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authorKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>2009-09-21 17:01:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-22 07:17:26 -0700
commitb904dcfed6967e9cfc8a54778498f6d289420309 (patch)
treeaf57711bb516ad30d622223d80f01932fe51a4fe /mm/rmap.c
parent57dd28fb0513d2f772bb215f27925165e7b9ce5f (diff)
mm: clean up page_remove_rmap()
page_remove_rmap() has multiple PageAnon() tests and it has deep nesting. Clean this up. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/rmap.c')
-rw-r--r--mm/rmap.c57
1 files changed, 30 insertions, 27 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index 0895b5c7cbf..1406e67f961 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -739,34 +739,37 @@ void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long
*/
void page_remove_rmap(struct page *page)
{
- if (atomic_add_negative(-1, &page->_mapcount)) {
- /*
- * Now that the last pte has gone, s390 must transfer dirty
- * flag from storage key to struct page. We can usually skip
- * this if the page is anon, so about to be freed; but perhaps
- * not if it's in swapcache - there might be another pte slot
- * containing the swap entry, but page not yet written to swap.
- */
- if ((!PageAnon(page) || PageSwapCache(page)) &&
- page_test_dirty(page)) {
- page_clear_dirty(page);
- set_page_dirty(page);
- }
- if (PageAnon(page))
- mem_cgroup_uncharge_page(page);
- __dec_zone_page_state(page,
- PageAnon(page) ? NR_ANON_PAGES : NR_FILE_MAPPED);
- mem_cgroup_update_mapped_file_stat(page, -1);
- /*
- * It would be tidy to reset the PageAnon mapping here,
- * but that might overwrite a racing page_add_anon_rmap
- * which increments mapcount after us but sets mapping
- * before us: so leave the reset to free_hot_cold_page,
- * and remember that it's only reliable while mapped.
- * Leaving it set also helps swapoff to reinstate ptes
- * faster for those pages still in swapcache.
- */
+ /* page still mapped by someone else? */
+ if (!atomic_add_negative(-1, &page->_mapcount))
+ return;
+
+ /*
+ * Now that the last pte has gone, s390 must transfer dirty
+ * flag from storage key to struct page. We can usually skip
+ * this if the page is anon, so about to be freed; but perhaps
+ * not if it's in swapcache - there might be another pte slot
+ * containing the swap entry, but page not yet written to swap.
+ */
+ if ((!PageAnon(page) || PageSwapCache(page)) && page_test_dirty(page)) {
+ page_clear_dirty(page);
+ set_page_dirty(page);
}
+ if (PageAnon(page)) {
+ mem_cgroup_uncharge_page(page);
+ __dec_zone_page_state(page, NR_ANON_PAGES);
+ } else {
+ __dec_zone_page_state(page, NR_FILE_MAPPED);
+ }
+ mem_cgroup_update_mapped_file_stat(page, -1);
+ /*
+ * It would be tidy to reset the PageAnon mapping here,
+ * but that might overwrite a racing page_add_anon_rmap
+ * which increments mapcount after us but sets mapping
+ * before us: so leave the reset to free_hot_cold_page,
+ * and remember that it's only reliable while mapped.
+ * Leaving it set also helps swapoff to reinstate ptes
+ * faster for those pages still in swapcache.
+ */
}
/*