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    SubjectRe: [PATCH v3 2/3] hvc_init(): Enforce one-time initialization.
    Hi,

    On (Mon) 28 Nov 2011 [15:40:41], Miche Baker-Harvey wrote:
    > Amit,
    >
    > You said that the work would be serialized "due to port additions
    > being on work items on the same workqueue". I'm not seeing that.

    You leave a lot of questions unanswered. What's your environment?
    Are you hot-plugging ports? Are you using qemu? What's your command
    line?

    > I've double checked this by using a mutex_trylock in
    > hvc_console::hvc_alloc(), and here's the relevant output from dmesg:
    >
    > root@myubuntu:~# dmesg | grep MBH
    > [3307216.210274] MBH: got hvc_ports_mutex
    > [3307216.210690] MBH: trylock of hvc_ports_mutex failed
    > [3307216.211143] MBH: got hvc_ports_mutex
    >
    > This is in a system with two virtio console ports, each of which is a
    > console. I think if the VIRTIO_CONSOLE_CONSOLE_PORT message handling
    > were actually being serialized, the trylock should never fail.

    Agreed.

    > What's the source of the serialization for the workqueue items? At
    > first reading it looks like the control_work_handler gets called for
    > each virtio interrupt?

    It all depends on how you add ports. If you're using qemu, they
    happen via the control work handler.

    Amit


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