From nobody Tue Dec 16 19:54:03 2025 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 A740BE95A8E for ; Mon, 9 Oct 2023 11:16:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346196AbjJILQz (ORCPT ); Mon, 9 Oct 2023 07:16:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58676 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345822AbjJILQy (ORCPT ); Mon, 9 Oct 2023 07:16:54 -0400 Received: from out-208.mta1.migadu.com (out-208.mta1.migadu.com [IPv6:2001:41d0:203:375::d0]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5DB2A94 for ; Mon, 9 Oct 2023 04:16:52 -0700 (PDT) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1696850210; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=iXX/1lVwKrWymkXfI3JV+KmeWnDZTSV8t81NoepFl1M=; b=BwdVQ61iisKUdcwp0cDeBS0BaWp7Pr84P53tpMsWcjG+HUU5Q2ey3f2+yPAUS4O0v8Gfhq aKGeOfXjgI6U8TGTA4jtmejSuvMmAiPvO99YXzaxs9UemrP7Yzrzf94lDg5aPzBpQx/CkQ JGCuupGlyLGYtrE77U2KO4zCoWX9kso= From: Yajun Deng To: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Yajun Deng , Alexander Lobakin Subject: [PATCH net-next v8] net/core: Introduce netdev_core_stats_inc() Date: Mon, 9 Oct 2023 19:16:33 +0800 Message-Id: <20231009111633.2319304-1-yajun.deng@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Although there is a kfree_skb_reason() helper function that can be used to find the reason why this skb is dropped, but most callers didn't increase one of rx_dropped, tx_dropped, rx_nohandler and rx_otherhost_dropped. For the users, people are more concerned about why the dropped in ip is increasing. Introduce netdev_core_stats_inc() for trace the caller of dev_core_stats_*_inc(). Also, add __code to netdev_core_stats_alloc(), as it's called with small probability. And add noinline make sure netdev_core_stats_inc was never inlined. Signed-off-by: Yajun Deng Suggested-by: Alexander Lobakin Reviewed-by: Eric Dumazet --- v8: use noinline and this_cpu_inc in netdev_core_stats_inc. v7: use WRITE_ONCE and READ_ONCE instead of '++' v6: merge netdev_core_stats and netdev_core_stats_inc together v5: Access the per cpu pointer before reach the relevant offset. v4: Introduce netdev_core_stats_inc() instead of export dev_core_stats_*_in= c() v3: __cold should be added to the netdev_core_stats_alloc(). v2: use __cold instead of inline in dev_core_stats(). v1: https://lore.kernel.org/netdev/20230911082016.3694700-1-yajun.deng@linu= x.dev/ --- include/linux/netdevice.h | 21 ++++----------------- net/core/dev.c | 21 +++++++++++++++++++-- 2 files changed, 23 insertions(+), 19 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index e070a4540fba..11d704bfec9b 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -4002,32 +4002,19 @@ static __always_inline bool __is_skb_forwardable(co= nst struct net_device *dev, return false; } =20 -struct net_device_core_stats __percpu *netdev_core_stats_alloc(struct net_= device *dev); - -static inline struct net_device_core_stats __percpu *dev_core_stats(struct= net_device *dev) -{ - /* This READ_ONCE() pairs with the write in netdev_core_stats_alloc() */ - struct net_device_core_stats __percpu *p =3D READ_ONCE(dev->core_stats); - - if (likely(p)) - return p; - - return netdev_core_stats_alloc(dev); -} +void netdev_core_stats_inc(struct net_device *dev, u32 offset); =20 #define DEV_CORE_STATS_INC(FIELD) \ static inline void dev_core_stats_##FIELD##_inc(struct net_device *dev) \ { \ - struct net_device_core_stats __percpu *p; \ - \ - p =3D dev_core_stats(dev); \ - if (p) \ - this_cpu_inc(p->FIELD); \ + netdev_core_stats_inc(dev, \ + offsetof(struct net_device_core_stats, FIELD)); \ } DEV_CORE_STATS_INC(rx_dropped) DEV_CORE_STATS_INC(tx_dropped) DEV_CORE_STATS_INC(rx_nohandler) DEV_CORE_STATS_INC(rx_otherhost_dropped) +#undef DEV_CORE_STATS_INC =20 static __always_inline int ____dev_forward_skb(struct net_device *dev, struct sk_buff *skb, diff --git a/net/core/dev.c b/net/core/dev.c index 606a366cc209..02949a929e7f 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -10497,7 +10497,8 @@ void netdev_stats_to_stats64(struct rtnl_link_stats= 64 *stats64, } EXPORT_SYMBOL(netdev_stats_to_stats64); =20 -struct net_device_core_stats __percpu *netdev_core_stats_alloc(struct net_= device *dev) +static __cold struct net_device_core_stats __percpu *netdev_core_stats_all= oc( + struct net_device *dev) { struct net_device_core_stats __percpu *p; =20 @@ -10510,7 +10511,23 @@ struct net_device_core_stats __percpu *netdev_core= _stats_alloc(struct net_device /* This READ_ONCE() pairs with the cmpxchg() above */ return READ_ONCE(dev->core_stats); } -EXPORT_SYMBOL(netdev_core_stats_alloc); + +noinline void netdev_core_stats_inc(struct net_device *dev, u32 offset) +{ + /* This READ_ONCE() pairs with the write in netdev_core_stats_alloc() */ + struct net_device_core_stats __percpu *p =3D READ_ONCE(dev->core_stats); + unsigned long __percpu *field; + + if (unlikely(!p)) { + p =3D netdev_core_stats_alloc(dev); + if (!p) + return; + } + + field =3D (__force unsigned long __percpu *)((__force void *)p + offset); + this_cpu_inc(*field); +} +EXPORT_SYMBOL_GPL(netdev_core_stats_inc); =20 /** * dev_get_stats - get network device statistics --=20 2.25.1