On 07/22/2016 05:57 PM, Max Reitz wrote:
> On 18.07.2016 22:57, John Snow wrote:
>> From: Fam Zheng <[email protected]>
>>
>> The added group of operations enables tracking of the changed bits in
>> the dirty bitmap.
>>
>> Signed-off-by: Fam Zheng <[email protected]>
>> Reviewed-by: Max Reitz <[email protected]>
>> Signed-off-by: John Snow <[email protected]>
>> ---
>> block/dirty-bitmap.c | 52
>> ++++++++++++++++++++++++++++++++++++++++++++
>> include/block/dirty-bitmap.h | 9 ++++++++
>> 2 files changed, 61 insertions(+)
>
> [...]
>
>> +int bdrv_dirty_bitmap_get_meta(BlockDriverState *bs,
>> + BdrvDirtyBitmap *bitmap, int64_t sector,
>> + int nb_sectors)
>> +{
>> + uint64_t i;
>> + int gran = hbitmap_granularity(bitmap->meta);
>
> /me is making a note first: If John says an optimization may be
> premature, it probably is.
>
> Did I say hbitmap_granularity()? I may have wanted to actually say
> "1 << hbitmap_granularity()". Sorry. :-/
>
> /me is making a second note now: Look up how something works before
> proposing it, not after someone has actually followed your advice.
>
> Max
>
Haha, alright. I will ACTUALLY sit down and make this nice tonight.
I'll have to turn off autopilot for a few bleeding moments.
--js
>> +
>> + /* To optimize: we can make hbitmap to internally check the range in a
>> + * coarse level, or at least do it word by word. */
>> + for (i = sector; i < sector + nb_sectors; i += gran) {
>> + if (hbitmap_get(bitmap->meta, i)) {
>> + return true;
>> + }
>> + }
>> + return false;
>> +}
>
