mm: shmem: use new radix tree iterator
In shmem_find_get_pages_and_swap(), use the faster radix tree iterator
construct from commit 78c1d78488a3 ("radix-tree: introduce bit-optimized
iterator").
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/shmem.c b/mm/shmem.c
index 5dd56f6..7162c58 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -335,19 +335,19 @@
pgoff_t start, unsigned int nr_pages,
struct page **pages, pgoff_t *indices)
{
- unsigned int i;
- unsigned int ret;
- unsigned int nr_found;
+ void **slot;
+ unsigned int ret = 0;
+ struct radix_tree_iter iter;
+
+ if (!nr_pages)
+ return 0;
rcu_read_lock();
restart:
- nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree,
- (void ***)pages, indices, start, nr_pages);
- ret = 0;
- for (i = 0; i < nr_found; i++) {
+ radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
struct page *page;
repeat:
- page = radix_tree_deref_slot((void **)pages[i]);
+ page = radix_tree_deref_slot(slot);
if (unlikely(!page))
continue;
if (radix_tree_exception(page)) {
@@ -364,17 +364,16 @@
goto repeat;
/* Has the page moved? */
- if (unlikely(page != *((void **)pages[i]))) {
+ if (unlikely(page != *slot)) {
page_cache_release(page);
goto repeat;
}
export:
- indices[ret] = indices[i];
+ indices[ret] = iter.index;
pages[ret] = page;
- ret++;
+ if (++ret == nr_pages)
+ break;
}
- if (unlikely(!ret && nr_found))
- goto restart;
rcu_read_unlock();
return ret;
}