[OLPC-devel] Re: [linux-mm-cc] Announce: Compressed cache alpha-005 release

[Allan Bezerra]

Hi Nitin and all,

I tested alpha-005 on a ARM based arch and it didn't crash. The tests had
been similar to Nitin use case.

* I tested this as:
RAM: 64MB
ccache for anon pages - size: 2.5MB (640 pages)
ccache for page cache pages - size: 5MB (1280 pages)

I'll do more tests and will send the results to list soon.

Regards,

Allan Bezerra


On 9/5/06, Nitin Gupta <nitingupta.mail at gmail.com> wrote:
>
> ------------
> Project: Compressed Caching for Linux (2.6.x kernels)
> Git (web): http://dev.laptop.org/git.do?p=projects/linux-mm-cc
> Git (git): git://dev.laptop.org/projects/linux-mm-cc
> Home Page: http://linuxcompressed.sourceforge.net
> ------------
>
>
> Hi all!
>
> This release brings a Major new addition to compressed caching
> feature (kernel 2.6.18-rc6) -- Now, both page-cache (clean &
> dirty) pages and swap-cache pages are compressed!
>
> Also fixed a lot of other bugs!
>
>
> * Usage:
> It creates two /proc entries:
> /proc/sys/vm/{max_anon_cc_size,max_fs_backed_cc_size}
>
> Use these to set compressed cache size (in unit of no. of
> pages) for anonymous(swap-cache) and
> filesystem-backed(page-cache) pages respectively.
>
>
> * I tested this as:
> RAM: 128MB
> ccache for anon pages - size: 5MB (1280 pages)
> ccache for page cache pages - size: 10MB (2560 pages)
>
> Launched openoffice-writer, gimp, firefox, kate, konsole. Closed
> these, re-opened, open some web-pages, some file in writer,
> close all, open all again --- it didn't crash on _my_ system.
> (Focusing on correctness for now!)
>
> If you test it and find _any_ problems, please mail me or on
> mailing list. Thanks!
>
>
> * NOTES
> -- page-cache and swap-cache compression can be separately
> turned on. So, you can do separate tests for these by keeping
> other to 0 size.
>
> -- Page-cache pages that could now be added to ccache are let
> goto disks (or simply freed for clean pages).
>
> -- Pages are cyclically compressed using WKdm, WK4x4 and LZO.
> You can easily change this behavior by changing single line in
> guess_algo() in mm/ccache.c (see function comments).
>
> -- You can further filter (like allowing only dirty page
> cache pages) which pages are compressed by simply adding
> criteria in should_add_to_ccache() in mm/ccache.c
>
>
> * TODO
> -- Export statistics like current anon and file-system backed
> ccache sizes (_whatever_ statistics are required to get useful
> benchmark figures).
>
> -- Analyze more properly conditions of _very_ low memory
> conditions like what happens if OOM killer kills a process
> whose pages are being compressed!
>
> -- Write in detail what exactly remains, present problems: also
> list requirements for long term goals like dynamic ccache
> resizing support.
>
> -- Code cleanups: like use proper log level for info/warning or
> debug messages. Don't use pr_info() throughout.
>
>
> If you test it please mail me the results! Thanks!
>
>
> * Patch (for kernel 2.6.18-rc6):
> http://prdownloads.sourceforge.net/linuxcompressed/patch-ccache-
> alpha-005-2.6.18-rc6?download
>
>
> Cheers,
> Nitin
> _______________________________________________
> linux-mm-cc mailing list
> linux-mm-cc at laptop.org
> http://mailman.laptop.org/mailman/listinfo/linux-mm-cc
>
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