Re: [PATCH] lib/vsprintf: add %pT[C012] format specifier

From: Geert Uytterhoeven
Date: Tue Jan 07 2014 - 13:29:02 EST

On Tue, Jan 7, 2014 at 6:56 PM, Pavel Machek <pavel@xxxxxx> 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.



Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

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
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