kernel/power/swsusp.c

   1 /*
   2  * linux/kernel/power/swsusp.c
   3  *
   4  * This file provides code to write suspend image to swap and read it back.
   5  *
   6  * Copyright (C) 1998-2001 Gabor Kuti <seasons@fornax.hu>
   7  * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@suse.cz>
   8  *
   9  * This file is released under the GPLv2.
  10  *
  11  * I'd like to thank the following people for their work:
  12  *
  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.
  16  *
  17  * Steve Doddi <dirk@loth.demon.co.uk>:
  18  * Support the possibility of hardware state restoring.
  19  *
  20  * Raph <grey.havens@earthling.net>:
  21  * Support for preserving states of network devices and virtual console
  22  * (including X and svgatextmode)
  23  *
  24  * Kurt Garloff <garloff@suse.de>:
  25  * Straightened the critical function in order to prevent compilers from
  26  * playing tricks with local variables.
  27  *
  28  * Andreas Mohr <a.mohr@mailto.de>
  29  *
  30  * Alex Badea <vampire@go.ro>:
  31  * Fixed runaway init
  32  *
  33  * Rafael J. Wysocki <rjw@sisk.pl>
  34  * Reworked the freeing of memory and the handling of swap
  35  *
  36  * More state savers are welcome. Especially for the scsi layer...
  37  *
  38  * For TODOs,FIXMEs also look in Documentation/power/swsusp.txt
  39  */
  40
  41 #include <linux/mm.h>
  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>
  47 #include <linux/pm.h>
  48 #include <linux/swapops.h>
  49 #include <linux/bootmem.h>
  50 #include <linux/syscalls.h>
  51 #include <linux/highmem.h>
  52 #include <linux/time.h>
  53 #include <linux/rbtree.h>
  54
  55 #include "power.h"
  56
  57 /*
  58  * Preferred image size in bytes (tunable via /sys/power/image_size).
  59  * When it is set to N, swsusp will do its best to ensure the image
  60  * size will not exceed N bytes, but if that is impossible, it will
  61  * try to create the smallest image possible.
  62  */
  63 unsigned long image_size = 500 * 1024 * 1024;
  64
  65 int in_suspend __nosavedata = 0;
  66
  67 /**
  68  *      The following functions are used for tracing the allocated
  69  *      swap pages, so that they can be freed in case of an error.
  70  */
  71
  72 struct swsusp_extent {
  73         struct rb_node node;
  74         unsigned long start;
  75         unsigned long end;
  76 };
  77
  78 static struct rb_root swsusp_extents = RB_ROOT;
  79
  80 static int swsusp_extents_insert(unsigned long swap_offset)
  81 {
  82         struct rb_node **new = &(swsusp_extents.rb_node);
  83         struct rb_node *parent = NULL;
  84         struct swsusp_extent *ext;
  85
  86         /* Figure out where to put the new node */
  87         while (*new) {
  88                 ext = container_of(*new, struct swsusp_extent, node);
  89                 parent = *new;
  90                 if (swap_offset < ext->start) {
  91                         /* Try to merge */
  92                         if (swap_offset == ext->start - 1) {
  93                                 ext->start--;
  94                                 return 0;
  95                         }
  96                         new = &((*new)->rb_left);
  97                 } else if (swap_offset > ext->end) {
  98                         /* Try to merge */
  99                         if (swap_offset == ext->end + 1) {
 100                                 ext->end++;
 101                                 return 0;
 102                         }
 103                         new = &((*new)->rb_right);
 104                 } else {
 105                         /* It already is in the tree */
 106                         return -EINVAL;
 107                 }
 108         }
 109         /* Add the new node and rebalance the tree. */
 110         ext = kzalloc(sizeof(struct swsusp_extent), GFP_KERNEL);
 111         if (!ext)
 112                 return -ENOMEM;
 113
 114         ext->start = swap_offset;
 115         ext->end = swap_offset;
 116         rb_link_node(&ext->node, parent, new);
 117         rb_insert_color(&ext->node, &swsusp_extents);
 118         return 0;
 119 }
 120
 121 /**
 122  *      alloc_swapdev_block - allocate a swap page and register that it has
 123  *      been allocated, so that it can be freed in case of an error.
 124  */
 125
 126 sector_t alloc_swapdev_block(int swap)
 127 {
 128         unsigned long offset;
 129
 130         offset = swp_offset(get_swap_page_of_type(swap));
 131         if (offset) {
 132                 if (swsusp_extents_insert(offset))
 133                         swap_free(swp_entry(swap, offset));
 134                 else
 135                         return swapdev_block(swap, offset);
 136         }
 137         return 0;
 138 }
 139
 140 /**
 141  *      free_all_swap_pages - free swap pages allocated for saving image data.
 142  *      It also frees the extents used to register which swap entres had been
 143  *      allocated.
 144  */
 145
 146 void free_all_swap_pages(int swap)
 147 {
 148         struct rb_node *node;
 149
 150         while ((node = swsusp_extents.rb_node)) {
 151                 struct swsusp_extent *ext;
 152                 unsigned long offset;
 153
 154                 ext = container_of(node, struct swsusp_extent, node);
 155                 rb_erase(node, &swsusp_extents);
 156                 for (offset = ext->start; offset <= ext->end; offset++)
 157                         swap_free(swp_entry(swap, offset));
 158
 159                 kfree(ext);
 160         }
 161 }
 162
 163 int swsusp_swap_in_use(void)
 164 {
 165         return (swsusp_extents.rb_node != NULL);
 166 }
 167
 168 /**
 169  *      swsusp_show_speed - print the time elapsed between two events represented by
 170  *      @start and @stop
 171  *
 172  *      @nr_pages -     number of pages processed between @start and @stop
 173  *      @msg -          introductory message to print
 174  */
 175
 176 void swsusp_show_speed(struct timeval *start, struct timeval *stop,
 177                         unsigned nr_pages, char *msg)
 178 {
 179         s64 elapsed_centisecs64;
 180         int centisecs;
 181         int k;
 182         int kps;
 183
 184         elapsed_centisecs64 = timeval_to_ns(stop) - timeval_to_ns(start);
 185         do_div(elapsed_centisecs64, NSEC_PER_SEC / 100);
 186         centisecs = elapsed_centisecs64;
 187         if (centisecs == 0)
 188                 centisecs = 1;  /* avoid div-by-zero */
 189         k = nr_pages * (PAGE_SIZE / 1024);
 190         kps = (k * 100) / centisecs;
 191         printk(KERN_INFO "PM: %s %d kbytes in %d.%02d seconds (%d.%02d MB/s)\n",
 192                         msg, k,
 193                         centisecs / 100, centisecs % 100,
 194                         kps / 1000, (kps % 1000) / 10);
 195 }
 196
 197 /**
 198  *      swsusp_shrink_memory -  Try to free as much memory as needed
 199  *
 200  *      ... but do not OOM-kill anyone
 201  *
 202  *      Notice: all userland should be stopped before it is called, or
 203  *      livelock is possible.
 204  */
 205
 206 #define SHRINK_BITE     10000
 207 static inline unsigned long __shrink_memory(long tmp)
 208 {
 209         if (tmp > SHRINK_BITE)
 210                 tmp = SHRINK_BITE;
 211         return shrink_all_memory(tmp);
 212 }
 213
 214 int swsusp_shrink_memory(void)
 215 {
 216         long tmp;
 217         struct zone *zone;
 218         unsigned long pages = 0;
 219         unsigned int i = 0;
 220         char *p = "-\\|/";
 221         struct timeval start, stop;
 222
 223         printk(KERN_INFO "PM: Shrinking memory...  ");
 224         do_gettimeofday(&start);
 225         do {
 226                 long size, highmem_size;
 227
 228                 highmem_size = count_highmem_pages();
 229                 size = count_data_pages() + PAGES_FOR_IO + SPARE_PAGES;
 230                 tmp = size;
 231                 size += highmem_size;
 232                 for_each_zone (zone)
 233                         if (populated_zone(zone)) {
 234                                 tmp += snapshot_additional_pages(zone);
 235                                 if (is_highmem(zone)) {
 236                                         highmem_size -=
 237                                         zone_page_state(zone, NR_FREE_PAGES);
 238                                 } else {
 239                                         tmp -= zone_page_state(zone, NR_FREE_PAGES);
 240                                         tmp += zone->lowmem_reserve[ZONE_NORMAL];
 241                                 }
 242                         }
 243
 244                 if (highmem_size < 0)
 245                         highmem_size = 0;
 246
 247                 tmp += highmem_size;
 248                 if (tmp > 0) {
 249                         tmp = __shrink_memory(tmp);
 250                         if (!tmp)
 251                                 return -ENOMEM;
 252                         pages += tmp;
 253                 } else if (size > image_size / PAGE_SIZE) {
 254                         tmp = __shrink_memory(size - (image_size / PAGE_SIZE));
 255                         pages += tmp;
 256                 }
 257                 printk("\b%c", p[i++%4]);
 258         } while (tmp > 0);
 259         do_gettimeofday(&stop);
 260         printk("\bdone (%lu pages freed)\n", pages);
 261         swsusp_show_speed(&start, &stop, pages, "Freed");
 262
 263         return 0;
 264 }