Commit ca0aec0f authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Linus Torvalds
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[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: default avatarRafael J. Wysocki <>
Acked-by: default avatarPavel Machek <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent b3a93a25
......@@ -41,3 +41,14 @@ to. Writing to this file will accept one of
It will only change to 'firmware' or 'platform' if the system supports
/sys/power/image_size controls the size of the image created by
the suspend-to-disk mechanism. It can be written a string
representing a non-negative integer that will be used as an upper
limit of the image size, in megabytes. The suspend-to-disk mechanism will
do its best to ensure the image size will not exceed that number. However,
if this turns out to be impossible, it will try to suspend anyway using the
smallest image possible. In particular, if "0" is written to this file, the
suspend image will be as small as possible.
Reading from this file will display the current image size limit, which
is set to 500 MB by default.
......@@ -27,6 +27,11 @@ echo shutdown > /sys/power/disk; echo disk > /sys/power/state
echo platform > /sys/power/disk; echo disk > /sys/power/state
If you want to limit the suspend image size to N megabytes, do
echo N > /sys/power/image_size
before suspend (it is limited to 500 MB by default).
Encrypted suspend image:
......@@ -365,9 +365,29 @@ out:
static ssize_t image_size_show(struct subsystem * subsys, char *buf)
return sprintf(buf, "%u\n", image_size);
static ssize_t image_size_store(struct subsystem * subsys, const char * buf, size_t n)
unsigned int size;
if (sscanf(buf, "%u", &size) == 1) {
image_size = size;
return n;
return -EINVAL;
static struct attribute * g[] = {
......@@ -52,11 +52,8 @@ extern const void __nosave_begin, __nosave_end;
extern unsigned int nr_copy_pages;
extern struct pbe *pagedir_nosave;
* Preferred image size in MB (set it to zero to get the smallest
* image possible)
#define IMAGE_SIZE 500
/* Preferred image size in MB (default 500) */
extern unsigned int image_size;
extern asmlinkage int swsusp_arch_suspend(void);
extern asmlinkage int swsusp_arch_resume(void);
......@@ -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;
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;
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