Re: [PATCH] Microoptimization of lib/poll.c

[Ralf Wildenhues]

Hi Paolo,

* Paolo Bonzini wrote on Wed, Aug 06, 2008 at 10:28:00AM CEST:
> --- a/lib/poll.c
> +++ b/lib/poll.c

>  #ifdef _SC_OPEN_MAX
> -  if (nfd > sysconf (_SC_OPEN_MAX))
> +  static int sc_open_max = -1;
> +
> +  if (nfd < 0
> +      || (nfd > sc_open_max
> +          && (sc_open_max != -1
> +           || nfd > (sc_open_max = sysconf (_SC_OPEN_MAX)))))

Doesn't this make poll non-reentrant?
Are there systems where assigning to an int is not atomic?

Thanks,
Ralf