hugepage mapping to memseg failure

[Dmitry Kozlyuk]

2024-09-10 20:42 (UTC+0000), Lombardo, Ed:
> Hi Dmitry,
> If I use grub for hugepages will the hugepages always be contiguous and we won’t see the mapping to memsegs issue?

There are no guarantees about physical addresses.
On bare metal, getting continuous addresses at system startup is more likely.
On VM, I think, it is always less likely because host memory is fragmented.

> I am investigating your option 2 you provided to see how much VIRT memory increases.

There might be a third option.
If your HW and hypervisor permit accessing IOMMU from guests
and if the NIC can be bound to vfio-pci driver,
then you could use IOVA-as-VA (--iova-mode=va)
and have no issues with physical addresses ever.

Out of curiosity, why legacy memory mode is preferable for your app?