Re: select/poll locking wrong?

On Thu, 28 Feb 2002, Matthew Dillon wrote:

> :> 
> :>     The cache appears to be there so select(), when it is getting ready
> :>     to return, can avoid traversing the list and removing the events that
> :>     have not occured.  This results in a potentially stale si_pid because
> :>     now the process can exit without doing any further cleanups.
> :
> :Yes, this is why we must now walk the list when leaving select/poll.
> :
> :..
> :Anyhow, hope that clarifies.  Any other ideas or improvements?
> :
> :Any idea on how we can avoid the list traversal at the end of
> :select?
> :
> :-- 
> :-Alfred Perlstein [[e-mail]]
> 
>     Walking the whole list is one solution.  Another would be to link
>     selinfo into a thread-based list (the thread it has been asigned to)
>     and just walk *that* list on exit in order to avoid having to lock
>     the entire descriptor list on every select().  I'm still not sure
>     which of these two approaches you are going for.
> 
>     I'm not sure how this would tie into KSE.  It might not be efficient
>     to walk the list on thread-exit since KSE creates and drops threads
>     all the time.

I need to add a generation number to threads.
And possibly a TID (like PID) (maybe the same thing?)
The TID would be just an incrementing number taken from a field in the
proc.
thus the full TID would be PID:TID
It hasn't been needed yet, but I can see it coming..



> 
> 					-Matt
> 					Matthew Dillon 
> 					<[e-mail]>
> 
> 
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