Messages in this thread |  | | From | Maxim Levitsky <> | | Date | Sat, 4 Nov 2017 01:33:31 +0200 | | Subject | Re: Collapse all Print all In new window Guaranteed allocation of huge pages (1G) using movablecore=N doesn't seem to work at all. |
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Sorry for garbaged title - I copy & pased from older mail which I by mistake sent in HTML (had to use gmail web interface here)
Beset regards, Maxim Levitsky
On Sat, Nov 4, 2017 at 1:31 AM, Maxim Levitsky <maximlevitsky@gmail.com> wrote: > Hi! > > My system has 64G of ram and I want to create 32 1G huge pages to use > in KVM virtualization, > on demand, only when VM is running. > > So I booted the kernel with > 'hugepagesz=1G hugepages=0 default_hugepagesz=1G movablecore=40G' > > However I still can't allocate the pages reliably. > For instance this simple script is enough to make it not possible to > even allocate one 1G huge page after few dozens of iterations: > > while true ; do > sudo hugeadm --enable-zone-movable --pool-pages-min 1G:0G > sudo hugeadm --enable-zone-movable --pool-pages-min 1G:60G > done > > > I disabled mlock systemwide (now ulimit -l shows 0), I still see 8 > pages mlocked in zone 'Movable' but this is not enough to explain > this > nr_mlock 8 > > I do have around 64GB of swap too, but I see no even an attempt to use it. > > > # free > total used free shared buff/cache available > Mem: 65887928 1748344 62640276 61688 1499308 62053832 > Swap: 67108860 0 67108860 > > Any idea about what is going on? > > This was tested on 4.14.0-rc5 (my custom compiled) and on several > older kernels from ubuntu repositories. > > Disabling/enabling transparent huge pages in the kernel config didn't > make a difference. > > VT-d was enabled during the tests (intel_iommu=on,igfx_off) is that > would make any difference, but no VM was started when I run the above > script, in fact I run it just after the system booted. > > Best regards, > Maxim Levitsky
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