From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [91.216.245.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1F4FF31CA5E; Wed, 15 Oct 2025 11:14:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.216.245.30 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760526892; cv=none; b=Ws1hduez/Z3CzHrazU1jhs49mP0IYiZK2fmBHy99vfy+m2udqPaI6KYHg41yFSY8jlvW7037unYRf3nczWzmTcbWmc2IoYa75wpi51Bu1Vrh/+8MckHchw05NE1XeU9V+DmgY3zOsiGh/99L/rOsIpiKcoJo5JbHGqY+JOXZF6E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760526892; c=relaxed/simple; bh=ZwOtUeDhzBVShiH61wkDeAhUAucVh3Z70Jw0fG2U3uc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=qCCbwzFnNE3N723mnR2y5ggXiDf/d9eXeloOmdaToBfmv873nqPrG2Rnvav8KMpLzYeTiR/En73kof5CA42pG1mbfX19c66llUW3ZN0gFLaM+G24bG6L4I1YCEGzj8EVJrOoCztnjpH4q2wgZjsDRTrQ6rGyiCpauUqlzeWy78U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de; spf=pass smtp.mailfrom=strlen.de; arc=none smtp.client-ip=91.216.245.30 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=strlen.de Received: by Chamillionaire.breakpoint.cc (Postfix, from userid 1003) id 4390160186; Wed, 15 Oct 2025 13:14:48 +0200 (CEST) Date: Wed, 15 Oct 2025 13:14:47 +0200 From: Florian Westphal To: Eric Dumazet Cc: Wang Liang , nhorman@tuxdriver.com, davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, yuehaibing@huawei.com, zhangchangzhong@huawei.com Subject: Re: [PATCH RFC net-next] net: drop_monitor: Add debugfs support Message-ID: References: <20251015101417.1511732-1-wangliang74@huawei.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Eric Dumazet wrote: > I do not understand the fascination with net/core/drop_monitor.c, > which looks very old school to me, > and misses all the features, flexibility, scalability that 'perf', > eBPF tracing, bpftrace, .... have today. > > Adding /sys/kernel/debug/drop_monitor/* is even more old school. > > Not mentioning the maintenance burden. > > For me the choice is easy : > > # CONFIG_NET_DROP_MONITOR is not set > > perf record -ag -e skb:kfree_skb sleep 1 > > perf script # or perf report Maybe: diff --git a/net/Kconfig b/net/Kconfig --- a/net/Kconfig +++ b/net/Kconfig @@ -400,15 +400,15 @@ config NET_PKTGEN module will be called pktgen. config NET_DROP_MONITOR - tristate "Network packet drop alerting service" + tristate "Legacy network packet drop alerting service" depends on INET && TRACEPOINTS help This feature provides an alerting service to userspace in the event that packets are discarded in the network stack. Alerts are broadcast via netlink socket to any listening user space - process. If you don't need network drop alerts, or if you are ok - just checking the various proc files and other utilities for - drop statistics, say N here. + process. This feature is NOT related to "perf" based drop monitoring. + Say N here unless you need to support older userspace tools like + "dropwatch".