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Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express devi
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express device |
Date: |
Thu, 13 Dec 2012 10:12:44 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:13.0) Gecko/20120605 Thunderbird/13.0 |
Am 13.12.2012 01:13, schrieb Busch, Keith:
> On Mon, Dec 10, 2012 at 7:11 AM, Stefan Hajnoczi <address@hidden> wrote:
>> Quick pointers to get started on Kevin's suggestion:
>>
>> bdrv_aio_readv(), bdrv_aio_writev(), bdrv_aio_flush(), and
>> bdrv_aio_discard() provide the block device operations that emulated
>> storage controllers use.
>
> There seems to be an issue with the bdrv_aio_[readv/writev] routines. I added
> some additional tracing in the block and coroutine code, and well, long story
> short, the coroutine "bdrv_co_io_em" needs to call "qemu_coroutine_yield"
> before his aio callback "bdrv_co_io_em_complete" invokes
> "qemu_coroutine_enter". It does not always win this race in my experiments,
> and qemu aborts with a recursive re-entry error. I don't know this coroutine
> code well enough to propose a fix -- I'd say maybe use locks but I think that
> defeats the purpose of using coroutines if I understand them correctly?
The block layer, like most other qemu functions, is supposed to run
under the qemu_global_mutex (also called BQL). Do you call into it from
a different thread that doesn't take this lock?
Kevin
- [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express device, Keith Busch, 2012/12/08
- Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express device, Stefan Weil, 2012/12/08
- Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express device, Stefan Weil, 2012/12/08
- Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express device, Andreas Färber, 2012/12/08
- Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express device, Keith Busch, 2012/12/08
- Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express device, Andreas Färber, 2012/12/08
- Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express device, Kevin Wolf, 2012/12/10
- Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express device, Stefan Hajnoczi, 2012/12/10
- Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express device, Busch, Keith, 2012/12/10
- Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express device, Busch, Keith, 2012/12/12
- Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express device,
Kevin Wolf <=
- Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express device, Paolo Bonzini, 2012/12/13
Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express device, Paolo Bonzini, 2012/12/13