[PATCH] swsusp: make image size limit tunable

Make the suspend image size limit tunable via /sys/power/image_size.

It is necessary for systems on which there is a limited amount of swap
available for suspend.  It can also be useful for optimizing performance of
swsusp on systems with 1 GB of RAM or more.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 9 insertions, 1 deletions

diff --git a/kernel/power/swsusp.c b/kernel/power/swsusp.c
index 6d5ceaf4c364..d760a6a719f0 100644
--- a/kernel/power/swsusp.c
+++ b/kernel/power/swsusp.c
@@ -69,6 +69,14 @@
 
 #include "power.h"
 
+/*
+ * Preferred image size in MB (tunable via /sys/power/image_size).
+ * When it is set to N, swsusp will do its best to ensure the image
+ * size will not exceed N MB, but if that is impossible, it will
+ * try to create the smallest image possible.
+ */
+unsigned int image_size = 500;
+
 #ifdef CONFIG_HIGHMEM
 unsigned int count_highmem_pages(void);
 int save_highmem(void);
@@ -647,7 +655,7 @@ int swsusp_shrink_memory(void)
                         if (!tmp)
                                 return -ENOMEM;
                         pages += tmp;
-                } else if (size > (IMAGE_SIZE * 1024 * 1024) / PAGE_SIZE) {
+                } else if (size > (image_size * 1024 * 1024) / PAGE_SIZE) {
                         tmp = shrink_all_memory(SHRINK_BITE);
                         pages += tmp;
                 }