[linux-mm-cc] Swap Compression

[IKEDA, Munehiro]

Hi Anderson,
How are you doing?

Anderson Briglia wrote:
> Hi all,
> 
> After some background activity regarding ARM-OMAP drivers and other
> stuff, I'm back to CCache activities  :) . Ikeda, if you have some
> update on those patches for ccache shrink operations, please, send
>  me and I can test them inside an embedded environment.

Well, I don't have any update from my last post, sorry.
The latest deliverable is available on

http://tree.celinuxforum.org/CelfPubWiki/JapanTechnicalJamboree16

Please download patches from "ccache_avoie-oom_v3.tar.bz2" link.
Especially, patch 0001 - 0004 are debugging patch so I guess they could 
help you even if the shrink operation is unnecessary for you.


> Well, I'm intending to do some performance measurements using Swap
>  compression on a block device, for instance, using
> MMC cards. I intend to use the Nitin's code as base and implement
> a kernel module which will do the swap operations. The main issue
> I see is the swap reference of the pages since I expect to have
> more than one compressed page inside a block.

Hmm...interesting.
You have a plan to swap out ccache'd data?
Or to compress a page data just before swapping it out?

Anyway, yes, indexing might be an issue as you mentioned.
Althoug just an idea, how about to define half block, quater block, 1/8 
block, and so on corresponding to compression ratio, and to use the 
highest some bits of offset(index) to refer them?


Best regards,
IKEDA, Munehiro