[linux-mm-cc] Are there plans to get zRam out of the staging directory ?

[Nitin Gupta]

Hi,

On 04/12/2012 04:15 PM, Mélodie wrote:>

> I have been a user of Compcache almost since the beginning. I had installed it to
> Archlinux, when it came out in version 5.x, then with the version 6.x, and have been very
> happy to use it and try it to a Debian minimal version I had installed to an old machine
> as well.
> 
> I am astonished to still see in my dmesg :
> 
> "zram: module is from the staging directory, the quality is unknown, you have been
> warned. " 
> 
> after... almost 5 years of development ?


The development usually happens only a few months every year. Combine
this with various time pressures and my laziness to try and push it into
mainline proper (out of staging).

> 
> I have been told at the #kernelnewbies chan that in the kernel 3.4.0-rc2
>  (at least his 3.4.0-rc2 era git tree) still has the zram module source code in
> drivers/staging.
> 
> I have seen that a few issues have been reported at the Compcache website project, so I
> suppose some issues do exist...
> 
> I am only a simple user, and can only say in my computers : PC with either Intel or AMD
> processors, single or dual-core, I didn't find any perverse effect. (Simple user, not
> sophisticated benchmark here).
> 
> I have now been using it with a script meant to load it with the default recommended
> configuration, making a device large as 1/4the of the available ram, one block device
> only, in PCLinuxOS, since 2 years, on 3 different machines minimum, with an visible
> improvement while using it : some virtual machines (in Virtualbox) which would not be
> usable otherwise were usable, and some people have tested installing with a gui installer
> needing some resource, on a machine having 128 MB ram, without the need to create a swap
> file to compensate the lack of RAM memory.
> 
> So I will have a simple question here : what is missing to Compcache for it to be taken
> out of the staging directory in the kernel tree ?
> 


As of now, zram memory allocator, xvmalloc, has been recently replaced
by zsmalloc[1] which is itself a staging module. Some folks are working
on resolving some of the outstanding issues with zsmalloc and when those
are resolved, zram (I think) can be moved out of staging.

[1] http://lwn.net/Articles/477067/

> Many regards, and lots of thanks for this component !!
> 


I'm glad you find it useful.

Thanks,
Nitin