[Arm-netbook] Genesi lowered the prices!
gordan at bobich.net
Mon Feb 28 16:12:59 GMT 2011
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
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