From patchwork Fri Jan 29 18:18:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wei Wang X-Patchwork-Id: 12056275 X-Patchwork-Delegate: kuba@kernel.org 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 4ACA6C433E6 for ; Fri, 29 Jan 2021 18:20:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2206364E08 for ; Fri, 29 Jan 2021 18:20:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232663AbhA2SUA (ORCPT ); Fri, 29 Jan 2021 13:20:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33714 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232588AbhA2STK (ORCPT ); Fri, 29 Jan 2021 13:19:10 -0500 Received: from mail-qt1-x84a.google.com (mail-qt1-x84a.google.com [IPv6:2607:f8b0:4864:20::84a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 99625C061786 for ; Fri, 29 Jan 2021 10:18:20 -0800 (PST) Received: by mail-qt1-x84a.google.com with SMTP id z19so6606593qtv.20 for ; Fri, 29 Jan 2021 10:18:20 -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=WDNro0VPXt/zC9TqV9DmvFjd3UBXqKHBzoaBbsunom4=; b=Bp506A/Q41AFHMS1hd5xrq0L1Ypi0R5HhgWjABMBui2/hxIC4CGw/AZo9n+Vcwj80/ +Z6DBrwORTCWHYR1sP6m5PqkE7KCvIIn/RMJFGtMGr9UaVX0QD+/tyGjw7ZeoCO8VK+C fnpvxfPSx94s5DUZy5P6itmbjnAY1ojpd7a1NzHR5mP7CJ3LOGTSES3RyDaIScVABjr7 I8fLWX8K6ai59GDZX4O8QM+SqzeLjB2FGT0n+1hu9Jwg/hEv5eQtBcLUeaOT+FcOLyB2 Ttq14wkb9dFlIxccEZS2hbpXKPWjuMa0+3IpxrDWM/QvyZnt5KIwEOC20jVKaJMlhl1Q aa/Q== 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=WDNro0VPXt/zC9TqV9DmvFjd3UBXqKHBzoaBbsunom4=; b=p3MG608EuWX2/KkXt0S6IL5FrYkZXNSzaIyJV+L2Gy+HGkexU+W/p4wGoss/3emOxa CtLBYr727IATbUM++NBmnNcLHGnYqUbTnb/9jHmbC+SPZfhnCMoVKbdiY0PhnrrYneVj OuAbKWiMjc+RiSxkf1VTPrCLk0wwlRaqh8ZXTE/KXmX5N/patPo4Z6nTP9G3bIQvlIIJ aLOW2ND0+Vvila+s40PmJUqPzgmxCvqnLT62ktJpOtof0dfKBlmNyaFBpQhYa+56rZPx 495lK0yk443Z+EVUM7ES+K6XZ0KFlDL3qSrgZb9oEDz2hXy7L8l9m5UNx80eyT+8jpFy udow== X-Gm-Message-State: AOAM533FxLu+UZJPK91DQbRgkEQP46ps9ysnYCQV3yiCEsGp/TcKCXW3 Jf0jvIFyx43/isQW/o7AtEvyBkBiCm4= X-Google-Smtp-Source: ABdhPJyO+cnv6gtR8rfGLZnyv5vlqhLUAzJyPHSzxuJ2HMcniBF0PFxS19GmEECFtx3G+Jev5byonqTQLsw= Sender: "weiwan via sendgmr" X-Received: from weiwan.svl.corp.google.com ([2620:15c:2c4:201:69ee:ceb1:90eb:1722]) (user=weiwan job=sendgmr) by 2002:ad4:56e8:: with SMTP id cr8mr5041740qvb.6.1611944299847; Fri, 29 Jan 2021 10:18:19 -0800 (PST) Date: Fri, 29 Jan 2021 10:18:12 -0800 In-Reply-To: <20210129181812.256216-1-weiwan@google.com> Message-Id: <20210129181812.256216-4-weiwan@google.com> Mime-Version: 1.0 References: <20210129181812.256216-1-weiwan@google.com> X-Mailer: git-send-email 2.30.0.365.g02bc693789-goog Subject: [PATCH net-next v9 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 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@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 f1e9fe9017ac..8ac2db361ae3 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);