Re: [guv v2 04/31] net: Replace __get_cpu_var uses

From: David Miller
Date: Mon Sep 02 2013 - 23:28:06 EST


From: David Howells <dhowells@xxxxxxxxxx>
Date: Mon, 02 Sep 2013 22:35:06 +0100

> Would it be possible to use __thread annotations for per-CPU
> variables, I wonder?

Paul Mackerras tried it on powerpc and you can't do it.

The problem is that there is no way to tell the compiler that sched()
and similar (potentially) change the thread pointer base.

It really will cache pre-computed __thread pointer calculations across
sched().
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