freebsd-dev/lib/libgeom/geom_stats.c

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/*-
* Copyright (c) 2003 Poul-Henning Kamp
* 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. The names of the authors may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*
* $FreeBSD$
*/
#include <paths.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libgeom.h>
#include <sys/mman.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/devicestat.h>
/************************************************************/
static uint npages, pagesize, spp;
static int statsfd = -1;
static u_char *statp;
void
geom_stats_close(void)
{
if (statsfd == -1)
return;
munmap(statp, npages *pagesize);
statp = NULL;
close (statsfd);
statsfd = -1;
}
void
geom_stats_resync(void)
{
void *p;
if (statsfd == -1)
return;
for (;;) {
p = mmap(statp, (npages + 1) * pagesize,
PROT_READ, 0, statsfd, 0);
if (p == MAP_FAILED)
break;
else
statp = p;
npages++;
}
}
int
geom_stats_open(void)
{
int error;
void *p;
if (statsfd != -1)
return (EBUSY);
statsfd = open(_PATH_DEV DEVSTAT_DEVICE_NAME, O_RDONLY);
if (statsfd < 0)
return (errno);
pagesize = getpagesize();
spp = pagesize / sizeof(struct devstat);
p = mmap(NULL, pagesize, PROT_READ, 0, statsfd, 0);
if (p == MAP_FAILED) {
error = errno;
close(statsfd);
statsfd = -1;
errno = error;
return (error);
}
statp = p;
npages = 1;
geom_stats_resync();
return (0);
}
struct snapshot {
u_char *ptr;
uint pages;
uint pagesize;
uint perpage;
struct timespec time;
/* used by getnext: */
uint u, v;
};
void *
geom_stats_snapshot_get(void)
{
struct snapshot *sp;
sp = malloc(sizeof *sp);
if (sp == NULL)
return (NULL);
memset(sp, 0, sizeof *sp);
sp->ptr = malloc(pagesize * npages);
if (sp->ptr == NULL) {
free(sp);
return (NULL);
}
memset(sp->ptr, 0, pagesize * npages); /* page in, cache */
clock_gettime(CLOCK_REALTIME, &sp->time);
memset(sp->ptr, 0, pagesize * npages); /* page in, cache */
memcpy(sp->ptr, statp, pagesize * npages);
sp->pages = npages;
sp->perpage = spp;
sp->pagesize = pagesize;
return (sp);
}
void
geom_stats_snapshot_free(void *arg)
{
struct snapshot *sp;
sp = arg;
free(sp->ptr);
free(sp);
}
void
geom_stats_snapshot_timestamp(void *arg, struct timespec *tp)
{
struct snapshot *sp;
sp = arg;
*tp = sp->time;
}
void
geom_stats_snapshot_reset(void *arg)
{
struct snapshot *sp;
sp = arg;
sp->u = sp->v = 0;
}
struct devstat *
geom_stats_snapshot_next(void *arg)
{
struct devstat *gsp;
struct snapshot *sp;
sp = arg;
gsp = (struct devstat *)
(sp->ptr + sp->u * pagesize + sp->v * sizeof *gsp);
if (++sp->v >= sp->perpage) {
if (++sp->u >= sp->pages)
return (NULL);
else
sp->v = 0;
}
return (gsp);
}