Hi, Currently, if a guest vm allocate a memory page, and freed it later in the guest, the memory is not freed on the host side.
Balloon device have a new option since qemu 5.1 "free-page-reporting" (and need host kernel 5.7) https://events19.linuxfoundation.org/wp-content/uploads/2017/12/KVMForum2018.pdf https://lwn.net/Articles/759413/ This is working like the discard option for disk, memory is freed async by the host when vm is freeing it. I'm running it production since 1 month without any problem. With a lot of vms and spiky workload, the memory freed is really huge. This patch enabled it by default, This don't break live migration from old qemu process with non-enable free page hinting --> new qemu process with enabled free page hinting, but this break migration in the reverse way. So I can enabled it by default for next qemu machine version or add an extra option to enable it. I don't known if we could extend the "baloon" option ? or add an extra option like "balloonoptions: ..." ? What do you think about it ? Alexandre Derumier (1): enable balloon free-page-reporting PVE/QemuServer.pm | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.30.2 _______________________________________________ pve-devel mailing list pve-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel
