Re: [PATCH RFC v4 1/1] random: WARN on large getrandom() waits and introduce getrandom2()

Ahmed S. Darwish
2019-09-20T17:56:56Z

On Fri, Sep 20, 2019 at 07:26:09PM +0200, Willy Tarreau wrote:
> Hi Ahmed,
>
> On Fri, Sep 20, 2019 at 03:46:09PM +0200, Ahmed S. Darwish wrote:
> > Problem is, glibc is still *really* slow in adopting linux syscall
> > wrappers, so I'm not optimistic about that...
> >
> > I still see the new system call as the sanest path, even provided
> > the cost of a new syscall number..
>
> New syscalls are always a pain to deal with in userland, because when
> they are introduced, everyone wants them long before they're available
> in glibc. So userland has to define NR_xxx for each supported arch and
> to perform the call itself.
>
> With flags adoption is instantaneous. Just #ifndef/#define, check if
> the flag is supported and that's done. The only valid reason for a new
> syscall is when the API changes (e.g. one extra arg, a la accept4()),
> which doesn't seem to be the case here. Otherwise please by all means
> avoid this in general.
>

I see. Thanks a lot for the explanation above :)

--
Ahmed Darwish