Re: [RFC 2/2] Hugetlb COW

[Adam Litke]

On Mon, 2005-11-07 at 15:38 -0600, Adam Litke wrote:
> [RFC] COW for hugepages
> (Patch originally from David Gibson <dwg@xxxxxxxxxxx>)
> 
> This patch implements copy-on-write for hugepages, hence allowing
> MAP_PRIVATE mappings of hugetlbfs.
> 
> This is chiefly useful for cases where we want to use hugepages
> "automatically" - that is to map hugepages without the knowledge of
> the code in the final application (either via kernel hooks, or with
> LD_PRELOAD).  We can use various heuristics to determine when
> hugepages might be a good idea, but changing the semantics of
> anonymous memory from MAP_PRIVATE to MAP_SHARED without the app's
> knowledge is clearly wrong.

I forgot to mention in the original post that this patch is currently
broken on ppc64 due to a problem with update_mmu_cache().  The proper
fix is understood but backed up behind the powerpc merge activity.  

-- 
Adam Litke - (agl at us.ibm.com)
IBM Linux Technology Center

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