X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=mm%2Fswap_state.c;h=029e56eb5e77c342559954e7c18c710a5c51092e;hb=570bc1c2e5ccdb408081e77507a385dc7ebed7fa;hp=a063a902ed03479f21db7d9f6067f255c88545f2;hpb=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2;p=linux-2.6

diff --git a/mm/swap_state.c b/mm/swap_state.c
index a063a902ed..029e56eb5e 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -124,6 +124,7 @@ void __delete_from_swap_cache(struct page *page)
 	BUG_ON(!PageLocked(page));
 	BUG_ON(!PageSwapCache(page));
 	BUG_ON(PageWriteback(page));
+	BUG_ON(PagePrivate(page));
 
 	radix_tree_delete(&swapper_space.page_tree, page->private);
 	page->private = 0;
@@ -143,7 +144,6 @@ void __delete_from_swap_cache(struct page *page)
 int add_to_swap(struct page * page)
 {
 	swp_entry_t entry;
-	int pf_flags;
 	int err;
 
 	if (!PageLocked(page))
@@ -154,29 +154,19 @@ int add_to_swap(struct page * page)
 		if (!entry.val)
 			return 0;
 
-		/* Radix-tree node allocations are performing
-		 * GFP_ATOMIC allocations under PF_MEMALLOC.  
-		 * They can completely exhaust the page allocator.  
-		 *
-		 * So PF_MEMALLOC is dropped here.  This causes the slab 
-		 * allocations to fail earlier, so radix-tree nodes will 
-		 * then be allocated from the mempool reserves.
+		/*
+		 * Radix-tree node allocations from PF_MEMALLOC contexts could
+		 * completely exhaust the page allocator. __GFP_NOMEMALLOC
+		 * stops emergency reserves from being allocated.
 		 *
-		 * We're still using __GFP_HIGH for radix-tree node
-		 * allocations, so some of the emergency pools are available,
-		 * just not all of them.
+		 * TODO: this could cause a theoretical memory reclaim
+		 * deadlock in the swap out path.
 		 */
-
-		pf_flags = current->flags;
-		current->flags &= ~PF_MEMALLOC;
-
 		/*
 		 * Add it to the swap cache and mark it dirty
 		 */
-		err = __add_to_swap_cache(page, entry, GFP_ATOMIC|__GFP_NOWARN);
-
-		if (pf_flags & PF_MEMALLOC)
-			current->flags |= PF_MEMALLOC;
+		err = __add_to_swap_cache(page, entry,
+				GFP_ATOMIC|__GFP_NOMEMALLOC|__GFP_NOWARN);
 
 		switch (err) {
 		case 0:				/* Success */
@@ -207,11 +197,6 @@ void delete_from_swap_cache(struct page *page)
 {
 	swp_entry_t entry;
 
-	BUG_ON(!PageSwapCache(page));
-	BUG_ON(!PageLocked(page));
-	BUG_ON(PageWriteback(page));
-	BUG_ON(PagePrivate(page));
-  
 	entry.val = page->private;
 
 	write_lock_irq(&swapper_space.tree_lock);