[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [RFC PATCH 03/17] block: add discard properties to Bloc
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [RFC PATCH 03/17] block: add discard properties to BlockDriverInfo |
Date: |
Fri, 09 Mar 2012 17:47:55 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:10.0.1) Gecko/20120209 Thunderbird/10.0.1 |
Am 08.03.2012 18:15, schrieb Paolo Bonzini:
> In the next patches we will declare the guest's semantics for discard
> to be "always zero the data". We need to know whether the operation
> need to be emulated or can be passed down. For this purpose we need
> to know the semantics of the operation and its granularity.
>
> The granularity may not be related to the cluster size (for example
> "raw" does not have a cluster size), so add it separately.
>
> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
> block.h | 4 ++++
> block/qcow2.c | 2 ++
> qemu-io.c | 5 ++++-
> 3 files changed, 10 insertions(+), 1 deletions(-)
>
> diff --git a/block.h b/block.h
> index 48d0bf3..7feda73 100644
> --- a/block.h
> +++ b/block.h
> @@ -15,6 +15,10 @@ typedef struct BlockDriverInfo {
> int cluster_size;
> /* offset at which the VM state can be saved (0 if not possible) */
> int64_t vm_state_offset;
> + /* whether discard is guaranteed to zero bytes */
> + bool discard_zeroes_data;
> + /* discard granularity in sectors */
> + int discard_granularity;
Why not in bytes? The arbitrary 512 byte units used in the block layer
were probably not the best idea ever and we shouldn't spread it further.
Kevin
- [Qemu-devel] [RFC PATCH 00/17] Improvements around discard and write zeroes, Paolo Bonzini, 2012/03/08
- [Qemu-devel] [RFC PATCH 02/17] qed: make write-zeroes bounce buffer smaller than a single cluster, Paolo Bonzini, 2012/03/08
- [Qemu-devel] [RFC PATCH 03/17] block: add discard properties to BlockDriverInfo, Paolo Bonzini, 2012/03/08
- Re: [Qemu-devel] [RFC PATCH 03/17] block: add discard properties to BlockDriverInfo,
Kevin Wolf <=
- [Qemu-devel] [RFC PATCH 06/17] block: use bdrv_{co, aio}_discard for write_zeroes operations, Paolo Bonzini, 2012/03/08
- Re: [Qemu-devel] [RFC PATCH 06/17] block: use bdrv_{co, aio}_discard for write_zeroes operations, Kevin Wolf, 2012/03/09
- Re: [Qemu-devel] [RFC PATCH 06/17] block: use bdrv_{co, aio}_discard for write_zeroes operations, Paolo Bonzini, 2012/03/09
- Re: [Qemu-devel] [RFC PATCH 06/17] block: use bdrv_{co, aio}_discard for write_zeroes operations, Richard Laager, 2012/03/10
- Re: [Qemu-devel] [RFC PATCH 06/17] block: use bdrv_{co, aio}_discard for write_zeroes operations, Paolo Bonzini, 2012/03/12
- Re: [Qemu-devel] [RFC PATCH 06/17] block: use bdrv_{co, aio}_discard for write_zeroes operations, Kevin Wolf, 2012/03/12
- Re: [Qemu-devel] [RFC PATCH 06/17] block: use bdrv_{co, aio}_discard for write_zeroes operations, Richard Laager, 2012/03/13
- Re: [Qemu-devel] [RFC PATCH 06/17] block: use bdrv_{co, aio}_discard for write_zeroes operations, Paolo Bonzini, 2012/03/14
- Re: [Qemu-devel] [RFC PATCH 06/17] block: use bdrv_{co, aio}_discard for write_zeroes operations, Kevin Wolf, 2012/03/14
- Re: [Qemu-devel] [RFC PATCH 06/17] block: use bdrv_{co, aio}_discard for write_zeroes operations, Paolo Bonzini, 2012/03/14