From: Akinobu Mita Date: Thu, 24 Jul 2008 04:28:38 +0000 (-0700) Subject: pm: hibernation: simplify memory bitmap X-Git-Tag: v2.6.27-rc1~733 X-Git-Url: http://ftp.safe.ca/?a=commitdiff_plain;h=0d83304c7e7bd3b05be90281b3a47841bc8f057a;p=safe%2Fjmp%2Flinux-2.6 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 Signed-off-by: Rafael J. Wysocki Acked-by: Pavel Machek Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index 5f91a07..5d2ab83 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) * objects. The main list's elements are of type struct zone_bitmap * and each of them corresonds to one zone. For each zone bitmap * object there is a list of objects of type struct bm_block that - * represent each blocks of bit chunks in which information is - * stored. + * represent each blocks of bitmap in which information is stored. * * struct memory_bitmap contains a pointer to the main list of zone * 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) * pfns that correspond to the start and end of the represented zone. * * struct bm_block contains a pointer to the memory page in which - * information is stored (in the form of a block of bit chunks - * of type unsigned long each). It also contains the pfns that - * correspond to the start and end of the represented memory area and - * the number of bit chunks in the block. + * information is stored (in the form of a block of bitmap) + * It also contains the pfns that correspond to the start and end of + * the represented memory area. */ #define BM_END_OF_MAP (~0UL) -#define BM_CHUNKS_PER_BLOCK (PAGE_SIZE / sizeof(long)) -#define BM_BITS_PER_CHUNK (sizeof(long) << 3) #define BM_BITS_PER_BLOCK (PAGE_SIZE << 3) struct bm_block { struct bm_block *next; /* next element of the list */ unsigned long start_pfn; /* pfn represented by the first bit */ unsigned long end_pfn; /* pfn represented by the last bit plus 1 */ - unsigned int size; /* number of bit chunks */ - unsigned long *data; /* chunks of bits representing pages */ + unsigned long *data; /* bitmap representing pages */ }; +static inline unsigned long bm_block_bits(struct bm_block *bb) +{ + return bb->end_pfn - bb->start_pfn; +} + struct zone_bitmap { struct zone_bitmap *next; /* next element of the list */ unsigned long start_pfn; /* minimal pfn in this zone */ @@ -257,7 +257,6 @@ struct zone_bitmap { struct bm_position { struct zone_bitmap *zone_bm; struct bm_block *block; - int chunk; int bit; }; @@ -272,12 +271,6 @@ struct memory_bitmap { /* Functions that operate on memory bitmaps */ -static inline void memory_bm_reset_chunk(struct memory_bitmap *bm) -{ - bm->cur.chunk = 0; - bm->cur.bit = -1; -} - static void memory_bm_position_reset(struct memory_bitmap *bm) { struct zone_bitmap *zone_bm; @@ -285,7 +278,7 @@ static void memory_bm_position_reset(struct memory_bitmap *bm) zone_bm = bm->zone_bm_list; bm->cur.zone_bm = zone_bm; bm->cur.block = zone_bm->bm_blocks; - memory_bm_reset_chunk(bm); + bm->cur.bit = 0; } static 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) bb->start_pfn = pfn; if (nr >= BM_BITS_PER_BLOCK) { pfn += BM_BITS_PER_BLOCK; - bb->size = BM_CHUNKS_PER_BLOCK; nr -= BM_BITS_PER_BLOCK; } else { /* This is executed only once in the loop */ pfn += nr; - bb->size = DIV_ROUND_UP(nr, BM_BITS_PER_CHUNK); } bb->end_pfn = pfn; bb = bb->next; @@ -478,8 +469,8 @@ static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn, } zone_bm->cur_block = bb; pfn -= bb->start_pfn; - *bit_nr = pfn % BM_BITS_PER_CHUNK; - *addr = bb->data + pfn / BM_BITS_PER_CHUNK; + *bit_nr = pfn; + *addr = bb->data; return 0; } @@ -528,36 +519,6 @@ static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn) return test_bit(bit, addr); } -/* Two auxiliary functions for memory_bm_next_pfn */ - -/* Find the first set bit in the given chunk, if there is one */ - -static inline int next_bit_in_chunk(int bit, unsigned long *chunk_p) -{ - bit++; - while (bit < BM_BITS_PER_CHUNK) { - if (test_bit(bit, chunk_p)) - return bit; - - bit++; - } - return -1; -} - -/* Find a chunk containing some bits set in given block of bits */ - -static inline int next_chunk_in_block(int n, struct bm_block *bb) -{ - n++; - while (n < bb->size) { - if (bb->data[n]) - return n; - - n++; - } - return -1; -} - /** * memory_bm_next_pfn - find the pfn that corresponds to the next set bit * 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) { struct zone_bitmap *zone_bm; struct bm_block *bb; - int chunk; int bit; do { bb = bm->cur.block; do { - chunk = bm->cur.chunk; bit = bm->cur.bit; - do { - bit = next_bit_in_chunk(bit, bb->data + chunk); - if (bit >= 0) - goto Return_pfn; - - chunk = next_chunk_in_block(chunk, bb); - bit = -1; - } while (chunk >= 0); + bit = find_next_bit(bb->data, bm_block_bits(bb), bit); + if (bit < bm_block_bits(bb)) + goto Return_pfn; + bb = bb->next; bm->cur.block = bb; - memory_bm_reset_chunk(bm); + bm->cur.bit = 0; } while (bb); zone_bm = bm->cur.zone_bm->next; if (zone_bm) { bm->cur.zone_bm = zone_bm; bm->cur.block = zone_bm->bm_blocks; - memory_bm_reset_chunk(bm); + bm->cur.bit = 0; } } while (zone_bm); memory_bm_position_reset(bm); return BM_END_OF_MAP; Return_pfn: - bm->cur.chunk = chunk; - bm->cur.bit = bit; - return bb->start_pfn + chunk * BM_BITS_PER_CHUNK + bit; + bm->cur.bit = bit + 1; + return bb->start_pfn + bit; } /**