[PATCH] fork() failing

[Marcelo Tosatti]

Linus,

As you know, we currently allow 1-order allocations to fail easily. 

However, there is one special case of 1-order allocations which cannot
fail: fork.

Here is the tested patch against pre4.

--- linux.orig/mm/page_alloc.c	Thu Oct 18 14:26:28 2001
+++ linux/mm/page_alloc.c	Thu Oct 18 16:23:15 2001
@@ -393,8 +393,13 @@
 		}
 	}
 
-	/* Don't let big-order allocations loop */
-	if (order)
+	/* We have one special 1-order alloc user: fork().
+	 * It obviously cannot fail easily like other 
+	 * high order allocations. This could also be fixed
+	 * by having a __GFP_LOOP flag to indicate that the 
+	 * high order allocation is "critical". 
+	 */
+	if (order > 1)
 		return NULL;
 
 	/* Yield for kswapd, and try again */