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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=unavailable 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 4BF1CC10F06 for ; Sun, 17 Feb 2019 23:50:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 24AE02177B for ; Sun, 17 Feb 2019 23:50:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727655AbfBQXu2 (ORCPT ); Sun, 17 Feb 2019 18:50:28 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:42898 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726304AbfBQXu2 (ORCPT ); Sun, 17 Feb 2019 18:50:28 -0500 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::bf5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 4359E1234135D; Sun, 17 Feb 2019 15:50:27 -0800 (PST) Date: Sun, 17 Feb 2019 15:50:26 -0800 (PST) Message-Id: <20190217.155026.2230689002634375366.davem@davemloft.net> To: alexander.duyck@gmail.com Cc: netdev@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, jannh@google.com Subject: Re: [net PATCH 0/2] Address recent issues found in netdev page_frag_alloc usage From: David Miller In-Reply-To: <20190215223741.16881.84864.stgit@localhost.localdomain> References: <20190215223741.16881.84864.stgit@localhost.localdomain> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Sun, 17 Feb 2019 15:50:27 -0800 (PST) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Alexander Duyck Date: Fri, 15 Feb 2019 14:44:05 -0800 > This patch set addresses a couple of issues that I had pointed out to Jann > Horn in response to a recent patch submission. > > The first issue is that I wanted to avoid the need to read/modify/write the > size value in order to generate the value for pagecnt_bias. Instead we can > just use a fixed constant which reduces the need for memory read operations > and the overall number of instructions to update the pagecnt bias values. > > The other, and more important issue is, that apparently we were letting tun > access the napi_alloc_cache indirectly through netdev_alloc_frag and as a > result letting it create unaligned accesses via unaligned allocations. In > order to prevent this I have added a call to SKB_DATA_ALIGN for the fragsz > field so that we will keep the offset in the napi_alloc_cache > SMP_CACHE_BYTES aligned. Series applied, thanks Alexander.