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, 11 insertions, 11 deletions

diff --git a/mm/mmap.c b/mm/mmap.c
index e3c365f..5ac533f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -199,14 +199,14 @@ static void __remove_shared_vm_struct(struct vm_area_struct *vma,
 
 	flush_dcache_mmap_lock(mapping);
 	if (unlikely(vma->vm_flags & VM_NONLINEAR))
-		list_del_init(&vma->shared.vm_set.list);
+		list_del_init(&vma->shared.nonlinear);
 	else
-		vma_prio_tree_remove(vma, &mapping->i_mmap);
+		vma_interval_tree_remove(vma, &mapping->i_mmap);
 	flush_dcache_mmap_unlock(mapping);
 }
 
 /*
- * Unlink a file-based vm structure from its prio_tree, to hide
+ * Unlink a file-based vm structure from its interval tree, to hide
  * vma from rmap and vmtruncate before freeing its page tables.
  */
 void unlink_file_vma(struct vm_area_struct *vma)
@@ -411,7 +411,7 @@ static void __vma_link_file(struct vm_area_struct *vma)
 		if (unlikely(vma->vm_flags & VM_NONLINEAR))
 			vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
 		else
-			vma_prio_tree_insert(vma, &mapping->i_mmap);
+			vma_interval_tree_insert(vma, &mapping->i_mmap);
 		flush_dcache_mmap_unlock(mapping);
 	}
 }
@@ -449,7 +449,7 @@ static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
 
 /*
  * Helper for vma_adjust() in the split_vma insert case: insert a vma into the
- * mm's list and rbtree.  It has already been inserted into the prio_tree.
+ * mm's list and rbtree.  It has already been inserted into the interval tree.
  */
 static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
 {
@@ -491,7 +491,7 @@ int vma_adjust(struct vm_area_struct *vma, unsigned long start,
 	struct vm_area_struct *next = vma->vm_next;
 	struct vm_area_struct *importer = NULL;
 	struct address_space *mapping = NULL;
-	struct prio_tree_root *root = NULL;
+	struct rb_root *root = NULL;
 	struct anon_vma *anon_vma = NULL;
 	struct file *file = vma->vm_file;
 	long adjust_next = 0;
@@ -554,7 +554,7 @@ again:			remove_next = 1 + (end > next->vm_end);
 		mutex_lock(&mapping->i_mmap_mutex);
 		if (insert) {
 			/*
-			 * Put into prio_tree now, so instantiated pages
+			 * Put into interval tree now, so instantiated pages
 			 * are visible to arm/parisc __flush_dcache_page
 			 * throughout; but we cannot insert into address
 			 * space until vma start or end is updated.
@@ -582,9 +582,9 @@ again:			remove_next = 1 + (end > next->vm_end);
 
 	if (root) {
 		flush_dcache_mmap_lock(mapping);
-		vma_prio_tree_remove(vma, root);
+		vma_interval_tree_remove(vma, root);
 		if (adjust_next)
-			vma_prio_tree_remove(next, root);
+			vma_interval_tree_remove(next, root);
 	}
 
 	vma->vm_start = start;
@@ -597,8 +597,8 @@ again:			remove_next = 1 + (end > next->vm_end);
 
 	if (root) {
 		if (adjust_next)
-			vma_prio_tree_insert(next, root);
-		vma_prio_tree_insert(vma, root);
+			vma_interval_tree_insert(next, root);
+		vma_interval_tree_insert(vma, root);
 		flush_dcache_mmap_unlock(mapping);
 	}