On Tue, Jan 7, 2014 at 6:56 PM, Pavel Machek <pa...@ucw.cz> wrote: >> The additional cost of using current vs NULL is ~zero. > > The additional cost of current vs NULL is cca 8 bytes per caller. Test > for NULL is cca 4 bytes, maybe 20 bytes total. I believe it is worth > it.
It depends (typical answer ;-) On architectures that keep current in a register, the cost of using it is usually zero, as there's typically no difference between pushing a register or a zero on the stack, or moving a register or a zero to another register. current_thread_info()->task is more expensive. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/