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Re: [Qemu-block] [PATCH v7 04/10] block: Support meta dirty bitmap
From: |
John Snow |
Subject: |
Re: [Qemu-block] [PATCH v7 04/10] block: Support meta dirty bitmap |
Date: |
Fri, 22 Jul 2016 17:58:45 -0400 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 |
On 07/22/2016 05:57 PM, Max Reitz wrote:
> On 18.07.2016 22:57, 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(+)
>
> [...]
>
>> +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;
>> +}
>
- [Qemu-block] [PATCH v7 00/10] Dirty bitmap changes for migration/persistence work, John Snow, 2016/07/18
- [Qemu-block] [PATCH v7 02/10] HBitmap: Introduce "meta" bitmap to track bit changes, John Snow, 2016/07/18
- [Qemu-block] [PATCH v7 04/10] block: Support meta dirty bitmap, John Snow, 2016/07/18
- [Qemu-block] [PATCH v7 01/10] block: Hide HBitmap in block dirty bitmap interface, John Snow, 2016/07/18
- [Qemu-block] [PATCH v7 05/10] block: Add two dirty bitmap getters, John Snow, 2016/07/18
- [Qemu-block] [PATCH v7 03/10] tests: Add test code for meta bitmap, John Snow, 2016/07/18
- [Qemu-block] [PATCH v7 06/10] block: Assert that bdrv_release_dirty_bitmap succeeded, John Snow, 2016/07/18
- [Qemu-block] [PATCH v7 07/10] hbitmap: serialization, John Snow, 2016/07/18
- [Qemu-block] [PATCH v7 08/10] block: BdrvDirtyBitmap serialization interface, John Snow, 2016/07/18
- [Qemu-block] [PATCH v7 09/10] tests: Add test code for hbitmap serialization, John Snow, 2016/07/18
- [Qemu-block] [PATCH v7 10/10] block: More operations for meta dirty bitmap, John Snow, 2016/07/18