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

[Wen Congyang <wency@cn.fujitsu.com>]

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 <wency@cn.fujitsu.com>
>>> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
>>> Signed-off-by: Gonglei <arei.gonglei@huawei.com>
>>> ---
>>>   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

> 
>>> +    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 <pbonzini@redhat.com>
>>
> .
>