[PATCH v7 28/61] page cache: Convert page deletion to XArray

[Matthew Wilcox]

From: Matthew Wilcox 

The code is slightly shorter and simpler.

Signed-off-by: Matthew Wilcox 
---
 mm/filemap.c | 30 ++
 1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index fcfdc146591b..0223f8054e3a 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -111,30 +111,28 @@
  *   ->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)
 {
-   int i, nr;
+   XA_STATE(xas, >pages, page->index);
+   unsigned int i, nr;
 
-   /* hugetlb pages are represented by one entry in the radix tree */
+   mapping_set_update(, mapping);
+
+   /* hugetlb pages are represented by a single entry in the xarray */
nr = PageHuge(page) ? 1 : hpage_nr_pages(page);
 
VM_BUG_ON_PAGE(!PageLocked(page), page);
VM_BUG_ON_PAGE(PageTail(page), page);
VM_BUG_ON_PAGE(nr != 1 && shadow, page);
 
-   for (i = 0; i < nr; i++) {
-   struct radix_tree_node *node;
-   void **slot;
-
-   __radix_tree_lookup(>pages, page->index + i,
-   , );
-
-   VM_BUG_ON_PAGE(!node && nr != 1, page);
-
-   radix_tree_clear_tags(>pages, node, slot);
-   __radix_tree_replace(>pages, node, slot, shadow,
-   workingset_lookup_update(mapping));
+   i = nr;
+repeat:
+   xas_store(, shadow);
+   xas_init_tags();
+   if (--i) {
+   xas_next();
+   goto repeat;
}
 
page->mapping = NULL;
@@ -234,7 +232,7 @@ void __delete_from_page_cache(struct page *page, void 
*shadow)
trace_mm_filemap_delete_from_page_cache(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,
-- 
2.16.1

[PATCH v7 28/61] page cache: Convert page deletion to XArray

[Matthew Wilcox]

From: Matthew Wilcox 

The code is slightly shorter and simpler.

Signed-off-by: Matthew Wilcox 
---
 mm/filemap.c | 30 ++
 1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index fcfdc146591b..0223f8054e3a 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -111,30 +111,28 @@
  *   ->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)
 {
-   int i, nr;
+   XA_STATE(xas, >pages, page->index);
+   unsigned int i, nr;
 
-   /* hugetlb pages are represented by one entry in the radix tree */
+   mapping_set_update(, mapping);
+
+   /* hugetlb pages are represented by a single entry in the xarray */
nr = PageHuge(page) ? 1 : hpage_nr_pages(page);
 
VM_BUG_ON_PAGE(!PageLocked(page), page);
VM_BUG_ON_PAGE(PageTail(page), page);
VM_BUG_ON_PAGE(nr != 1 && shadow, page);
 
-   for (i = 0; i < nr; i++) {
-   struct radix_tree_node *node;
-   void **slot;
-
-   __radix_tree_lookup(>pages, page->index + i,
-   , );
-
-   VM_BUG_ON_PAGE(!node && nr != 1, page);
-
-   radix_tree_clear_tags(>pages, node, slot);
-   __radix_tree_replace(>pages, node, slot, shadow,
-   workingset_lookup_update(mapping));
+   i = nr;
+repeat:
+   xas_store(, shadow);
+   xas_init_tags();
+   if (--i) {
+   xas_next();
+   goto repeat;
}
 
page->mapping = NULL;
@@ -234,7 +232,7 @@ void __delete_from_page_cache(struct page *page, void 
*shadow)
trace_mm_filemap_delete_from_page_cache(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,
-- 
2.16.1