From: Alexandre Derumier <aderumier@odiso.com>
To: pve-devel@lists.proxmox.com
Subject: [pve-devel] [PATCH V2 qemu-server 0/2] enable balloon free-page-reporting
Date: Sun, 6 Mar 2022 13:46:45 +0100 [thread overview]
Message-ID: <20220306124647.2267293-1-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.
Here an example of a host with 650GB+200GB ksm going down to 250GB memory
https://mutulin1.odiso.net/ballon-size.png
(around 400vms with 2GB max memory, previously always allocated)
This patch enabled it by default force machine version >= 6.2.
changelogv2:
- enabled it only for machine version > 6.2
- add test
Alexandre Derumier (2):
enable balloon free-page-reporting
add test for virtio-balloon free-page-reporting=on. (qemu 6.2)
PVE/QemuServer.pm | 4 ++-
test/cfg2cmd/q35-simple-7.0.conf.cmd | 2 +-
.../simple-balloon-free-page-reporting.conf | 15 +++++++++
...imple-balloon-free-page-reporting.conf.cmd | 33 +++++++++++++++++++
4 files changed, 52 insertions(+), 2 deletions(-)
create mode 100644 test/cfg2cmd/simple-balloon-free-page-reporting.conf
create mode 100644 test/cfg2cmd/simple-balloon-free-page-reporting.conf.cmd
--
2.30.2
next reply other threads:[~2022-03-06 12:46 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-06 12:46 Alexandre Derumier [this message]
2022-03-06 12:46 ` [pve-devel] [PATCH V2 qemu-server 1/2] " Alexandre Derumier
2022-03-16 17:48 ` Thomas Lamprecht
2022-03-16 19:32 ` DERUMIER, Alexandre
2022-03-17 8:35 ` Thomas Lamprecht
2022-03-28 10:06 ` DERUMIER, Alexandre
2022-03-06 12:46 ` [pve-devel] [PATCH V2 qemu-server 2/2] add test for virtio-balloon free-page-reporting=on. (qemu 6.2) Alexandre Derumier
2022-04-27 9:23 ` [pve-devel] applied: [PATCH V2 qemu-server 0/2] enable balloon free-page-reporting Thomas Lamprecht
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220306124647.2267293-1-aderumier@odiso.com \
--to=aderumier@odiso.com \
--cc=pve-devel@lists.proxmox.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox