hbitmap: add next_zero function

The function searches for next zero bit.
Also add interface for BdrvDirtyBitmap and unit test.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 20171012135313.227864-2-vsementsov@virtuozzo.com
Signed-off-by: Jeff Cody <jcody@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2017-10-12 16:53:09 +03:00 committed by Jeff Cody
parent 411ad78115
commit 56207df55e
5 changed files with 114 additions and 0 deletions

View file

@ -715,3 +715,8 @@ char *bdrv_dirty_bitmap_sha256(const BdrvDirtyBitmap *bitmap, Error **errp)
{
return hbitmap_sha256(bitmap->bitmap, errp);
}
int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t offset)
{
return hbitmap_next_zero(bitmap->bitmap, offset);
}

View file

@ -91,5 +91,6 @@ bool bdrv_has_changed_persistent_bitmaps(BlockDriverState *bs);
BdrvDirtyBitmap *bdrv_dirty_bitmap_next(BlockDriverState *bs,
BdrvDirtyBitmap *bitmap);
char *bdrv_dirty_bitmap_sha256(const BdrvDirtyBitmap *bitmap, Error **errp);
int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t start);
#endif

View file

@ -292,6 +292,14 @@ void hbitmap_iter_init(HBitmapIter *hbi, const HBitmap *hb, uint64_t first);
*/
unsigned long hbitmap_iter_skip_words(HBitmapIter *hbi);
/* hbitmap_next_zero:
* @hb: The HBitmap to operate on
* @start: The bit to start from.
*
* Find next not dirty bit.
*/
int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start);
/* hbitmap_create_meta:
* Create a "meta" hbitmap to track dirtiness of the bits in this HBitmap.
* The caller owns the created bitmap and must call hbitmap_free_meta(hb) to

View file

@ -925,6 +925,61 @@ static void test_hbitmap_iter_and_reset(TestHBitmapData *data,
hbitmap_iter_next(&hbi);
}
static void test_hbitmap_next_zero_check(TestHBitmapData *data, int64_t start)
{
int64_t ret1 = hbitmap_next_zero(data->hb, start);
int64_t ret2 = start;
for ( ; ret2 < data->size && hbitmap_get(data->hb, ret2); ret2++) {
;
}
if (ret2 == data->size) {
ret2 = -1;
}
g_assert_cmpint(ret1, ==, ret2);
}
static void test_hbitmap_next_zero_do(TestHBitmapData *data, int granularity)
{
hbitmap_test_init(data, L3, granularity);
test_hbitmap_next_zero_check(data, 0);
test_hbitmap_next_zero_check(data, L3 - 1);
hbitmap_set(data->hb, L2, 1);
test_hbitmap_next_zero_check(data, 0);
test_hbitmap_next_zero_check(data, L2 - 1);
test_hbitmap_next_zero_check(data, L2);
test_hbitmap_next_zero_check(data, L2 + 1);
hbitmap_set(data->hb, L2 + 5, L1);
test_hbitmap_next_zero_check(data, 0);
test_hbitmap_next_zero_check(data, L2 + 1);
test_hbitmap_next_zero_check(data, L2 + 2);
test_hbitmap_next_zero_check(data, L2 + 5);
test_hbitmap_next_zero_check(data, L2 + L1 - 1);
test_hbitmap_next_zero_check(data, L2 + L1);
hbitmap_set(data->hb, L2 * 2, L3 - L2 * 2);
test_hbitmap_next_zero_check(data, L2 * 2 - L1);
test_hbitmap_next_zero_check(data, L2 * 2 - 2);
test_hbitmap_next_zero_check(data, L2 * 2 - 1);
test_hbitmap_next_zero_check(data, L2 * 2);
test_hbitmap_next_zero_check(data, L3 - 1);
hbitmap_set(data->hb, 0, L3);
test_hbitmap_next_zero_check(data, 0);
}
static void test_hbitmap_next_zero_0(TestHBitmapData *data, const void *unused)
{
test_hbitmap_next_zero_do(data, 0);
}
static void test_hbitmap_next_zero_4(TestHBitmapData *data, const void *unused)
{
test_hbitmap_next_zero_do(data, 4);
}
int main(int argc, char **argv)
{
g_test_init(&argc, &argv, NULL);
@ -985,6 +1040,12 @@ int main(int argc, char **argv)
hbitmap_test_add("/hbitmap/iter/iter_and_reset",
test_hbitmap_iter_and_reset);
hbitmap_test_add("/hbitmap/next_zero/next_zero_0",
test_hbitmap_next_zero_0);
hbitmap_test_add("/hbitmap/next_zero/next_zero_4",
test_hbitmap_next_zero_4);
g_test_run();
return 0;

View file

@ -188,6 +188,45 @@ void hbitmap_iter_init(HBitmapIter *hbi, const HBitmap *hb, uint64_t first)
}
}
int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start)
{
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);
int64_t res;
cur |= (1UL << start_bit_offset) - 1;
assert((start >> hb->granularity) < hb->size);
if (cur == (unsigned long)-1) {
do {
pos++;
} while (pos < sz && last_lev[pos] == (unsigned long)-1);
if (pos >= sz) {
return -1;
}
cur = last_lev[pos];
}
res = (pos << BITS_PER_LEVEL) + ctol(cur);
if (res >= hb->size) {
return -1;
}
res = res << hb->granularity;
if (res < start) {
assert(((start - res) >> hb->granularity) == 0);
return start;
}
return res;
}
bool hbitmap_empty(const HBitmap *hb)
{
return hb->count == 0;