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 81D3877052 for ; Mon, 26 Apr 2021 20:04:26 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 7179018FC3 for ; Mon, 26 Apr 2021 20:04:26 +0200 (CEST) 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)) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS id C478B18FB2 for ; Mon, 26 Apr 2021 20:04:24 +0200 (CEST) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 761A644571 for ; Mon, 26 Apr 2021 20:04:24 +0200 (CEST) Date: Mon, 26 Apr 2021 20:04:21 +0200 (CEST) From: Dietmar Maurer To: Proxmox Backup Server development discussion , Stefan Reiter Message-ID: <199969737.469.1619460262044@webmail.proxmox.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Priority: 3 Importance: Normal X-Mailer: Open-Xchange Mailer v7.10.5-Rev9 X-Originating-Client: open-xchange-appsuite X-SPAM-LEVEL: Spam detection results: 0 AWL 0.528 Adjusted score from AWL reputation of From: address 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 Subject: Re: [pbs-devel] [PATCH proxmox-backup-restore-image 4/4] add workaround kernel patch for vsock panics X-BeenThere: pbs-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox Backup Server development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 26 Apr 2021 18:04:26 -0000 Such small buffer sizes can reduce performance. I usually go for a minimum of 256K. So do we really need this? What is a 128 MiB RAM machine??? > On 04/26/2021 3:04 PM Stefan Reiter wrote: > > > Allocation failures for vsock packet buffers occur routinely when > downloading more than one stream at the same time, with less then 512 > MiB of RAM it sometimes even occurs for single downloads. > > This appears to fix it in all of my reproducer scenarios, tested with up > to 6 downloads at once in a 128 MiB RAM machine. > > Signed-off-by: Stefan Reiter > --- > .../0003-vsock-reduce-packet-size.patch | 36 +++++++++++++++++++ > 1 file changed, 36 insertions(+) > create mode 100644 src/patches/kernel/0003-vsock-reduce-packet-size.patch > > diff --git a/src/patches/kernel/0003-vsock-reduce-packet-size.patch b/src/patches/kernel/0003-vsock-reduce-packet-size.patch > new file mode 100644 > index 0000000..378da53 > --- /dev/null > +++ b/src/patches/kernel/0003-vsock-reduce-packet-size.patch > @@ -0,0 +1,36 @@ > +From a437d428733881f408b5d42eb75812600083cb75 Mon Sep 17 00:00:00 2001 > +From: Stefan Reiter > +Date: Mon, 26 Apr 2021 14:08:36 +0200 > +Subject: [PATCH] vsock: reduce packet size > + > +Reduce the maximum packet size to avoid allocation errors in VMs with > +very little memory available (since the buffer needs a contiguous > +block of memory, which can get rare for 64kB blocks). > + > +4kB used to be the default, and according to [0] increasing it makes > +the difference between ~25Gb/s and ~40Gb/s - certainly a lot faster, > +but both within the realm of unreachable for our restore scenario. > + > +[0] https://stefano-garzarella.github.io/posts/2019-11-08-kvmforum-2019-vsock/ > + > +Signed-off-by: Stefan Reiter > +--- > + include/linux/virtio_vsock.h | 2 +- > + 1 file changed, 1 insertion(+), 1 deletion(-) > + > +diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h > +index dc636b727179..18c09ff72929 100644 > +--- a/include/linux/virtio_vsock.h > ++++ b/include/linux/virtio_vsock.h > +@@ -9,7 +9,7 @@ > + > + #define VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE (1024 * 4) > + #define VIRTIO_VSOCK_MAX_BUF_SIZE 0xFFFFFFFFUL > +-#define VIRTIO_VSOCK_MAX_PKT_BUF_SIZE (1024 * 64) > ++#define VIRTIO_VSOCK_MAX_PKT_BUF_SIZE (1024 * 4) > + > + enum { > + VSOCK_VQ_RX = 0, /* for host to guest data */ > +-- > +2.20.1 > + > -- > 2.20.1 > > > > _______________________________________________ > pbs-devel mailing list > pbs-devel@lists.proxmox.com > https://lists.proxmox.com/cgi-bin/mailman/listinfo/pbs-devel