MEMINFO(2) System Calls MEMINFO(2)
NAME
meminfo - provide information about memory
SYNOPSIS
#include <sys/types.h>
#include <sys/mman.h>
int meminfo(
const uint64_t inaddr[],
int addr_count,
const uint_t info_req[],
int info_count,
uint64_t outdata[],
uint_t validity[]);
PARAMETERS
inaddr array of input addresses; the maximum number of
addresses that can be processed for each call is
MAX_MEMINFO_CNT addr_count number of addresses
info_req array of types of information requested
info_count number of pieces of information requested for each
address in
inaddr outdata array into which results are placed; array size must be
the product of
info_count and
addr_count validity array of size
addr_count containing bitwise result
codes; 0th bit evaluates validity of corresponding
input address, 1st bit validity of response to first
member of
info_req, and so on
DESCRIPTION
The
meminfo() function provides information about virtual and
physical memory particular to the calling process. The user or
developer of performance utilities can use this information to
analyze system memory allocations and develop a better understanding
of the factors affecting application performance.
The caller of
meminfo() can obtain the following types of information
about both virtual and physical memory.
MEMINFO_VPHYSICAL physical address corresponding to virtual
address
MEMINFO_VLGRP locality group of physical page
corresponding to virtual address
MEMINFO_VPAGESIZE size of physical page corresponding to
virtual address
MEMINFO_VREPLCNT number of replicated physical pages
corresponding to specified virtual address
MEMINFO_VREPL |
n nth physical replica of specified virtual
address
MEMINFO_VREPL_LGRP |
n lgrp of
nth physical replica of specified
virtual address
MEMINFO_PLGRP locality group of specified physical
address
All but
MEMINFO_VLGRP and
MEMINFO_VPAGESIZE require the
PRIV_PROC_MEMINFO privilege.
RETURN VALUES
Upon successful completion
meminfo() returns 0. Otherwise -1 is
returned and
errno is set to indicate the error.
ERRORS
The
meminfo() function will fail if:
EFAULT The area pointed to by
outdata or
validity could not be
written, or the data pointed to by
info_req or
inaddr could
not be read.
EINVAL The value of
info_count is greater than 31 or less than 1,
or the value of
addr_count is less than 1.
EXAMPLES
Example 1: Print physical pages and page sizes corresponding to a set
of virtual addresses.
The following example prints the physical pages and page sizes
corresponding to a set of virtual addresses.
void
print_info(void **addrvec, int how_many)
{
static const uint_t info[] = {
MEMINFO_VPHYSICAL,
MEMINFO_VPAGESIZE
};
int info_num = sizeof (info) / sizeof (info[0]);
int i;
uint64_t *inaddr = alloca(sizeof (uint64_t) * how_many);
uint64_t *outdata = alloca(sizeof (uint64_t) * how_many * info_num);
uint_t *validity = alloca(sizeof (uint_t) * how_many);
for (i = 0; i < how_many; i++)
inaddr[i] = (uint64_t)addrvec[i];
if (meminfo(inaddr, how_many, info, info_num, outdata,
validity) < 0) {
perror("meminfo");
return;
}
for (i = 0; i < how_many; i++) {
if ((validity[i] & 1) == 0)
printf("address 0x%llx not part of address space\n",
inaddr[i]);
else if ((validity[i] & 2) == 0)
printf("address 0x%llx has no physical page "
"associated with it\n", inaddr[i]);
else {
char buff[80];
if ((validity[i] & 4) == 0)
strcpy(buff, "<Unknown>");
else
sprintf(buff, "%lld",
outdata[i * info_num + 1]);
printf("address 0x%llx is backed by physical "
"page 0x%llx of size %s\n",
inaddr[i], outdata[i * info_num], buff);
}
}
}
ATTRIBUTES
See
attributes(7) for descriptions of the following attributes:
+--------------------+-------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------+
|Interface Stability | Stable |
+--------------------+-------------------+
|MT-Level | Async-Signal-Safe |
+--------------------+-------------------+
SEE ALSO
memcntl(2),
mmap(2),
gethomelgroup(3C),
getpagesize(3C),
madvise(3C),
sysconf(3C),
attributes(7),
privileges(7) March 10, 2015 MEMINFO(2)
