On Mon, Aug 26, 2013 at 10:44 PM, Christoph Lameter <[email protected]> wrote:
> __get_cpu_var() is used for multiple purposes in the kernel source. One of
> them is
> address calculation via the form &__get_cpu_var(x). This calculates the
> address for
> the instance of the percpu variable of the current processor based on an
> offset.
>
> Others usage cases are for storing and retrieving data from the current
> processors percpu area.
use cases
> __get_cpu_var() always only does a address determination. However, store and
> retrieve operations
an address
> This patch converts __get_cpu_var into either and explicit address
> calculation using this_cpu_ptr()
an explicit
> 4. Retrieve the content of a percpu struct
>
> DEFINE_PER_CPU(struct mystruct, y);
> struct mystruct x = __get_cpu_var(y);
>
> Converts to
>
> memcpy(this_cpu_ptr(&y), x, sizeof(x));
Let's hope the actual code copies in the other direction ;-)
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
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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