Virtuozzo VPS System Usage Meter Wrong

I have noticed a weird thing lately with two VPS accounts. Virtuozzo's system usage meter on the Resources page creeps up to 100% over the course of 24 hours or so and stays there, but stays green and I don't get any QoS alerts. The servers both seem to be running fine, and I haven't had any crashes. One VPS is running a few Wordpress blogs.

The other is running some Joomla sites.

Both are running Virtuozzo on CentOS 4.7 i686 with WHM 11.24.2 and cPanel 11.24.4-R32486.

In the past, when the system usage meter in Virtuozzo got anywhere near 100%, it turned yellow or red, I had sites go down, and all kinds of QoS alerts for privmpages were thrown. It turned out back then that I had a bad PHP script eating tons of memory with too many MySQL queries. That doesn't appear to be the case here, since I'm not having any apparent problems with either server. It seems like a "non-problem" but it has me concerned because I'm used to using that system usage meter in Virtuozzo to keep an eye on the health of the VPS..

When I look at memory used in WHM (WHM->Server Status->Server Status) it shows only 31% used, which is what I used to see in Virtuozzo.

When I run free, I get:

root@server [~]# free
total used free shared buffers cached
Mem: 524288 133804 390484 0 0 0
-/+ buffers/cache: 133804 390484
Swap: 0 0 0
When I run Free, I get:
root@server [~]# Free
Memory limit...: 8388604 MB (burstable: 8388604 MB)
Current usage..: 120 MB (0%) (requested: 264 MB)
Free memory....: 8388484 MB (100%)

Initially, I suspected it was another problem with MySQL, and restarting MySQL does drop the system usage meter down to ~31% in Virtuozzo for a while--without changing the actual memory used on the System Processes page--but the memory usage for MySQL with Virtuozzo pegged is only 6.23% in WHM.

Here's the really weird thing: If I look at Virtuozzo->System Processes it shows only 0.4% (I think they mean 40%) of total memory used, half of which is mysqld and the rest is spamd.

With no sign of problems, it looks like Virtuozzo is incorrectly reporting memory usage in the system usage meter, but correctly in the system processes list.

The web host's response was:

We use SLM for managing VPSes. This enforces your per VPS limits and doesn't let your VPS use more then it should be. It sounds like you guys may have some memory hogs in your applications.

Have you guys considered cutting down some of the unneeded plugins and stuff?

That doesn't make any sense to me given the disparity between the memory usage meter and the amount of memory usage reported in System Processes and with free/Free as well as the lack of QoS alerts, but maybe SLM prevents any alerts? I don't want to let a memory hog run free on my system if one exists.