From: Alexandre Derumier <aderumier@odiso.com>
To: pve-devel@lists.proxmox.com
Subject: [pve-devel] [PATCH qemu-server 0/1] enable balloon free-page-reporting
Date: Wed, 2 Mar 2022 07:46:24 +0100 [thread overview]
Message-ID: <20220302064625.4095116-1-aderumier@odiso.com> (raw)
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
next reply other threads:[~2022-03-02 6:46 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-02 6:46 Alexandre Derumier [this message]
2022-03-02 6:46 ` [pve-devel] [PATCH qemu-server 1/1] " Alexandre Derumier
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