geom_stats.c revision 110545 
1/*-
2 * Copyright (c) 2003 Poul-Henning Kamp
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. The names of the authors may not be used to endorse or promote
14 *    products derived from this software without specific prior written
15 *    permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $FreeBSD: head/lib/libgeom/geom_stats.c 110545 2003-02-08 15:15:56Z phk $
30 */
31
32#include <paths.h>
33#include <errno.h>
34#include <fcntl.h>
35#include <stdlib.h>
36#include <string.h>
37#include <unistd.h>
38#include <libgeom.h>
39
40#include <sys/mman.h>
41#include <sys/time.h>
42#include <sys/types.h>
43
44#include <geom/geom_stats.h>
45#if 0
46#include <stdio.h>
47#include <stdint.h>
48#include <err.h>
49#endif
50
51/************************************************************/
52static uint npages, pagesize, spp;
53static int statsfd = -1;
54static u_char *statp;
55
56void
57geom_stats_close(void)
58{
59	if (statsfd == -1)
60		return;
61	munmap(statp, npages *pagesize);
62	statp = NULL;
63	close (statsfd);
64	statsfd = -1;
65}
66
67void
68geom_stats_resync(void)
69{
70	void *p;
71
72	if (statsfd == -1)
73		return;
74	for (;;) {
75		p = mmap(statp, (npages + 1) * pagesize,
76		    PROT_READ, 0, statsfd, 0);
77		if (p == MAP_FAILED)
78			break;
79		else
80			statp = p;
81		npages++;
82	}
83}
84
85int
86geom_stats_open(void)
87{
88	int error;
89	void *p;
90
91	if (statsfd != -1)
92		return (EBUSY);
93	statsfd = open(_PATH_DEV GEOM_STATS_DEVICE, O_RDONLY);
94	if (statsfd < 0)
95		return (errno);
96	pagesize = getpagesize();
97	spp = pagesize / sizeof(struct g_stat);
98	p = mmap(NULL, pagesize, PROT_READ, 0, statsfd, 0);
99	if (p == MAP_FAILED) {
100		error = errno;
101		close(statsfd);
102		statsfd = -1;
103		errno = error;
104		return (error);
105	}
106	statp = p;
107	npages = 1;
108	geom_stats_resync();
109	return (0);
110}
111
112struct snapshot {
113	u_char		*ptr;
114	uint		pages;
115	uint		pagesize;
116	uint		perpage;
117	struct timespec	time;
118	/* used by getnext: */
119	uint		u, v;
120};
121
122void *
123geom_stats_snapshot_get(void)
124{
125	struct snapshot *sp;
126
127	sp = malloc(sizeof *sp);
128	if (sp == NULL)
129		return (NULL);
130	memset(sp, 0, sizeof *sp);
131	sp->ptr = malloc(pagesize * npages);
132	if (sp->ptr == NULL) {
133		free(sp);
134		return (NULL);
135	}
136	memset(sp->ptr, 0, pagesize * npages); 	/* page in, cache */
137	clock_gettime(CLOCK_REALTIME, &sp->time);
138	memset(sp->ptr, 0, pagesize * npages); 	/* page in, cache */
139	memcpy(sp->ptr, statp, pagesize * npages);
140	sp->pages = npages;
141	sp->perpage = spp;
142	sp->pagesize = pagesize;
143	return (sp);
144}
145
146void
147geom_stats_snapshot_free(void *arg)
148{
149	struct snapshot *sp;
150
151	sp = arg;
152	free(sp->ptr);
153	free(sp);
154}
155
156void
157geom_stats_snapshot_timestamp(void *arg, struct timespec *tp)
158{
159	struct snapshot *sp;
160
161	sp = arg;
162	*tp = sp->time;
163}
164
165void
166geom_stats_snapshot_reset(void *arg)
167{
168	struct snapshot *sp;
169
170	sp = arg;
171	sp->u = sp->v = 0;
172}
173
174struct g_stat *
175geom_stats_snapshot_next(void *arg)
176{
177	struct g_stat *gsp;
178	struct snapshot *sp;
179
180	sp = arg;
181	gsp = (struct g_stat *)
182	    (sp->ptr + sp->u * pagesize + sp->v * sizeof *gsp);
183	if (++sp->v >= sp->perpage) {
184		if (++sp->u >= sp->pages)
185			return (NULL);
186		else
187			sp->v = 0;
188	}
189	return (gsp);
190}
191