Eric Lee / linux-smarc-t335x-v3.2

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Commit ca0aec0f7a94bf9f07fefa8bfd23282d4e8ceb8a

Authored by Rafael J. Wysocki
Committed by Linus Torvalds
1 parent b3a93a255e
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

[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>

Showing 5 changed files with 47 additions and 6 deletions Side-by-side Diff

Documentation/power/interface.txt
Diff comments   View file @ ca0aec0
... ... @@ -40,4 +40,16 @@
40 40  
41 41 It will only change to 'firmware' or 'platform' if the system supports
42 42 it.
  43 +
  44 +/sys/power/image_size controls the size of the image created by
  45 +the suspend-to-disk mechanism. It can be written a string
  46 +representing a non-negative integer that will be used as an upper
  47 +limit of the image size, in megabytes. The suspend-to-disk mechanism will
  48 +do its best to ensure the image size will not exceed that number. However,
  49 +if this turns out to be impossible, it will try to suspend anyway using the
  50 +smallest image possible. In particular, if "0" is written to this file, the
  51 +suspend image will be as small as possible.
  52 +
  53 +Reading from this file will display the current image size limit, which
  54 +is set to 500 MB by default.
Documentation/power/swsusp.txt
Diff comments   View file @ ca0aec0
... ... @@ -27,6 +27,11 @@
27 27  
28 28 echo platform > /sys/power/disk; echo disk > /sys/power/state
29 29  
  30 +If you want to limit the suspend image size to N megabytes, do
  31 +
  32 +echo N > /sys/power/image_size
  33 +
  34 +before suspend (it is limited to 500 MB by default).
30 35  
31 36 Encrypted suspend image:
32 37 ------------------------
... ... @@ -365,9 +365,29 @@
365 365  
366 366 power_attr(resume);
367 367  
  368 +static ssize_t image_size_show(struct subsystem * subsys, char *buf)
  369 +{
  370 + return sprintf(buf, "%u\n", image_size);
  371 +}
  372 +
  373 +static ssize_t image_size_store(struct subsystem * subsys, const char * buf, size_t n)
  374 +{
  375 + unsigned int size;
  376 +
  377 + if (sscanf(buf, "%u", &size) == 1) {
  378 + image_size = size;
  379 + return n;
  380 + }
  381 +
  382 + return -EINVAL;
  383 +}
  384 +
  385 +power_attr(image_size);
  386 +
368 387 static struct attribute * g[] = {
369 388 &disk_attr.attr,
370 389 &resume_attr.attr,
  390 + &image_size_attr.attr,
371 391 NULL,
372 392 };
373 393  
kernel/power/power.h
Diff comments   View file @ ca0aec0
... ... @@ -52,11 +52,8 @@
52 52 extern unsigned int nr_copy_pages;
53 53 extern struct pbe *pagedir_nosave;
54 54  
55   -/*
56   - * Preferred image size in MB (set it to zero to get the smallest
57   - * image possible)
58   - */
59   -#define IMAGE_SIZE 500
  55 +/* Preferred image size in MB (default 500) */
  56 +extern unsigned int image_size;
60 57  
61 58 extern asmlinkage int swsusp_arch_suspend(void);
62 59 extern asmlinkage int swsusp_arch_resume(void);
kernel/power/swsusp.c
Diff comments   View file @ ca0aec0
... ... @@ -69,6 +69,14 @@
69 69  
70 70 #include "power.h"
71 71  
  72 +/*
  73 + * Preferred image size in MB (tunable via /sys/power/image_size).
  74 + * When it is set to N, swsusp will do its best to ensure the image
  75 + * size will not exceed N MB, but if that is impossible, it will
  76 + * try to create the smallest image possible.
  77 + */
  78 +unsigned int image_size = 500;
  79 +
72 80 #ifdef CONFIG_HIGHMEM
73 81 unsigned int count_highmem_pages(void);
74 82 int save_highmem(void);
... ... @@ -647,7 +655,7 @@
647 655 if (!tmp)
648 656 return -ENOMEM;
649 657 pages += tmp;
650   - } else if (size > (IMAGE_SIZE * 1024 * 1024) / PAGE_SIZE) {
  658 + } else if (size > (image_size * 1024 * 1024) / PAGE_SIZE) {
651 659 tmp = shrink_all_memory(SHRINK_BITE);
652 660 pages += tmp;
653 661 }