Re: [pve-devel] auto ballooning && ksm thresholds both at 80%

Re: [pve-devel] auto ballooning && ksm thresholds both at 80%

[Dietmar Maurer]

> Currently both are at 80%,
> that mean that ballooning is vm reducing memory fast, and ksm don't
> have time to run.
> 
> as ballooning is a lot more intrusive than ksm, I wonder if it couldn't
> be set to something like 90%.

That sounds reasonable to me, but can you see that theoretical effect when you run your test?

Re: [pve-devel] auto ballooning && ksm thresholds both at 80%

[DERUMIER, Alexandre]

Le vendredi 31 décembre 2021 à 15:31 +0100, Dietmar Maurer a écrit :
Currently both are at 80%,
that mean that ballooning is vm reducing memory fast, and ksm don't
have time to run.

as ballooning is a lot more intrusive than ksm, I wonder if it couldn't
be set to something like 90%.

That sounds reasonable to me, but can you see that theoretical effect when you run your test?


Hi Dietmar,
Happy new year ! (I'm currently in holiday this week, so, I check that next week)


I'll do more tests to be sure. (I don't use ballooning in production, but I'm a big user of ksm, I have some big nodes with something like 200GB ksm on 700GB servers).


My Idea behind this is to implement auto-balancing, vm migration, when memory threshold is between ksm && autoballoonig).

1) 80%: ksm
2) ~= 85-89% : auto balancing/migration
3) ~= 90% : auto ballonning
4) ~= 100% : swap

[pve-devel] auto ballooning && ksm thresholds both at 80%

[DERUMIER, Alexandre]

Hi,

I'm still working on ha manager ressource aware && loadbalancing (I
have some big improvements to send soon before review)

I currently looking at memory balancing doing a lot of tests,

and I wonder if auto-ballooning threshold shouldn't be a little bit
bigger than ksm.

Currently both are at 80%,
that mean that ballooning is vm reducing memory fast, and ksm don't
have time to run.

as ballooning is a lot more intrusive than ksm, I wonder if it couldn't
be set to something like 90%.

Like this, ksm can try to keep memory at 80%, and if memory is growing
too fast up to 90% or if ksm can't really deduplicate pages anymore, we
have ballooning in action.

What do you think about it ?