From 07ac4cdb570c9cf6aed0338414f4f09fee0b549c Mon Sep 17 00:00:00 2001 From: Fam Zheng Date: Thu, 13 Oct 2016 17:58:22 -0400 Subject: HBitmap: Introduce "meta" bitmap to track bit changes Upon each bit toggle, the corresponding bit in the meta bitmap will be set. Signed-off-by: Fam Zheng [Amended text inline. --js] Reviewed-by: Max Reitz Signed-off-by: John Snow Message-id: 1476395910-8697-3-git-send-email-jsnow@redhat.com Signed-off-by: Max Reitz --- util/hbitmap.c | 69 +++++++++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 54 insertions(+), 15 deletions(-) (limited to 'util') diff --git a/util/hbitmap.c b/util/hbitmap.c index 99fd2ba..f303975 100644 --- a/util/hbitmap.c +++ b/util/hbitmap.c @@ -78,6 +78,9 @@ struct HBitmap { */ int granularity; + /* A meta dirty bitmap to track the dirtiness of bits in this HBitmap. */ + HBitmap *meta; + /* A number of progressively less coarse bitmaps (i.e. level 0 is the * coarsest). Each bit in level N represents a word in level N+1 that * has a set bit, except the last level where each bit represents the @@ -209,25 +212,27 @@ static uint64_t hb_count_between(HBitmap *hb, uint64_t start, uint64_t last) } /* Setting starts at the last layer and propagates up if an element - * changes from zero to non-zero. + * changes. */ static inline bool hb_set_elem(unsigned long *elem, uint64_t start, uint64_t last) { unsigned long mask; - bool changed; + unsigned long old; assert((last >> BITS_PER_LEVEL) == (start >> BITS_PER_LEVEL)); assert(start <= last); mask = 2UL << (last & (BITS_PER_LONG - 1)); mask -= 1UL << (start & (BITS_PER_LONG - 1)); - changed = (*elem == 0); + old = *elem; *elem |= mask; - return changed; + return old != *elem; } -/* The recursive workhorse (the depth is limited to HBITMAP_LEVELS)... */ -static void hb_set_between(HBitmap *hb, int level, uint64_t start, uint64_t last) +/* The recursive workhorse (the depth is limited to HBITMAP_LEVELS)... + * Returns true if at least one bit is changed. */ +static bool hb_set_between(HBitmap *hb, int level, uint64_t start, + uint64_t last) { size_t pos = start >> BITS_PER_LEVEL; size_t lastpos = last >> BITS_PER_LEVEL; @@ -256,23 +261,28 @@ static void hb_set_between(HBitmap *hb, int level, uint64_t start, uint64_t last if (level > 0 && changed) { hb_set_between(hb, level - 1, pos, lastpos); } + return changed; } void hbitmap_set(HBitmap *hb, uint64_t start, uint64_t count) { /* Compute range in the last layer. */ + uint64_t first, n; uint64_t last = start + count - 1; trace_hbitmap_set(hb, start, count, start >> hb->granularity, last >> hb->granularity); - start >>= hb->granularity; + first = start >> hb->granularity; last >>= hb->granularity; - count = last - start + 1; assert(last < hb->size); + n = last - first + 1; - hb->count += count - hb_count_between(hb, start, last); - hb_set_between(hb, HBITMAP_LEVELS - 1, start, last); + hb->count += n - hb_count_between(hb, first, last); + if (hb_set_between(hb, HBITMAP_LEVELS - 1, first, last) && + hb->meta) { + hbitmap_set(hb->meta, start, count); + } } /* Resetting works the other way round: propagate up if the new @@ -293,8 +303,10 @@ static inline bool hb_reset_elem(unsigned long *elem, uint64_t start, uint64_t l return blanked; } -/* The recursive workhorse (the depth is limited to HBITMAP_LEVELS)... */ -static void hb_reset_between(HBitmap *hb, int level, uint64_t start, uint64_t last) +/* The recursive workhorse (the depth is limited to HBITMAP_LEVELS)... + * Returns true if at least one bit is changed. */ +static bool hb_reset_between(HBitmap *hb, int level, uint64_t start, + uint64_t last) { size_t pos = start >> BITS_PER_LEVEL; size_t lastpos = last >> BITS_PER_LEVEL; @@ -337,22 +349,29 @@ static void hb_reset_between(HBitmap *hb, int level, uint64_t start, uint64_t la if (level > 0 && changed) { hb_reset_between(hb, level - 1, pos, lastpos); } + + return changed; + } void hbitmap_reset(HBitmap *hb, uint64_t start, uint64_t count) { /* Compute range in the last layer. */ + uint64_t first; uint64_t last = start + count - 1; trace_hbitmap_reset(hb, start, count, start >> hb->granularity, last >> hb->granularity); - start >>= hb->granularity; + first = start >> hb->granularity; last >>= hb->granularity; assert(last < hb->size); - hb->count -= hb_count_between(hb, start, last); - hb_reset_between(hb, HBITMAP_LEVELS - 1, start, last); + hb->count -= hb_count_between(hb, first, last); + if (hb_reset_between(hb, HBITMAP_LEVELS - 1, first, last) && + hb->meta) { + hbitmap_set(hb->meta, start, count); + } } void hbitmap_reset_all(HBitmap *hb) @@ -381,6 +400,7 @@ bool hbitmap_get(const HBitmap *hb, uint64_t item) void hbitmap_free(HBitmap *hb) { unsigned i; + assert(!hb->meta); for (i = HBITMAP_LEVELS; i-- > 0; ) { g_free(hb->levels[i]); } @@ -458,6 +478,9 @@ void hbitmap_truncate(HBitmap *hb, uint64_t size) (size - old) * sizeof(*hb->levels[i])); } } + if (hb->meta) { + hbitmap_truncate(hb->meta, hb->size << hb->granularity); + } } @@ -493,3 +516,19 @@ bool hbitmap_merge(HBitmap *a, const HBitmap *b) return true; } + +HBitmap *hbitmap_create_meta(HBitmap *hb, int chunk_size) +{ + assert(!(chunk_size & (chunk_size - 1))); + assert(!hb->meta); + hb->meta = hbitmap_alloc(hb->size << hb->granularity, + hb->granularity + ctz32(chunk_size)); + return hb->meta; +} + +void hbitmap_free_meta(HBitmap *hb) +{ + assert(hb->meta); + hbitmap_free(hb->meta); + hb->meta = NULL; +} -- cgit v1.1 From 8258888e222ff03bf791d81a0001cdc40b878de4 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 13 Oct 2016 17:58:27 -0400 Subject: hbitmap: serialization Functions to serialize / deserialize(restore) HBitmap. HBitmap should be saved to linear sequence of bits independently of endianness and bitmap array element (unsigned long) size. Therefore Little Endian is chosen. These functions are appropriate for dirty bitmap migration, restoring the bitmap in several steps is available. To save performance, every step writes only the last level of the bitmap. All other levels are restored by hbitmap_deserialize_finish() as a last step of restoring. So, HBitmap is inconsistent while restoring. Signed-off-by: Vladimir Sementsov-Ogievskiy [Fix left shift operand to 1UL; add "finish" parameter. - Fam] Signed-off-by: Fam Zheng Signed-off-by: John Snow Message-id: 1476395910-8697-8-git-send-email-jsnow@redhat.com Signed-off-by: Max Reitz --- util/hbitmap.c | 137 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 137 insertions(+) (limited to 'util') diff --git a/util/hbitmap.c b/util/hbitmap.c index f303975..5d1a21c 100644 --- a/util/hbitmap.c +++ b/util/hbitmap.c @@ -397,6 +397,143 @@ bool hbitmap_get(const HBitmap *hb, uint64_t item) return (hb->levels[HBITMAP_LEVELS - 1][pos >> BITS_PER_LEVEL] & bit) != 0; } +uint64_t hbitmap_serialization_granularity(const HBitmap *hb) +{ + /* Require at least 64 bit granularity to be safe on both 64 bit and 32 bit + * hosts. */ + return 64 << hb->granularity; +} + +/* Start should be aligned to serialization granularity, chunk size should be + * aligned to serialization granularity too, except for last chunk. + */ +static void serialization_chunk(const HBitmap *hb, + uint64_t start, uint64_t count, + unsigned long **first_el, uint64_t *el_count) +{ + uint64_t last = start + count - 1; + uint64_t gran = hbitmap_serialization_granularity(hb); + + assert((start & (gran - 1)) == 0); + assert((last >> hb->granularity) < hb->size); + if ((last >> hb->granularity) != hb->size - 1) { + assert((count & (gran - 1)) == 0); + } + + start = (start >> hb->granularity) >> BITS_PER_LEVEL; + last = (last >> hb->granularity) >> BITS_PER_LEVEL; + + *first_el = &hb->levels[HBITMAP_LEVELS - 1][start]; + *el_count = last - start + 1; +} + +uint64_t hbitmap_serialization_size(const HBitmap *hb, + uint64_t start, uint64_t count) +{ + uint64_t el_count; + unsigned long *cur; + + if (!count) { + return 0; + } + serialization_chunk(hb, start, count, &cur, &el_count); + + return el_count * sizeof(unsigned long); +} + +void hbitmap_serialize_part(const HBitmap *hb, uint8_t *buf, + uint64_t start, uint64_t count) +{ + uint64_t el_count; + unsigned long *cur, *end; + + if (!count) { + return; + } + serialization_chunk(hb, start, count, &cur, &el_count); + end = cur + el_count; + + while (cur != end) { + unsigned long el = + (BITS_PER_LONG == 32 ? cpu_to_le32(*cur) : cpu_to_le64(*cur)); + + memcpy(buf, &el, sizeof(el)); + buf += sizeof(el); + cur++; + } +} + +void hbitmap_deserialize_part(HBitmap *hb, uint8_t *buf, + uint64_t start, uint64_t count, + bool finish) +{ + uint64_t el_count; + unsigned long *cur, *end; + + if (!count) { + return; + } + serialization_chunk(hb, start, count, &cur, &el_count); + end = cur + el_count; + + while (cur != end) { + memcpy(cur, buf, sizeof(*cur)); + + if (BITS_PER_LONG == 32) { + le32_to_cpus((uint32_t *)cur); + } else { + le64_to_cpus((uint64_t *)cur); + } + + buf += sizeof(unsigned long); + cur++; + } + if (finish) { + hbitmap_deserialize_finish(hb); + } +} + +void hbitmap_deserialize_zeroes(HBitmap *hb, uint64_t start, uint64_t count, + bool finish) +{ + uint64_t el_count; + unsigned long *first; + + if (!count) { + return; + } + serialization_chunk(hb, start, count, &first, &el_count); + + memset(first, 0, el_count * sizeof(unsigned long)); + if (finish) { + hbitmap_deserialize_finish(hb); + } +} + +void hbitmap_deserialize_finish(HBitmap *bitmap) +{ + int64_t i, size, prev_size; + int lev; + + /* restore levels starting from penultimate to zero level, assuming + * that the last level is ok */ + size = MAX((bitmap->size + BITS_PER_LONG - 1) >> BITS_PER_LEVEL, 1); + for (lev = HBITMAP_LEVELS - 1; lev-- > 0; ) { + prev_size = size; + size = MAX((size + BITS_PER_LONG - 1) >> BITS_PER_LEVEL, 1); + memset(bitmap->levels[lev], 0, size * sizeof(unsigned long)); + + for (i = 0; i < prev_size; ++i) { + if (bitmap->levels[lev + 1][i]) { + bitmap->levels[lev][i >> BITS_PER_LEVEL] |= + 1UL << (i & (BITS_PER_LONG - 1)); + } + } + } + + bitmap->levels[0][0] |= 1UL << (BITS_PER_LONG - 1); +} + void hbitmap_free(HBitmap *hb) { unsigned i; -- cgit v1.1