linux-kernel - Re: Zram for FreeBSD

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Date:   Mon, 10 Oct 2016 15:44:04 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:     Cory Pruce <cpruce@...iper.net>
Cc:     Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        Nitin Gupta <nitingupta910@...il.com>,
        "minchan@...nel.org" <minchan@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: Zram for FreeBSD

On (10/07/16 17:30), Cory Pruce wrote:
> Cool, I am starting to get a good grasp on what is going on (I’ll probably
> need to use FreeBSD’s archive.h as opposed to Linux’s crypto.h). I am trying
> to get a hold on what exactly I need to port to FreeBSD. I see that (as Nitin
> suggested) zsmalloc is the main brains of handling the objects and that it
> creates a fixed amount of sharded “pages” which a compressed (or
> uncompressed) actual page can span. I see also that that depends on zpool.

zsmalloc doesn't depend on zpool. zpool is an abstraction layer used
by zswap.

> I will probably find all “dependencies”; however, if one of you could
> describe the components used/implemented for this, that’d be awesome. Also,
> any linux specific setup/layout details come to mind?

there is a whole bunch of hacks that Nitin, Minchan and others used
in zsmalloc() to minimize its space consumption (struct page fields
re-usage, etc). comments in zsmalloc() can shed some light.

	-ss