Re: [this_cpu_xx V4 00/20] Introduce per cpu atomic operations andavoid per cpu address arithmetic

From: Ingo Molnar
Date: Fri Oct 02 2009 - 05:55:42 EST



* Tejun Heo <tj@xxxxxxxxxx> wrote:

> Hello,
>
> cl@xxxxxxxxxxxxxxxxxxxx wrote:
> > V3->V4:
> > - Fix various macro definitions.
> > - Provider experimental percpu based fastpath that does not disable
> > interrupts for SLUB.
>
> The series looks very good to me. [...]

Seconded, very nice series!

One final step/cleanup seems to be missing from it: it should replace
current uses of percpu_op() [percpu_read(), etc.] in the x86 tree and
elsewhere with the new this_cpu_*() primitives. this_cpu_*() is using
per_cpu_from_op/per_cpu_to_op directly, we dont need those percpu_op()
variants anymore.

There should also be a kernel image size comparison done for that step,
to make sure all the new primitives are optimized to the max on the
instruction level.

> [...] percpu#for-next now has ia64 bits included and the legacy
> allocator is gone there so it can carry this series. Sans the last
> one, they seem they can be stable and incremental from now on, right?
> Shall I include this series into the percpu tree?

I'd definitely recommend doing that - it should be tested early and wide
for v2.6.33, and together with other percpu bits.

Ingo
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