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authorAkinobu Mita <akinobu.mita@gmail.com>2008-07-24 00:28:38 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-24 13:47:23 -0400
commit0d83304c7e7bd3b05be90281b3a47841bc8f057a (patch)
tree148e2dcfbbe385356af87629b59e71262adc68ce /kernel/power
parent8111d1b552349921aae1acf73e4e8cea98e80970 (diff)
pm: hibernation: simplify memory bitmap
This patch simplifies the memory bitmap manipulations. - remove the member size in struct bm_block It is not necessary for struct bm_block to have the number of bit chunks that can be calculated by using end_pfn and start_pfn. - use find_next_bit() for memory_bm_next_pfn No need to invent the bitmap library only for the memory bitmap. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/power')
-rw-r--r--kernel/power/snapshot.c88
1 files changed, 21 insertions, 67 deletions
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 5f91a07c4eac..5d2ab836e998 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -205,8 +205,7 @@ static void chain_free(struct chain_allocator *ca, int clear_page_nosave)
205 * objects. The main list's elements are of type struct zone_bitmap 205 * objects. The main list's elements are of type struct zone_bitmap
206 * and each of them corresonds to one zone. For each zone bitmap 206 * and each of them corresonds to one zone. For each zone bitmap
207 * object there is a list of objects of type struct bm_block that 207 * object there is a list of objects of type struct bm_block that
208 * represent each blocks of bit chunks in which information is 208 * represent each blocks of bitmap in which information is stored.
209 * stored.
210 * 209 *
211 * struct memory_bitmap contains a pointer to the main list of zone 210 * struct memory_bitmap contains a pointer to the main list of zone
212 * bitmap objects, a struct bm_position used for browsing the bitmap, 211 * bitmap objects, a struct bm_position used for browsing the bitmap,
@@ -224,26 +223,27 @@ static void chain_free(struct chain_allocator *ca, int clear_page_nosave)
224 * pfns that correspond to the start and end of the represented zone. 223 * pfns that correspond to the start and end of the represented zone.
225 * 224 *
226 * struct bm_block contains a pointer to the memory page in which 225 * struct bm_block contains a pointer to the memory page in which
227 * information is stored (in the form of a block of bit chunks 226 * information is stored (in the form of a block of bitmap)
228 * of type unsigned long each). It also contains the pfns that 227 * It also contains the pfns that correspond to the start and end of
229 * correspond to the start and end of the represented memory area and 228 * the represented memory area.
230 * the number of bit chunks in the block.
231 */ 229 */
232 230
233#define BM_END_OF_MAP (~0UL) 231#define BM_END_OF_MAP (~0UL)
234 232
235#define BM_CHUNKS_PER_BLOCK (PAGE_SIZE / sizeof(long))
236#define BM_BITS_PER_CHUNK (sizeof(long) << 3)
237#define BM_BITS_PER_BLOCK (PAGE_SIZE << 3) 233#define BM_BITS_PER_BLOCK (PAGE_SIZE << 3)
238 234
239struct bm_block { 235struct bm_block {
240 struct bm_block *next; /* next element of the list */ 236 struct bm_block *next; /* next element of the list */
241 unsigned long start_pfn; /* pfn represented by the first bit */ 237 unsigned long start_pfn; /* pfn represented by the first bit */
242 unsigned long end_pfn; /* pfn represented by the last bit plus 1 */ 238 unsigned long end_pfn; /* pfn represented by the last bit plus 1 */
243 unsigned int size; /* number of bit chunks */ 239 unsigned long *data; /* bitmap representing pages */
244 unsigned long *data; /* chunks of bits representing pages */
245}; 240};
246 241
242static inline unsigned long bm_block_bits(struct bm_block *bb)
243{
244 return bb->end_pfn - bb->start_pfn;
245}
246
247struct zone_bitmap { 247struct zone_bitmap {
248 struct zone_bitmap *next; /* next element of the list */ 248 struct zone_bitmap *next; /* next element of the list */
249 unsigned long start_pfn; /* minimal pfn in this zone */ 249 unsigned long start_pfn; /* minimal pfn in this zone */
@@ -257,7 +257,6 @@ struct zone_bitmap {
257struct bm_position { 257struct bm_position {
258 struct zone_bitmap *zone_bm; 258 struct zone_bitmap *zone_bm;
259 struct bm_block *block; 259 struct bm_block *block;
260 int chunk;
261 int bit; 260 int bit;
262}; 261};
263 262
@@ -272,12 +271,6 @@ struct memory_bitmap {
272 271
273/* Functions that operate on memory bitmaps */ 272/* Functions that operate on memory bitmaps */
274 273
275static inline void memory_bm_reset_chunk(struct memory_bitmap *bm)
276{
277 bm->cur.chunk = 0;
278 bm->cur.bit = -1;
279}
280
281static void memory_bm_position_reset(struct memory_bitmap *bm) 274static void memory_bm_position_reset(struct memory_bitmap *bm)
282{ 275{
283 struct zone_bitmap *zone_bm; 276 struct zone_bitmap *zone_bm;
@@ -285,7 +278,7 @@ static void memory_bm_position_reset(struct memory_bitmap *bm)
285 zone_bm = bm->zone_bm_list; 278 zone_bm = bm->zone_bm_list;
286 bm->cur.zone_bm = zone_bm; 279 bm->cur.zone_bm = zone_bm;
287 bm->cur.block = zone_bm->bm_blocks; 280 bm->cur.block = zone_bm->bm_blocks;
288 memory_bm_reset_chunk(bm); 281 bm->cur.bit = 0;
289} 282}
290 283
291static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free); 284static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free);
@@ -394,12 +387,10 @@ memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask, int safe_needed)
394 bb->start_pfn = pfn; 387 bb->start_pfn = pfn;
395 if (nr >= BM_BITS_PER_BLOCK) { 388 if (nr >= BM_BITS_PER_BLOCK) {
396 pfn += BM_BITS_PER_BLOCK; 389 pfn += BM_BITS_PER_BLOCK;
397 bb->size = BM_CHUNKS_PER_BLOCK;
398 nr -= BM_BITS_PER_BLOCK; 390 nr -= BM_BITS_PER_BLOCK;
399 } else { 391 } else {
400 /* This is executed only once in the loop */ 392 /* This is executed only once in the loop */
401 pfn += nr; 393 pfn += nr;
402 bb->size = DIV_ROUND_UP(nr, BM_BITS_PER_CHUNK);
403 } 394 }
404 bb->end_pfn = pfn; 395 bb->end_pfn = pfn;
405 bb = bb->next; 396 bb = bb->next;
@@ -478,8 +469,8 @@ static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
478 } 469 }
479 zone_bm->cur_block = bb; 470 zone_bm->cur_block = bb;
480 pfn -= bb->start_pfn; 471 pfn -= bb->start_pfn;
481 *bit_nr = pfn % BM_BITS_PER_CHUNK; 472 *bit_nr = pfn;
482 *addr = bb->data + pfn / BM_BITS_PER_CHUNK; 473 *addr = bb->data;
483 return 0; 474 return 0;
484} 475}
485 476
@@ -528,36 +519,6 @@ static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn)
528 return test_bit(bit, addr); 519 return test_bit(bit, addr);
529} 520}
530 521
531/* Two auxiliary functions for memory_bm_next_pfn */
532
533/* Find the first set bit in the given chunk, if there is one */
534
535static inline int next_bit_in_chunk(int bit, unsigned long *chunk_p)
536{
537 bit++;
538 while (bit < BM_BITS_PER_CHUNK) {
539 if (test_bit(bit, chunk_p))
540 return bit;
541
542 bit++;
543 }
544 return -1;
545}
546
547/* Find a chunk containing some bits set in given block of bits */
548
549static inline int next_chunk_in_block(int n, struct bm_block *bb)
550{
551 n++;
552 while (n < bb->size) {
553 if (bb->data[n])
554 return n;
555
556 n++;
557 }
558 return -1;
559}
560
561/** 522/**
562 * memory_bm_next_pfn - find the pfn that corresponds to the next set bit 523 * memory_bm_next_pfn - find the pfn that corresponds to the next set bit
563 * in the bitmap @bm. If the pfn cannot be found, BM_END_OF_MAP is 524 * in the bitmap @bm. If the pfn cannot be found, BM_END_OF_MAP is
@@ -571,40 +532,33 @@ static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
571{ 532{
572 struct zone_bitmap *zone_bm; 533 struct zone_bitmap *zone_bm;
573 struct bm_block *bb; 534 struct bm_block *bb;
574 int chunk;
575 int bit; 535 int bit;
576 536
577 do { 537 do {
578 bb = bm->cur.block; 538 bb = bm->cur.block;
579 do { 539 do {
580 chunk = bm->cur.chunk;
581 bit = bm->cur.bit; 540 bit = bm->cur.bit;
582 do { 541 bit = find_next_bit(bb->data, bm_block_bits(bb), bit);
583 bit = next_bit_in_chunk(bit, bb->data + chunk); 542 if (bit < bm_block_bits(bb))
584 if (bit >= 0) 543 goto Return_pfn;
585 goto Return_pfn; 544
586
587 chunk = next_chunk_in_block(chunk, bb);
588 bit = -1;
589 } while (chunk >= 0);
590 bb = bb->next; 545 bb = bb->next;
591 bm->cur.block = bb; 546 bm->cur.block = bb;
592 memory_bm_reset_chunk(bm); 547 bm->cur.bit = 0;
593 } while (bb); 548 } while (bb);
594 zone_bm = bm->cur.zone_bm->next; 549 zone_bm = bm->cur.zone_bm->next;
595 if (zone_bm) { 550 if (zone_bm) {
596 bm->cur.zone_bm = zone_bm; 551 bm->cur.zone_bm = zone_bm;
597 bm->cur.block = zone_bm->bm_blocks; 552 bm->cur.block = zone_bm->bm_blocks;
598 memory_bm_reset_chunk(bm); 553 bm->cur.bit = 0;
599 } 554 }
600 } while (zone_bm); 555 } while (zone_bm);
601 memory_bm_position_reset(bm); 556 memory_bm_position_reset(bm);
602 return BM_END_OF_MAP; 557 return BM_END_OF_MAP;
603 558
604 Return_pfn: 559 Return_pfn:
605 bm->cur.chunk = chunk; 560 bm->cur.bit = bit + 1;
606 bm->cur.bit = bit; 561 return bb->start_pfn + bit;
607 return bb->start_pfn + chunk * BM_BITS_PER_CHUNK + bit;
608} 562}
609 563
610/** 564/**