s390/numa: add topology tree infrastructure

NUMA emulation needs proper means to mangle the book/mc/core topology
of the machine. The topology tree (toptree) consistently maintains cpu
masks for the root, each node, and all leaves of the tree while the
user may use the toptree functions to rearrange the tree in various
ways.

This patch contains several changes from Michael Holzheu.

Signed-off-by: Philipp Hachtmann <phacht@linux.vnet.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/arch/s390/numa/toptree.h b/arch/s390/numa/toptree.h
new file mode 100644
index 000000000000..bdf502027af4
--- /dev/null
+++ b/arch/s390/numa/toptree.h
@@ -0,0 +1,60 @@
+/*
+ * NUMA support for s390
+ *
+ * A tree structure used for machine topology mangling
+ *
+ * Copyright IBM Corp. 2015
+ */
+#ifndef S390_TOPTREE_H
+#define S390_TOPTREE_H
+
+#include <linux/cpumask.h>
+#include <linux/list.h>
+
+struct toptree {
+	int level;
+	int id;
+	cpumask_t mask;
+	struct toptree *parent;
+	struct list_head sibling;
+	struct list_head children;
+};
+
+struct toptree *toptree_alloc(int level, int id);
+void toptree_free(struct toptree *cand);
+void toptree_update_mask(struct toptree *cand);
+void toptree_unify(struct toptree *cand);
+struct toptree *toptree_get_child(struct toptree *cand, int id);
+void toptree_move(struct toptree *cand, struct toptree *target);
+int toptree_count(struct toptree *context, int level);
+
+struct toptree *toptree_first(struct toptree *context, int level);
+struct toptree *toptree_next(struct toptree *cur, struct toptree *context,
+			     int level);
+
+#define toptree_for_each_child(child, ptree)				\
+	list_for_each_entry(child,  &ptree->children, sibling)
+
+#define toptree_for_each_child_safe(child, ptmp, ptree)			\
+	list_for_each_entry_safe(child, ptmp, &ptree->children, sibling)
+
+#define toptree_is_last(ptree)					\
+	((ptree->parent == NULL) ||				\
+	 (ptree->parent->children.prev == &ptree->sibling))
+
+#define toptree_for_each(ptree, cont, ttype)		\
+	for (ptree = toptree_first(cont, ttype);	\
+	     ptree != NULL;				\
+	     ptree = toptree_next(ptree, cont, ttype))
+
+#define toptree_for_each_safe(ptree, tmp, cont, ttype)		\
+	for (ptree = toptree_first(cont, ttype),		\
+		     tmp = toptree_next(ptree, cont, ttype);	\
+	     ptree != NULL;					\
+	     ptree = tmp,					\
+		     tmp = toptree_next(ptree, cont, ttype))
+
+#define toptree_for_each_sibling(ptree, start)			\
+	toptree_for_each(ptree, start->parent, start->level)
+
+#endif /* S390_TOPTREE_H */