sg_get_mem_stats, sg_get_mem_stats_r, sg_free_mem_stats, sg_get_swap_stats, sg_get_swap_stats_r, sg_free_swap_stats — get VM statistics
#include <statgrab.h>
sg_mem_stats *sg_get_mem_stats( | entries); |
size_t *entries;sg_mem_stats *sg_get_mem_stats_r( | entries); |
size_t *entries;sg_error sg_free_mem_stats( | data); |
sg_mem_stats *data;sg_swap_stats *sg_get_swap_stats( | entries); |
size_t *entries;sg_swap_stats *sg_get_swap_stats_r( | entries); |
size_t *entries;sg_error sg_free_swap_stats( | data); |
sg_swap_stats *data;
Memory statistics are accessed through the
sg_get_mem_stats() function and the
sg_get_mem_stats_r() function. Both return a
pointer to a sg_mem_stats buffer.
Note that this statistic doesn't need to map the entire physical
memory usage, it represents the real memory usable by the operating
system.
Memory statistics are accessed through the
sg_get_swap_stats() function and the
sg_get_swap_stats_r() function. Both return a
pointer to a sg_swap_stats buffer.
Table 1. API Shortcut
| function | returns | data owner |
|---|---|---|
| sg_get_mem_stats | sg_mem_stats * | libstatgrab (thread local) |
| sg_get_mem_stats_r | sg_mem_stats * | caller |
| sg_get_swap_stats | sg_swap_stats * | libstatgrab (thread local) |
| sg_get_swap_stats_r | sg_swap_stats * | caller |
The sg_mem_stats buffer received from
sg_get_mem_stats_r() and the
sg_swap_stats buffer received from
sg_get_swap_stats_r() must be freed using
sg_free_mem_stats() or the
sg_free_swap_stats(), respectively, when not
needed any more. The caller is responsible for doing it.
On the FreeBSD operating system elevated privileges are required to access the swap statistics. Making the program setgid kmem should be sufficient. Programs running as root will not have this problem.
The VM system calls can return a pointer to either a sg_mem_stats or a sg_swap_stats.
typedef struct{
unsigned long long total;
unsigned long long free;
unsigned long long used;
unsigned long long cache;
time_t systime;
} sg_mem_stats;
total
The total amount of real memory in bytes.
free
The free amount of real memory in bytes.
used
The used amount of real memory in bytes.
cache
The amount of real memory in bytes used for caching.
systimethe timestamp when the above stats where collected in seconds since epoch
typedef struct {
unsigned long long total;
unsigned long long used;
unsigned long long free;
time_t systime;
} sg_swap_stats;
total
The total swap space in bytes.
used
The used swap in bytes.
free
The free swap in bytes.
systimeThe timestamp when the above stats where collected in seconds since epoch