[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] Re: [PATCH 2/2] Add flush=off parameter to -drive
From: |
Alexander Graf |
Subject: |
[Qemu-devel] Re: [PATCH 2/2] Add flush=off parameter to -drive |
Date: |
Wed, 12 May 2010 17:05:08 +0200 |
User-agent: |
Thunderbird 2.0.0.23 (X11/20090817) |
Kevin Wolf wrote:
> Am 10.05.2010 23:51, schrieb Alexander Graf:
>
>> Usually the guest can tell the host to flush data to disk. In some cases we
>> don't want to flush though, but try to keep everything in cache.
>>
>> So let's add a new parameter to -drive that allows us to set the flushing
>> behavior to "on" or "off", defaulting to enabling the guest to flush.
>>
>> Signed-off-by: Alexander Graf <address@hidden>
>>
>
> What about another cache=... value instead of adding more options? I'm
> quite sure you'll only ever need this with writeback caching. So we
> could have cache=none|writethrough|writeback|wb-noflush or something
> like that.
>
>
Yes, cache=volatile seems reasonable. Or cache=unsafe.
>> ---
>> block/raw-posix.c | 13 +++++++++++++
>>
>
> This is obviously wrong. If you want to introduce new behaviour to the
> block layer, you must do it consistently and not just for one block
> driver. So these changes should be made to the generic functions in
> block.c instead.
>
How so? The callback functions are called using bdrv->drv->xxx. If I
modify that pointer, I end up affecting all other virtual disks as well.
Alex
- Re: [Qemu-devel] Re: [PATCH 2/2] Add flush=off parameter to -drive, (continued)
- Re: [Qemu-devel] Re: [PATCH 2/2] Add flush=off parameter to -drive, Alexander Graf, 2010/05/11
- Re: [Qemu-devel] Re: [PATCH 2/2] Add flush=off parameter to -drive, Jamie Lokier, 2010/05/11
- Re: [Qemu-devel] Re: [PATCH 2/2] Add flush=off parameter to -drive, Paul Brook, 2010/05/11
- Re: [Qemu-devel] Re: [PATCH 2/2] Add flush=off parameter to -drive, Paul Brook, 2010/05/11
- Re: [Qemu-devel] Re: [PATCH 2/2] Add flush=off parameter to -drive, Jamie Lokier, 2010/05/12
- Re: [Qemu-devel] Re: [PATCH 2/2] Add flush=off parameter to -drive, Christoph Hellwig, 2010/05/17
- Re: [Qemu-devel] Re: [PATCH 2/2] Add flush=off parameter to -drive, Markus Armbruster, 2010/05/14
- Re: [Qemu-devel] Re: [PATCH 2/2] Add flush=off parameter to -drive, Christoph Hellwig, 2010/05/17
- Re: [Qemu-devel] Re: [PATCH 2/2] Add flush=off parameter to -drive, Alexander Graf, 2010/05/17
- Re: [Qemu-devel] Re: [PATCH 2/2] Add flush=off parameter to -drive, Avi Kivity, 2010/05/11
- [Qemu-devel] Re: [PATCH 2/2] Add flush=off parameter to -drive,
Alexander Graf <=
- [Qemu-devel] Re: [PATCH 2/2] Add flush=off parameter to -drive, Kevin Wolf, 2010/05/12
- [Qemu-devel] Re: [PATCH 2/2] Add flush=off parameter to -drive, Alexander Graf, 2010/05/12
Re: [Qemu-devel] [PATCH 1/2] Add no-op aio emulation stub, Stefan Hajnoczi, 2010/05/11
[Qemu-devel] Re: [PATCH 1/2] Add no-op aio emulation stub, Kevin Wolf, 2010/05/11
Re: [Qemu-devel] [PATCH 0/2] Enable qemu block layer to not flush, Anthony Liguori, 2010/05/10