Hi!
> From: Rafael J. Wysocki <rjw@xxxxxxx>
> Subject: PM / Hibernate: Make default image size depend on total RAM size
>
> The default hibernation image size is currently hard coded and euqal
> to 500 MB, which is not a reasonable default on many contemporary
> systems. Make it equal 2/5 of the total RAM size (this is slightly
> below the maximum, i.e. 1/2 of the total RAM size, and seems to be
> generally suitable).
I do not think I agree here.
Making limit say 1GB may be good idea, but by making it 2/5 of RAM you
essentialy make it useless -- 40% RAM is very similar to 50% RAM.
I have box with lot of memory and old distro -- it mostly uses RAM for
cache. Now you have made my suspend/resume 6 times slower... And when I
add more memory to the machine, it will slow down even further.
Pavel
> ---
> Documentation/power/interface.txt | 2 +-
> kernel/power/main.c | 1 +
> kernel/power/power.h | 9 ++++++++-
> kernel/power/snapshot.c | 7 ++++++-
> 4 files changed, 16 insertions(+), 3 deletions(-)
>
> Index: linux-2.6/kernel/power/snapshot.c
> ===================================================================
> --- linux-2.6.orig/kernel/power/snapshot.c
> +++ linux-2.6/kernel/power/snapshot.c
> @@ -46,7 +46,12 @@ static void swsusp_unset_page_forbidden(
> * size will not exceed N bytes, but if that is impossible, it will
> * try to create the smallest image possible.
> */
> -unsigned long image_size = 500 * 1024 * 1024;
> +unsigned long image_size;
> +
> +void __init hibernate_image_size_init(void)
> +{
> + image_size = ((totalram_pages * 2) / 5) * PAGE_SIZE;
> +}
>
> /* List of PBEs needed for restoring the pages that were allocated before
> * the suspend and included in the suspend image, but have also been
> Index: linux-2.6/kernel/power/power.h
> ===================================================================
> --- linux-2.6.orig/kernel/power/power.h
> +++ linux-2.6/kernel/power/power.h
> @@ -14,6 +14,9 @@ struct swsusp_info {
> } __attribute__((aligned(PAGE_SIZE)));
>
> #ifdef CONFIG_HIBERNATION
> +/* kernel/power/snapshot.c */
> +extern void __init hibernate_image_size_init(void);
> +
> #ifdef CONFIG_ARCH_HIBERNATION_HEADER
> /* Maximum size of architecture specific data in a hibernation header */
> #define MAX_ARCH_HEADER_SIZE (sizeof(struct new_utsname) + 4)
> @@ -49,7 +52,11 @@ static inline char *check_image_kernel(s
> extern int hibernation_snapshot(int platform_mode);
> extern int hibernation_restore(int platform_mode);
> extern int hibernation_platform_enter(void);
> -#endif
> +
> +#else /* !CONFIG_HIBERNATION */
> +
> +static inline void hibernate_image_size_init(void) {}
> +#endif /* !CONFIG_HIBERNATION */
>
> extern int pfn_is_nosave(unsigned long);
>
> Index: linux-2.6/kernel/power/main.c
> ===================================================================
> --- linux-2.6.orig/kernel/power/main.c
> +++ linux-2.6/kernel/power/main.c
> @@ -321,6 +321,7 @@ static int __init pm_init(void)
> int error = pm_start_workqueue();
> if (error)
> return error;
> + hibernate_image_size_init();
> power_kobj = kobject_create_and_add("power", NULL);
> if (!power_kobj)
> return -ENOMEM;
> Index: linux-2.6/Documentation/power/interface.txt
> ===================================================================
> --- linux-2.6.orig/Documentation/power/interface.txt
> +++ linux-2.6/Documentation/power/interface.txt
> @@ -57,7 +57,7 @@ smallest image possible. In particular,
> 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.
> +is set to 2/5 of available RAM by default.
>
> /sys/power/pm_trace controls the code which saves the last PM event point in
> the RTC across reboots, so that you can debug a machine that just hangs
>
> --
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--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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