From patchwork Tue Jan 26 01:11:09 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wei Wang X-Patchwork-Id: 371209 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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham 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 C091EC433E6 for ; Tue, 26 Jan 2021 05:35:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8ACAA22DD6 for ; Tue, 26 Jan 2021 05:35:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728919AbhAZFdt (ORCPT ); Tue, 26 Jan 2021 00:33:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46618 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728433AbhAZBeK (ORCPT ); Mon, 25 Jan 2021 20:34:10 -0500 Received: from mail-pj1-x104a.google.com (mail-pj1-x104a.google.com [IPv6:2607:f8b0:4864:20::104a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF4A8C0610D6 for ; Mon, 25 Jan 2021 17:11:17 -0800 (PST) Received: by mail-pj1-x104a.google.com with SMTP id hg20so694322pjb.3 for ; Mon, 25 Jan 2021 17:11:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=7rHfeoR/rzjDxDJmcyo6Qv9sSR5oFjlaIjUi/wlTGcs=; b=EumdQGmvD35r7d5GonAwcFtWzhL2JSjmNkx4u+IufZemSS8OvpV3XQfhgzRLcWMiUI 0P5uHOtc8G46ON0Tk3hqRmBnhO5x91bs6v0JORYi7/codUHmxNaH5VG95DIXKWViYFn2 CLaoIYekKpDaQlUjqfVD+i6kbIL9vp4oIyhWZZ1wapUWMK4Cyj9cLdoyVH0g4GvoTiuK Buob52svQk10Geh7QDKFFhqxP9Z8TIlVYH5oVxs86XTCXHiD+8igQXmqZIvwJJIp16YN Xcd0H9DiF5P86B9ehdcnwmMeYhvW1eco7//ak03KCUqSegHmXbWHGCrtdozKVVN6G+Oq dETg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=7rHfeoR/rzjDxDJmcyo6Qv9sSR5oFjlaIjUi/wlTGcs=; b=KsjuGs/z4Y5BVSYPx18KLIoaFwrqndOa/jQmoL9MxNwYjKGXf+gQi3EAJyFrapVSQ2 +z9KZNZvkOkccuw34Js/bIIX4iyYZVn2YRbaet3UpB8uHg4ktGYXpsOXhxLrSvav+f7o C7kLkNwTHqCTTgu+jGTe6wHmGmxFGO7x+J9C+nsGk/nqzce4DgtzWtOhT5uRuBiWQoxA aqsYDPItdStumHkh5JK4g/ZP+JTgHi81pwMuTjzq5Ta/gCaF2owmAVmrYV6OWUTaHWF9 H6gbb13s2Znwh4NyMdsHn/Mjnd7vZVsBsIxnUJ9Zs7LPF27fRyLDgT7QBu5ROw3Y4dwb BpZw== X-Gm-Message-State: AOAM533bigiJQePnY87FzeGz3Hc3hrXpmoIGEg4SkIyaOfjdXfp1Cpi2 aBM7hYztQF9+z80AiJy/yPKDhrkfwpQ= X-Google-Smtp-Source: ABdhPJzpvJx9nk6bu8vRYVQNqEI4tSu8FBLmlnRqVGEaP8eYBusP0wj29JYxoPtUmueQMGeChKaZRTkfR0c= Sender: "weiwan via sendgmr" X-Received: from weiwan.svl.corp.google.com ([2620:15c:2c4:201:1ea0:b8ff:fe75:cf08]) (user=weiwan job=sendgmr) by 2002:a62:3503:0:b029:1aa:6f15:b9fe with SMTP id c3-20020a6235030000b02901aa6f15b9femr2921572pfa.65.1611623477124; Mon, 25 Jan 2021 17:11:17 -0800 (PST) Date: Mon, 25 Jan 2021 17:11:09 -0800 In-Reply-To: <20210126011109.2425966-1-weiwan@google.com> Message-Id: <20210126011109.2425966-4-weiwan@google.com> Mime-Version: 1.0 References: <20210126011109.2425966-1-weiwan@google.com> X-Mailer: git-send-email 2.30.0.280.ga3ce27912f-goog Subject: [PATCH net-next v8 3/3] net: add sysfs attribute to control napi threaded mode From: Wei Wang To: David Miller , netdev@vger.kernel.org, Jakub Kicinski Cc: Eric Dumazet , Paolo Abeni , Hannes Frederic Sowa , Felix Fietkau , Alexander Duyck Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This patch adds a new sysfs attribute to the network device class. Said attribute provides a per-device control to enable/disable the threaded mode for all the napi instances of the given network device, without the need for a device up/down. User sets it to 1 or 0 to enable or disable threaded mode. Co-developed-by: Paolo Abeni Signed-off-by: Paolo Abeni Co-developed-by: Hannes Frederic Sowa Signed-off-by: Hannes Frederic Sowa Co-developed-by: Felix Fietkau Signed-off-by: Felix Fietkau Signed-off-by: Wei Wang --- Documentation/ABI/testing/sysfs-class-net | 15 ++++++ include/linux/netdevice.h | 2 + net/core/dev.c | 61 ++++++++++++++++++++++- net/core/net-sysfs.c | 50 +++++++++++++++++++ 4 files changed, 126 insertions(+), 2 deletions(-) diff --git a/Documentation/ABI/testing/sysfs-class-net b/Documentation/ABI/testing/sysfs-class-net index 1f2002df5ba2..1419103d11f9 100644 --- a/Documentation/ABI/testing/sysfs-class-net +++ b/Documentation/ABI/testing/sysfs-class-net @@ -337,3 +337,18 @@ Contact: netdev@vger.kernel.org Description: 32-bit unsigned integer counting the number of times the link has been down + +What: /sys/class/net//threaded +Date: Jan 2021 +KernelVersion: 5.12 +Contact: netdev@vger.kernel.org +Description: + Boolean value to control the threaded mode per device. User could + set this value to enable/disable threaded mode for all napi + belonging to this device, without the need to do device up/down. + + Possible values: + == ================================== + 0 threaded mode disabled for this dev + 1 threaded mode enabled for this dev + == ================================== diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 8cb8d43ea5fa..26c3e8cf4c01 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -497,6 +497,8 @@ static inline bool napi_complete(struct napi_struct *n) return napi_complete_done(n, 0); } +int dev_set_threaded(struct net_device *dev, bool threaded); + /** * napi_disable - prevent NAPI from scheduling * @n: NAPI context diff --git a/net/core/dev.c b/net/core/dev.c index 743dd69fba19..1897af6a46eb 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4288,8 +4288,9 @@ static inline void ____napi_schedule(struct softnet_data *sd, if (test_bit(NAPI_STATE_THREADED, &napi->state)) { /* Paired with smp_mb__before_atomic() in - * napi_enable(). Use READ_ONCE() to guarantee - * a complete read on napi->thread. Only call + * napi_enable()/napi_set_threaded(). + * Use READ_ONCE() to guarantee a complete + * read on napi->thread. Only call * wake_up_process() when it's not NULL. */ thread = READ_ONCE(napi->thread); @@ -6740,6 +6741,62 @@ static void init_gro_hash(struct napi_struct *napi) napi->gro_bitmask = 0; } +static int napi_set_threaded(struct napi_struct *n, bool threaded) +{ + int err = 0; + + if (threaded == !!test_bit(NAPI_STATE_THREADED, &n->state)) + return 0; + + if (!threaded) { + clear_bit(NAPI_STATE_THREADED, &n->state); + return 0; + } + + if (!n->thread) { + err = napi_kthread_create(n); + if (err) + return err; + } + + /* Make sure kthread is created before THREADED bit + * is set. + */ + smp_mb__before_atomic(); + set_bit(NAPI_STATE_THREADED, &n->state); + + return 0; +} + +static void dev_disable_threaded_all(struct net_device *dev) +{ + struct napi_struct *napi; + + list_for_each_entry(napi, &dev->napi_list, dev_list) + napi_set_threaded(napi, false); + dev->threaded = 0; +} + +int dev_set_threaded(struct net_device *dev, bool threaded) +{ + struct napi_struct *napi; + int ret; + + dev->threaded = threaded; + list_for_each_entry(napi, &dev->napi_list, dev_list) { + ret = napi_set_threaded(napi, threaded); + if (ret) { + /* Error occurred on one of the napi, + * reset threaded mode on all napi. + */ + dev_disable_threaded_all(dev); + break; + } + } + + return ret; +} + void netif_napi_add(struct net_device *dev, struct napi_struct *napi, int (*poll)(struct napi_struct *, int), int weight) { diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index daf502c13d6d..884f049ee395 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -538,6 +538,55 @@ static ssize_t phys_switch_id_show(struct device *dev, } static DEVICE_ATTR_RO(phys_switch_id); +static ssize_t threaded_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct net_device *netdev = to_net_dev(dev); + int ret; + + if (!rtnl_trylock()) + return restart_syscall(); + + if (!dev_isalive(netdev)) { + ret = -EINVAL; + goto unlock; + } + + if (list_empty(&netdev->napi_list)) { + ret = -EOPNOTSUPP; + goto unlock; + } + + ret = sprintf(buf, fmt_dec, netdev->threaded); + +unlock: + rtnl_unlock(); + return ret; +} + +static int modify_napi_threaded(struct net_device *dev, unsigned long val) +{ + int ret; + + if (list_empty(&dev->napi_list)) + return -EOPNOTSUPP; + + if (val != 0 && val != 1) + return -EOPNOTSUPP; + + ret = dev_set_threaded(dev, val); + + return ret; +} + +static ssize_t threaded_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t len) +{ + return netdev_store(dev, attr, buf, len, modify_napi_threaded); +} +static DEVICE_ATTR_RW(threaded); + static struct attribute *net_class_attrs[] __ro_after_init = { &dev_attr_netdev_group.attr, &dev_attr_type.attr, @@ -570,6 +619,7 @@ static struct attribute *net_class_attrs[] __ro_after_init = { &dev_attr_proto_down.attr, &dev_attr_carrier_up_count.attr, &dev_attr_carrier_down_count.attr, + &dev_attr_threaded.attr, NULL, }; ATTRIBUTE_GROUPS(net_class);