From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752182AbdBERPq (ORCPT ); Sun, 5 Feb 2017 12:15:46 -0500 Received: from bombadil.infradead.org ([65.50.211.133]:33993 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751906AbdBERPo (ORCPT ); Sun, 5 Feb 2017 12:15:44 -0500 From: Christoph Hellwig To: mst@redhat.com, jasowang@redhat.com Cc: axboe@kernel.dk, pbonzini@redhat.com, virtualization@lists.linux-foundation.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 4/9] virtio_pci: simplify MSI-X setup Date: Sun, 5 Feb 2017 18:15:21 +0100 Message-Id: <20170205171526.6224-5-hch@lst.de> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170205171526.6224-1-hch@lst.de> References: <20170205171526.6224-1-hch@lst.de> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Try to grab the MSI-X vectors early and fall back to the shared one before doing lots of allocations. Signed-off-by: Christoph Hellwig Reviewed-by: Jason Wang --- drivers/virtio/virtio_pci_common.c | 35 ++++++++++++++++++----------------- 1 file changed, 18 insertions(+), 17 deletions(-) diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c index b83053082875..822f8e5dcee4 100644 --- a/drivers/virtio/virtio_pci_common.c +++ b/drivers/virtio/virtio_pci_common.c @@ -142,14 +142,13 @@ void vp_del_vqs(struct virtio_device *vdev) } static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs, - struct virtqueue *vqs[], - vq_callback_t *callbacks[], - const char * const names[], - bool per_vq_vectors) + struct virtqueue *vqs[], vq_callback_t *callbacks[], + const char * const names[]) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); const char *name = dev_name(&vp_dev->vdev.dev); int i, err = -ENOMEM, allocated_vectors, nvectors; + bool shared = false; u16 msix_vec; nvectors = 1; @@ -157,12 +156,16 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs, if (callbacks[i]) nvectors++; - if (per_vq_vectors) { - err = pci_alloc_irq_vectors(vp_dev->pci_dev, nvectors, nvectors, - PCI_IRQ_MSIX); - } else { + /* Try one vector per queue first. */ + err = pci_alloc_irq_vectors(vp_dev->pci_dev, nvectors, nvectors, + PCI_IRQ_MSIX); + if (err < 0) { + /* Fallback to one vector for config, one shared for queues. */ + shared = true; err = pci_alloc_irq_vectors(vp_dev->pci_dev, 2, 2, PCI_IRQ_MSIX); + if (err < 0) + return err; } if (err < 0) return err; @@ -190,7 +193,7 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs, err = request_irq(pci_irq_vector(vp_dev->pci_dev, 0), vp_config_changed, 0, vp_dev->msix_names[0], vp_dev); if (err) - goto out_free_irq_vectors; + goto out_free_msix_affinity_masks; /* Verify we had enough resources to assign the vector */ if (vp_dev->config_vector(vp_dev, 0) == VIRTIO_MSI_NO_VECTOR) { @@ -240,7 +243,11 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs, } vp_dev->msix_vector_map[i] = msix_vec; - if (per_vq_vectors) + /* + * Use a different vector for each queue if they are available, + * else share the same vector for all VQs. + */ + if (!shared) allocated_vectors++; } @@ -307,15 +314,9 @@ int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs, { int err; - /* Try MSI-X with one vector per queue. */ - err = vp_find_vqs_msix(vdev, nvqs, vqs, callbacks, names, true); - if (!err) - return 0; - /* Fallback: MSI-X with one vector for config, one shared for queues. */ - err = vp_find_vqs_msix(vdev, nvqs, vqs, callbacks, names, false); + err = vp_find_vqs_msix(vdev, nvqs, vqs, callbacks, names); if (!err) return 0; - /* Finally fall back to regular interrupts. */ return vp_find_vqs_intx(vdev, nvqs, vqs, callbacks, names); } -- 2.11.0