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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41908C433EF for ; Wed, 1 Jun 2022 04:00:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229550AbiFAEAY (ORCPT ); Wed, 1 Jun 2022 00:00:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57762 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229447AbiFAEAV (ORCPT ); Wed, 1 Jun 2022 00:00:21 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3133D9A9BD for ; Tue, 31 May 2022 21:00:14 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id AB749B80F79 for ; Wed, 1 Jun 2022 04:00:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPS id 3C211C34119; Wed, 1 Jun 2022 04:00:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654056012; bh=GbhPSamtydDBES8MbHnz5pLQI3wIs9En+il/RLQUydc=; h=Subject:From:Date:References:In-Reply-To:To:Cc:From; b=irabpDq6XEABiZ1+pZ2ORlmPrY+8WAQ6ku2505eDgK2s5J5H/DA/5689NWxQ8h9gi aQ+o0H0DfPkudjwihTnoNMy01iF7YyKG5tPosJ/C5YLljWOhSY6EORdxVFhjERzbT7 9DBzFWcQOaXsYMa15w1nKkWxCBkDaDZ1kNd0XYS0n7GkWTM4Mnm0J9GSLwIdvCgRx7 2dFv+NvtG2C7Mpa2+lD6Zo7/Rq1h1EgpPlMk3XpU2rtiU0j38mZEioBygms/2pVjZS tgdleMCnr6hVAoq9nLqYwgr1e3BlNkW04hNUS+01OXXPUBfbPJ7Q+XGcDRD7Xu1NUh UqEYGbQ8rbEgw== Received: from aws-us-west-2-korg-oddjob-1.ci.codeaurora.org (localhost.localdomain [127.0.0.1]) by aws-us-west-2-korg-oddjob-1.ci.codeaurora.org (Postfix) with ESMTP id 20E0CEAC081; Wed, 1 Jun 2022 04:00:12 +0000 (UTC) Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: Re: [PATCH v4 net] net: sched: add barrier to fix packet stuck problem for lockless qdisc From: patchwork-bot+netdevbpf@kernel.org Message-Id: <165405601213.26403.11241639383072394003.git-patchwork-notify@kernel.org> Date: Wed, 01 Jun 2022 04:00:12 +0000 References: <20220528101628.120193-1-gjfang@linux.alibaba.com> In-Reply-To: <20220528101628.120193-1-gjfang@linux.alibaba.com> To: Guoju Fang Cc: linyunsheng@huawei.com, davem@davemloft.net, edumazet@google.com, eric.dumazet@gmail.com, guoju.fgj@alibaba-inc.com, kuba@kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, rgauguey@kalrayinc.com, sjones@kalrayinc.com, vladimir.oltean@nxp.com, vray@kalrayinc.com, will@kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hello: This patch was applied to netdev/net.git (master) by Jakub Kicinski : On Sat, 28 May 2022 18:16:28 +0800 you wrote: > In qdisc_run_end(), the spin_unlock() only has store-release semantic, > which guarantees all earlier memory access are visible before it. But > the subsequent test_bit() has no barrier semantics so may be reordered > ahead of the spin_unlock(). The store-load reordering may cause a packet > stuck problem. > > The concurrent operations can be described as below, > CPU 0 | CPU 1 > qdisc_run_end() | qdisc_run_begin() > . | . > > [...] Here is the summary with links: - [v4,net] net: sched: add barrier to fix packet stuck problem for lockless qdisc https://git.kernel.org/netdev/net/c/2e8728c955ce You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html