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 36A122690CB; Mon, 14 Jul 2025 15:21:36 +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=1752506497; cv=none; b=QdxxpdfsJKA3H6chc9vkuG7mkhJGGfNnrNdXjhGMU06zCok7yum05sjdSFHIp3gMagkWlh1XTCuBopC5+FJ883CGSmhX2fOtzW6LtNoSh34RyBCDwiC4dTMs38p7oV1OV6xSdfPpRR4QuWHU33zICpWQgYkhJ0JbPlIqyQnNmRE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752506497; c=relaxed/simple; bh=VC+ApeBCzBvySjxO+5RtrC8kfJb3G3Dm+10WW4fjuOE=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=gAl1No+sjWhW4c9bdzbz+Aq74jy96hAyXpzvnGrXW1RNVKJEl1xllWzgIJ/eXaaPO1iRMbvBZae5patZfwgrpQUMIssNYTrelkrCBYuIW3o/npdUjx4FDCWYFnlc7xnFuCCCXajns/jX9iZ2ewsMim5fdaVVW+Ldy7jL+5eJaq8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=c/Dg0YK7; 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="c/Dg0YK7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8BD69C4CEED; Mon, 14 Jul 2025 15:21:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1752506496; bh=VC+ApeBCzBvySjxO+5RtrC8kfJb3G3Dm+10WW4fjuOE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=c/Dg0YK7VVpqlxi6jGzlQbBi0jkqGeBzsmhRp1bJpie+mZwa3XqOK5DalJAe79gbz +j1CVnIbRPSBmiH3eXf3tLNU73P/liN+4BOw57lL5vBvzp5hW7l2NqTvsa3uxu8Dom BO0Zg1qETSn9Ey2PnIdGjliDesuWY5TMILr5d1iN7MuVN3Xl+Yuv01EOhH4xq0Py0P dyBycMNqcVPGBBk+G/1WyD+J+ZBYBBiwBUnlK6B6nUttCkOH8Kj8Pgp+i9odAEnbCu lEyhXHs4GiXhvdju1bP3NqLieqZjm/oeHjh1+nVQKOm8a/Z2c7u9TT40erRrbSt//y OyQYwtGONWCag== 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 v3 9/9] vsock/virtio: Allocate nonlinear SKBs for handling large transmit buffers Date: Mon, 14 Jul 2025 16:21:03 +0100 Message-Id: <20250714152103.6949-10-will@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250714152103.6949-1-will@kernel.org> References: <20250714152103.6949-1-will@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@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. Reviewed-by: Stefano Garzarella 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..fe92e5fa95b4 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, len); + 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