Re: [PATCH 0/5] Reduce cross CPU IPI interference

[Peter Zijlstra]

On Mon, 2011-09-26 at 11:43 +0300, Gilad Ben-Yossef wrote:
> On Mon, Sep 26, 2011 at 10:20 AM, Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:
> > On Sun, 2011-09-25 at 11:54 +0300, Gilad Ben-Yossef wrote:
> >> This first version creates an on_each_cpu_mask infrastructure API
> >
> > But we already have the existing smp_call_function_many() doing that.
> 
> I might be wrong but my understanding is that smp_call_function_many()
> does not invoke the IPI handler on the current processor. The original
> code I replaced uses on_each_cpu() which does, so I figured a wrapper
> was in order and then I discovered the same wrapper in arch specific
> code.
> 
> > The on_each_cpu() thing is mostly a hysterical relic and could be
> > completely depricated
> 
> Wont this require each caller to call smp_call_function_* and then
> check to see if it needs to also invoke the IPI handler locally ? I
> thought that was the reason for on_each_cpu existence... What have I
> missed?

Gah, you're right.. early.. tea.. more. 

Looks fine then.
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