Added per-box configuration of CPU and NUMA node sets

cg.c

@@ -196,11 +196,14 @@ cg_prepare(void)
 	die("Failed to create control group %s: %m", path);
     }
 
-  // If cpuset module is enabled, copy allowed cpus and memory nodes from parent group
+  // If the cpuset module is enabled, set up allowed cpus and memory nodes.
+  // If per-box configuration exists, use it; otherwise, inherit the settings
+  // from the parent cgroup.
+  struct cf_per_box *cf = cf_current_box();
   if (cg_read(CG_PARENT | CG_CPUSET, "?cpuset.cpus", buf))
-    cg_write(CG_CPUSET, "cpuset.cpus", "%s", buf);
+    cg_write(CG_CPUSET, "cpuset.cpus", "%s", cf->cpus ? cf->cpus : buf);
   if (cg_read(CG_PARENT | CG_CPUSET, "?cpuset.mems", buf))
-    cg_write(CG_CPUSET, "cpuset.mems", "%s", buf);
+    cg_write(CG_CPUSET, "cpuset.mems", "%s", cf->mems ? cf->mems : buf);
 }
 
 void

config.c

@@ -20,6 +20,7 @@ int cf_first_gid;
 int cf_num_boxes;
 
 static int line_number;
+static struct cf_per_box *per_box_configs;
 
 static void NONRET
 cf_err(char *msg)
@@ -46,7 +47,8 @@ cf_int(char *val)
   return x;
 }
 
-void cf_entry(char *key, char *val)
+static void
+cf_entry_toplevel(char *key, char *val)
 {
   if (!strcmp(key, "box_root"))
     cf_box_root = cf_string(val);
@@ -62,6 +64,35 @@ void cf_entry(char *key, char *val)
     cf_err("Unknown configuration item");
 }
 
+static void
+cf_entry_compound(char *key, char *subkey, char *val)
+{
+  if (strncmp(key, "box", 3))
+    cf_err("Unknown configuration section");
+  int box_id = cf_int(key + 3);
+  struct cf_per_box *c = cf_per_box(box_id);
+
+  if (!strcmp(subkey, "cpus"))
+    c->cpus = cf_string(val);
+  else if (!strcmp(subkey, "mems"))
+    c->mems = cf_string(val);
+  else
+    cf_err("Unknown per-box configuration item");
+}
+
+static void
+cf_entry(char *key, char *val)
+{
+  char *dot = strchr(key, '.');
+  if (!dot)
+    cf_entry_toplevel(key, val);
+  else
+    {
+      *dot++ = 0;
+      cf_entry_compound(key, dot, val);
+    }
+}
+
 static void
 cf_check(void)
 {
@@ -109,3 +140,25 @@ cf_parse(void)
   fclose(f);
   cf_check();
 }
+
+struct cf_per_box *
+cf_per_box(int box_id)
+{
+  struct cf_per_box *c;
+
+  for (c = per_box_configs; c; c = c->next)
+    if (c->box_id == box_id)
+      return c;
+
+  c = xmalloc(sizeof(*c));
+  c->next = per_box_configs;
+  per_box_configs = c;
+  c->box_id = box_id;
+  return c;
+}
+
+struct cf_per_box *
+cf_current_box(void)
+{
+  return cf_per_box(box_id);
+}

default.cf

@@ -12,3 +12,9 @@ cg_root = /sys/fs/cgroup
 first_uid = 60000
 first_gid = 60000
 num_boxes = 1000
+
+# Per-box settings of the set of allowed CPUs and NUMA nodes
+# (see linux/Documentation/cgroups/cpusets.txt for precise syntax)
+
+#box0.cpus = 4-7
+#box0.mems = 1

isolate.h

@@ -72,4 +72,13 @@ extern int cf_first_uid;
 extern int cf_first_gid;
 extern int cf_num_boxes;
 
+struct cf_per_box {
+  struct cf_per_box *next;
+  int box_id;
+  char *cpus;
+  char *mems;
+};
+
 void cf_parse(void);
+struct cf_per_box *cf_per_box(int box_id);
+struct cf_per_box *cf_current_box(void);