Re: [Qemu-block] [Qemu-devel] [PATCH COLO v3 10/14] util/hbitmap: Add an API to reset all set bits in hbitmap

[Wen Congyang]

On 05/08/2015 02:32 AM, John Snow wrote:
> 
> 
> On 05/06/2015 10:20 PM, Wen Congyang wrote:
>> On 05/02/2015 12:47 AM, John Snow wrote:
>>>
>>>
>>> On 04/03/2015 07:05 AM, Paolo Bonzini wrote:
>>>>
>>>>
>>>> On 03/04/2015 12:01, Wen Congyang wrote:
>>>>> Signed-off-by: Wen Congyang <address@hidden>
>>>>> Signed-off-by: zhanghailiang <address@hidden>
>>>>> Signed-off-by: Gonglei <address@hidden>
>>>>> ---
>>>>>   include/qemu/hbitmap.h |  8 ++++++++
>>>>>   tests/test-hbitmap.c   | 39 +++++++++++++++++++++++++++++++++++++++
>>>>>   util/hbitmap.c         | 16 ++++++++++++++++
>>>>>   3 files changed, 63 insertions(+)
>>>>>
>>>>> diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h
>>>>> index 550d7ce..95a55e4 100644
>>>>> --- a/include/qemu/hbitmap.h
>>>>> +++ b/include/qemu/hbitmap.h
>>>>> @@ -109,6 +109,14 @@ void hbitmap_set(HBitmap *hb, uint64_t start, 
>>>>> uint64_t count);
>>>>>   void hbitmap_reset(HBitmap *hb, uint64_t start, uint64_t count);
>>>>>
>>>>>   /**
>>>>> + * hbitmap_reset_all:
>>>>> + * @hb: HBitmap to operate on.
>>>>> + *
>>>>> + * Reset all bits in an HBitmap.
>>>>> + */
>>>>> +void hbitmap_reset_all(HBitmap *hb);
>>>>> +
>>>>> +/**
>>>>>    * hbitmap_get:
>>>>>    * @hb: HBitmap to operate on.
>>>>>    * @item: Bit to query (0-based).
>>>>> diff --git a/tests/test-hbitmap.c b/tests/test-hbitmap.c
>>>>> index 8c902f2..1f0078a 100644
>>>>> --- a/tests/test-hbitmap.c
>>>>> +++ b/tests/test-hbitmap.c
>>>>> @@ -11,6 +11,7 @@
>>>>>
>>>>>   #include <glib.h>
>>>>>   #include <stdarg.h>
>>>>> +#include <string.h>
>>>>>   #include "qemu/hbitmap.h"
>>>>>
>>>>>   #define LOG_BITS_PER_LONG          (BITS_PER_LONG == 32 ? 5 : 6)
>>>>> @@ -143,6 +144,23 @@ static void hbitmap_test_reset(TestHBitmapData *data,
>>>>>       }
>>>>>   }
>>>>>
>>>>> +static void hbitmap_test_reset_all(TestHBitmapData *data)
>>>>> +{
>>>>> +    size_t n;
>>>>> +
>>>>> +    hbitmap_reset_all(data->hb);
>>>>> +
>>>>> +    n = (data->size + BITS_PER_LONG - 1) / BITS_PER_LONG;
>>>>> +    if (n == 0) {
>>>>> +        n = 1;
>>>>> +    }
>>>>> +    memset(data->bits, 0, n * sizeof(unsigned long));
>>>>> +
>>>>> +    if (data->granularity == 0) {
>>>>> +        hbitmap_test_check(data, 0);
>>>>> +    }
>>>>> +}
>>>>> +
>>>>>   static void hbitmap_test_check_get(TestHBitmapData *data)
>>>>>   {
>>>>>       uint64_t count = 0;
>>>>> @@ -323,6 +341,26 @@ static void test_hbitmap_reset(TestHBitmapData *data,
>>>>>       hbitmap_test_set(data, L3 / 2, L3);
>>>>>   }
>>>>>
>>>>> +static void test_hbitmap_reset_all(TestHBitmapData *data,
>>>>> +                                   const void *unused)
>>>>> +{
>>>>> +    hbitmap_test_init(data, L3 * 2, 0);
>>>>> +    hbitmap_test_set(data, L1 - 1, L1 + 2);
>>>>> +    hbitmap_test_reset_all(data);
>>>>> +    hbitmap_test_set(data, 0, L1 * 3);
>>>>> +    hbitmap_test_reset_all(data);
>>>>> +    hbitmap_test_set(data, L2, L1);
>>>>> +    hbitmap_test_reset_all(data);
>>>>> +    hbitmap_test_set(data, L2, L3 - L2 + 1);
>>>>> +    hbitmap_test_reset_all(data);
>>>>> +    hbitmap_test_set(data, L3 - 1, 3);
>>>>> +    hbitmap_test_reset_all(data);
>>>>> +    hbitmap_test_set(data, 0, L3 * 2);
>>>>> +    hbitmap_test_reset_all(data);
>>>>> +    hbitmap_test_set(data, L3 / 2, L3);
>>>>> +    hbitmap_test_reset_all(data);
>>>>> +}
>>>>> +
>>>>>   static void test_hbitmap_granularity(TestHBitmapData *data,
>>>>>                                        const void *unused)
>>>>>   {
>>>>> @@ -394,6 +432,7 @@ int main(int argc, char **argv)
>>>>>       hbitmap_test_add("/hbitmap/set/overlap", test_hbitmap_set_overlap);
>>>>>       hbitmap_test_add("/hbitmap/reset/empty", test_hbitmap_reset_empty);
>>>>>       hbitmap_test_add("/hbitmap/reset/general", test_hbitmap_reset);
>>>>> +    hbitmap_test_add("/hbitmap/reset/all", test_hbitmap_reset_all);
>>>>>       hbitmap_test_add("/hbitmap/granularity", test_hbitmap_granularity);
>>>>>       g_test_run();
>>>>>
>>>>> diff --git a/util/hbitmap.c b/util/hbitmap.c
>>>>> index ab13971..acce93c 100644
>>>>> --- a/util/hbitmap.c
>>>>> +++ b/util/hbitmap.c
>>>>> @@ -353,6 +353,22 @@ void hbitmap_reset(HBitmap *hb, uint64_t start, 
>>>>> uint64_t count)
>>>>>       hb_reset_between(hb, HBITMAP_LEVELS - 1, start, last);
>>>>>   }
>>>>>
>>>>> +void hbitmap_reset_all(HBitmap *hb)
>>>>> +{
>>>>> +    uint64_t size = hb->size;
>>>>> +    unsigned int i;
>>>>> +
>>>>> +    /* Same as hbitmap_alloc() except memset() */
>>>>> +    for (i = HBITMAP_LEVELS; --i >= 1; ) {
>>>>> +        size = MAX((size + BITS_PER_LONG - 1) >> BITS_PER_LEVEL, 1);
>>>>> +        memset(hb->levels[i], 0, size * sizeof(unsigned long));
>>>>> +    }
>>>>> +
>>>
>>> For what it's worth, I recently added in a hb->sizes[i] cache to store the 
>>> size of each array so you don't have to recompute this all the time.
>>
>> Yes, will fix it in the next version.
>>
>> Thanks
>> Wen Congyang
>>
> 
> Since the reset stuff is useful all by itself, you can send that patch
> by itself, CC me, and I'll review it.
> 
> You can update the existing call in block.c:
> 
> bdrv_clear_dirty_bitmap() {
>     hbitmap_reset(bitmap->bitmap, 0, bitmap->size);
> }
> 
> to using your faster hbitmap_reset_all call.

OK, I will do it.

Thanks
Wen Congyang

> 
> Thanks,
> 
> --js
> 
>>>
>>>>> +    assert(size == 1);
>>>>> +    hb->levels[0][0] = 1UL << (BITS_PER_LONG - 1);
>>>>> +    hb->count = 0;
>>>>> +}
>>>>> +
>>>>>   bool hbitmap_get(const HBitmap *hb, uint64_t item)
>>>>>   {
>>>>>       /* Compute position and bit in the last layer.  */
>>>>>
>>>>
>>>> Acked-by: Paolo Bonzini <address@hidden>
>>>>
>>> .
>>>
>>
>>
> .
>