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, 3 insertions, 3 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 5a8a273d5b2f..c617ed024df8 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -401,7 +401,7 @@ struct inodes_stat_t {
 #include <linux/cache.h>
 #include <linux/list.h>
 #include <linux/radix-tree.h>
-#include <linux/prio_tree.h>
+#include <linux/rbtree.h>
 #include <linux/init.h>
 #include <linux/pid.h>
 #include <linux/bug.h>
@@ -669,7 +669,7 @@ struct address_space {
         struct radix_tree_root  page_tree;      /* radix tree of all pages */
         spinlock_t              tree_lock;      /* and lock protecting it */
         unsigned int            i_mmap_writable;/* count VM_SHARED mappings */
-        struct prio_tree_root   i_mmap;         /* tree of private and shared mappings */
+        struct rb_root          i_mmap;         /* tree of private and shared mappings */
         struct list_head        i_mmap_nonlinear;/*list VM_NONLINEAR mappings */
         struct mutex            i_mmap_mutex;   /* protect tree, count, list */
         /* Protected by tree_lock together with the radix tree */
@@ -741,7 +741,7 @@ int mapping_tagged(struct address_space *mapping, int tag);
  */
 static inline int mapping_mapped(struct address_space *mapping)
 {
-        return  !prio_tree_empty(&mapping->i_mmap) ||
+        return  !RB_EMPTY_ROOT(&mapping->i_mmap) ||
                 !list_empty(&mapping->i_mmap_nonlinear);
 }