Re: [lc-devel] Initial Compressed Cache structure

[<asb...@if...>]

Nitin Gupta wrote:
> I've been working on Compressed Cache structure for last few days.
> Following is the brain dump of all the details required for ccache
> structure implementation. This doc is a *headache* to follow (poorly
> written, no diagrams included) -- but I'll later sketch them if
> required for any part.

<snip>

> When shrinking, see pages belonging to which inode's mapping are
> mostly being freed (using simple hooks in shrink_list()-vmscan.c).
> This shows that a particular inode's (file's) pages are not being used=
.
> So, when shrinking, search the radix tree for compressed pages (search
> based on PAGECACHE_TAG_COMPRESSED tag) and free all the associated
> chunks. Since a page can only be freed when all the chunks contained
> within are freed, relocate the remaining chunks in the page to free
> chunks in other pages and finally free the page.
>
I'm not sure I follow, at least I need some clarification, when do you
know a page is empty (so that it can be freed) or if you choose a page,
how do you know what compressed page a chunk belongs to?

PS! I might be confused since I have been looking at storing anonymous
memory into the compressed area.

Mvh,
Asbj=F8rn Sannes