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mm: shmem: use new radix tree iterator 

In shmem_find_get_pages_and_swap(), use the faster radix tree iterator
construct from commit 78c1d78488 ("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>
This commit is contained in:
Johannes Weiner 2013-02-22 16:35:17 -08:00 committed by Linus Torvalds
parent ef4d43a807
commit 860f2759d9
1 changed files with 12 additions and 13 deletions
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25
mm/shmem.c
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@ -335,19 +335,19 @@ 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)) {
@ -364,17 +364,16 @@ 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;
}