virDomainMemoryStatStruct 以及 virDomainMemoryStatStruct的使用

#include <libvirt/libvirt.h>
#include <libvirt/virterror.h>
#include "include/proxy.h"
#include "include/rpc.h"

int main(int argc, char ** argv) {
    virConnectPtr conn = virConnectOpen("qemu:///system");
    if(conn == NULL) {
        printf("error connecting qemu driver\n");
        exit(1);
    }
    virDomainPtr vm_ptr = virDomainLookupByName(conn, "template");
    if(vm_ptr == NULL) {
        printf("error finding domain\n");
        virConnectClose(conn);
        exit(1);
    }
    virDomainMemoryStatStruct stats[3];
    int res = virDomainMemoryStats(vm_ptr, stats, 3, 0);
    if(res >= 0) {
        for(int i = 0 ; i < res; i++) {
            printf("%d %llu\n", stats[i].tag, stats[i].val);
        }
    }
    virDomainFree(vm_ptr);
    virConnectClose(conn);
    return 0;
}

struct virDomainMemoryStatStruct {
    int  tag;
    unsigned long ling val;
}

其中 tag取值：
4  The amount of memory left completely unused by the system. Memory that is available but used for reclai   mable caches should NOT be reported as free. This value is expressed in kB.
5  The total amount of usable memory as seen by the domain. This value may be less than the amount of memo   ry assigned to the domain if a balloon driver is in use or if the guest OS does not initialize all assi   gned pages. This value is expressed in kB.
6  Current balloon value (in KB)
7  Resident Set Size of the process running the domain. This value is in kB  

对于普通的kvm虚拟机中，没有使用balloon driver，只能获得6和7参数。其中参数6是memory指定的数值，7会一直长到比6稍微大一点（如果没有设置currentMemory)