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#include <sys/types.h>
#include <sys/sysctl.h>
#include <vm/vm_param.h>
#include <unistd.h>
long long int mem_total, mem_used, mem_buffers, mem_cached;
long long int swp_total, swp_used;
enum { total, active, laundry, wired, buffers, swap };
int mib[swap - total + 1][4];
/*
* Values below are in kilobytes: we don't need higher granulation,
* and it allows to keep numbers relatively small.
*/
unsigned int mem[swap - total];
int pagesize;
void
mem_init()
{
size_t len = 4;
/* Precache MIB name vectors for faster lookups later */
sysctlnametomib("vm.stats.vm.v_page_count", mib[total], &len);
sysctlnametomib("vm.stats.vm.v_active_count", mib[active], &len);
sysctlnametomib("vm.stats.vm.v_laundry_count", mib[laundry], &len);
sysctlnametomib("vm.stats.vm.v_wire_count", mib[wired], &len);
len = 2;
sysctlnametomib("vfs.bufspace", mib[buffers], &len);
sysctlnametomib("vm.swap_info", mib[swap], &len);
pagesize = getpagesize() / 1024;
}
static void
get_swap_info()
{
struct xswdev xsw;
size_t len = sizeof(xsw);
int n;
for (swp_total = swp_used = n = 0; ; ++n) {
mib[swap][2] = n;
if (sysctl(mib[swap], 3, &xsw, &len, NULL, 0) == -1)
break;
swp_total += pagesize * xsw.xsw_nblks;
swp_used += pagesize * xsw.xsw_used;
}
}
void
mem_getfree()
{
size_t len = 4;
int n;
for (n = 0; n < buffers - total; ++n)
sysctl(mib[n], 4, &mem[n], &len, NULL, 0);
sysctl(mib[buffers], 2, &mem[buffers], &len, NULL, 0);
/*
* See the following links for explanation which pages we consider
* free and used (cf. Linux vs. FreeBSD):
* https://unix.stackexchange.com/questions/14102/real-memory-usage
* https://unix.stackexchange.com/questions/134862/what-do-the-different-memory-counters-in-freebsd-mean
*/
mem_total = pagesize * mem[total];
/* On FreeBSD, "Laundry" had replaced "Cache" in November 2016 */
mem_cached = pagesize * mem[laundry];
mem_buffers = mem[buffers] / 1024;
mem_used = pagesize * (mem[active] + mem[wired]);
mem_used += mem_cached + mem_buffers;
get_swap_info();
}
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