Re: [PATCH 1/4] Zero based percpu: Infrastructure to rebase theper cpu area to zero

[Ingo Molnar]

* Mike Travis <travis@xxxxxxx> wrote:

>     * Support an option
> 
> 	CONFIG_HAVE_ZERO_BASED_PER_CPU
> 
>       to make offsets for per cpu variables to start at zero.
> 
>       If a percpu area starts at zero then:
> 
> 	-  We do not need RELOC_HIDE anymore
> 
> 	-  Provides for the future capability of architectures providing
> 	   a per cpu allocator that returns offsets instead of pointers.
> 	   The offsets would be independent of the processor so that
> 	   address calculations can be done in a processor independent way.
> 	   Per cpu instructions can then add the processor specific offset
> 	   at the last minute possibly in an atomic instruction.
> 
>       The data the linker provides is different for zero based percpu segments:
> 
> 	__per_cpu_load	-> The address at which the percpu area was loaded
> 	__per_cpu_size	-> The length of the per cpu area
> 
>     * Removes the &__per_cpu_x in lockdep. The __per_cpu_x are already
>       pointers. There is no need to take the address.
> 
>     * Updates kernel/module.c to be able to deal with a percpu area that
>       is loaded at __per_cpu_load but is accessed at __per_cpu_start.
> 
> Based on linux-2.6.tip

applied to tip/core/percpu, thanks.

	Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/