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=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 0F153C433ED for ; Fri, 9 Apr 2021 10:16:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D97EE6103E for ; Fri, 9 Apr 2021 10:16:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234288AbhDIKQZ (ORCPT ); Fri, 9 Apr 2021 06:16:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55896 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232395AbhDIKJU (ORCPT ); Fri, 9 Apr 2021 06:09:20 -0400 Received: from mail-pj1-x102e.google.com (mail-pj1-x102e.google.com [IPv6:2607:f8b0:4864:20::102e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 25804C0613E9; Fri, 9 Apr 2021 03:08:29 -0700 (PDT) Received: by mail-pj1-x102e.google.com with SMTP id il9-20020a17090b1649b0290114bcb0d6c2so4760353pjb.0; Fri, 09 Apr 2021 03:08:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=n7cLDIdYcgU+mE5TUxJG9IpNvG+bT4Z9CaGQY0UABEM=; b=eO1g9mHi9rw1lcqt+vPW/flltV4uWv6nPOUvg6TJmcq62yHCCkFDBynbBSmIKt5xGw InHhSvkBgKbuJwxbpTuUBD1Ww8lI8Bvf/f6ACS9N9adDcmL0PEcll3eII8hZPIT4u2lM SWcLBK+zHMg6Mm3NVjplADrMbDa9/lrQ2J4wdCkOnLkJMPnHhyVSieRV0I+fJWoRS1RP Y5vVMC/7qOoINS0zffsOZVYo1QQAHciIJ2ny+AFQfIfrSePxjAHEA/VVX44MFXI5q/1K gMzZFUDPpjn1J0pLfCK/7lgzSGgKG9hZRGddg2oBOEQNo67k0Nx9tYCs6g7S58KeFUS4 opiw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=n7cLDIdYcgU+mE5TUxJG9IpNvG+bT4Z9CaGQY0UABEM=; b=t2mRTRMWlO8k2mDWFms2/YM80IhUPLZacYBWRPCXLsGjPBZ6Vg23Q/SwjDTlci1AFi PkNaDXGOnfkKotsEeqikGMAmNS1JLHV7GXs/g6eiGbTVTFd2IJvkDRK8HjADAJTHKzMU 7tqihTY3duIphtD4P4DCJt0+GdeV0rEIOlqWqrpz6s7KF7nflVchCBQJQo6CTDUl/PKA TgB8gIasVOck3Wac/uBUSqGFfJPevF2Zq01e3hxPS7XCqKpOp496rAjKocZuNlDxdAT7 QsnAfD2O4BmxqRCsBlHlAoMoHdecW2Nx3SH97949RdK+PwZW52fL8l/4flPX+g2bCz3B beyQ== X-Gm-Message-State: AOAM531RsBTktQcKOQLG30Lw7vbyr9WqL7uCx3M/b95oSEo90iaZBULq AAMAnJPBFuNxfxjehnusi0GVvyNxA3h3aAwOWCM= X-Google-Smtp-Source: ABdhPJwPyj4MH1bwqianuKmRYQPS7KJxJKjIvxVO1ksn9/Xhg021RDm2ZdHh3WSHu1AQEegl28yAOLheWOITv4WmkSw= X-Received: by 2002:a17:90a:28a1:: with SMTP id f30mr13337448pjd.198.1617962908715; Fri, 09 Apr 2021 03:08:28 -0700 (PDT) MIME-Version: 1.0 References: <20210409073046.GI3697@techsingularity.net> <20210409084436.GK3697@techsingularity.net> <20210409095808.GL3697@techsingularity.net> In-Reply-To: <20210409095808.GL3697@techsingularity.net> From: Xie He Date: Fri, 9 Apr 2021 03:08:17 -0700 Message-ID: Subject: Re: Problem in pfmemalloc skb handling in net/core/dev.c To: Mel Gorman Cc: Mel Gorman , jslaby@suse.cz, Neil Brown , Peter Zijlstra , Mike Christie , Eric B Munson , Eric Dumazet , Sebastian Andrzej Siewior , Christoph Lameter , Andrew Morton , "David S. Miller" , Jakub Kicinski , Linux Kernel Network Developers , LKML Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 9, 2021 at 2:58 AM Mel Gorman wrote: > > On Fri, Apr 09, 2021 at 02:14:12AM -0700, Xie He wrote: > > > > Do you mean that at the time "sk_memalloc_socks()" changes from "true" > > to "false", there would be no in-flight skbs currently being received, > > and all network communications have been paused? > > Not all network communication, but communication with swap devices > should have stopped once sk_memalloc_socks is false. But all incoming network traffic can be allocated as pfmemalloc skbs, regardless whether or not it is related to swap devices. My protocols don't need and cannot handle pfmemalloc skbs, therefore I want to make sure my protocols never receive pfmemalloc skbs. The current code doesn't seem to guarantee this.