From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 46B501F428F; Tue, 1 Jul 2025 16:45:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751388337; cv=none; b=k/jN6hw/BSQHNKX6SzfQ64/HlwpRYQVQNGCi2s1Vq3dDxOITewe3LF8kekG24nQhe9IZJGXbKRCzdyM0E1O+vYS1cjugrRlArM3jQ0scJfsvxt7SagQY+uTNNwur67XDvOYFkY5DVqkgsPHwZR78WsnIWxb9GJVpyboHo9fN6Sg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751388337; c=relaxed/simple; bh=rxWh8Ki7CjYyO7eLldQromF2K92SNjwMD3JOw4J+aS8=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=raL2s83e0URX9cx5aoVzIahOrHjMuKbIvqKpqEHrvGZRIgy/f7EItclu4MMmeMEj1adMUWQ6K7VkBeMxFyGpveEGt+QKHUnNzCYimP+rlG/HKzqEAPb5NOQ5HrDXSjTb8pdhzL6HdHnYBUF84dlbPBenqfqfistUCaYnNat1Tzk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eR9QmGzH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eR9QmGzH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E886CC4CEEB; Tue, 1 Jul 2025 16:45:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751388337; bh=rxWh8Ki7CjYyO7eLldQromF2K92SNjwMD3JOw4J+aS8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eR9QmGzHQTPJOUXHscZaXBiFkTMBbyTzR7G/sBld7Ic9V60jXRqf0m5M5vMZ7wnKU cGnWMNe+NAuvcs/Xk4dPNlNxSMBH3BBY6cXSO+ztptHOI/AsT9DSr4gJoHjC3wMhir 2uaEB2a2bLz6mV6zgTIDZ3pw2vIIv6qKD5oQynQ3S10ZaACE8f92q/ulo0Sd06tT9k SXMkoKdYpgENjdYG+qf2++gTzhJDr5lvHbFli5S/CY4yOZvuRF5Ri2kb8EhxdW2aYu Zc+a9cnrZl0qcGQ5/FXC4PTEFttpitUVXiV/QT5tVh/P2frGhVHvT65AWOfKc3sFG2 qOifKOFuNz3ng== From: Will Deacon To: linux-kernel@vger.kernel.org Cc: Will Deacon , Keir Fraser , Steven Moreland , Frederick Mayle , Stefan Hajnoczi , Stefano Garzarella , "Michael S. Tsirkin" , Jason Wang , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , netdev@vger.kernel.org, virtualization@lists.linux.dev Subject: [PATCH v2 8/8] vsock/virtio: Allocate nonlinear SKBs for handling large transmit buffers Date: Tue, 1 Jul 2025 17:45:07 +0100 Message-Id: <20250701164507.14883-9-will@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250701164507.14883-1-will@kernel.org> References: <20250701164507.14883-1-will@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When transmitting a vsock packet, virtio_transport_send_pkt_info() calls virtio_transport_alloc_linear_skb() to allocate and fill SKBs with the transmit data. Unfortunately, these are always linear allocations and can therefore result in significant pressure on kmalloc() considering that the maximum packet size (VIRTIO_VSOCK_MAX_PKT_BUF_SIZE + VIRTIO_VSOCK_SKB_HEADROOM) is a little over 64KiB, resulting in a 128KiB allocation for each packet. Rework the vsock SKB allocation so that, for sizes with page order greater than PAGE_ALLOC_COSTLY_ORDER, a nonlinear SKB is allocated instead with the packet header in the SKB and the transmit data in the fragments. No that this affects both the vhost and virtio transports. Signed-off-by: Will Deacon --- net/vmw_vsock/virtio_transport_common.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index c9eb7f7ac00d..f74677c3511e 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -109,7 +109,8 @@ static int virtio_transport_fill_skb(struct sk_buff *skb, return __zerocopy_sg_from_iter(info->msg, NULL, skb, &info->msg->msg_iter, len, NULL); - return memcpy_from_msg(skb_put(skb, len), info->msg, len); + virtio_vsock_skb_put(skb); + return skb_copy_datagram_from_iter(skb, 0, &info->msg->msg_iter, len); } static void virtio_transport_init_hdr(struct sk_buff *skb, @@ -261,7 +262,7 @@ static struct sk_buff *virtio_transport_alloc_skb(struct virtio_vsock_pkt_info * if (!zcopy) skb_len += payload_len; - skb = virtio_vsock_alloc_linear_skb(skb_len, GFP_KERNEL); + skb = virtio_vsock_alloc_skb(skb_len, GFP_KERNEL); if (!skb) return NULL; -- 2.50.0.727.gbf7dc18ff4-goog