mm: non-atomically mark page accessed during page cache allocation where possible

[cascardo/linux.git] / include / linux / pagemap.h

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 45598f1..0a97b58 100644 (file)
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -110,7 +110,7 @@ static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
 
 #define page_cache_get(page)           get_page(page)
 #define page_cache_release(page)       put_page(page)
-void release_pages(struct page **pages, int nr, int cold);
+void release_pages(struct page **pages, int nr, bool cold);
 
 /*
  * speculatively take a reference to a page.
@@ -259,12 +259,109 @@ pgoff_t page_cache_next_hole(struct address_space *mapping,
 pgoff_t page_cache_prev_hole(struct address_space *mapping,
                             pgoff_t index, unsigned long max_scan);
 
+#define FGP_ACCESSED           0x00000001
+#define FGP_LOCK               0x00000002
+#define FGP_CREAT              0x00000004
+#define FGP_WRITE              0x00000008
+#define FGP_NOFS               0x00000010
+#define FGP_NOWAIT             0x00000020
+
+struct page *pagecache_get_page(struct address_space *mapping, pgoff_t offset,
+               int fgp_flags, gfp_t cache_gfp_mask, gfp_t radix_gfp_mask);
+
+/**
+ * find_get_page - find and get a page reference
+ * @mapping: the address_space to search
+ * @offset: the page index
+ *
+ * Looks up the page cache slot at @mapping & @offset.  If there is a
+ * page cache page, it is returned with an increased refcount.
+ *
+ * Otherwise, %NULL is returned.
+ */
+static inline struct page *find_get_page(struct address_space *mapping,
+                                       pgoff_t offset)
+{
+       return pagecache_get_page(mapping, offset, 0, 0, 0);
+}
+
+static inline struct page *find_get_page_flags(struct address_space *mapping,
+                                       pgoff_t offset, int fgp_flags)
+{
+       return pagecache_get_page(mapping, offset, fgp_flags, 0, 0);
+}
+
+/**
+ * find_lock_page - locate, pin and lock a pagecache page
+ * pagecache_get_page - find and get a page reference
+ * @mapping: the address_space to search
+ * @offset: the page index
+ *
+ * Looks up the page cache slot at @mapping & @offset.  If there is a
+ * page cache page, it is returned locked and with an increased
+ * refcount.
+ *
+ * Otherwise, %NULL is returned.
+ *
+ * find_lock_page() may sleep.
+ */
+static inline struct page *find_lock_page(struct address_space *mapping,
+                                       pgoff_t offset)
+{
+       return pagecache_get_page(mapping, offset, FGP_LOCK, 0, 0);
+}
+
+/**
+ * find_or_create_page - locate or add a pagecache page
+ * @mapping: the page's address_space
+ * @index: the page's index into the mapping
+ * @gfp_mask: page allocation mode
+ *
+ * Looks up the page cache slot at @mapping & @offset.  If there is a
+ * page cache page, it is returned locked and with an increased
+ * refcount.
+ *
+ * If the page is not present, a new page is allocated using @gfp_mask
+ * and added to the page cache and the VM's LRU list.  The page is
+ * returned locked and with an increased refcount.
+ *
+ * On memory exhaustion, %NULL is returned.
+ *
+ * find_or_create_page() may sleep, even if @gfp_flags specifies an
+ * atomic allocation!
+ */
+static inline struct page *find_or_create_page(struct address_space *mapping,
+                                       pgoff_t offset, gfp_t gfp_mask)
+{
+       return pagecache_get_page(mapping, offset,
+                                       FGP_LOCK|FGP_ACCESSED|FGP_CREAT,
+                                       gfp_mask, gfp_mask & GFP_RECLAIM_MASK);
+}
+
+/**
+ * grab_cache_page_nowait - returns locked page at given index in given cache
+ * @mapping: target address_space
+ * @index: the page index
+ *
+ * Same as grab_cache_page(), but do not wait if the page is unavailable.
+ * This is intended for speculative data generators, where the data can
+ * be regenerated if the page couldn't be grabbed.  This routine should
+ * be safe to call while holding the lock for another page.
+ *
+ * Clear __GFP_FS when allocating the page to avoid recursion into the fs
+ * and deadlock against the caller's locked page.
+ */
+static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
+                               pgoff_t index)
+{
+       return pagecache_get_page(mapping, index,
+                       FGP_LOCK|FGP_CREAT|FGP_NOFS|FGP_NOWAIT,
+                       mapping_gfp_mask(mapping),
+                       GFP_NOFS);
+}
+
 struct page *find_get_entry(struct address_space *mapping, pgoff_t offset);
-struct page *find_get_page(struct address_space *mapping, pgoff_t offset);
 struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset);
-struct page *find_lock_page(struct address_space *mapping, pgoff_t offset);
-struct page *find_or_create_page(struct address_space *mapping, pgoff_t index,
-                                gfp_t gfp_mask);
 unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
                          unsigned int nr_entries, struct page **entries,
                          pgoff_t *indices);
@@ -287,8 +384,6 @@ static inline struct page *grab_cache_page(struct address_space *mapping,
        return find_or_create_page(mapping, index, mapping_gfp_mask(mapping));
 }
 
-extern struct page * grab_cache_page_nowait(struct address_space *mapping,
-                               pgoff_t index);
 extern struct page * read_cache_page(struct address_space *mapping,
                                pgoff_t index, filler_t *filler, void *data);
 extern struct page * read_cache_page_gfp(struct address_space *mapping,
@@ -425,6 +520,8 @@ static inline void wait_on_page_writeback(struct page *page)
 extern void end_page_writeback(struct page *page);
 void wait_for_stable_page(struct page *page);
 
+void page_endio(struct page *page, int rw, int err);
+
 /*
  * Add an arbitrary waiter to a page's wait queue
  */