Re: RFC - freeing up ar.k5

From: Russ Anderson <>
Date: 2004-09-18 05:43:16
Tony Luck wrote:
> Well, this is what a patch to free up ar.k5 by replacing its use
> with a percpu variable looks like.
> Downside is a possible cache miss reading the variable in 'schedule()'.
> Upside is freeing up ar.k5 ... whose use would get rid of much ugliness
> in the mca tlb recovery code (and in the impending per-cpu save areas
> for INIT/MCA).

I certainly do not object to using ar.k5 for a percpu physical address pointer.  

Just to understand the rest, I assume this means:

  * The ia64_mca_tlb_list[] array goes away and each cpu will have a 
    ia64_mca_tlb_info structure (a physical address pointer to the structure 
    being in ar.k5).  The memory for each structure will be allocated on
    the same node as the CPU.

  * A physcial address pointer to the per data MCA/INIT area added to 
    the ia64_mca_tlb_info structure.

  * Then whe an MCA or INIT occurs, the pointer is waiting in ar.k5.

Russ Anderson, OS RAS/Partitioning Project Lead  
SGI - Silicon Graphics Inc
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Received on Fri Sep 17 15:43:39 2004

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