FTP Server busy waiting when file descriptors are exhausted

[Thomas Rauscher]

> -----Original Message-----
> From: Chris Johns [mailto:chrisj at rtems.org] 
> Sent: Tuesday, March 28, 2006 5:24 AM
> To: Thomas Rauscher
> Cc: rtems-users
> Subject: Re: FTP Server busy waiting when file descriptors 
> are exhausted
> 
> Thomas Rauscher wrote:
> > 
> > we've found a bug in the RTEMS FTP server and would like to 
> develop a
> > patch.
> > 
> > The problem is also described in PR930.
> 
> I do not think the test in the PR is valid.
> 
> If you size the system to have less descriptors than required 
> by the ftp server you have a problem in your configuration. The fd
pool 
> is a fixed resource and your application has to respect this.
> 

You are right, a well designed application should not run into this
situation.

However, in my opinion the FTP server should handle this case more
gracefully
and not hang up exhausting the entire CPU time. Currently, the
problem that all fds are used triggers another problem that all lower
priority
threads are preempted by a not very productive thread.

This is what I'm trying to address with my two proposed solution
sketches.

Regards,
Thomas Rauscher

--
Thomas Rauscher
LOYTEC electronics GmbH