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) server-digest SHA256) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id 17A4F99576 for ; Tue, 14 Nov 2023 11:20:42 +0100 (CET) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id F05C51DB54 for ; Tue, 14 Nov 2023 11:20:41 +0100 (CET) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [94.136.29.106]) (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 for ; Tue, 14 Nov 2023 11:20:41 +0100 (CET) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 07C244285F for ; Tue, 14 Nov 2023 11:20:41 +0100 (CET) Message-ID: <7b260560-7394-4908-bd85-42f0c6f517d2@proxmox.com> Date: Tue, 14 Nov 2023 11:20:40 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Content-Language: en-US To: Fiona Ebner , Proxmox VE development discussion References: <20231113170916.184994-1-f.weber@proxmox.com> <20231113170916.184994-2-f.weber@proxmox.com> <39993056-a0d8-418b-8abd-71df1b86be99@proxmox.com> From: Friedrich Weber In-Reply-To: <39993056-a0d8-418b-8abd-71df1b86be99@proxmox.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-SPAM-LEVEL: Spam detection results: 0 AWL -0.126 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DMARC_MISSING 0.1 Missing DMARC policy KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record T_SCC_BODY_TEXT_LINE -0.01 - URIBL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to URIBL was blocked. See http://wiki.apache.org/spamassassin/DnsBlocklists#dnsbl-block for more information. [proxmox.com] Subject: Re: [pve-devel] [PATCH docs 1/2] pci passthrough: mention incompatibility with ballooning 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: Tue, 14 Nov 2023 10:20:42 -0000 On 14/11/2023 09:30, Fiona Ebner wrote: > Am 13.11.23 um 18:09 schrieb Friedrich Weber: >> >> +xref:qm_ballooning[Automatic memory allocation (ballooning)] is not possible >> +when using PCI(e) passthrough. As the PCI device may use DMA (Direct Memory >> +Access), QEMU needs to map the complete guest memory on VM startup. Hence, the >> +QEMU process will use at least the (maximum) configured amount of VM memory and >> +setting a minimum amount does not have any effect. When using PCI(e) >> +passthrough, it is recommended to set memory and minimum memory to the same >> +amount and keep the balloning device enabled. However, keep in mind that the > > typo: s/balloning/ballooning/ Oops, thanks. > Is there any advantage to keeping the ballooning device enabled? > >> +memory consumption reported in the GUI for the VM may be much lower than the >> +memory consumption of the QEMU process. > > Maybe mention what the reported value is? In my understanding: If the ballooning device is enabled (and a balloon driver present in the guest), the VM memory usage numbers are taken as reported by the balloon driver [1] (I'd say "as seen from within the guest"?). If the ballooning device is disabled, they are inferred from the rss and vsize of the QEMU process [2], so I'd say "as seen from the host". I guess in the end the user has to decide which perspective they care about? I'll try to make this clearer in the v2. [1] https://git.proxmox.com/?p=qemu-server.git;a=blob;f=PVE/QemuServer.pm;h=c465fb6f64ae30dec5112fc4439f9181c2eba4e9;hb=feb51881d#l3013 [2] https://git.proxmox.com/?p=qemu-server.git;a=blob;f=PVE/QemuServer.pm;h=c465fb6f64ae30dec5112fc4439f9181c2eba4e9;hb=feb51881d#l2967