From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4940DC4338F for ; Fri, 30 Jul 2021 10:45:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 24D0860462 for ; Fri, 30 Jul 2021 10:45:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238403AbhG3KqB (ORCPT ); Fri, 30 Jul 2021 06:46:01 -0400 Received: from wout4-smtp.messagingengine.com ([64.147.123.20]:49051 "EHLO wout4-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238395AbhG3KqB (ORCPT ); Fri, 30 Jul 2021 06:46:01 -0400 Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailout.west.internal (Postfix) with ESMTP id 031443200941; Fri, 30 Jul 2021 06:45:55 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute4.internal (MEProxy); Fri, 30 Jul 2021 06:45:56 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kroah.com; h= date:from:to:cc:subject:message-id:references:mime-version :content-type:in-reply-to; s=fm1; bh=3Ryv1JmOe1JkjEOUvtOGERn7k97 vo8ZTRSlnzLdjKbA=; b=Yi/XeteNq/glhHLodGtfAGRyAilW/mRkYpJNcQVBv75 DzywqWGL1vGHrB1QFKIWli1EPSvE8TuwbKfCExvXH66H+POFzDBYFVsn8OZjizsD cNlZc6SnXPJ7C5RzSQ+yf8lVFMkTrPD9KEz/WOcgROfZmgBC2OM840GX4aVYBanv gZYZYGsepaZ6mBcqCPooXjAByIOcnJm3GCyz8kXuPbKIR3olZFTQSfcPXE5EBXI/ qJqCvaz2qSwq3Gs9q1T8xml2UXePRTSWQMbMj37P5AnOlzr+tNtjw+h6GHugIV/7 wlIA3GWUtHK6/D7hJxa7lT5kl7PM6tqTO3nREcYftxg== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; bh=3Ryv1J mOe1JkjEOUvtOGERn7k97vo8ZTRSlnzLdjKbA=; b=s27cdZcLQI7TTpg77cbUUI H35LueB4/X1UXqFAK+4IGQESIr47f/T6aKLHB0e4NEfw3qu6VXF58bZew+pigw4U 3pxbCRezLfw8Gq5v4FaVZwHETr+1LTQ9qCVTNNX7/dOrPKcAeO0iuDFEibIUB0Rj PGo4nJLZupsXUa8ESqGq9Z48Aww6vZ+xQlz9bFgAaE+Nio+ZjWOawmWxcGnZWRnx 7PU5LLNr98TMfnQ4wnK8hZdR605TV9G//AGRc+yIQAqmQ5VB8yAOlcppE+ouGV3M R8Th3iQEBt4PsW987ZCaLjcRE+MIKeSFuwXhMljNrRPL5rMELoo6Doo30QFMqvag == X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvtddrheehgddvkecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenuc fjughrpeffhffvuffkfhggtggujgesthdtredttddtvdenucfhrhhomhepifhrvghgucfm jfcuoehgrhgvgheskhhrohgrhhdrtghomheqnecuggftrfgrthhtvghrnhepveeuheejgf ffgfeivddukedvkedtleelleeghfeljeeiueeggeevueduudekvdetnecuvehluhhsthgv rhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomhepghhrvghgsehkrhhorghhrd gtohhm X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA; Fri, 30 Jul 2021 06:45:54 -0400 (EDT) Date: Fri, 30 Jul 2021 12:45:52 +0200 From: Greg KH To: Matthieu Baerts Cc: stable@vger.kernel.org, Eric Dumazet Subject: Re: [PATCH 4.19 0/2] Backport fixes for 3226b158e67c Message-ID: References: <20210729184427.3202526-1-matthieu.baerts@tessares.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210729184427.3202526-1-matthieu.baerts@tessares.net> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Thu, Jul 29, 2021 at 08:44:25PM +0200, Matthieu Baerts wrote: > Commit 3226b158e67c ("net: avoid 32 x truesize under-estimation for tiny skbs") > introduces a ~10% performance drop when using virtio-net drivers. > > This commit has been backported to v4.19 in commit 669c0b5782fb and this > performance drop is also visible there. > Here at Tessares, we can also notice this drop with the MPTCP fork [1] > on top of the v4.19 kernel. > > Eric Dumazet already fixed this issue a few months ago, see > commit 0f6925b3e8da ("virtio_net: Do not pull payload in skb->head"). > > Unfortunately, this patch has not been backported to < v5.4 because it > caused issues [2]. Indeed, after having backported it, the kernel failed > to compile because one commit was missing, see > commit 503d539a6e41 ("virtio_net: Add XDP meta data support"). However, > this missing commit has been added in 4.19.186 but probably because > there were still some opened discussions [3] around > commit 0f6925b3e8da ("virtio_net: Do not pull payload in skb->head"), > the latter has not been backported at all in v4.19. > > A cherry-pick of this patch without any modification is proposed here. > It has been validated: it fixes the original issue on v4.19 as well. > > Please note that there is also a fix for the fix, see > commit 38ec4944b593 ("gro: ensure frag0 meets IP header alignment"). > > This second fix has also not been backported because it caused issues as > well [4]. Here, it was due to a conflict but also a compilation error > when the conflict has been resolved. Please refer to patch 2/2 for more > details. > > One last note: these two patches have also been backported and validated > on a v4.14 release. A second series is going to be sent. > It looks like it could be interesting to backport these two patches to > v4.9 and v4.4 as well but unfortunately, the backport of these two > patches fails with conflicts and I don't have any setup to validate the > performance drop and fix with v4.9 and v4.4 kernels. Both sets of series now queued up, thanks! greg k-h