node_memory: Add new parameter field to tune the new sysfs knob

Upstream kernel introduced new sysfs knob "merge_across_nodes" to
specify if pages from different numa nodes can be merged. When set
to 0, only pages which physically reside in the memory area of
same NUMA node can be merged. When set to 1, pages from all nodes
can be merged.

This patch supports the tuning by adding new param field
"shm_merge_across_nodes".

diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
index a4e8ca9212532c9e594b20de450dd6361aced71b..149055892f53c354ede68d2915c67fe60131f2ab 100644 (file)
--- a/include/libvirt/libvirt.h.in
+++ b/include/libvirt/libvirt.h.in
@@ -4490,6 +4490,18 @@ typedef virMemoryParameter *virMemoryParameterPtr;
  */
 # define VIR_NODE_MEMORY_SHARED_FULL_SCANS         "shm_full_scans"
 
+/* VIR_NODE_MEMORY_SHARED_MERGE_ACROSS_NODES:
+ *
+ * Macro for typed parameter that represents whether pages from
+ * different NUMA nodes can be merged. The parameter has type int,
+ * when its value is 0, only pages which physically reside in the
+ * memory area of same NUMA node are merged; When its value is 1,
+ * pages from all nodes can be merged. Other values are reserved
+ * for future use.
+ */
+# define VIR_NODE_MEMORY_SHARED_MERGE_ACROSS_NODES "shm_merge_across_nodes"
+
+
 int virNodeGetMemoryParameters(virConnectPtr conn,
                                virTypedParameterPtr params,
                                int *nparams,

diff --git a/src/nodeinfo.c b/src/nodeinfo.c
index c0e60d8099ef5bf89fcf4b5c48dc4916fbf829ab..8f96b8b2f664274c10f7266d5d6c8cbe138e5cbb 100644 (file)
--- a/src/nodeinfo.c
+++ b/src/nodeinfo.c
@@ -1005,6 +1005,8 @@ nodeSetMemoryParameters(virConnectPtr conn ATTRIBUTE_UNUSED,
                                        VIR_TYPED_PARAM_UINT,
                                        VIR_NODE_MEMORY_SHARED_SLEEP_MILLISECS,
                                        VIR_TYPED_PARAM_UINT,
+                                       VIR_NODE_MEMORY_SHARED_MERGE_ACROSS_NODES,
+                                       VIR_TYPED_PARAM_UINT,
                                        NULL) < 0)
         return -1;
 
@@ -1022,6 +1024,13 @@ nodeSetMemoryParameters(virConnectPtr conn ATTRIBUTE_UNUSED,
                          VIR_NODE_MEMORY_SHARED_SLEEP_MILLISECS)) {
             ret = nodeSetMemoryParameterValue("sleep_millisecs", param);
 
+            /* Out of memory */
+            if (ret == -2)
+                return -1;
+        } else if (STREQ(param->field,
+                         VIR_NODE_MEMORY_SHARED_MERGE_ACROSS_NODES)) {
+            ret = nodeSetMemoryParameterValue("merge_across_nodes", param);
+
             /* Out of memory */
             if (ret == -2)
                 return -1;
@@ -1060,8 +1069,9 @@ nodeGetMemoryParameterValue(const char *field,
     if ((tmp = strchr(buf, '\n')))
         *tmp = '\0';
 
-    if (STREQ(field, "pages_to_scan") ||
-        STREQ(field, "sleep_millisecs"))
+    if (STREQ(field, "pages_to_scan")   ||
+        STREQ(field, "sleep_millisecs") ||
+        STREQ(field, "merge_across_nodes"))
         rc = virStrToLong_ui(buf, NULL, 10, (unsigned int *)value);
     else if (STREQ(field, "pages_shared")    ||
              STREQ(field, "pages_sharing")   ||
@@ -1084,7 +1094,7 @@ cleanup:
 }
 #endif
 
-#define NODE_MEMORY_PARAMETERS_NUM 7
+#define NODE_MEMORY_PARAMETERS_NUM 8
 int
 nodeGetMemoryParameters(virConnectPtr conn ATTRIBUTE_UNUSED,
                         virTypedParameterPtr params ATTRIBUTE_UNUSED,
@@ -1096,6 +1106,7 @@ nodeGetMemoryParameters(virConnectPtr conn ATTRIBUTE_UNUSED,
 #ifdef __linux__
     unsigned int pages_to_scan;
     unsigned int sleep_millisecs;
+    unsigned int merge_across_nodes;
     unsigned long long pages_shared;
     unsigned long long pages_sharing;
     unsigned long long pages_unshared;
@@ -1189,6 +1200,17 @@ nodeGetMemoryParameters(virConnectPtr conn ATTRIBUTE_UNUSED,
 
             break;
 
+        case 7:
+            if (nodeGetMemoryParameterValue("merge_across_nodes",
+                                            &merge_across_nodes) < 0)
+                return -1;
+
+            if (virTypedParameterAssign(param, VIR_NODE_MEMORY_SHARED_MERGE_ACROSS_NODES,
+                                        VIR_TYPED_PARAM_UINT, merge_across_nodes) < 0)
+                return -1;
+
+            break;
+
         default:
             break;
         }

diff --git a/tools/virsh-host.c b/tools/virsh-host.c
index 5cf192de65b90dadc48bd2275055fa4c5441f8e1..106f5e9e0d3d6ab6bd668aa02ec9787dc62ac756 100644 (file)
--- a/tools/virsh-host.c
+++ b/tools/virsh-host.c
@@ -920,6 +920,8 @@ static const vshCmdOptDef opts_node_memory_tune[] = {
     {"shm-sleep-millisecs", VSH_OT_INT, VSH_OFLAG_NONE,
       N_("number of millisecs the shared memory service should "
          "sleep before next scan")},
+    {"shm-merge-across-nodes", VSH_OT_INT, VSH_OFLAG_NONE,
+      N_("Specifies if pages from different numa nodes can be merged")},
     {NULL, 0, 0, NULL}
 };
 
@@ -931,6 +933,7 @@ cmdNodeMemoryTune(vshControl *ctl, const vshCmd *cmd)
     unsigned int flags = 0;
     unsigned int shm_pages_to_scan = 0;
     unsigned int shm_sleep_millisecs = 0;
+    unsigned int shm_merge_across_nodes = 0;
     bool ret = false;
     int i = 0;
 
@@ -946,12 +949,21 @@ cmdNodeMemoryTune(vshControl *ctl, const vshCmd *cmd)
         return false;
     }
 
+    if (vshCommandOptUInt(cmd, "shm-merge-across-nodes",
+                          &shm_merge_across_nodes) < 0) {
+        vshError(ctl, "%s", _("invalid shm-merge-across-nodes number"));
+        return false;
+    }
+
     if (shm_pages_to_scan)
         nparams++;
 
     if (shm_sleep_millisecs)
         nparams++;
 
+    if (shm_merge_across_nodes)
+        nparams++;
+
     if (nparams == 0) {
         /* Get the number of memory parameters */
         if (virNodeGetMemoryParameters(ctl->conn, NULL, &nparams, flags) != 0) {
@@ -1003,6 +1015,14 @@ cmdNodeMemoryTune(vshControl *ctl, const vshCmd *cmd)
                 goto error;
         }
 
+        if (i < nparams && shm_merge_across_nodes) {
+            if (virTypedParameterAssign(&params[i++],
+                                        VIR_NODE_MEMORY_SHARED_MERGE_ACROSS_NODES,
+                                        VIR_TYPED_PARAM_UINT,
+                                        shm_merge_across_nodes) < 0)
+                goto error;
+        }
+
         if (virNodeSetMemoryParameters(ctl->conn, params, nparams, flags) != 0)
             goto error;
         else

diff --git a/tools/virsh.pod b/tools/virsh.pod
index 2d90b7bdecad8dd6ed6ac445cbb03197c88fb013..0481e1fb54899e5ed827c33d3c82f7cffae65ec2 100644 (file)
--- a/tools/virsh.pod
+++ b/tools/virsh.pod
@@ -303,7 +303,10 @@ 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.
+sleep before next scan; I<shm-merge-across-nodes> specifies if pages from
+different numa nodes can be merged. When set to 0, only pages which physically
+reside in the memory area of same NUMA node can be merged. When set to 1,
+pages from all nodes can be merged. Default to 1.
 
 =item B<capabilities>