From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id D91B3641ED for ; Wed, 2 Mar 2022 07:46:33 +0100 (CET) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id D777D267DB for ; Wed, 2 Mar 2022 07:46:33 +0100 (CET) Received: from bastionodiso.odiso.net (bastionodiso.odiso.net [IPv6:2a0a:1580:2000::2d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS id E005D267C7 for ; Wed, 2 Mar 2022 07:46:32 +0100 (CET) Received: from kvmformation3.odiso.net (formationkvm3.odiso.net [10.3.94.12]) by bastionodiso.odiso.net (Postfix) with ESMTP id 45F4140496; Wed, 2 Mar 2022 07:46:26 +0100 (CET) Received: by kvmformation3.odiso.net (Postfix, from userid 0) id 2C49C151D7F; Wed, 2 Mar 2022 07:46:26 +0100 (CET) From: Alexandre Derumier To: pve-devel@lists.proxmox.com Date: Wed, 2 Mar 2022 07:46:24 +0100 Message-Id: <20220302064625.4095116-1-aderumier@odiso.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL -0.001 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% HEADER_FROM_DIFFERENT_DOMAINS 0.25 From and EnvelopeFrom 2nd level mail domains are different KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment KAM_LAZY_DOMAIN_SECURITY 1 Sending domain does not have any anti-forgery methods KAM_SHORT 0.001 Use of a URL Shortener for very short URL NO_DNS_FOR_FROM 0.001 Envelope sender has no MX or A DNS records SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_NONE 0.001 SPF: sender does not publish an SPF Record T_SCC_BODY_TEXT_LINE -0.01 - Subject: [pve-devel] [PATCH qemu-server 0/1] enable balloon free-page-reporting X-BeenThere: pve-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox VE development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 02 Mar 2022 06:46:33 -0000 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