mm: further cleanup page_add_new_anon_rmap

Moving lru_cache_add_active_or_unevictable() into page_add_new_anon_rmap()
was good but stupid: we can and should SetPageSwapBacked() there too; and
we know for sure that this anonymous, swap-backed page is not file cache.
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Acked-by: NRik van Riel <riel@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/memory.c

@@ -1948,7 +1948,6 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
 		 * thread doing COW.
 		 */
 		ptep_clear_flush_notify(vma, address, page_table);
-		SetPageSwapBacked(new_page);
 		page_add_new_anon_rmap(new_page, vma, address);
 		set_pte_at(mm, address, page_table, entry);
 		update_mmu_cache(vma, address, entry);
@@ -2444,7 +2443,6 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	if (!pte_none(*page_table))
 		goto release;
 	inc_mm_counter(mm, anon_rss);
-	SetPageSwapBacked(page);
 	page_add_new_anon_rmap(page, vma, address);
 	set_pte_at(mm, address, page_table, entry);
 
@@ -2592,7 +2590,6 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
 			entry = maybe_mkwrite(pte_mkdirty(entry), vma);
 		if (anon) {
 			inc_mm_counter(mm, anon_rss);
-			SetPageSwapBacked(page);
 			page_add_new_anon_rmap(page, vma, address);
 		} else {
 			inc_mm_counter(mm, file_rss);

mm/rmap.c

@@ -47,7 +47,6 @@
 #include <linux/rmap.h>
 #include <linux/rcupdate.h>
 #include <linux/module.h>
-#include <linux/mm_inline.h>
 #include <linux/kallsyms.h>
 #include <linux/memcontrol.h>
 #include <linux/mmu_notifier.h>
@@ -673,10 +672,11 @@ void page_add_new_anon_rmap(struct page *page,
 	struct vm_area_struct *vma, unsigned long address)
 {
 	VM_BUG_ON(address < vma->vm_start || address >= vma->vm_end);
-	atomic_set(&page->_mapcount, 0); /* elevate count by 1 (starts at -1) */
+	SetPageSwapBacked(page);
+	atomic_set(&page->_mapcount, 0); /* increment count (starts at -1) */
 	__page_set_anon_rmap(page, vma, address);
 	if (page_evictable(page, vma))
-		lru_cache_add_lru(page, LRU_ACTIVE + page_is_file_cache(page));
+		lru_cache_add_lru(page, LRU_ACTIVE_ANON);
 	else
 		add_page_to_unevictable_list(page);
 }