page cache: Convert hole search to XArray
The page cache offers the ability to search for a miss in the previous or
next N locations. Rather than teach the XArray about the page cache's
definition of a miss, use xas_prev() and xas_next() to search the page
array. This should be more efficient as it does not have to start the
lookup from the top for each index.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
diff --git a/mm/readahead.c b/mm/readahead.c
index de65707..fc4dd36 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -336,7 +336,7 @@ static pgoff_t count_history_pages(struct address_space *mapping,
pgoff_t head;
rcu_read_lock();
- head = page_cache_prev_hole(mapping, offset - 1, max);
+ head = page_cache_prev_miss(mapping, offset - 1, max);
rcu_read_unlock();
return offset - 1 - head;
@@ -425,7 +425,7 @@ ondemand_readahead(struct address_space *mapping,
pgoff_t start;
rcu_read_lock();
- start = page_cache_next_hole(mapping, offset + 1, max_pages);
+ start = page_cache_next_miss(mapping, offset + 1, max_pages);
rcu_read_unlock();
if (!start || start - offset > max_pages)