From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752178AbeBHSpM (ORCPT ); Thu, 8 Feb 2018 13:45:12 -0500 Received: from shards.monkeyblade.net ([184.105.139.130]:47862 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751094AbeBHSpL (ORCPT ); Thu, 8 Feb 2018 13:45:11 -0500 Date: Thu, 08 Feb 2018 13:45:06 -0500 (EST) Message-Id: <20180208.134506.1374787894560277876.davem@davemloft.net> To: bigeasy@linutronix.de Cc: frederic@kernel.org, linux-kernel@vger.kernel.org, alexander.levin@verizon.com, peterz@infradead.org, mchehab@s-opensource.com, torvalds@linux-foundation.org, 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 2/4] softirq: Per vector deferment to workqueue From: David Miller In-Reply-To: <20180208174450.qjvjy752jf4ngt2g@breakpoint.cc> References: <1516376774-24076-1-git-send-email-frederic@kernel.org> <1516376774-24076-3-git-send-email-frederic@kernel.org> <20180208174450.qjvjy752jf4ngt2g@breakpoint.cc> X-Mailer: Mew version 6.7 on Emacs 25.3 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sebastian Andrzej Siewior Date: Thu, 8 Feb 2018 18:44:52 +0100 > May I instead suggest to stick to ksoftirqd? So you run in softirq > context (after return from IRQ) and if takes too long, you offload the > vector to ksoftirqd instead. You may want to play with the metric on > which you decide when you want switch to ksoftirqd / account how long a > vector runs. Having read over this stuff for the past few weeks this is how I feel as well. Just make ksofbitrq do what we want (only execute the overloaded softirq vectors). The more I look at the workqueue stuff, the more complications and weird behavioral artifacts we are getting for questionable gain.