libnuma: Export interface to set/get preferred nodes

For now this will just fall back to single node with warning when
needed.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Feng Tang <feng.tang@intel.com>

libnuma.c

@@ -1070,6 +1070,8 @@ void numa_set_bind_policy(int strict)
 {
 	if (strict)
 		bind_policy = MPOL_BIND;
+	else if (has_preferred_many)
+		bind_policy = MPOL_PREFERRED_MANY;
 	else
 		bind_policy = MPOL_PREFERRED;
 }
@@ -1839,6 +1841,20 @@ int numa_has_preferred_many(void)
 	return has_preferred_many;
 }
 
+void numa_set_preferred_many(struct bitmask *bitmask)
+{
+	if (!has_preferred_many) {
+		numa_error("Unable to handle MANY preferred nodes. Falling back to first node\n");
+		__numa_set_preferred(bitmask);
+	}
+	setpol(MPOL_PREFERRED_MANY, bitmask);
+}
+
+struct bitmask *numa_preferred_many()
+{
+	return __numa_preferred();
+}
+
 void numa_set_localalloc(void)
 {
 	setpol(MPOL_LOCAL, numa_no_nodes_ptr);

numa.h

@@ -189,6 +189,12 @@ void numa_set_preferred(int node);
 /* Returns whether or not the platform supports MPOL_PREFERRED_MANY */
 int numa_has_preferred_many(void);
 
+/* Set of nodes to preferably allocate memory from for task. */
+void numa_set_preferred_many(struct bitmask *bitmask);
+
+/* Return preferred nodes */
+struct bitmask *numa_preferred_many(void);
+
 /* Set local memory allocation policy for task */
 void numa_set_localalloc(void);
 

versions.ldscript

@@ -159,6 +159,8 @@ libnuma_1.5 {
 libnuma_1.6{
   global:
     numa_has_preferred_many;
+    numa_set_preferred_many;
+    numa_preferred_many;
   local:
     *;
 } libnuma_1.5;