From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Sun, 8 Jan 2017 11:01:52 +0100 From: Christoph Hellwig To: Keith Busch Cc: linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, Jens Axboe , Jens Axboe , Christoph Hellwig , Thomas Gleixner , Marc Merlin Subject: Re: [PATCH 2/6] irq/affinity: Assign offline CPUs a vector Message-ID: <20170108100152.GA26025@lst.de> References: <1483569671-1462-1-git-send-email-keith.busch@intel.com> <1483569671-1462-3-git-send-email-keith.busch@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1483569671-1462-3-git-send-email-keith.busch@intel.com> List-ID: On Wed, Jan 04, 2017 at 05:41:07PM -0500, Keith Busch wrote: > The offline CPUs need to assigned to something incase they come online > later, otherwise anyone using the mapping for things other than affinity > will have blank entries for that online CPU. I don't really like the idea behind it. Back when we came up with this code I had some discussion with Thomas if we should do the assignment only for online CPUs, or maybe for all possible CPUs. Except for some big iron with physical node hotplug the difference usually is just that some nodes have been temporarily offlined. So maybe we need to bite the bullet and move the irq and block code to consider all possible cpus. From mboxrd@z Thu Jan 1 00:00:00 1970 From: hch@lst.de (Christoph Hellwig) Date: Sun, 8 Jan 2017 11:01:52 +0100 Subject: [PATCH 2/6] irq/affinity: Assign offline CPUs a vector In-Reply-To: <1483569671-1462-3-git-send-email-keith.busch@intel.com> References: <1483569671-1462-1-git-send-email-keith.busch@intel.com> <1483569671-1462-3-git-send-email-keith.busch@intel.com> Message-ID: <20170108100152.GA26025@lst.de> On Wed, Jan 04, 2017@05:41:07PM -0500, Keith Busch wrote: > The offline CPUs need to assigned to something incase they come online > later, otherwise anyone using the mapping for things other than affinity > will have blank entries for that online CPU. I don't really like the idea behind it. Back when we came up with this code I had some discussion with Thomas if we should do the assignment only for online CPUs, or maybe for all possible CPUs. Except for some big iron with physical node hotplug the difference usually is just that some nodes have been temporarily offlined. So maybe we need to bite the bullet and move the irq and block code to consider all possible cpus.