add_to_page_cache only deals with newly allocated pages except in the
swap -> shm case. Take advantage of this to optimise add_to_page_cache,
and introduce a new __add_to_page_cache for use on pages other than
newly allocated ones.
Index: linux-2.6/mm/filemap.c
===================================================================
--- linux-2.6.orig/mm/filemap.c
+++ linux-2.6/mm/filemap.c
@@ -400,6 +400,45 @@ int add_to_page_cache(struct page *page,
int error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM);
if (error == 0) {
+ /*
+ * Can get away with less atomic ops and without using
+ * Set/ClearPageNoNewRefs if we order operations correctly.
+ */
+ page_cache_get(page);
+ __SetPageLocked(page);
+ page->mapping = mapping;
+ page->index = offset;
+
+ write_lock_irq(&mapping->tree_lock);
+ error = radix_tree_insert(&mapping->page_tree, offset, page);
+ if (!error) {
+ mapping->nrpages++;
+ pagecache_acct(1);
+ }
+ write_unlock_irq(&mapping->tree_lock);
+ radix_tree_preload_end();
+
+ if (error) {
+ page->mapping = NULL;
+ __put_page(page);
+ __ClearPageLocked(page);
+ }
+ }
+ return error;
+}
+EXPORT_SYMBOL(add_to_page_cache);
+
+/*
+ * Same as add_to_page_cache, but works on pages that are already in
+ * swapcache and possibly visible to external lookups.
+ * (special case for move_from_swap_cache).
+ */
+int __add_to_page_cache(struct page *page, struct address_space *mapping,
+ pgoff_t offset, gfp_t gfp_mask)
+{
+ int error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM);
+
+ if (error == 0) {
SetPageNoNewRefs(page);
write_lock_irq(&mapping->tree_lock);
error = radix_tree_insert(&mapping->page_tree, offset, page);
@@ -417,7 +456,6 @@ int add_to_page_cache(struct page *page,
}
return error;
}
-EXPORT_SYMBOL(add_to_page_cache);
int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
pgoff_t offset, gfp_t gfp_mask)
Index: linux-2.6/mm/swap_state.c
===================================================================
--- linux-2.6.orig/mm/swap_state.c
+++ linux-2.6/mm/swap_state.c
@@ -234,7 +234,7 @@ int move_to_swap_cache(struct page *page
int move_from_swap_cache(struct page *page, unsigned long index,
struct address_space *mapping)
{
- int err = add_to_page_cache(page, mapping, index, GFP_ATOMIC);
+ int err = __add_to_page_cache(page, mapping, index, GFP_ATOMIC);
if (!err) {
delete_from_swap_cache(page);
/* shift page from clean_pages to dirty_pages list */
Index: linux-2.6/include/linux/pagemap.h
===================================================================
--- linux-2.6.orig/include/linux/pagemap.h
+++ linux-2.6/include/linux/pagemap.h
@@ -183,6 +183,8 @@ extern int read_cache_pages(struct addre
int add_to_page_cache(struct page *page, struct address_space *mapping,
unsigned long index, gfp_t gfp_mask);
+int __add_to_page_cache(struct page *page, struct address_space *mapping,
+ unsigned long index, gfp_t gfp_mask);
int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
unsigned long index, gfp_t gfp_mask);
extern void remove_from_page_cache(struct page *page);
Index: linux-2.6/include/linux/page-flags.h
===================================================================
--- linux-2.6.orig/include/linux/page-flags.h
+++ linux-2.6/include/linux/page-flags.h
@@ -214,16 +214,13 @@ extern void __mod_page_state_offset(unsi
/*
* Manipulation of page state flags
*/
-#define PageLocked(page) \
- test_bit(PG_locked, &(page)->flags)
-#define SetPageLocked(page) \
- set_bit(PG_locked, &(page)->flags)
-#define TestSetPageLocked(page) \
- test_and_set_bit(PG_locked, &(page)->flags)
-#define ClearPageLocked(page) \
- clear_bit(PG_locked, &(page)->flags)
-#define TestClearPageLocked(page) \
- test_and_clear_bit(PG_locked, &(page)->flags)
+#define PageLocked(page) test_bit(PG_locked, &(page)->flags)
+#define SetPageLocked(page) set_bit(PG_locked, &(page)->flags)
+#define __SetPageLocked(page) __set_bit(PG_locked, &(page)->flags)
+#define TestSetPageLocked(page) test_and_set_bit(PG_locked, &(page)->flags)
+#define ClearPageLocked(page) clear_bit(PG_locked, &(page)->flags)
+#define __ClearPageLocked(page) __clear_bit(PG_locked, &(page)->flags)
+#define TestClearPageLocked(page) test_and_clear_bit(PG_locked, &(page)->flags)
#define PageError(page) test_bit(PG_error, &(page)->flags)
#define SetPageError(page) set_bit(PG_error, &(page)->flags)
-
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