEM processes
in SSTOP state.

In vfs_shutdown() use suspendsched() suspend scheduling, and use tsleep()
instead of DELAY to give kernel threads a chance to run (needed to flush
buffers to a RAID disk). Also, keep trying flushing buffers when the number of
dirty buffers decreases (20 rounds may not be enouth for a very large buffer
cache).

diffstat:

 sys/kern/kern_synch.c |  38 +++++++++++++++++++++++++++++++++++++-
 sys/kern/vfs_subr.c   |  19 ++++++++++++++-----
 sys/sys/proc.h        |   3 ++-
 3 files changed, 53 insertions(+), 7 deletions(-)

diffs (128 lines):

diff -r 9a416a388b15 -r 8556cde5c748 sys/kern/kern_synch.c
--- a/sys/kern/kern_synch.c     Wed Sep 06 06:08:33 2000 +0000
+++ b/sys/kern/kern_synch.c     Wed Sep 06 08:41:41 2000 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_synch.c,v 1.78.2.2 2000/08/11 23:10:15 thorpej Exp $      */
+/*     $NetBSD: kern_synch.c,v 1.78.2.3 2000/09/06 08:41:42 bouyer Exp $       */
 
 /*-
  * Copyright (c) 1999, 2000 The NetBSD Foundation, Inc.
@@ -960,3 +960,39 @@
        if (p->p_priority >= PUSER)
                p->p_priority = p->p_usrpri;
 }
+
+void
+suspendsched()
+{
+       int s, i;
+       struct proc *p, *next;
+       
+       s = splclock();
+
+       /*
+        * Convert all non-P_SYSTEM SSLEEP processes to SSTOP. Curproc is
+        * necesserelly SONPROC.
+        */
+       for (p = LIST_FIRST(&allproc); p != NULL; p = next) {
+               next = LIST_NEXT(p, p_list);
+               if (p->p_stat != SSLEEP || p == curproc ||
+                   (p->p_flag & P_SYSTEM) != 0)
+                       continue;
+               p->p_stat = SSTOP;
+       }
+       /* go through the run queues, remove non-P_SYSTEM processes */
+       for (i = 0; i < RUNQUE_NQS; i++) {
+               for (p = (struct proc *)&sched_qs[i];
+                   p->p_forw != (struct proc *)&sched_qs[i]; p = next) {
+                       next = p->p_forw;
+                       if ((p->p_flag & P_SYSTEM) == 0) {
+                               if (p->p_flag & P_INMEM)
+                                       remrunqueue(p);
+                               p->p_stat = SSTOP;
+                       }
+               }
+       }
+       /* XXX SMP: we need to deal with processes on others CPU ! */
+
+       splx(s);
+}
diff -r 9a416a388b15 -r 8556cde5c748 sys/kern/vfs_subr.c
--- a/sys/kern/vfs_subr.c       Wed Sep 06 06:08:33 2000 +0000
+++ b/sys/kern/vfs_subr.c       Wed Sep 06 08:41:41 2000 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_subr.c,v 1.128.2.3 2000/07/20 00:14:40 fvdl Exp $  */
+/*     $NetBSD: vfs_subr.c,v 1.128.2.4 2000/09/06 08:41:42 bouyer Exp $        */
 
 /*-
  * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
@@ -88,6 +88,7 @@
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/proc.h>
+#include <sys/kernel.h>
 #include <sys/mount.h>
 #include <sys/time.h>
 #include <sys/fcntl.h>
@@ -2352,7 +2353,7 @@
 vfs_shutdown()
 {
        struct buf *bp;
-       int iter, nbusy, dcount, s;
+       int iter, nbusy, nbusy_prev = 0, dcount, s;
        struct proc *p = curproc;
 
        /* XXX we're certainly not running in proc0's context! */
@@ -2361,7 +2362,8 @@
        
        printf("syncing disks... ");
 
-       /* XXX Should suspend scheduling. */
+       /* remove user process from run queue */
+       suspendsched();
        (void) spl0();
 
        /* avoid coming back this way again if we panic. */
@@ -2371,7 +2373,7 @@
 
        /* Wait for sync to finish. */
        dcount = 10000;
-       for (iter = 0; iter < 20; iter++) {
+       for (iter = 0; iter < 20;) {
                nbusy = 0;
                for (bp = &buf[nbuf]; --bp >= buf; ) {
                        if ((bp->b_flags & (B_BUSY|B_INVAL|B_READ)) == B_BUSY)
@@ -2398,8 +2400,15 @@
                }
                if (nbusy == 0)
                        break;
+               if (nbusy_prev == 0)
+                       nbusy_prev = nbusy;
                printf("%d ", nbusy);
-               DELAY(40000 * iter);
+               tsleep(&nbusy, PRIBIO, "bflush",
+                   (iter == 0) ? 1 : hz / 25 * iter);
+               if (nbusy >= nbusy_prev) /* we didn't flush anything */
+                       iter++;
+               else
+                       nbusy_prev = nbusy;
        }
        if (nbusy) {
 fail:
diff -r 9a416a388b15 -r 8556cde5c748 sys/sys/proc.h
--- a/sys/sys/proc.h    Wed Sep 06 06:08:33 2000 +0000
+++ b/sys/sys/proc.h    Wed Sep 06 08:41:41 2000 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: proc.h,v 1.98.2.1 2000/08/11 23:07:41 thorpej Exp $    */
+/*     $NetBSD: proc.h,v 1.98.2.2 2000/09/06 08:41:41 bouyer Exp $     */
 
 /*-
  * Copyright (c) 1986, 1989, 1991, 1993
@@ -386,6 +386,7 @@
 void   resetpriority __P((struct proc *));
 void   setrunnable __P((struct proc *));
 void   setrunqueue __P((struct proc *));
+void   suspendsched __P((void));
 int    ltsleep __P((void *chan, int pri, const char *wmesg, int timo,
            __volatile struct simplelock *));
 void   unsleep __P((struct proc *));