node_memory: Expose the APIs to virsh

New command node-memory-tune to get/set the node memory parameters,
only two parameters are allowed to set (pages_to_scan, and sleep_millisecs,
see documents in this patch for more details).

Example of node-memory-tune's output:

Shared memory:
	pages_to_scan   100
	sleep_millisecs 20
	pages_shared    0
	pages_sharing   0
	pages_unshared  0
	pages_volatile  0
	full_scans      0

tools/virsh-host.c

@@ -37,6 +37,7 @@
 #include "util.h"
 #include "virsh-domain.h"
 #include "xml.h"
+#include "virtypedparam.h"
 
 /*
  * "capabilities" command
@@ -884,12 +885,127 @@ cmdVersion(vshControl *ctl, const vshCmd *cmd ATTRIBUTE_UNUSED)
     return true;
 }
 
+static const vshCmdInfo info_node_memory_tune[] = {
+    {"help", N_("Get or set node memory parameters")},
+    {"desc", N_("Get or set node memory parameters"
+                "    To get the memory parameters, use following command: \n\n"
+                "    virsh # node-memory-tune")},
+    {NULL, NULL}
+};
+
+static const vshCmdOptDef opts_node_memory_tune[] = {
+    {"shm-pages-to-scan", VSH_OT_INT, VSH_OFLAG_NONE,
+      N_("number of pages to scan before the shared memory service "
+         "goes to sleep")},
+    {"shm-sleep-millisecs", VSH_OT_INT, VSH_OFLAG_NONE,
+      N_("number of millisecs the shared memory service should "
+         "sleep before next scan")},
+    {NULL, 0, 0, NULL}
+};
+
+static bool
+cmdNodeMemoryTune(vshControl *ctl, const vshCmd *cmd)
+{
+    virTypedParameterPtr params = NULL;
+    int nparams = 0;
+    unsigned int flags = 0;
+    unsigned int shm_pages_to_scan = 0;
+    unsigned int shm_sleep_millisecs = 0;
+    bool ret = false;
+    int i = 0;
+
+    if (vshCommandOptUInt(cmd, "shm-pages-to-scan",
+                          &shm_pages_to_scan) < 0) {
+        vshError(ctl, "%s", _("invalid shm-pages-to-scan number"));
+        return false;
+    }
+
+    if (vshCommandOptUInt(cmd, "shm-sleep-millisecs",
+                          &shm_sleep_millisecs) < 0) {
+        vshError(ctl, "%s", _("invalid shm-sleep-millisecs number"));
+        return false;
+    }
+
+    if (shm_pages_to_scan)
+        nparams++;
+
+    if (shm_sleep_millisecs)
+        nparams++;
+
+    if (nparams == 0) {
+        /* Get the number of memory parameters */
+        if (virNodeGetMemoryParameters(ctl->conn, NULL, &nparams, flags) != 0) {
+            vshError(ctl, "%s",
+                     _("Unable to get number of memory parameters"));
+            goto cleanup;
+        }
+
+        if (nparams == 0) {
+            ret = true;
+            goto cleanup;
+        }
+
+        /* Now go get all the memory parameters */
+        params = vshCalloc(ctl, nparams, sizeof(*params));
+        if (virNodeGetMemoryParameters(ctl->conn, params, &nparams, flags) != 0) {
+            vshError(ctl, "%s", _("Unable to get memory parameters"));
+            goto cleanup;
+        }
+
+        /* XXX: Need to sort the returned params once new parameter
+         * fields not of shared memory are added.
+         */
+        vshPrint(ctl, _("Shared memory:\n"));
+        for (i = 0; i < nparams; i++) {
+            char *str = vshGetTypedParamValue(ctl, &params[i]);
+            vshPrint(ctl, "\t%-15s %s\n", params[i].field, str);
+            VIR_FREE(str);
+        }
+
+        ret = true;
+    } else {
+        /* Set the memory parameters */
+        params = vshCalloc(ctl, nparams, sizeof(*params));
+
+        if (i < nparams && shm_pages_to_scan) {
+            if (virTypedParameterAssign(&params[i++],
+                                        VIR_NODE_MEMORY_SHARED_PAGES_TO_SCAN,
+                                        VIR_TYPED_PARAM_UINT,
+                                        shm_pages_to_scan) < 0)
+                goto error;
+        }
+
+        if (i < nparams && shm_sleep_millisecs) {
+            if (virTypedParameterAssign(&params[i++],
+                                        VIR_NODE_MEMORY_SHARED_SLEEP_MILLISECS,
+                                        VIR_TYPED_PARAM_UINT,
+                                        shm_sleep_millisecs) < 0)
+                goto error;
+        }
+
+        if (virNodeSetMemoryParameters(ctl->conn, params, nparams, flags) != 0)
+            goto error;
+        else
+            ret = true;
+    }
+
+cleanup:
+    VIR_FREE(params);
+    return ret;
+
+error:
+    vshError(ctl, "%s", _("Unable to change memory parameters"));
+    goto cleanup;
+}
+
 const vshCmdDef hostAndHypervisorCmds[] = {
     {"capabilities", cmdCapabilities, NULL, info_capabilities, 0},
     {"connect", cmdConnect, opts_connect, info_connect,
      VSH_CMD_FLAG_NOCONNECT},
     {"freecell", cmdFreecell, opts_freecell, info_freecell, 0},
     {"hostname", cmdHostname, NULL, info_hostname, 0},
+    {"node-memory-tune", cmdNodeMemoryTune,
+     opts_node_memory_tune, info_node_memory_tune, 0},
     {"nodecpustats", cmdNodeCpuStats, opts_node_cpustats, info_nodecpustats, 0},
     {"nodeinfo", cmdNodeinfo, NULL, info_nodeinfo, 0},
     {"nodememstats", cmdNodeMemStats, opts_node_memstats, info_nodememstats, 0},

tools/virsh.pod

@@ -293,6 +293,14 @@ Real-Time-Clock interrupt to fire (to wake up the node) after a time delay
 specified by the 'duration' parameter. The duration time should be
 at least 60 seconds.
 
+=item B<node-memory-tune> [I<shm-pages-to-scan>] [I<shm-sleep-millisecs>]
+
+Allows you to display or set the node memory parameters.
+I<shm-pages-to-scan> can be used to set the number of pages to scan
+before the shared memory service goes to sleep; I<shm-sleep-millisecs>
+can be used to set the number of millisecs the shared memory service should
+sleep before next scan.
+
 =item B<capabilities>
 
 Print an XML document describing the capabilities of the hypervisor