1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright 2002 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
28 /* All Rights Reserved */
29
30 /*
31 * University Copyright- Copyright (c) 1982, 1986, 1988
32 * The Regents of the University of California
33 * All Rights Reserved
34 *
35 * University Acknowledgment- Portions of this document are derived from
36 * software developed by the University of California, Berkeley, and its
37 * contributors.
38 */
39
40 #include <sys/types.h>
41 #include <sys/param.h>
42 #include <sys/sysmacros.h>
43 #include <sys/systm.h>
44 #include <sys/vmsystm.h>
45 #include <sys/cpuvar.h>
46 #include <sys/sysinfo.h>
47
48 /*
49 * This define represents the number of
50 * useful pages transferred per paging i/o operation, under the assumption
51 * that half of the total number is actually useful. However, if there's
52 * only one page transferred per operation, we assume that it's useful.
53 */
54
55 #ifdef lint
56 #define UsefulPagesPerIO 1
57 #else /* lint */
58 #define UsefulPagesPerIO nz((MAXBSIZE/PAGESIZE)/2)
59 #endif /* lint */
60
61 extern int dopageout;
62
63 /* Average new into old with aging factor time */
64 #define ave(smooth, cnt, time) \
65 smooth = ((time - 1) * (smooth) + (cnt)) / (time)
66
67 /*
68 * pagein and pageout rates for use by swapper.
69 */
70 ulong_t pginrate; /* 5 second average */
71 ulong_t pgoutrate; /* 5 second average */
72
73 static ulong_t ogpagein; /* pagein rate a sec ago */
74 static ulong_t ogpageout; /* pageout rate a sec ago */
75
76 /*
77 * Called once a second to gather statistics.
78 */
79 void
vmmeter(void)80 vmmeter(void)
81 {
82 cpu_t *cp;
83 ulong_t gpagein, gpageout;
84
85 /*
86 * Compute 5 sec and 30 sec average free memory values.
87 */
88 ave(avefree, freemem, 5);
89 ave(avefree30, freemem, 30);
90
91 /*
92 * Compute the 5 secs average of pageins and pageouts.
93 */
94 gpagein = gpageout = 0;
95
96 cp = cpu_list;
97 do {
98 gpagein += (ulong_t)CPU_STATS(cp, vm.pgin);
99 gpageout += (ulong_t)CPU_STATS(cp, vm.pgout);
100 } while ((cp = cp->cpu_next) != cpu_list);
101
102 if ((gpagein >= ogpagein) && (gpageout >= ogpageout)) {
103 ave(pginrate, gpagein - ogpagein, 5);
104 ave(pgoutrate, gpageout - ogpageout, 5);
105 }
106
107 /*
108 * Save the current pagein/pageout values.
109 */
110 ogpagein = gpagein;
111 ogpageout = gpageout;
112
113 if (!lotsfree || !dopageout)
114 return;
115
116 /*
117 * Decay deficit by the expected number of pages brought in since
118 * the last call (i.e., in the last second). The calculation
119 * assumes that one half of the pages brought in are actually
120 * useful (see comment above), and that half of the overall
121 * paging i/o activity is pageins as opposed to pageouts (the
122 * trailing factor of 2) It also assumes that paging i/o is done
123 * in units of MAXBSIZE bytes, which is a dubious assumption to
124 * apply to all file system types.
125 */
126 deficit -= MIN(deficit,
127 MAX(deficit / 10, UsefulPagesPerIO * maxpgio / 2));
128 }
129