Re: [PATCH 00/11] x86: cpumask: some more cpumask cleanups - flush_tlb_*

[Mike Travis]

Rusty Russell wrote:
> On Tuesday 06 January 2009 14:19:35 Mike Travis wrote:
>> Ingo Molnar wrote:
>>> Quite good! Can we fix those TLB flush cpumask uses too?
>> Here is one proposal.
> 
> Here's what I had.  It's untested though...
> 
> x86: change flush_tlb_others to take a const struct cpumask *. FIXME: REVIEW
> 
> This is made a little more tricky by uv_flush_tlb_others which
> actually alters its argument, for an IPI to be sent to the remaining
> cpus in the mask.
> 
> I solve this by allocating a cpumask_var_t for this case and falling back
> to IPI should this fail.

I thought about this but I wondered if we wanted to add the overhead of a kmalloc
call for every tlb flush?  For a UV system, simultaneous flushes will be quite common,
so introducing two kmalloc's in the path could really hamper performance.

Thanks,
Mike
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