Re: Kernel patches enabling better POSIX AIO (Was Re: [3/4] kevent: AIO, aio_sendfile)

["Sébastien Dugué" <sebastien.dugue@bull.net>]

On Sat, 2006-08-12 at 12:10 -0700, Ulrich Drepper wrote:
> Suparna Bhattacharya wrote:
> > I am wondering about that too. IIRC, the IO_NOTIFY_* constants are not
> > part of the ABI, but only internal to the kernel implementation. I think
> > Zach had suggested inferring THREAD_ID notification if the pid specified
> > is not zero. But, I don't see why ->sigev_notify couldn't used directly
> > (just like the POSIX timers code does) thus doing away with the 
> > new constants altogether. Sebestian/Laurent, do you recall?
> 
> I suggest to model the implementation after the timer code which does
> exactly what we need.
> 

  Will do.

> 
> > I'm guessing they are being used for validation of permissions at the time
> > of sending the signal, but maybe saving the task pointer in the iocb instead
> > of the pid would suffice ?
> 
> Why should any verification be necessary?  The requests are generated in
> the same process which will receive the notification.  Even if the POSIX
> process (aka, kernel process group) changes the IDs the notifications
> should be set.  The key is that notifications cannot be sent to another
> POSIX process.
> 
> Adding this as a feature just makes things so much more complicated.
> 

  Agreed.

  Sébastien.


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  Sébastien Dugué                BULL/FREC:B1-247
  phone: (+33) 476 29 77 70      Bullcom: 229-7770

  mailto:sebastien.dugue@bull.net

  Linux POSIX AIO: http://www.bullopensource.org/posix
                   http://sourceforge.net/projects/paiol

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