Re: Problems raising fd limits in 1.3.78-1.3.80

David ``Joel Katz'' Schwartz (
Tue, 2 Apr 1996 13:35:47 -0500 (EST)

Nothing would make me happier than to see the default number of
fds per process increased to 1,024. I've tried to increase it in kernels
after 1.3.78 but they just crash. It used to be fairly easy; anyone know
what changed?


On Tue, 2 Apr 1996, Stephen Tweedie wrote:

> > On Mon, 1 Apr 1996 wrote:
> >> It is not recommended to increase __FD_SET's size. Unfortunately,
> >> however large you make it, libc simply cannot cope with a select size
> >> larger than 256 fd's.
> > Libc doesn't have to do anything. I just need the fdset macros to
> > work and I need select to work.
> Yup. I wonder if it's worth upping the limit in libc (as exported by
> linux/fs.h) to 1024 anyway? It only really affects the size of the
> fd_set, so it doesn't cost much. It ought to be pretty easy to make
> the kernel's maximum fd number configurable, with processes inheriting
> the current default value on fork() (we probably don't want to change
> the fd table size dynamically on existing processes).