Re: [PATCH 0/2] Page migration via Swap V2: Overview

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

Hi,

Christoph Lameter wrote:

> The disadvantage over direct page migration are:
> 
> A. Performance: Having to go through swap is slower.
> 
> B. The need for swap space: The area to be migrated must fit into swap.
> 
I think migration cache will work well for A & B :)
migraction cache is virtual swap, just unmap a page and modifies it as a swap cache.

> C. Placement of pages at swapin is done under the memory policy in
>    effect at that time. This may destroy nodeset relative positioning.
> 
How about this ?
==
1. do_mbind()
2. unmap and moves to migraction cache
3. touch all pages
==
For 3., 2. should gather all present virtual address list...

D. We need another page-cache migration functions for moving page-cache :(
    Moving just anon is not for memory-hotplug.
    (BTW, how should pages in page cache be affected by memory location control ??
     I think some people discussed about that...)

-- Kame

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