From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Date: Wed, 30 Aug 2017 17:50:02 -0400 From: Keith Busch To: Bjorn Helgaas Cc: "linux-pci@vger.kernel.org" , Bjorn Helgaas , "Derrick, Jonathan" , Christoph Hellwig Subject: Re: [PATCH] vmd: Remove IRQ affinity Message-ID: <20170830215002.GB17331@localhost.localdomain> References: <1504109704-17033-1-git-send-email-keith.busch@intel.com> <20170830164020.GC18250@bhelgaas-glaptop.roam.corp.google.com> <20170830202340.GA17331@localhost.localdomain> <20170830214139.GY8154@bhelgaas-glaptop.roam.corp.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20170830214139.GY8154@bhelgaas-glaptop.roam.corp.google.com> List-ID: On Wed, Aug 30, 2017 at 04:41:39PM -0500, Bjorn Helgaas wrote: > I added some breadcrumbs to the changelog about this connection > between affinity and limiting the number of IRQs. Did I get this > right? > > This is on pci/host-vmd for v4.14. Awesome, sounds good to me! > commit be85af02e1b00d49cd678d8f2ea6f391bdbaca19 > Author: Keith Busch > Date: Wed Aug 30 12:15:04 2017 -0400 > > PCI: vmd: Remove IRQ affinity so we can allocate more IRQs > > VMD hardware has to share its vectors among child devices in its PCI > domain so we should allocate as many as possible rather than just ones > that can be affinitized. > > pci_alloc_irq_vectors_affinity() limits the number of affinitized IRQs to > the number of present CPUs (see irq_calc_affinity_vectors()). But we'd > prefer to have more vectors, even if they aren't distributed across the > CPUs, so use pci_alloc_irq_vectors() instead. > > Reported-by: Brad Goodman > Signed-off-by: Keith Busch > [bhelgaas: add irq_calc_affinity_vectors() reference to changelog] > Signed-off-by: Bjorn Helgaas