[PATCH] malloc: s/max_node/num_nodes/

[Joern Engel <joern at purestorage dot com>]

Costa complained and I once had a bug because I confused max_node for
num_nodes.  Also renames parse_node_count and turns it into a function.
You expect something called foo_init to have side-effects, but not
necessarily something called parse_foo.

JIRA: PURE-27597
---
 tpc/malloc2.13/arena.h  | 22 ++++++++++++----------
 tpc/malloc2.13/malloc.c |  7 +++++--
 2 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/tpc/malloc2.13/arena.h b/tpc/malloc2.13/arena.h
index 9236a3231f07..685822897d97 100644
--- a/tpc/malloc2.13/arena.h
+++ b/tpc/malloc2.13/arena.h
@@ -297,7 +297,7 @@ ptmalloc_init_minimal (void)
 
 static struct malloc_state *_int_new_arena(size_t size, int numa_node);
 
-static int max_node = -1;
+static int num_nodes = 0;
 
 #include <sys/types.h>
 #include <dirent.h>
@@ -306,26 +306,28 @@ static int max_node = -1;
 /*
  * Wouldn't it be nice to get this with a single syscall instead?
  */
-static void parse_node_count(void)
+static int numa_node_count(void)
 {
 	DIR *d;
 	struct dirent *de;
+	int ret;
 
 	d = opendir("/sys/devices/system/node");
 	if (!d) {
-		max_node = 0;
+		ret = 1;
 	} else {
 		while ((de = readdir(d)) != NULL) {
 			int nd;
 			if (strncmp(de->d_name, "node", 4))
 				continue;
 			nd = strtoul(de->d_name + 4, NULL, 0);
-			if (max_node < nd)
-				max_node = nd;
+			if (ret < nd + 1)
+				ret = nd + 1;
 		}
 		closedir(d);
 	}
-	assert(max_node < MAX_NUMA_NODES);
+	assert(ret <= MAX_NUMA_NODES);
+	return ret;
 }
 
 static void ptmalloc_init(void)
@@ -355,8 +357,8 @@ static void ptmalloc_init(void)
 	mutex_init(&main_arena.mutex);
 	main_arena.next = &main_arena;
 	main_arena.numa_node = -1;
-	parse_node_count();
-	for (i = 0; i <= max_node; i++) {
+	num_nodes = numa_node_count();
+	for (i = 0; i < num_nodes; i++) {
 		numa_arena[i] = _int_new_arena(0, i);
 		numa_arena[i]->local_next = numa_arena[i];
 		(void)mutex_unlock(&numa_arena[i]->mutex);
@@ -474,8 +476,8 @@ static void mbind_memory(void *mem, size_t size, int node)
 	unsigned long node_mask = 1 << node;
 	int err;
 
-	assert(max_node < sizeof(unsigned long));
-	err = mbind(mem, size, MPOL_PREFERRED, &node_mask, max_node + 1, 0);
+	assert(num_nodes <= sizeof(unsigned long));
+	err = mbind(mem, size, MPOL_PREFERRED, &node_mask, num_nodes, 0);
 	assert(!err);
 }
 
diff --git a/tpc/malloc2.13/malloc.c b/tpc/malloc2.13/malloc.c
index 94b7e223ec6f..46b3545aaa8f 100644
--- a/tpc/malloc2.13/malloc.c
+++ b/tpc/malloc2.13/malloc.c
@@ -2154,9 +2154,12 @@ struct malloc_par {
 static struct malloc_state main_arena;
 
 /*
- * For numa locality, have a per-node list of arenas.
+ * For numa locality, have a per-node list of arenas.  64 ought to be
+ * enough to anybody - for a while, at least.  Having it match
+ * wordsize is convenient, as mbind_memory() will need to be changed
+ * at the same time MAX_NUMA_NODES.
  */
-#define MAX_NUMA_NODES 2
+#define MAX_NUMA_NODES sizeof(unsigned long)
 static struct malloc_state *numa_arena[MAX_NUMA_NODES];
 
 /* There is only one instance of the malloc parameters.  */
-- 
2.7.0.rc3