[Click] Handler Synchronization question

[Eddie Kohler]

Hi Roman,

Fair question, and at first I thought the question was harder than it is.  If 
you want to use Handler::NONEXCLUSIVE with locking, try SpinlockIRQ.  I 
believe this will work even when Click is compiled for uniprocessor.

Eddie


On 2/11/11 10:27 AM, Roman Chertov wrote:
> I have a question regarding synchronization between the handlers and the main
> element code.  As far as I understand, using Handler::NONEXCLUSIVE flag when
> defining a handler allows for the case where the main thread executes a task for
> some element, while at the same time the handler for that element can get
> called.
>
> However, the following comment for SpinLock got me confused as to how ensure
> atomic operations when the element task and the handler execute at the same
> time.
>
>   * Spinlock operations do nothing unless Click was compiled with SMP support
>   * (with --enable-multithread).  Therefore, Spinlock should not be used to,
>   * for example, synchronize handlers with main element threads.  See also
>   * SpinlockIRQ.
>
> If Spinlock is not the proper mechanism, what is the proper way to do it when
> building an element that must work in user and kernel levels?
>
> Thanks,
>
> Roman
>
>
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