2 * linux/kernel/power/swsusp.c
4 * This file provides code to write suspend image to swap and read it back.
6 * Copyright (C) 1998-2001 Gabor Kuti <seasons@fornax.hu>
7 * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@suse.cz>
9 * This file is released under the GPLv2.
11 * I'd like to thank the following people for their work:
13 * Pavel Machek <pavel@ucw.cz>:
14 * Modifications, defectiveness pointing, being with me at the very beginning,
15 * suspend to swap space, stop all tasks. Port to 2.4.18-ac and 2.5.17.
17 * Steve Doddi <dirk@loth.demon.co.uk>:
18 * Support the possibility of hardware state restoring.
20 * Raph <grey.havens@earthling.net>:
21 * Support for preserving states of network devices and virtual console
22 * (including X and svgatextmode)
24 * Kurt Garloff <garloff@suse.de>:
25 * Straightened the critical function in order to prevent compilers from
26 * playing tricks with local variables.
28 * Andreas Mohr <a.mohr@mailto.de>
30 * Alex Badea <vampire@go.ro>:
33 * Rafael J. Wysocki <rjw@sisk.pl>
34 * Reworked the freeing of memory and the handling of swap
36 * More state savers are welcome. Especially for the scsi layer...
38 * For TODOs,FIXMEs also look in Documentation/power/swsusp.txt
42 #include <linux/suspend.h>
43 #include <linux/spinlock.h>
44 #include <linux/kernel.h>
45 #include <linux/major.h>
46 #include <linux/swap.h>
48 #include <linux/swapops.h>
49 #include <linux/bootmem.h>
50 #include <linux/syscalls.h>
51 #include <linux/highmem.h>
56 * Preferred image size in bytes (tunable via /sys/power/image_size).
57 * When it is set to N, swsusp will do its best to ensure the image
58 * size will not exceed N bytes, but if that is impossible, it will
59 * try to create the smallest image possible.
61 unsigned long image_size = 500 * 1024 * 1024;
63 int in_suspend __nosavedata = 0;
66 * The following functions are used for tracing the allocated
67 * swap pages, so that they can be freed in case of an error.
69 * The functions operate on a linked bitmap structure defined
73 void free_bitmap(struct bitmap_page *bitmap)
75 struct bitmap_page *bp;
79 free_page((unsigned long)bitmap);
84 struct bitmap_page *alloc_bitmap(unsigned int nr_bits)
86 struct bitmap_page *bitmap, *bp;
92 bitmap = (struct bitmap_page *)get_zeroed_page(GFP_KERNEL);
94 for (n = BITMAP_PAGE_BITS; n < nr_bits; n += BITMAP_PAGE_BITS) {
95 bp->next = (struct bitmap_page *)get_zeroed_page(GFP_KERNEL);
105 static int bitmap_set(struct bitmap_page *bitmap, unsigned long bit)
109 n = BITMAP_PAGE_BITS;
110 while (bitmap && n <= bit) {
111 n += BITMAP_PAGE_BITS;
112 bitmap = bitmap->next;
116 n -= BITMAP_PAGE_BITS;
119 while (bit >= BITS_PER_CHUNK) {
120 bit -= BITS_PER_CHUNK;
123 bitmap->chunks[n] |= (1UL << bit);
127 unsigned long alloc_swap_page(int swap, struct bitmap_page *bitmap)
129 unsigned long offset;
131 offset = swp_offset(get_swap_page_of_type(swap));
133 if (bitmap_set(bitmap, offset)) {
134 swap_free(swp_entry(swap, offset));
141 void free_all_swap_pages(int swap, struct bitmap_page *bitmap)
148 for (n = 0; n < BITMAP_PAGE_CHUNKS; n++)
149 for (test = 1UL; test; test <<= 1) {
150 if (bitmap->chunks[n] & test)
151 swap_free(swp_entry(swap, bit));
154 bitmap = bitmap->next;
159 * swsusp_shrink_memory - Try to free as much memory as needed
161 * ... but do not OOM-kill anyone
163 * Notice: all userland should be stopped before it is called, or
164 * livelock is possible.
167 #define SHRINK_BITE 10000
168 static inline unsigned long __shrink_memory(long tmp)
170 if (tmp > SHRINK_BITE)
172 return shrink_all_memory(tmp);
175 int swsusp_shrink_memory(void)
179 unsigned long pages = 0;
183 printk("Shrinking memory... ");
185 size = 2 * count_special_pages();
186 size += size / 50 + count_data_pages();
187 size += (size + PBES_PER_PAGE - 1) / PBES_PER_PAGE +
191 if (!is_highmem(zone) && populated_zone(zone)) {
192 tmp -= zone->free_pages;
193 tmp += zone->lowmem_reserve[ZONE_NORMAL];
196 tmp = __shrink_memory(tmp);
200 } else if (size > image_size / PAGE_SIZE) {
201 tmp = __shrink_memory(size - (image_size / PAGE_SIZE));
204 printk("\b%c", p[i++%4]);
206 printk("\bdone (%lu pages freed)\n", pages);
211 int swsusp_suspend(void)
215 if ((error = arch_prepare_suspend()))
218 /* At this point, device_suspend() has been called, but *not*
219 * device_power_down(). We *must* device_power_down() now.
220 * Otherwise, drivers for some devices (e.g. interrupt controllers)
221 * become desynchronized with the actual state of the hardware
222 * at resume time, and evil weirdness ensues.
224 if ((error = device_power_down(PMSG_FREEZE))) {
225 printk(KERN_ERR "Some devices failed to power down, aborting suspend\n");
229 if ((error = save_special_mem())) {
230 printk(KERN_ERR "swsusp: Not enough free pages for highmem\n");
231 goto Restore_highmem;
234 save_processor_state();
235 if ((error = swsusp_arch_suspend()))
236 printk(KERN_ERR "Error %d suspending\n", error);
237 /* Restore control flow magically appears here */
238 restore_processor_state();
240 restore_special_mem();
247 int swsusp_resume(void)
251 if (device_power_down(PMSG_FREEZE))
252 printk(KERN_ERR "Some devices failed to power down, very bad\n");
253 /* We'll ignore saved state, but this gets preempt count (etc) right */
254 save_processor_state();
255 error = swsusp_arch_resume();
256 /* Code below is only ever reached in case of failure. Otherwise
257 * execution continues at place where swsusp_arch_suspend was called
260 /* The only reason why swsusp_arch_resume() can fail is memory being
261 * very tight, so we have to free it as soon as we can to avoid
262 * subsequent failures
265 restore_processor_state();
266 restore_special_mem();
267 touch_softlockup_watchdog();