Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755247AbbBOIU3 (ORCPT ); Sun, 15 Feb 2015 03:20:29 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:19999 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755187AbbBOIUW (ORCPT ); Sun, 15 Feb 2015 03:20:22 -0500 From: Bob Liu To: xen-devel@lists.xen.org Cc: david.vrabel@citrix.com, linux-kernel@vger.kernel.org, roger.pau@citrix.com, konrad.wilk@oracle.com, felipe.franciosi@citrix.com, axboe@fb.com, hch@infradead.org, avanzini.arianna@gmail.com, Bob Liu Subject: [PATCH 09/10] xen/blkback: get hardware queue number from blkfront Date: Sun, 15 Feb 2015 16:19:04 +0800 Message-Id: <1423988345-4005-10-git-send-email-bob.liu@oracle.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1423988345-4005-1-git-send-email-bob.liu@oracle.com> References: <1423988345-4005-1-git-send-email-bob.liu@oracle.com> X-Source-IP: acsinet22.oracle.com [141.146.126.238] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3929 Lines: 118 Backend advertise the max number it supported to "multi-queue-max-queues", and read the negotiate value from "multi-queue-num-queues". Signed-off-by: Bob Liu --- drivers/block/xen-blkback/blkback.c | 8 ++++++++ drivers/block/xen-blkback/xenbus.c | 36 ++++++++++++++++++++++++++++++------ 2 files changed, 38 insertions(+), 6 deletions(-) diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index 0969e7e..34d72b0 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -80,6 +80,11 @@ module_param_named(max_persistent_grants, xen_blkif_max_pgrants, int, 0644); MODULE_PARM_DESC(max_persistent_grants, "Maximum number of grants to map persistently"); +unsigned int xenblk_max_queues; +module_param_named(max_queues, xenblk_max_queues, uint, 0644); +MODULE_PARM_DESC(max_queues, + "Maximum number of hardware queues per virtual disk"); + /* * The LRU mechanism to clean the lists of persistent grants needs to * be executed periodically. The time interval between consecutive executions @@ -1390,6 +1395,9 @@ static int __init xen_blkif_init(void) if (!xen_domain()) return -ENODEV; + /* Allow as many queues as there are CPUs, by default */ + xenblk_max_queues = num_online_cpus(); + rc = xen_blkif_interface_init(); if (rc) goto failed_init; diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index 93e5f38..c33d8c9 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -21,6 +21,8 @@ #include #include "common.h" +extern unsigned int xenblk_max_queues; + struct backend_info { struct xenbus_device *dev; struct xen_blkif *blkif; @@ -225,12 +227,6 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid) atomic_set(&blkif->drain, 0); INIT_WORK(&blkif->free_work, xen_blkif_deferred_free); - blkif->nr_rings = 1; - if (xen_blkif_alloc_rings(blkif)) { - kmem_cache_free(xen_blkif_cachep, blkif); - return ERR_PTR(-ENOMEM); - } - return blkif; } @@ -647,6 +643,14 @@ static int xen_blkbk_probe(struct xenbus_device *dev, goto fail; } + /* Multi-queue support: This is an optional feature. */ + err = xenbus_printf(XBT_NIL, dev->nodename, + "multi-queue-max-queues", "%u", xenblk_max_queues); + if (err) { + pr_debug("Error writing multi-queue-num-queues\n"); + goto fail; + } + /* setup back pointer */ be->blkif->be = be; @@ -927,6 +931,7 @@ static int connect_ring(struct backend_info *be) char *xspath; size_t xspathsize; const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */ + unsigned int requested_num_queues = 0; DPRINTK("%s", dev->otherend); @@ -954,6 +959,25 @@ static int connect_ring(struct backend_info *be) be->blkif->vbd.feature_gnt_persistent = pers_grants; be->blkif->vbd.overflow_max_grants = 0; + /* + * Read the number of hardware queus from frontend. + */ + err = xenbus_scanf(XBT_NIL, dev->otherend, "multi-queue-num-queues", "%u", &requested_num_queues); + if (err < 0) { + requested_num_queues = 1; + } else { + if (requested_num_queues > xenblk_max_queues) { + /* buggy or malicious guest */ + xenbus_dev_fatal(dev, err, + "guest requested %u queues, exceeding the maximum of %u.", + requested_num_queues, xenblk_max_queues); + return -1; + } + } + be->blkif->nr_rings = requested_num_queues; + if (xen_blkif_alloc_rings(be->blkif)) + return -ENOMEM; + if (be->blkif->nr_rings == 1) { err = xenbus_gather(XBT_NIL, dev->otherend, "ring-ref", "%lu", &ring_ref, "event-channel", "%u", &evtchn, NULL); -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/