Commit 56207df5 authored by Vladimir Sementsov-Ogievskiy's avatar Vladimir Sementsov-Ogievskiy Committed by Jeff Cody
Browse files

hbitmap: add next_zero function 



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

Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: default avatarJohn Snow <jsnow@redhat.com>
Message-id: 20171012135313.227864-2-vsementsov@virtuozzo.com
Signed-off-by: default avatarJeff Cody <jcody@redhat.com>
parent 411ad781

block/dirty-bitmap.c

+5 −0
Original line number Diff line number Diff line
@@ -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);

}

include/block/dirty-bitmap.h

+1 −0
Original line number Diff line number Diff line
@@ -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

include/qemu/hbitmap.h

+8 −0
Original line number Diff line number Diff line
@@ -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

tests/test-hbitmap.c

+61 −0
Original line number Diff line number Diff line
@@ -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;

util/hbitmap.c

+39 −0
Original line number Diff line number Diff line
@@ -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;