Re: [RFC/PATCH] Make powerpc64 use __thread for per-cpu variables

David S. Miller writes:

From: Richard Henderson <redacted>
Date: Wed, 10 May 2006 08:47:13 -0700

quoted

How do you plan to address the compiler optimizing

 ...

quoted

Across the schedule, we may have changed cpus, making the cached
address invalid.

Per-cpu variables need to be accessed only with preemption
disabled.  And the preemption enable/disable operations
provide a compiler memory barrier.

No, Richard has a point, it's not the value that is the concern, it's
the address, which gcc could assume is still valid after a barrier.
Drat.

Paul.