#ifdef CONFIG_SOFTWARE_SUSPEND
-extern int pm_suspend_disk(void);
+/*
+ * Keep some memory free so that I/O operations can succeed without paging
+ * [Might this be more than 4 MB?]
+ */
+#define PAGES_FOR_IO ((4096 * 1024) >> PAGE_SHIFT)
+/*
+ * Keep 1 MB of memory free so that device drivers can allocate some pages in
+ * their .suspend() routines without breaking the suspend to disk.
+ */
+#define SPARE_PAGES ((1024 * 1024) >> PAGE_SHIFT)
+extern int pm_suspend_disk(void);
#else
static inline int pm_suspend_disk(void)
{