From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750933AbeAUQaO (ORCPT ); Sun, 21 Jan 2018 11:30:14 -0500 Received: from mail.kernel.org ([198.145.29.99]:33934 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750825AbeAUQaN (ORCPT ); Sun, 21 Jan 2018 11:30:13 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 647D3214E1 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=frederic@kernel.org Date: Sun, 21 Jan 2018 17:30:09 +0100 From: Frederic Weisbecker To: David Miller Cc: torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, alexander.levin@verizon.com, peterz@infradead.org, mchehab@s-opensource.com, hannes@stressinduktion.org, paulmck@linux.vnet.ibm.com, wanpeng.li@hotmail.com, dima@arista.com, tglx@linutronix.de, akpm@linux-foundation.org, pabeni@redhat.com, rrendec@arista.com, mingo@kernel.org, sgruszka@redhat.com, riel@redhat.com, edumazet@google.com Subject: Re: [RFC PATCH 1/4] softirq: Limit vector to a single iteration on IRQ tail Message-ID: <20180121163008.GB2879@lerouge> References: <1516376774-24076-2-git-send-email-frederic@kernel.org> <20180119.111625.1700179370745007835.davem@davemloft.net> <20180119.134727.512994648781037639.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180119.134727.512994648781037639.davem@davemloft.net> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 19, 2018 at 01:47:27PM -0500, David Miller wrote: > From: Linus Torvalds > Date: Fri, 19 Jan 2018 10:25:03 -0800 > > > On Fri, Jan 19, 2018 at 8:16 AM, David Miller wrote: > >> > >> So this "get requeued" condition I think will trigger always for > >> networking tunnel decapsulation. > > > > Hmm. Interesting and a perhaps bit discouraging. > > > > Will it always be just a _single_ level of indirection, or will double > > tunnels (I assume some people do that, just because the universe is > > out to get us) then result in this perhaps repeating several times? > > Every level of tunnel encapsulation will trigger a new softirq. > > So if you have an IP tunnel inside of an IP tunnel that will trigger > twice. So we may likely need to come back to a call counter based limit :-s