Commit 5c024e6a authored by Matthew Wilcox's avatar Matthew Wilcox
Browse files

page cache: Convert page deletion to XArray 



The code is slightly shorter and simpler.

Signed-off-by: default avatarMatthew Wilcox <willy@infradead.org>
parent 74d60958

mm/filemap.c

+13 −18
Original line number Original line Diff line number Diff line
@@ -111,31 +111,26 @@ 
 *   ->tasklist_lock            (memory_failure, collect_procs_ao)

 *   ->tasklist_lock            (memory_failure, collect_procs_ao)

 */

 */





static void page_cache_tree_delete(struct address_space *mapping,

static void page_cache_delete(struct address_space *mapping,

				   struct page *page, void *shadow)

				   struct page *page, void *shadow)

{

{

	int i, nr;

	XA_STATE(xas, &mapping->i_pages, page->index);

	unsigned int nr = 1;





	/* hugetlb pages are represented by one entry in the radix tree */

	mapping_set_update(&xas, mapping);

	nr = PageHuge(page) ? 1 : hpage_nr_pages(page);



	/* hugetlb pages are represented by a single entry in the xarray */

	if (!PageHuge(page)) {

		xas_set_order(&xas, page->index, compound_order(page));

		nr = 1U << compound_order(page);

	}





	VM_BUG_ON_PAGE(!PageLocked(page), page);

	VM_BUG_ON_PAGE(!PageLocked(page), page);

	VM_BUG_ON_PAGE(PageTail(page), page);

	VM_BUG_ON_PAGE(PageTail(page), page);

	VM_BUG_ON_PAGE(nr != 1 && shadow, page);

	VM_BUG_ON_PAGE(nr != 1 && shadow, page);





	for (i = 0; i < nr; i++) {

	xas_store(&xas, shadow);

		struct radix_tree_node *node;

	xas_init_marks(&xas);

		void **slot;



		__radix_tree_lookup(&mapping->i_pages, page->index + i,

				    &node, &slot);



		VM_BUG_ON_PAGE(!node && nr != 1, page);



		radix_tree_clear_tags(&mapping->i_pages, node, slot);

		__radix_tree_replace(&mapping->i_pages, node, slot, shadow,

				workingset_lookup_update(mapping));

	}





	page->mapping = NULL;

	page->mapping = NULL;

	/* Leave page->index set: truncation lookup relies upon it */

	/* Leave page->index set: truncation lookup relies upon it */
@@ -234,7 +229,7 @@ void __delete_from_page_cache(struct page *page, void *shadow) 
	trace_mm_filemap_delete_from_page_cache(page);

	trace_mm_filemap_delete_from_page_cache(page);





	unaccount_page_cache_page(mapping, page);

	unaccount_page_cache_page(mapping, page);

	page_cache_tree_delete(mapping, page, shadow);

	page_cache_delete(mapping, page, shadow);

}

}





static void page_cache_free_page(struct address_space *mapping,

static void page_cache_free_page(struct address_space *mapping,