Re: [PATCH v3 06/10] block/dirty-bitmap: add _next_dirty API

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

20.01.2020 16:14, Max Reitz wrote:
> On 19.12.19 11:03, Vladimir Sementsov-Ogievskiy wrote:
>> We have bdrv_dirty_bitmap_next_zero, let's add corresponding
>> bdrv_dirty_bitmap_next_dirty, which is more comfortable to use than
>> bitmap iterators in some cases.
>>
>> For test modify test_hbitmap_next_zero_check_range to check both
>> next_zero and next_dirty and add some new checks.
>>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
>> ---
>>   include/block/dirty-bitmap.h |   2 +
>>   include/qemu/hbitmap.h       |  13 ++++
>>   block/dirty-bitmap.c         |   6 ++
>>   tests/test-hbitmap.c         | 130 ++++++++++++++++++++---------------
>>   util/hbitmap.c               |  60 ++++++++--------
>>   5 files changed, 126 insertions(+), 85 deletions(-)
> 
> [...]
> 
>> diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h
>> index b6e85f3d5d..a4b032b270 100644
>> --- a/include/qemu/hbitmap.h
>> +++ b/include/qemu/hbitmap.h
>> @@ -297,6 +297,19 @@ void hbitmap_free(HBitmap *hb);
>>    */
>>   void hbitmap_iter_init(HBitmapIter *hbi, const HBitmap *hb, uint64_t first);
>>   
>> +/*
>> + * hbitmap_next_dirty:
>> + *
>> + * Find next dirty bit within selected range. If not found, return -1.
>> + *
>> + * @hb: The HBitmap to operate on
>> + * @start: The bit to start from.
>> + * @count: Number of bits to proceed. If @start+@count > bitmap size, the whole
>> + * bitmap is looked through. You can use UINT64_MAX as @count to search up to
> 
> I would’ve said s/looked through/scanned/, but it matches
> hbitmap_next_zero()’s documentation, so it’s fine.
> 
> But definitely s/UINT64_MAX/INT64_MAX/.
> 
>> + * the bitmap end.
>> + */
>> +int64_t hbitmap_next_dirty(const HBitmap *hb, int64_t start, int64_t count);
>> +
>>   /* hbitmap_next_zero:
>>    *
>>    * Find next not dirty bit within selected range. If not found, return -1.
> 
> [...]
> 
>> diff --git a/tests/test-hbitmap.c b/tests/test-hbitmap.c
>> index 0e1e5c64dd..e3f1b3f361 100644
>> --- a/tests/test-hbitmap.c
>> +++ b/tests/test-hbitmap.c
>> @@ -816,92 +816,108 @@ static void test_hbitmap_iter_and_reset(TestHBitmapData *data,
>>       hbitmap_iter_next(&hbi);
>>   }
>>   
>> -static void test_hbitmap_next_zero_check_range(TestHBitmapData *data,
>> -                                               uint64_t start,
>> -                                               uint64_t count)
>> +static void test_hbitmap_next_x_check_range(TestHBitmapData *data,
>> +                                            uint64_t start,
>> +                                            uint64_t count)
> 
> Why not change the parameters to be signed while we’re already here?
> 
> [...]
> 
>> diff --git a/util/hbitmap.c b/util/hbitmap.c
>> index df22f06be6..d23f4b9678 100644
>> --- a/util/hbitmap.c
>> +++ b/util/hbitmap.c
>> @@ -193,6 +193,30 @@ void hbitmap_iter_init(HBitmapIter *hbi, const HBitmap *hb, uint64_t first)
>>       }
>>   }
>>   
>> +int64_t hbitmap_next_dirty(const HBitmap *hb, int64_t start, int64_t count)
>> +{
>> +    HBitmapIter hbi;
>> +    int64_t firt_dirty_off;
> 
> Pre-existing, but isn’t this just a typo that you could fix here?  (i.e.
> s/firt/first/)
> 
> Apart from this minor things:

Agree with them.

> 
> Reviewed-by: Max Reitz <mreitz@redhat.com>
> 
>> +    uint64_t end;
>> +
>> +    assert(start >= 0 && count >= 0);
>> +
>> +    if (start >= hb->orig_size || count == 0) {
>> +        return -1;
>> +    }
>> +
>> +    end = count > hb->orig_size - start ?
> 


-- 
Best regards,
Vladimir