Re: [Qemu-devel] [PATCH 4/5] coroutine-lock: make qemu_co_enter_next thread-safe

[Eric Blake <eblake@redhat.com>]

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On 01/25/2018 11:59 AM, Paolo Bonzini wrote:
> qemu_co_queue_next does not need to release and re-acquire the mutex,
> because the queued coroutine does not run immediately.  However, this
> does not hold for qemu_co_enter_next.  Now that qemu_co_queue_wait
> can synchronize (via QemuLockable) with code that is not running in
> coroutine context, it's important that code using qemu_co_enter_next
> can easily use a standardized locking idiom.
> 
> First of all, qemu_co_enter_next must use aio_co_wake to restart the
> coroutine.  Second, the function gains a second argument, a QemuLockable*,
> and the comments of qemu_co_queue_next and qemu_co_queue_restart_all
> are adjusted to clarify the difference.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---

>  /**
> - * Restarts all coroutines in the CoQueue and leaves the queue empty.
> + * Empties the CoQueue; all coroutines in it will run in FIFO orer as soon

s/orer/order/

> + * as the current one yields.
>   */
>  void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue);


-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


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