diff -urN vm-ref/fs/exec.c vm/fs/exec.c
--- vm-ref/fs/exec.c	Sun Nov 18 07:24:48 2001
+++ vm/fs/exec.c	Sun Nov 18 07:25:03 2001
@@ -275,7 +275,6 @@
 		goto out;
 	if (!pte_none(*pte))
 		goto out;
-	lru_cache_add(page);
 	flush_dcache_page(page);
 	flush_page_to_ram(page);
 	set_pte(pte, pte_mkdirty(pte_mkwrite(mk_pte(page, PAGE_COPY))));
diff -urN vm-ref/include/linux/pagemap.h vm/include/linux/pagemap.h
--- vm-ref/include/linux/pagemap.h	Sun Nov 18 07:24:53 2001
+++ vm/include/linux/pagemap.h	Sun Nov 18 07:25:03 2001
@@ -29,7 +29,7 @@
 #define PAGE_CACHE_ALIGN(addr)	(((addr)+PAGE_CACHE_SIZE-1)&PAGE_CACHE_MASK)
 
 #define page_cache_get(x)	get_page(x)
-extern void FASTCALL(page_cache_release(struct page *));
+#define page_cache_release(x)	__free_page(x)
 
 static inline struct page *page_cache_alloc(struct address_space *x)
 {
diff -urN vm-ref/include/linux/swap.h vm/include/linux/swap.h
--- vm-ref/include/linux/swap.h	Sun Nov 18 07:24:53 2001
+++ vm/include/linux/swap.h	Sun Nov 18 07:25:03 2001
@@ -176,6 +176,8 @@
 		BUG();				\
 	if (PageActive(page))			\
 		BUG();				\
+	if (page_count(page) <= 0)		\
+		BUG();				\
 } while (0)
 
 #define inc_nr_active_pages(page)				\
@@ -262,12 +264,14 @@
 	list_del(&(page)->lru);			\
 	ClearPageActive(page);			\
 	dec_nr_active_pages(page);		\
+	DEBUG_LRU_PAGE(page);			\
 } while (0)
 
 #define del_page_from_inactive_list(page)	\
 do {						\
 	list_del(&(page)->lru);			\
 	dec_nr_inactive_pages(page);		\
+	DEBUG_LRU_PAGE(page);			\
 } while (0)
 
 #define inc_nr_cache_pages(page)				\
diff -urN vm-ref/kernel/ksyms.c vm/kernel/ksyms.c
--- vm-ref/kernel/ksyms.c	Sun Nov 18 07:24:53 2001
+++ vm/kernel/ksyms.c	Sun Nov 18 07:25:03 2001
@@ -95,7 +95,6 @@
 EXPORT_SYMBOL(alloc_pages_node);
 EXPORT_SYMBOL(__get_free_pages);
 EXPORT_SYMBOL(get_zeroed_page);
-EXPORT_SYMBOL(page_cache_release);
 EXPORT_SYMBOL(__free_pages);
 EXPORT_SYMBOL(free_pages);
 EXPORT_SYMBOL(free_exact);
diff -urN vm-ref/mm/memory.c vm/mm/memory.c
--- vm-ref/mm/memory.c	Sun Nov 18 07:24:53 2001
+++ vm/mm/memory.c	Sun Nov 18 07:25:03 2001
@@ -952,7 +952,6 @@
 		if (PageReserved(old_page))
 			++mm->rss;
 		break_cow(vma, new_page, address, page_table);
-		lru_cache_add(new_page);
 
 		/* Free the old page.. */
 		new_page = old_page;
@@ -1183,7 +1182,6 @@
 		mm->rss++;
 		flush_page_to_ram(page);
 		entry = pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
-		lru_cache_add(page);
 	}
 
 	set_pte(page_table, entry);
@@ -1235,7 +1233,6 @@
 			return -1;
 		copy_user_highpage(page, new_page, address);
 		page_cache_release(new_page);
-		lru_cache_add(page);
 		new_page = page;
 	}
 
diff -urN vm-ref/mm/page_alloc.c vm/mm/page_alloc.c
--- vm-ref/mm/page_alloc.c	Sun Nov 18 07:24:53 2001
+++ vm/mm/page_alloc.c	Sun Nov 18 07:25:03 2001
@@ -446,15 +446,6 @@
 	return 0;
 }
 
-void page_cache_release(struct page *page)
-{
-	if (!PageReserved(page) && put_page_testzero(page)) {
-		if (PageLRU(page))
-			lru_cache_del(page);
-		__free_pages_ok(page, 0);
-	}
-}
-
 void __free_pages(struct page *page, unsigned int order)
 {
 	if (!PageReserved(page) && put_page_testzero(page))
diff -urN vm-ref/mm/shmem.c vm/mm/shmem.c
--- vm-ref/mm/shmem.c	Sun Nov 18 06:04:47 2001
+++ vm/mm/shmem.c	Sun Nov 18 07:25:03 2001
@@ -449,6 +449,7 @@
 		BUG();
 
 	/* Remove it from the page cache */
+	lru_cache_del(page);
 	remove_inode_page(page);
 	page_cache_release(page);
 
diff -urN vm-ref/mm/swap.c vm/mm/swap.c
--- vm-ref/mm/swap.c	Sun Nov 18 07:24:53 2001
+++ vm/mm/swap.c	Sun Nov 18 07:25:05 2001
@@ -61,11 +61,13 @@
  */
 void lru_cache_add(struct page * page)
 {
-	if (!TestSetPageLRU(page)) {
-		spin_lock(&pagemap_lru_lock);
-		add_page_to_inactive_list(page);
-		spin_unlock(&pagemap_lru_lock);
-	}
+	if (unlikely(!PageLocked(page)))
+		BUG();
+	spin_lock(&pagemap_lru_lock);
+	if (unlikely(TestSetPageLRU(page)))
+		BUG();
+	add_page_to_inactive_list(page);
+	spin_unlock(&pagemap_lru_lock);
 }
 
 /**
@@ -77,13 +79,13 @@
  */
 void __lru_cache_del(struct page * page)
 {
-	if (TestClearPageLRU(page)) {
-		if (PageActive(page)) {
-			del_page_from_active_list(page);
-		} else {
-			del_page_from_inactive_list(page);
-		}
+	if (PageActive(page)) {
+		del_page_from_active_list(page);
+	} else {
+		del_page_from_inactive_list(page);
 	}
+	if (unlikely(!TestClearPageLRU(page)))
+		BUG();
 }
 
 /**
@@ -92,6 +94,9 @@
  */
 void lru_cache_del(struct page * page)
 {
+	if (unlikely(!PageLocked(page)))
+		BUG();
+
 	spin_lock(&pagemap_lru_lock);
 	__lru_cache_del(page);
 	spin_unlock(&pagemap_lru_lock);
diff -urN vm-ref/mm/swap_state.c vm/mm/swap_state.c
--- vm-ref/mm/swap_state.c	Sun Nov 18 07:24:53 2001
+++ vm/mm/swap_state.c	Sun Nov 18 07:25:03 2001
@@ -120,6 +120,7 @@
 	if (!block_flushpage(page, 0))
 		/* an anonymous page cannot have page->buffers set */
 		BUG();
+	lru_cache_del(page);
 
 	entry.val = page->index;
 
diff -urN vm-ref/mm/swapfile.c vm/mm/swapfile.c
--- vm-ref/mm/swapfile.c	Sun Nov 18 07:24:53 2001
+++ vm/mm/swapfile.c	Sun Nov 18 07:25:03 2001
@@ -322,9 +322,12 @@
 		return 0;
 
 	entry.val = page->index;
+	spin_lock(&pagemap_lru_lock);
 	p = swap_info_get(entry);
-	if (unlikely(!p))
+	if (unlikely(!p)) {
+		spin_unlock(&pagemap_lru_lock);
 		return 0;
+	}
 
 	/* Is the only swap cache user the cache itself? */
 	retval = 0;
@@ -335,6 +338,7 @@
 			if (page->buffers && !try_to_free_buffers(page, 0))
 				/* an anonymous page cannot have page->buffers set */
 				BUG();
+			__lru_cache_del(page);
 			__delete_from_swap_cache(page);
 			swap_entry_free(p, SWP_OFFSET(entry));
 			SetPageDirty(page);
@@ -343,6 +347,7 @@
 		spin_unlock(&pagecache_lock);
 	}
 	swap_info_put(p);
+	spin_unlock(&pagemap_lru_lock);
 
 	if (retval)
 		page_cache_release(page);
diff -urN vm-ref/mm/vmscan.c vm/mm/vmscan.c
--- vm-ref/mm/vmscan.c	Sun Nov 18 07:24:53 2001
+++ vm/mm/vmscan.c	Sun Nov 18 07:25:03 2001
@@ -37,7 +37,7 @@
  * "vm_mapped_ratio" controls when we start to swapout, the lower,
  * the earlier we'll start to swapout.
  */
-int vm_mapped_ratio = 100;
+int vm_mapped_ratio = 50;
 
 /*
  * "vm_lru_balance_ratio" controls the balance between active and