From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932219Ab3AOWbV (ORCPT ); Tue, 15 Jan 2013 17:31:21 -0500 Received: from mail.kernel.org ([198.145.19.201]:42219 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757589Ab3AOWbN (ORCPT ); Tue, 15 Jan 2013 17:31:13 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Ian Campbell , Sander Eikelenboom , Konrad Rzeszutek Wilk , annie li , Eric Dumazet , "David S. Miller" , xen-devel@lists.xen.org, netdev@vger.kernel.org Subject: [ 103/221] xen/netfront: improve truesize tracking Date: Tue, 15 Jan 2013 10:50:30 -0800 Message-Id: <20130115185005.470007939@linuxfoundation.org> X-Mailer: git-send-email 1.8.1.336.g94702dd In-Reply-To: <20130115184958.025580322@linuxfoundation.org> References: <20130115184958.025580322@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.7-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ian Campbell commit d9a58a782e396a0f04e8445b7ba3763c8a48c7fe upstream. Using RX_COPY_THRESHOLD is incorrect if the SKB is actually smaller than that. We have already accounted for this in NETFRONT_SKB_CB(skb)->pull_to so use that instead. Fixes WARN_ON from skb_try_coalesce. Signed-off-by: Ian Campbell Cc: Sander Eikelenboom Cc: Konrad Rzeszutek Wilk Cc: annie li Cc: xen-devel@lists.xen.org Cc: netdev@vger.kernel.org Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/xen-netfront.c | 27 ++++----------------------- 1 file changed, 4 insertions(+), 23 deletions(-) --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -1015,29 +1015,10 @@ err: i = xennet_fill_frags(np, skb, &tmpq); /* - * Truesize approximates the size of true data plus - * any supervisor overheads. Adding hypervisor - * overheads has been shown to significantly reduce - * achievable bandwidth with the default receive - * buffer size. It is therefore not wise to account - * for it here. - * - * After alloc_skb(RX_COPY_THRESHOLD), truesize is set - * to RX_COPY_THRESHOLD + the supervisor - * overheads. Here, we add the size of the data pulled - * in xennet_fill_frags(). - * - * We also adjust for any unused space in the main - * data area by subtracting (RX_COPY_THRESHOLD - - * len). This is especially important with drivers - * which split incoming packets into header and data, - * using only 66 bytes of the main data area (see the - * e1000 driver for example.) On such systems, - * without this last adjustement, our achievable - * receive throughout using the standard receive - * buffer size was cut by 25%(!!!). - */ - skb->truesize += skb->data_len - RX_COPY_THRESHOLD; + * Truesize is the actual allocation size, even if the + * allocation is only partially used. + */ + skb->truesize += PAGE_SIZE * skb_shinfo(skb)->nr_frags; skb->len += skb->data_len; if (rx->flags & XEN_NETRXF_csum_blank)