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Re: [Qemu-devel] [PATCH v6 04/10] block: Support meta dirty bitmap
From: |
John Snow |
Subject: |
Re: [Qemu-devel] [PATCH v6 04/10] block: Support meta dirty bitmap |
Date: |
Mon, 18 Jul 2016 12:24:01 -0400 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 |
On 07/18/2016 10:57 AM, Max Reitz wrote:
> On 15.07.2016 22:27, John Snow wrote:
>> From: Fam Zheng <address@hidden>
>>
>> The added group of operations enables tracking of the changed bits in
>> the dirty bitmap.
>>
>> Signed-off-by: Fam Zheng <address@hidden>
>> Reviewed-by: Max Reitz <address@hidden>
>> Signed-off-by: John Snow <address@hidden>
>> ---
>> block/dirty-bitmap.c | 52
>> ++++++++++++++++++++++++++++++++++++++++++++
>> include/block/dirty-bitmap.h | 9 ++++++++
>> 2 files changed, 61 insertions(+)
>>
>> diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
>> index 628b77c..9c53c56 100644
>> --- a/block/dirty-bitmap.c
>> +++ b/block/dirty-bitmap.c
>> @@ -38,6 +38,7 @@
>
> [...]
>
>> +int bdrv_dirty_bitmap_get_meta(BlockDriverState *bs,
>> + BdrvDirtyBitmap *bitmap, int64_t sector,
>> + int nb_sectors)
>> +{
>> + uint64_t i;
>> + int gran = bdrv_dirty_bitmap_granularity(bitmap) >> BDRV_SECTOR_BITS;
>> +
>> + /* To optimize: we can make hbitmap to internally check the range in a
>> + * coarse level, or at least do it word by word. */
>
> So you really want to leave even the simple optimizations for later? :-)
>
I guess partly I felt bad about not going all the way on it, but I can
bring it a little closer :)
> (i.e. "int gran = hbitmap_granularity(bitmap->meta);")
>
> Max
>
>> + for (i = sector; i < sector + nb_sectors; i += gran) {
>> + if (hbitmap_get(bitmap->meta, i)) {
>> + return true;
>> + }
>> + }
>> + return false;
>> +}
>
>
- [Qemu-devel] [PATCH v6 00/10] Dirty bitmap changes for migration/persistence work, John Snow, 2016/07/15
- [Qemu-devel] [PATCH v6 02/10] HBitmap: Introduce "meta" bitmap to track bit changes, John Snow, 2016/07/15
- [Qemu-devel] [PATCH v6 03/10] tests: Add test code for meta bitmap, John Snow, 2016/07/15
- [Qemu-devel] [PATCH v6 04/10] block: Support meta dirty bitmap, John Snow, 2016/07/15
- [Qemu-devel] [PATCH v6 01/10] block: Hide HBitmap in block dirty bitmap interface, John Snow, 2016/07/15
- [Qemu-devel] [PATCH v6 08/10] block: BdrvDirtyBitmap serialization interface, John Snow, 2016/07/15
- [Qemu-devel] [PATCH v6 06/10] block: Assert that bdrv_release_dirty_bitmap succeeded, John Snow, 2016/07/15
- [Qemu-devel] [PATCH v6 05/10] block: Add two dirty bitmap getters, John Snow, 2016/07/15
- [Qemu-devel] [PATCH v6 07/10] hbitmap: serialization, John Snow, 2016/07/15
- [Qemu-devel] [PATCH v6 10/10] block: More operations for meta dirty bitmap, John Snow, 2016/07/15
- [Qemu-devel] [PATCH v6 09/10] tests: Add test code for hbitmap serialization, John Snow, 2016/07/15