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Re: [Qemu-devel] [Qemu-block] [PATCH v2 06/17] hbitmap: add hbitmap_merg
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [Qemu-block] [PATCH v2 06/17] hbitmap: add hbitmap_merge |
Date: |
Wed, 11 Mar 2015 15:43:44 +0000 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Mon, Mar 02, 2015 at 06:19:52PM -0500, John Snow wrote:
> We add a bitmap merge operation to assist in error cases
> where we wish to combine two bitmaps together.
>
> This is algorithmically O(bits) provided HBITMAP_LEVELS remains
> constant. For a full bitmap on a 64bit machine:
> sum(bits/64^k, k, 0, HBITMAP_LEVELS) ~= 1.01587 * bits
>
> We may be able to improve running speed for particularly sparse
> bitmaps by using iterators, but the running time for dense maps
> will be worse.
>
> We present the simpler solution first, and we can refine it later
> if needed.
>
> Signed-off-by: John Snow <address@hidden>
> Reviewed-by: Max Reitz <address@hidden>
> Reviewed-by: Stefan Hajnoczi <address@hidden>
> ---
> include/qemu/hbitmap.h | 11 +++++++++++
> util/hbitmap.c | 32 ++++++++++++++++++++++++++++++++
> 2 files changed, 43 insertions(+)
Reviewed-by: Stefan Hajnoczi <address@hidden>
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- [Qemu-devel] [PATCH v2 00/17] block: transactionless incremental backup series, John Snow, 2015/03/02
- [Qemu-devel] [PATCH v2 06/17] hbitmap: add hbitmap_merge, John Snow, 2015/03/02
- Re: [Qemu-devel] [Qemu-block] [PATCH v2 06/17] hbitmap: add hbitmap_merge,
Stefan Hajnoczi <=
- [Qemu-devel] [PATCH v2 05/17] block: Introduce bdrv_dirty_bitmap_granularity(), John Snow, 2015/03/02
- [Qemu-devel] [PATCH v2 03/17] qmp: Ensure consistent granularity type, John Snow, 2015/03/02
- [Qemu-devel] [PATCH v2 07/17] block: Add bitmap disabled status, John Snow, 2015/03/02
- [Qemu-devel] [PATCH v2 01/17] docs: incremental backup documentation, John Snow, 2015/03/02