Re: [GIT PATCH] x86,percpu: fix pageattr handling with remap allocator

Tejun Heo
2009-05-16T15:15:54Z

Hello, Suresh.

Suresh Siddha wrote:
> Tejun, Can you please educate me why we need to map this first
> percpu chunk (which is pre-allocated during boot and is physically
> contiguous) into vmalloc area?

To make areas for each cpu congruent such that the address offset of a
percpu symbol for CPU N is always the same from the address for CPU 0.

> Perhaps even for the other dynamically allocated secondary chunks?
> (as far as I can see, all the chunk allocations seems to be
> physically contiguous and later mapped into vmalloc area)..
>
> That should simplify these things quite a bit(atleast for first
> percpu chunk). I am missing something obvious I guess.

Hmm... Sorry I don't really follow. Can you please elaborate the
question?

thanks.

--
tejun