[OLPC-devel] Announce: Compressed cache 'alpha-002' release

[Nitin Gupta]

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Project: Compressed Caching for Linux
Git (web): http://dev.laptop.org/git.do?p=projects/linux-mm-cc
Git (git): git://dev.laptop.org/projects/linux-mm-cc
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Hi!

This is weekly work summary [10/12] or I thought, better call it 'Announce' ;)

Attached is patch for compressed caching for anon pages (2.6.18-rc3) -
'alpha-002' :)

Finally, 'better' locking scheme in find_get_page() is working together
with compression structure. This equates to 'nearly' complete compressed
caching feature for anonymous pages. But, I haven't yet made any benchmarks
though!

Many of the suggestions from previous post for cache-alpha-1 have been taken to
this patch. I will be glad if you can take time to look at this patch too for
_any_ of suggestions you have. There are also some known glitches which I
couldn't solve now.

Known problems:
-- Pages once decompressed are not put back on LRU (active?). Doing so is
causing system freeze and I couldn't get to the cause yet.

-- LZO is still giving problems. System freezes just after some pages are
compressed. Biggest problem is that it requires mammoth 64K buffer to compress a
single page.

-- How to 'migrate' incompressible pages to swap disk? This is not an issue for
OLPC as they do not have a swap.

So, here's what I aim by end of SoC:
(Riel, can you please suggest here?)
* Either
	Start work on to add support for page cache pages and heuristic for
	adaptive ccache resize.
* Or
	Work to stabilize this much for anonymous pages, code cleanups, testing
	on OLPC board, (maybe) document all this stuff.


Cheers,
Nitin
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