Messages in this thread | | | Date | Fri, 20 Jun 2014 10:23:57 -0500 (CDT) | From | Christoph Lameter <> | Subject | Re: [PATCH RFC] percpu: add data dependency barrier in percpu accessors and operations |
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On Thu, 19 Jun 2014, Tejun Heo wrote:
> Again, data dependency barrier is noop in all in-use archs.
A barrier limits what the compiler can do.
> > Remote write events are contrary to that design and are exceedingly rare. > > An IPI is justifiable for such a rare event. At least in my use cases I > > have always found that to be sufficient. Well, I designed the data > > structures in a way that made this possible because of the design criteria > > that did not allow me remote write access to other processors per cpu > > data. > > You're repeatedly getting wayside in the discussion. What are you > suggesting? Sending IPIs on each percpu allocation?
No this is about sending an IPI if you want to modify the percpu data of another process. There was a mentionig of code that modifies the per cpu data of another processor?
> Again, I'm leaning towards just clarifying the init write ownership to > the allocating CPU as that seems the most straight forward way to deal > with it, but please stop brining up the raw performance thing. Nobody > is doing anything to that. It's not relevant in the discussion.
Ok sounds good.
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