Johannes Weiner wrote:
In shmem_find_get_pages_and_swap, use the faster radix tree iterator
construct from 78c1d78 "radix-tree: introduce bit-optimized iterator".
Signed-off-by: Johannes Weiner<hannes@xxxxxxxxxxx>
Hmm, ACK. shmem_unuse_inode() also can be redone in this way.
I did something similar year ago: https://lkml.org/lkml/2012/2/10/388
As result we can rid of radix_tree_locate_item() and shmem_find_get_pages_and_swap()
---
mm/shmem.c | 25 ++++++++++++-------------
1 file changed, 12 insertions(+), 13 deletions(-)
diff --git a/mm/shmem.c b/mm/shmem.c
index a368a1c..c5dc8ae 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -336,19 +336,19 @@ static unsigned shmem_find_get_pages_and_swap(struct address_space *mapping,
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)) {
@@ -365,17 +365,16 @@ static unsigned shmem_find_get_pages_and_swap(struct address_space *mapping,
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;
}
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>