How to really disable huge pages?

andy713 · 04-24-2019, 02:38 PM

Running vmware, kcompactd0 uses 100% of one CPU and the VM is basically hung until it finishes. I set transparent_hugepage=never in the kernel command line but after I rebooted I still see it running. AnonHugePages is 0kB in /proc/meminfo. It doesn't appear to offer a "really never" option, but how can I make that happen? The VM is configured for 4 GB of RAM on a 16 GB system so it shouldn't have to compact pages. This is using Slackware kernel 4.19.32.

volkerdi · 04-24-2019, 03:19 PM

I'm not sure the issue actually has to do with transparent huge pages. We already set the default to "madvise", so THP would not be used unless vmware requested it, and if it were actually a source of trouble then I don't think they'd be doing that. I am seeing a few other similar reports, and it's possible that a newer kernel could contain a fix.

Also, you might try booting with slub_max_order=0 to see if that helps at all.

andy713 · 04-25-2019, 09:05 AM

Setting slub_max_order=0 seems to have knocked it down some more, but I still saw it briefly pop up on top a few times. At least it's livable right now for what I'm doing, which I suppose means I'm not trying hard enough.