On 9/25/26 07:44, Lance Yang wrote: > Hi all, > > I was reading DeepSeek's new DSec paper[1] and found a nice use of DAMON > and virtio-balloon: > > With this kind of workload, an agent may read a file once and never touch > it again, while those pages remain in the guest page cache. Without memory > pressure in the guest, they can stay cached even though the host would > like that memory back ... > > The trick is DAMON + virtio-balloon free-page reporting :) DAMON reclaims
Heh, I read "virtio-balloon" and thought "balloon inflation/deflation, what year is it?!". Free-page reporting makes much more sense. > cold file pages from the guest page cache; buddy gets a chance to coalesce > them into reportable blocks, and virtio-balloon passes those blocks to > Firecracker. Firecracker can then drop the host backing with MADV_DONTNEED. When I was at RH we were looking at this issue as well. virtio-pmem was one way of avoiding the page cache in VM entirely. But it has its own limitations. Thanks for sharing! -- Cheers, David
