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Subject: Re: [v7 0/8] Reduce cross CPU IPI interference
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Gilad Ben-Yossef <gilad@benyossef.com>
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        Milton Miller <miltonm@bga.com>
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Date: Fri, 10 Feb 2012 19:39:08 +0100
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On Sun, 2012-02-05 at 13:46 +0200, Gilad Ben-Yossef wrote:
> > /*
> >  * Cause all memory mappings to be populated in the page table.
> >  * Specifying this when entering dataplane mode ensures that no future
> >  * page fault events will occur to cause interrupts into the Linux
> >  * kernel, as long as no new mappings are installed by mmap(), etc.
> >  * Note that since the hardware TLB is of finite size, there will
> >  * still be the potential for TLB misses that the hypervisor handles,
> >  * either via its software TLB cache (fast path) or by walking the
> >  * kernel page tables (slow path), so touching large amounts of memory
> >  * will still incur hypervisor interrupt overhead.
> >  */
> > #define DP_POPULATE     0x8
> 
> hmm... I've probably missed something, but doesn't this replicate
> mlockall (MCL_CURRENT|MCL_FUTURE) ? 

Never use mlockall() its a sign you're doing it wrong, also his comment
seems to imply MCL_FUTURE isn't required.