diff options
author | Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> | 2019-01-15 18:26:49 -0500 |
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committer | John Snow <jsnow@redhat.com> | 2019-01-15 18:26:49 -0500 |
commit | 76d570dc495c56bbdcc4574bfc6d512dcb8e9aa9 (patch) | |
tree | 80b114f05c7c9f30dcd1655cfa50c1f1330572d2 /util | |
parent | 4b9f0b0f7c84eea2dfb0d5be3e0254bc91319dbc (diff) |
dirty-bitmap: improve bdrv_dirty_bitmap_next_zero
Add bytes parameter to the function, to limit searched range.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Diffstat (limited to 'util')
-rw-r--r-- | util/hbitmap.c | 27 |
1 files changed, 22 insertions, 5 deletions
diff --git a/util/hbitmap.c b/util/hbitmap.c index 8d402c59d9..09b3719e44 100644 --- a/util/hbitmap.c +++ b/util/hbitmap.c @@ -53,6 +53,9 @@ */ struct HBitmap { + /* Size of the bitmap, as requested in hbitmap_alloc. */ + uint64_t orig_size; + /* Number of total bits in the bottom level. */ uint64_t size; @@ -192,16 +195,28 @@ void hbitmap_iter_init(HBitmapIter *hbi, const HBitmap *hb, uint64_t first) } } -int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start) +int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, uint64_t count) { size_t pos = (start >> hb->granularity) >> BITS_PER_LEVEL; unsigned long *last_lev = hb->levels[HBITMAP_LEVELS - 1]; - uint64_t sz = hb->sizes[HBITMAP_LEVELS - 1]; unsigned long cur = last_lev[pos]; - unsigned start_bit_offset = - (start >> hb->granularity) & (BITS_PER_LONG - 1); + unsigned start_bit_offset; + uint64_t end_bit, sz; int64_t res; + if (start >= hb->orig_size || count == 0) { + return -1; + } + + end_bit = count > hb->orig_size - start ? + hb->size : + ((start + count - 1) >> hb->granularity) + 1; + sz = (end_bit + BITS_PER_LONG - 1) >> BITS_PER_LEVEL; + + /* There may be some zero bits in @cur before @start. We are not interested + * in them, let's set them. + */ + start_bit_offset = (start >> hb->granularity) & (BITS_PER_LONG - 1); cur |= (1UL << start_bit_offset) - 1; assert((start >> hb->granularity) < hb->size); @@ -218,7 +233,7 @@ int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start) } res = (pos << BITS_PER_LEVEL) + ctol(cur); - if (res >= hb->size) { + if (res >= end_bit) { return -1; } @@ -652,6 +667,8 @@ HBitmap *hbitmap_alloc(uint64_t size, int granularity) HBitmap *hb = g_new0(struct HBitmap, 1); unsigned i; + hb->orig_size = size; + assert(granularity >= 0 && granularity < 64); size = (size + (1ULL << granularity) - 1) >> granularity; assert(size <= ((uint64_t)1 << HBITMAP_LOG_MAX_SIZE)); |