[src/trunk]: src/common/lib/libutil Add a version of proc_compare that works ...

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

details:   https://anonhg.NetBSD.org/src/rev/daa1030f1d5b
branches:  trunk
changeset: 770540:daa1030f1d5b
user:      christos <christos%NetBSD.org@localhost>
date:      Fri Oct 21 02:09:00 2011 +0000

description:
Add a version of proc_compare that works both for kernel and userland
(and uses the same algorithm!)

diffstat:

 common/lib/libutil/Makefile.inc   |    4 +-
 common/lib/libutil/proc_compare.c |  146 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 148 insertions(+), 2 deletions(-)

diffs (160 lines):

diff -r c1c92716eaf3 -r daa1030f1d5b common/lib/libutil/Makefile.inc
--- a/common/lib/libutil/Makefile.inc   Fri Oct 21 02:08:09 2011 +0000
+++ b/common/lib/libutil/Makefile.inc   Fri Oct 21 02:09:00 2011 +0000
@@ -1,4 +1,4 @@
-#      $NetBSD: Makefile.inc,v 1.2 2011/08/16 10:33:17 christos Exp $
+#      $NetBSD: Makefile.inc,v 1.3 2011/10/21 02:09:00 christos Exp $
 .PATH.c: ${.PARSEDIR}
-SRCS+= snprintb.c
+SRCS+= snprintb.c proc_compare.c
 COPTS.snprintb.c = -Wno-format-nonliteral
diff -r c1c92716eaf3 -r daa1030f1d5b common/lib/libutil/proc_compare.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/common/lib/libutil/proc_compare.c Fri Oct 21 02:09:00 2011 +0000
@@ -0,0 +1,146 @@
+/*     $NetBSD: proc_compare.c,v 1.1 2011/10/21 02:09:00 christos Exp $        */
+
+/*-
+ * Copyright (c) 1990, 1993
+ *     The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+#ifndef _STANDALONE
+# ifndef _KERNEL
+
+#  if HAVE_NBTOOL_CONFIG_H
+#   include "nbtool_config.h"
+#  endif
+
+#  include <sys/cdefs.h>
+#  if defined(LIBC_SCCS) && !defined(lint)
+__RCSID("$NetBSD: proc_compare.c,v 1.1 2011/10/21 02:09:00 christos Exp $");
+#  endif
+
+#  include <sys/types.h>
+#  include <sys/inttypes.h>
+#  include <sys/sysctl.h>
+#  include <stdio.h>
+#  include <util.h>
+#  include <errno.h>
+#  define PROC         struct kinfo_proc2
+#  define LWP          struct kinfo_lwp
+#  define P_RTIME_SEC  p_rtime_sec
+#  define P_RTIME_USEC p_rtime_usec
+# else
+#  include <sys/cdefs.h>
+__KERNEL_RCSID(0, "$NetBSD: proc_compare.c,v 1.1 2011/10/21 02:09:00 christos Exp $");
+#  include <sys/param.h>
+#  include <sys/inttypes.h>
+#  include <sys/systm.h>
+#  include <sys/proc.h>
+#  include <sys/lwp.h>
+#  include <lib/libkern/libkern.h>
+#  define PROC         struct proc
+#  define LWP          struct lwp
+#  define P_RTIME_SEC  p_rtime.sec
+#  define P_RTIME_USEC p_rtime.frac
+# endif
+/*
+ * Returns 1 if p2 is "better" than p1
+ *
+ * The algorithm for picking the "interesting" process is thus:
+ *
+ *     1) Only foreground processes are eligible - implied.
+ *     2) Runnable processes are favored over anything else.  The runner
+ *        with the highest CPU utilization is picked (l_pctcpu).  Ties are
+ *        broken by picking the highest pid.
+ *     3) The sleeper with the shortest sleep time is next.  With ties,
+ *        we pick out just "short-term" sleepers (P_SINTR == 0).
+ *     4) Further ties are broken by picking the one started last.
+ *     5) Finally the one with the biggest pid wins, but that is nonsense
+ *        because of pid randomization.
+ */
+#define        ISRUN(p)        ((p)->p_nrlwps > 0)
+#define        TESTAB(a, b)    (((a) << 1) | (b))
+#define        ONLYA   2
+#define        ONLYB   1
+#define        BOTH    3
+
+int
+proc_compare(const PROC *p1, const LWP *l1, const PROC *p2, const LWP *l2)
+{
+       /*
+        * see if at least one of them is runnable
+        */
+       switch (TESTAB(ISRUN(p1), ISRUN(p2))) {
+       case ONLYA:
+               return 0;
+       case ONLYB:
+               return 1;
+       case BOTH:
+               /*
+                * tie - favor one with highest recent CPU utilization
+                */
+               if (l2->l_pctcpu > l1->l_pctcpu)
+                       return 1;
+               goto out;
+       }
+       /*
+        * weed out zombies
+        */
+       switch (TESTAB(P_ZOMBIE(p1), P_ZOMBIE(p2))) {
+       case ONLYA:
+               return 1;
+       case ONLYB:
+               return 0;
+       case BOTH:
+               goto out;
+       }
+       /*
+        * pick the one with the smallest sleep time
+        */
+       if (l1->l_slptime < l2->l_slptime)
+               return 0;
+       if (l2->l_slptime < l1->l_slptime)
+               return 1;
+
+       /*
+        * favor one sleeping in a non-interruptible sleep
+        */
+       if ((l1->l_flag & LW_SINTR) && (l2->l_flag & LW_SINTR) == 0)
+               return 0;
+       if ((l2->l_flag & LW_SINTR) && (l1->l_flag & LW_SINTR) == 0)
+               return 1;
+out:
+       /* tie, return the one with the smallest realtime */
+       if (p1->P_RTIME_SEC < p2->P_RTIME_SEC)
+               return 0;
+       if (p2->P_RTIME_SEC < p1->P_RTIME_SEC)
+               return 1;
+       if (p1->P_RTIME_USEC < p2->P_RTIME_USEC)
+               return 0;
+       if (p2->P_RTIME_USEC < p1->P_RTIME_USEC)
+               return 1;
+               
+       return p2->p_pid > p1->p_pid;   /* Nonsense */
+}
+#endif /* STANDALONE */