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

[PinakR90]

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

[natoscott]

I've added the following metrics to PCP:

$ pminfo hyperv.balloon
hyperv.balloon.state
hyperv.balloon.pagesize
hyperv.balloon.added
hyperv.balloon.onlined
hyperv.balloon.ballooned
hyperv.balloon.total_committed

Does anyone else have spare cycles to add the pcp-xsos reporting of these?