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Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express devi
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express device |
Date: |
Thu, 13 Dec 2012 10:34:58 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 |
Il 13/12/2012 10:12, Kevin Wolf ha scritto:
>>> 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?
Yes, that's the main problem.
Paolo
- Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express device, (continued)
- 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, 2012/12/13
- Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express device,
Paolo Bonzini <=
Re: [Qemu-devel] [PATCH] NVMe: Initial commit to add an NVM Express device, Paolo Bonzini, 2012/12/13