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, 4 insertions, 5 deletions

diff --git a/mm/memory.c b/mm/memory.c
index e09c04813186..d205e4381a34 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2801,14 +2801,13 @@ static void unmap_mapping_range_vma(struct vm_area_struct *vma,
 	zap_page_range_single(vma, start_addr, end_addr - start_addr, details);
 }
 
-static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
+static inline void unmap_mapping_range_tree(struct rb_root *root,
 					    struct zap_details *details)
 {
 	struct vm_area_struct *vma;
-	struct prio_tree_iter iter;
 	pgoff_t vba, vea, zba, zea;
 
-	vma_prio_tree_foreach(vma, &iter, root,
+	vma_interval_tree_foreach(vma, root,
 			details->first_index, details->last_index) {
 
 		vba = vma->vm_pgoff;
@@ -2839,7 +2838,7 @@ static inline void unmap_mapping_range_list(struct list_head *head,
 	 * across *all* the pages in each nonlinear VMA, not just the pages
 	 * whose virtual address lies outside the file truncation point.
 	 */
-	list_for_each_entry(vma, head, shared.vm_set.list) {
+	list_for_each_entry(vma, head, shared.nonlinear) {
 		details->nonlinear_vma = vma;
 		unmap_mapping_range_vma(vma, vma->vm_start, vma->vm_end, details);
 	}
@@ -2883,7 +2882,7 @@ void unmap_mapping_range(struct address_space *mapping,
 
 
 	mutex_lock(&mapping->i_mmap_mutex);
-	if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
+	if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap)))
 		unmap_mapping_range_tree(&mapping->i_mmap, &details);
 	if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
 		unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);