migration/dirtyrate: Introduce domdirtyrate-calc virsh api

Introduce domdirtyrate-calc virsh api to start calculating domain's
memory dirty rate:
	# virsh domdirtyrate-calc <domain> [--seconds <sec>]

Signed-off-by: Hao Wang <wanghao232@huawei.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

docs/manpages/virsh.rst

@@ -1704,6 +1704,23 @@ states other than "ok" or "error" the command also prints number of
 seconds elapsed since the control interface entered its current state.
 
 
+domdirtyrate-calc
+-----------------
+
+**Syntax:**
+
+::
+
+   domdirtyrate-calc <domain> [--seconds <sec>]
+
+Calculate an active domain's memory dirty rate which may be expected by
+user in order to decide whether it's proper to be migrated out or not.
+The ``seconds`` parameter can be used to calculate dirty rate in a
+specific time which allows 60s at most now and would be default to 1s
+if missing. The calculated dirty rate information is available by calling
+'domstats --dirtyrate'.
+
+
 domdisplay
 ----------
 

tools/virsh-domain.c

@@ -14402,6 +14402,58 @@ cmdSetUserSSHKeys(vshControl *ctl, const vshCmd *cmd)
 }
 
 
+/*
+ * "domdirtyrate" command
+ */
+static const vshCmdInfo info_domdirtyrate_calc[] = {
+    {.name = "help",
+     .data = N_("Calculate a vm's memory dirty rate")
+    },
+    {.name = "desc",
+     .data = N_("Calculate memory dirty rate of a domain in order to "
+                "decide whether it's proper to be migrated out or not.\n"
+                "The calculated dirty rate information is available by "
+                "calling 'domstats --dirtyrate'.")
+    },
+    {.name = NULL}
+};
+
+static const vshCmdOptDef opts_domdirtyrate_calc[] = {
+    VIRSH_COMMON_OPT_DOMAIN_FULL(0),
+    {.name = "seconds",
+     .type = VSH_OT_INT,
+     .help = N_("calculate memory dirty rate within specified seconds, "
+                "the supported value range from 1 to 60, default to 1.")
+    },
+    {.name = NULL}
+};
+
+static bool
+cmdDomDirtyRateCalc(vshControl *ctl, const vshCmd *cmd)
+{
+    virDomainPtr dom = NULL;
+    int seconds = 1; /* the default value is 1 */
+    bool ret = false;
+
+    if (!(dom = virshCommandOptDomain(ctl, cmd, NULL)))
+        return false;
+
+    if (vshCommandOptInt(ctl, cmd, "seconds", &seconds) < 0)
+        goto cleanup;
+
+    if (virDomainStartDirtyRateCalc(dom, seconds, 0) < 0)
+        goto cleanup;
+
+    vshPrintExtra(ctl, _("Start to calculate domain's memory "
+                         "dirty rate successfully.\n"));
+    ret = true;
+
+ cleanup:
+    virshDomainFree(dom);
+    return ret;
+}
+
+
 const vshCmdDef domManagementCmds[] = {
     {.name = "attach-device",
      .handler = cmdAttachDevice,
@@ -15041,5 +15093,11 @@ const vshCmdDef domManagementCmds[] = {
      .info = info_guestinfo,
      .flags = 0
     },
+    {.name = "domdirtyrate-calc",
+     .handler = cmdDomDirtyRateCalc,
+     .opts = opts_domdirtyrate_calc,
+     .info = info_domdirtyrate_calc,
+     .flags = 0
+    },
     {.name = NULL}
 };