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

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

20.01.2020 19:30, Vladimir Sementsov-Ogievskiy wrote:
> 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?

Now I think that better to do it in previous patch.

>>
>> [...]
>>
>>> 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