Comment # 20 on bug 1165351 from Thorsten Kukuk

(In reply to Luis Chamberlain from comment #19)
> (In reply to Thorsten Kukuk from comment #17)

> > As far as I understand the code, no, this will not work. To be fast they are
> > doing something which is very fast, but also very memory consuming: have a
> > table for all possible file descriptors to lookup the data instead of going
> > through a list of existing file descriptors.
> 
> Let us think proactively as well, if this was done, was it inspired by
> another codebase? Who else might be doing similar practice?

Of course, this was common best practice 25 years ago if you needed
performance. 

> > If you set the limit lower than
> > possible, you could get a out of array access.
> > The code was written at a time, when 1024 file handles was the maximum
> > possible, not for that big numbers as of today.
> 
> chivo:~/:[0]# cat /proc/sys/fs/file-max
> 9223372036854775807

That's why this is no good practice today anymore and needs to be rewritten.