Re: [RFC patch 08/18] cnt32_to_63 should use smp_rmb()

From: David Howells
Date: Fri Nov 07 2008 - 06:00:19 EST


Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:

> I mean, the darned thing is called from sched_clock(), which can be
> concurrently called on separate CPUs and which can be called from
> interrupt context (with an arbitrary nesting level!) while it was running
> in process context.
>
> Who let that thing into Linux?

Having crawled all over it, and argued with Nicolas and Panasonic about it, I
think it's safe in sched_clock(), provided sched_clock() never gets preempted -
which appears to be the case.

David
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