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Re: [Qemu-devel] [PATCH v3 13/38] block: Remove wr_highest_sector from B
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [PATCH v3 13/38] block: Remove wr_highest_sector from BlockAcctStats |
Date: |
Wed, 03 Jun 2015 14:47:29 -0600 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 |
On 06/03/2015 01:43 PM, Max Reitz wrote:
> BlockAcctStats contains statistics about the data transferred from and
> to the device; wr_highest_sector does not fit in with the rest.
>
> Furthermore, those statistics are supposed to be specific for a certain
> device and not necessarily for a BDS (see the comment above
> bdrv_get_stats()); on the other hand, wr_highest_sector may be a rather
> important information to know for each BDS. When BlockAcctStats is
> finally removed from the BDS, we will want to keep wr_highest_sector in
> the BDS.
See also Berto's thread on I/O accounting overhaul:
https://lists.gnu.org/archive/html/qemu-devel/2015-06/msg00994.html
I think eventually we want stats at both BDS and BB levels. But for
now, you are must moving things around to where they make sense, so I
can live with it as incremental improvement.
>
> Finally, wr_highest_sector is renamed to wr_highest_offset and given the
> appropriate meaning. Externally, it is represented as an offset so there
> is no point in doing something different internally. Its definition is
> changed to match that in qapi/block-core.json which is "the offset after
> the greatest byte written to". Doing so should not cause any harm since
> if external programs tried to calculate the volume usage by
> (wr_highest_offset + 512) / volume_size, after this patch they will just
> assume the volume to be full slightly earlier than before.
>
> Signed-off-by: Max Reitz <address@hidden>
> ---
> block/accounting.c | 8 --------
> block/io.c | 4 +++-
> block/qapi.c | 4 ++--
> include/block/accounting.h | 3 ---
> include/block/block_int.h | 3 +++
> qmp-commands.hx | 4 ++--
> 6 files changed, 10 insertions(+), 16 deletions(-)
>
Reviewed-by: Eric Blake <address@hidden>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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- Re: [Qemu-devel] [PATCH v3 10/38] hw/usb-storage: Check whether BB is inserted, (continued)
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- [Qemu-devel] [PATCH v3 12/38] block: Move guest_block_size into BlockBackend, Max Reitz, 2015/06/03
- [Qemu-devel] [PATCH v3 13/38] block: Remove wr_highest_sector from BlockAcctStats, Max Reitz, 2015/06/03
- [Qemu-devel] [PATCH v3 14/38] block: Move BlockAcctStats into BlockBackend, Max Reitz, 2015/06/03
- Re: [Qemu-devel] [Qemu-block] [PATCH v3 14/38] block: Move BlockAcctStats into BlockBackend, Alberto Garcia, 2015/06/05
- [Qemu-devel] [PATCH v3 16/38] block: Add BlockBackendRootState, Max Reitz, 2015/06/03
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