[Arm-netbook] Genesi lowered the prices!

[Gordan Bobic]

Luke Kenneth Casson Leighton wrote:

>> If you're stuck with low RAM, you may want to look at the compcache
>> (ramzswap/zram) project.
> 
>  ah.  yes.  this apparently has extremely good effect on firefox
> because much of its memory-leaks in its data structures are extremely
> regular.  so they compress _right_ down, real easy :)

It's actually even better than that - you'd be surprised just how many 
0-filled pages there are floating around on an average desktop Linux 
system. compcache marks these as empty and throws them away completely 
when they get swapped out, so you quite literally get all that memory 
back for free.

>  i'm kinda surprised that compcache (and compswap) aren't more widely deployed.

compcache (ramzswap/zram - there is no such thing as "compswap") has 
been a bit dodgy/leaky until recently. It didn't free unswapped memory 
back, so the swap RAM is still used (and can be reused for swapping), 
even when the system is showing nothing is swapped out. As recently as 
2.6.35, zram (the more generic replacement of ramzswap) there's been an 
unfortunate transitional hangover issue of the zram config program 
source being pulled from the SVN, but the /sys/ interface for 
configuring the module wasn't there.

All of this has been addressed in the most recent mainline, though. I've 
been using it ever since I started using SSDs heavily (to avoid swapping 
onto flash), and it works great, not to mention that it is massively 
faster than actual disk swapping (doubly so onto cheap, slow-to-write 
flash).

Gordan