@inproceedings{Wrenger:2025,
abstract = {The provisioning of the right amount of {DRAM} to virtual machines ({VMs}) is still a major challenge and cost driver in virtualization settings. Many {VMs} run applications with highly volatile memory demands, which either leads to massive overprovisioning in low-demand phases or poor {QoS} in high-demand phases. Memory hotplugging and ballooning have become established techniques (in Linux/{KVM} available via virtio-mem and virtio-balloon) to dynamically de/inflate the physical memory of a {VM} cooperatively, by having the guests give back unused memory to the hypervisor. However, current {VM} deflation techniques are either not {DMA}-safe, preventing the passthrough of important devices like {GPUs} or {NICs}, or are not flexible or fast enough to cope with the frequently changing demands of the guest.We present {HyperAlloc}, a {DMA}-safe and extremely efficient mechanism for virtual machine de/inflation. The core idea is to provide the hypervisor direct access to the guest's page-frame allocator, greatly reducing the communication overhead. {HyperAlloc} can shrink virtual machines 362 times faster than virtio-balloon and 10 times faster than virtio-mem while having no measurable impact on the guest's performance. {HyperAlloc}'s automatic reclamation provides for better memory elasticity by reducing the average memory footprint of a clang compilation by 17 percent compared to virtio-balloon's free-page reporting while, again, having no measurable impact on the guest's performance.},
author = {Wrenger, Lars and Albes, Kenny and Wurps, Marco and Dietrich, Christian and Lohmann, Daniel},
booktitle = {Proceedings of the Twentieth European Conference on Computer Systems},
date = {2025-03-30},
doi = {10.1145/3689031.3717484},
isbn = {9798400711961},
location = {New York, {NY}, {USA}},
pages = {702–719},
publisher = {Association for Computing Machinery},
series = {{EuroSys} '25},
shorttitle = {{HyperAlloc}},
title = {{HyperAlloc}: Efficient {VM} Memory De/Inflation via Hypervisor-Shared Page-Frame Allocators},
url = {https://dl.acm.org/doi/10.1145/3689031.3717484},
}
