mm: replace vma prio_tree with an interval tree

Implement an interval tree as a replacement for the VMA prio_tree.  The
algorithms are similar to lib/interval_tree.c; however that code can't be
directly reused as the interval endpoints are not explicitly stored in the
VMA.  So instead, the common algorithm is moved into a template and the
details (node type, how to get interval endpoints from the node, etc) are
filled in using the C preprocessor.

Once the interval tree functions are available, using them as a
replacement to the VMA prio tree is a relatively simple, mechanical job.

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 13 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 5ddb11b2b4bb..0f671ef09eba 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -10,7 +10,6 @@
 #include <linux/list.h>
 #include <linux/mmzone.h>
 #include <linux/rbtree.h>
-#include <linux/prio_tree.h>
 #include <linux/atomic.h>
 #include <linux/debug_locks.h>
 #include <linux/mm_types.h>
@@ -1355,22 +1354,27 @@ extern void zone_pcp_reset(struct zone *zone);
 extern atomic_long_t mmap_pages_allocated;
 extern int nommu_shrink_inode_mappings(struct inode *, size_t, size_t);
 
-/* prio_tree.c */
-void vma_prio_tree_add(struct vm_area_struct *, struct vm_area_struct *old);
-void vma_prio_tree_insert(struct vm_area_struct *, struct prio_tree_root *);
-void vma_prio_tree_remove(struct vm_area_struct *, struct prio_tree_root *);
-struct vm_area_struct *vma_prio_tree_next(struct vm_area_struct *vma,
-        struct prio_tree_iter *iter);
-
-#define vma_prio_tree_foreach(vma, iter, root, begin, end)      \
-        for (prio_tree_iter_init(iter, root, begin, end), vma = NULL;   \
-                (vma = vma_prio_tree_next(vma, iter)); )
+/* interval_tree.c */
+void vma_interval_tree_add(struct vm_area_struct *vma,
+                           struct vm_area_struct *old,
+                           struct address_space *mapping);
+void vma_interval_tree_insert(struct vm_area_struct *node,
+                              struct rb_root *root);
+void vma_interval_tree_remove(struct vm_area_struct *node,
+                              struct rb_root *root);
+struct vm_area_struct *vma_interval_tree_iter_first(struct rb_root *root,
+                                unsigned long start, unsigned long last);
+struct vm_area_struct *vma_interval_tree_iter_next(struct vm_area_struct *node,
+                                unsigned long start, unsigned long last);
+
+#define vma_interval_tree_foreach(vma, root, start, last)               \
+        for (vma = vma_interval_tree_iter_first(root, start, last);     \
+             vma; vma = vma_interval_tree_iter_next(vma, start, last))
 
 static inline void vma_nonlinear_insert(struct vm_area_struct *vma,
                                         struct list_head *list)
 {
-        vma->shared.vm_set.parent = NULL;
-        list_add_tail(&vma->shared.vm_set.list, list);
+        list_add_tail(&vma->shared.nonlinear, list);
 }
 
 /* mmap.c */