GitHub user akrasnov-drv closed a discussion: Support for hugepages in KVM VMs
### The required feature described as a wish
We use hugepages and some other tweaks to optimize performance of KVM VMs.
I managed to use our KVM VM config in CloudStack by updating VM xml via hook.
The problem is that CloudStack checks free memory of Linux and ignores free
hugepages.
As I understand, in the earlier version of CloudStack it used shell to get free
memory info, but now it uses Java calls that I can't change without patching
and rebuilding agent code.
The following changes should do what I miss:
I'd like to have config option (in Cloudstack config, or in agent.properties)
to enable hugepages (defaults to off). IMHO, it's quite easy to do. The option
will
- add the following block to each KVM VM created
```
<memoryBacking>
<hugepages/>
</memoryBacking>
```
- change check of free memory from `MemFree` to `HugePages_Free × Hugepagesize`
Something like the following
```
long hpFree = map.getOrDefault(HUGEPAGE_FREE_KEY, 0L);
long hpSize = map.getOrDefault(HUGEPAGE_SIZE_KEY, 1024L); // KiB
return (hpFree * hpSize) + memFree;
```
Another option, though less preferable, is to allow using external script (e.g.
`host.stats.command.script`) to override internally acquired values (e.g.
`MemFree`)
GitHub link: https://github.com/apache/cloudstack/discussions/11187
----
This is an automatically sent email for [email protected].
To unsubscribe, please send an email to: [email protected]
