[RFC][PATCH v2 1/8] Replace page_mapping_inuse() with page_mapped()

KOSAKI Motohiro
2009-12-10T07:29:50Z

page reclaim logic need to distingish mapped and unmapped pages.
However page_mapping_inuse() don't provide proper test way. it test
the address space (i.e. file) is mmpad(). Why `page' reclaim need
care unrelated page's mapped state? it's unrelated.

Thus, This patch replace page_mapping_inuse() with page_mapped()

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
---
mm/vmscan.c | 25 ++-----------------------
1 files changed, 2 insertions(+), 23 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 2bbee91..3366bec 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -262,27 +262,6 @@ unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask,
return ret;
}

-/* Called without lock on whether page is mapped, so answer is unstable */
-static inline int page_mapping_inuse(struct page *page)
-{
- struct address_space *mapping;
-
- /* Page is in somebody's page tables. */
- if (page_mapped(page))
- return 1;
-
- /* Be more reluctant to reclaim swapcache than pagecache */
- if (PageSwapCache(page))
- return 1;
-
- mapping = page_mapping(page);
- if (!mapping)
- return 0;
-
- /* File is mmap'd by somebody? */
- return mapping_mapped(mapping);
-}
-
static inline int is_page_cache_freeable(struct page *page)
{
/*
@@ -649,7 +628,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
* try_to_unmap moves it to unevictable list
*/
if (sc->order <= PAGE_ALLOC_COSTLY_ORDER &&
- referenced && page_mapping_inuse(page)
+ referenced && page_mapped(page)
&& !(vm_flags & VM_LOCKED))
goto activate_locked;

@@ -1351,7 +1330,7 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
}

/* page_referenced clears PageReferenced */
- if (page_mapping_inuse(page) &&
+ if (page_mapped(page) &&
page_referenced(page, 0, sc->mem_cgroup, &vm_flags)) {
nr_rotated++;
/*