Hyper-V Balloon Usage Information:

cat /sys/kernel/debug/hv-balloon

host_version : 2.0
capabilities : enabled hot_add state : 1 (Initialized) page_size : 4096 / HV Page Size / pages_added : 0 / Pages added with hot_add to the Guest / pages_onlined : 0 / Pages that are "onlined"/used from pages_added / pages_ballooned : 3276800 / Pages we have given back to host / total_pages_committed : 4026223
max_dynamic_page_count: 4706304

Here's the corresponding kernel source code: drivers/hv/hv_balloon.c

/**

hv_balloon_debug_show - shows statistics of balloon operations.
@f: pointer to the &struct seq_file.
@offset: ignored.
Provides the statistics that can be accessed in hv-balloon in the debugfs.

Return: zero on success or an error code. / static int hv_balloon_debug_show(struct seq_file f, void offset) { struct hv_dynmem_device dm = f->private; char *sname;

seq_printf(f, "%-22s: %u.%u\n", "host_version",
                        DYNMEM_MAJOR_VERSION(dm->version),
                        DYNMEM_MINOR_VERSION(dm->version));

seq_printf(f, "%-22s:", "capabilities");
if (ballooning_enabled())
        seq_puts(f, " enabled");

if (hot_add_enabled())
        seq_puts(f, " hot_add");

seq_puts(f, "\n");

seq_printf(f, "%-22s: %u", "state", dm->state);
switch (dm->state) {
case DM_INITIALIZING:
                sname = "Initializing";
                break;
case DM_INITIALIZED:
                sname = "Initialized";
                break;
case DM_BALLOON_UP:
                sname = "Balloon Up";
                break;
case DM_BALLOON_DOWN:
                sname = "Balloon Down";
                break;
case DM_HOT_ADD:
                sname = "Hot Add";
                break;
case DM_INIT_ERROR:
                sname = "Error";
                break;
default:
                sname = "Unknown";
}
seq_printf(f, " (%s)\n", sname);

/* HV Page Size */
seq_printf(f, "%-22s: %ld\n", "page_size", HV_HYP_PAGE_SIZE);

/* Pages added with hot_add */
seq_printf(f, "%-22s: %u\n", "pages_added", dm->num_pages_added);

/* pages that are "onlined"/used from pages_added */
seq_printf(f, "%-22s: %u\n", "pages_onlined", dm->num_pages_onlined);

/* pages we have given back to host */
seq_printf(f, "%-22s: %u\n", "pages_ballooned", dm->num_pages_ballooned);   <<< - - - 

seq_printf(f, "%-22s: %lu\n", "total_pages_committed",
                        get_pages_committed(dm));

seq_printf(f, "%-22s: %llu\n", "max_dynamic_page_count",
                        dm->max_dynamic_page_count);

return 0;

}

struct hv_dynmem_device { struct hv_device *dev; enum hv_dm_state state; struct completion host_event; struct completion config_event;

    /*
     * Number of pages we have currently ballooned out.
     */
    unsigned int num_pages_ballooned;          <<< - - -

Refer Jira: https://issues.redhat.com/browse/RHEL-45715

performancecopilot / xsos-pcp

pcp-xsos should also include Hyper-V balloon usage information #13

cat /sys/kernel/debug/hv-balloon