From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from verein.lst.de ([213.95.11.211]:41780 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726554AbeIKOHx (ORCPT ); Tue, 11 Sep 2018 10:07:53 -0400 Date: Tue, 11 Sep 2018 11:13:54 +0200 From: Christoph Hellwig To: Thomas Gleixner Cc: Dou Liyang , Kashyap Desai , Ming Lei , Sumit Saxena , Ming Lei , Christoph Hellwig , Linux Kernel Mailing List , Shivasharan Srikanteshwara , linux-block , Dou Liyang Subject: Re: Affinity managed interrupts vs non-managed interrupts Message-ID: <20180911091354.GA9898@lst.de> References: <602cee6381b9f435a938bbaf852d07f9@mail.gmail.com> <66256272c020be186becdd7a3f049302@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org On Thu, Sep 06, 2018 at 01:46:46PM +0200, Thomas Gleixner wrote: > There are a few things we need to clarify upfront: > > Right now the pre and post vectors are marked managed and their > affinity mask is set to the irq default affinity mask. > > The default affinity mask is by default ALL cpus, but it can be tweaked > both on the kernel command line and via proc. > > If that mask is only a subset of CPUs and all of them go offline > then these vectors are shutdown in managed mode. > > That means we need to set the affinity mask of the pre and post vectors to > possible mask, but that doesn't make much sense either, unless there is a > reason to have them marked managed. > > I think the right solution for these pre/post vectors is to _NOT_ mark > them managed and leave them as regular interrupts which can be affinity > controlled and also can move freely on hotplug. Yes, agreed. Marking the pre/post vector as managed was a mistake (and I don't think it even was intentional, at least on my part).