Pagecache: find_or_create_page does not call a proper page allocatorfunction

[Christoph Lameter]

The find_or_create function calls alloc_page with a local gfp mask instead
of using page_cache_alloc. This means that the page allocation will not
obey cpuset memory spreading and page allocation will not properly use the
gfp flags in the address space. Highmem is not set correctly.

It turns out that there is no function to allocate a page for the page cache
with a gfp mask. So we create one ORing the context gfp flags with the gfp flags
from the mapping.

Signed-off-by: Christoph Lameter <clameter@xxxxxxx>

---
 include/linux/pagemap.h |   10 ++++++++--
 mm/filemap.c            |    3 ++-
 2 files changed, 10 insertions(+), 3 deletions(-)

Index: linux-2.6.21-rc7/include/linux/pagemap.h
===================================================================
--- linux-2.6.21-rc7.orig/include/linux/pagemap.h	2007-04-23 13:52:20.000000000 -0700
+++ linux-2.6.21-rc7/include/linux/pagemap.h	2007-04-23 14:01:09.000000000 -0700
@@ -60,14 +60,20 @@ static inline struct page *__page_cache_
 }
 #endif
 
+static inline struct page *page_cache_alloc_mask(struct address_space *x,
+			gfp_t gfp)
+{
+	return __page_cache_alloc(mapping_gfp_mask(x) | gfp);
+}
+
 static inline struct page *page_cache_alloc(struct address_space *x)
 {
-	return __page_cache_alloc(mapping_gfp_mask(x));
+	return page_cache_alloc_mask(x, 0);
 }
 
 static inline struct page *page_cache_alloc_cold(struct address_space *x)
 {
-	return __page_cache_alloc(mapping_gfp_mask(x)|__GFP_COLD);
+	return page_cache_alloc_mask(x, __GFP_COLD);
 }
 
 typedef int filler_t(void *, struct page *);
Index: linux-2.6.21-rc7/mm/filemap.c
===================================================================
--- linux-2.6.21-rc7.orig/mm/filemap.c	2007-04-23 13:50:24.000000000 -0700
+++ linux-2.6.21-rc7/mm/filemap.c	2007-04-23 13:52:14.000000000 -0700
@@ -670,7 +670,8 @@ repeat:
 	page = find_lock_page(mapping, index);
 	if (!page) {
 		if (!cached_page) {
-			cached_page = alloc_page(gfp_mask);
+			cached_page =
+				page_cache_alloc_mask(mapping, gfp_mask);
 			if (!cached_page)
 				return NULL;
 		}
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/