Re: [PATCH 4/9] net: openvswitch: use this_cpu_ptr per-cpu helper

[Jesse Gross]

On Thu, Nov 1, 2012 at 7:33 AM, Christoph Lameter <cl@xxxxxxxxx> wrote:
> On Thu, 1 Nov 2012, Shan Wei wrote:
>
>> But for different field in same per-cpu variable, how to guarantee n_missed
>> and n_hit are from same cpu?
>> this_cpu_read(dp->stats_percpu->n_missed);
>> [processor changed]
>> this_cpu_read(dp->stats_percpu->n_hit);
>
> What does current guarantee that? If it is guaranteed then you can use the
> __this_cpu_xxx ops.

Preemption is disabled in all of the places where writes are done and
all of the reads are from foreign CPUs.
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