Re: page migration patchset

[Steve Longerbeam <stevel@mvista.com>]

Andi Kleen wrote:

>On Wed, Jan 05, 2005 at 03:56:29PM -0800, Steve Longerbeam wrote:
>  
>
>>Hugetlbfs is also defining its own shared policy RB tree in its
>>inode info struct, but it doesn't seem to be used, just initialized
>>and freed at alloc/destroy inode time. Does anyone know why that
>>is there? A place-holder for future hugetlbfs mempolicy support?
>>If so, it can be removed and use the generic_file policies instead.
>>    
>>
>
>You need lazy hugetlbfs to use it (= allocate at page fault time,
>not mmap time). Otherwise the policy can never be applied. I implemented 
>my own version of lazy allocation for SLES9, but when I wanted to 
>merge it into mainline some other people told they had a much better 
>singing&dancing lazy hugetlb patch. So I waited for them, but they 
>never went forward with their stuff and their code seems to be dead
>now. So this is still a dangling end :/
>
>If nothing happens soon regarding the "other" hugetlb code I will
>forward port my SLES9 code. It already has NUMA policy support.
>
>For now you can remove the hugetlb policy code from mainline if you
>want, it would be easy to readd it when lazy hugetlbfs is merged.
>  
>

if you don't mind I'd like to. Sounds as if lazy hugetlbfs would be able to
make use of the generic file mapping->policy instead of a hugetlb-specific
policy anyway. Same goes for shmem.

Steve