On 2002.01.15 02:07 Phil Deane wrote:
> Hi Folks
Hi Phil,
Not seen you at a meeting in a while. How are things.
> Anyway I was reading an interview, or an excerpt of one with Linus who said
> that with the 2.4.* kernals you REALLY needed twice as much swap space as
> you have RAM
They say the guy linus knows Linux well. Perhaps he's right.
Also of that opinion ia Alan Cox. see
http://kt.zork.net/kernel-traffic/kt20010611_121.html#9
Elsewhere, Alan Cox [*] replied to the original report, pointing out:
Linus 2.4.0 notes are quite clear that you need at least twice RAM of swap with
2.4.
Marcelo is working to change that but right now you are running something
explicitly explained as not going to work as you want
So I guess that _was_ true.
In real life, everyone knew 2.4.x _just_wasn't_right_. About 2.4.4 I switched back to
2.2.19, and it felt like I had upgraded my machine.
Hands were waved. ( http://www.tuxedo.org/~esr/jargon/html/entry/handwave.html ) for a
while, until SuSE kernel hacker Andrea Arcangeli rippled the waters with a mail to the
kernel hackers list stating
After a few days of developement I think I'm ready to release the VM rewrite I did.
And
At the moment it's of course still a bit experimental and subject to changes but
I'm writing this email on top of it and it's perfectly usable.
This isn't an hack/band-aid or a small set of changes, it's a complete rewrite
from scratch of the whole memory balancing including garbage collections lru lists,
kswapd etc...
Rik was sceptical
Rik van Riel [*] said, "I doubt you'll be able to achieve all of those without
really major changes, but I'll take a look at your code when you make it public ;)
Read about it here. http://kt.zork.net/kernel-traffic/kt20011001_135.html#2
A few days later the ripples in the water became tidal waves. Best to read it here
http://kt.zork.net/kernel-traffic/kt20011001_135.html#4
But here's a taster
There was some discussion in reply to this, in the course of which Rik said:
Look, the problem is that Linus is being an asshole and integrating conflicting
ideas into both the VM and the VFS, without giving anybody prior notice and later
blame others.
Just look at how he's now trying to force Al Viro into implementing his ideas
yesterday because he broke stuff again...
If you want a stable kernel, use Alan's kernel.
Alexander replied:
Rik, in case you've missed that, I can and do speak for myself. I had spent ten
years dodging the draft; when I decide to get enlisted into something it will happen
on _my_ decision and _my_ conditions. When I decide that I'm being forced into
something I do not accept - you'll know it from posting with URL of forked tree.
FWIW, I'm less than thrilled by the Andrea's patch, but it is salvagable. I'm also
less than thrilled by the whole situation with VM - all sides of it. I seriously
suspect that we need a limited multi-way fork in that area, so that you guys would
stop stepping on each others' toes. I'm taking no part in your merry 5-way clusterfuck
- sort that mess out between yourselves.
Again, when I decide that situation is unacceptable for me - I'll simply fork the
tree. I do _not_ appreciate being enlisted into anyone's holy wars, so unless you
really want to go _way_ up in my personal shitlist (several positions below .ru DoD) -
don't play politics in my vicinity.
So all was not happy
So what is the latest word on the virtual macine?
Last month the saga had got to about here
Rik replied, "Without documentation, you can only know what the code does, never
what it is supposed to do or why it does it. This makes fixing problems a lot harder,
especially since people will never agree on what a piece of code is supposed to do."
Andrea countered:
I only care about "what the code does" and "what are the results and the
bugreports". Anything else is vaopurware and I don't care about that.
So, if you really want to know what is happening, RTFSource code. :-)
Of course, not everyone is happy
Elsewhere, Henning P. Schmiedehausen [*] was appalled by Andrea's lack of concern
for documentation, particularly that Andrea didn't consider that lack to be a bug. He
said, "I'm not happy about your usage of magic numbers, either. So it is still running
on solid 2.2.19 until further notice (or until Rik loses his patience." Rik replied,
"I've lost patience and have decided to move development away from the main tree.
http://kt.zork.net/kernel-traffic/kt20011224_147.html#1
But I digress. You asked if you REALLY need twice the swap space as RAM.
My answer. I don't know. Sorry. And if I did my answer may not apply next week. ;-)
>From what I understand of the early 2.4.x VM, even core memory was mapped to swap, so
>if you had identical sized swap and ram, the ram would be mapped to the swapfile,
>filling it, and therefore in effect giving you no swap space. Hence the kind of
>ballpark, double your ram, figure. I _think_ this was changed in Andreas VM.
enough rambling. Back to work.
cheers
Lawrence
--
perl -e'$\=O;$\++for-1..53*101<<6;print'
--------------------------------------------------------------------
http://www.lug.org.uk http://www.linuxportal.co.uk
http://www.linuxjob.co.uk http://www.linuxshop.co.uk
--------------------------------------------------------------------
