From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752790AbbIEMl6 (ORCPT ); Sat, 5 Sep 2015 08:41:58 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:39296 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752026AbbIEMk6 (ORCPT ); Sat, 5 Sep 2015 08:40:58 -0400 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, rafal.mielniczuk@citrix.com, boris.ostrovsky@oracle.com, jonathan.davies@citrix.com, Bob Liu Subject: [PATCH v3 6/9] xen/blkfront: negotiate the number of hw queues/rings with backend Date: Sat, 5 Sep 2015 20:39:39 +0800 Message-Id: <1441456782-31318-7-git-send-email-bob.liu@oracle.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1441456782-31318-1-git-send-email-bob.liu@oracle.com> References: <1441456782-31318-1-git-send-email-bob.liu@oracle.com> X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The max number of hardware queues for xen/blkfront is set by parameter 'max_queues', while the number xen/blkback supported is notified through xenstore("multi-queue-max-queues"). The negotiated number was the smaller one, and was written back to xen/blkback as "multi-queue-num-queues". Signed-off-by: Bob Liu --- drivers/block/xen-blkfront.c | 142 ++++++++++++++++++++++++++++++++---------- 1 file changed, 108 insertions(+), 34 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 1cae76b..1aa66c9 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -107,6 +107,10 @@ static unsigned int xen_blkif_max_ring_order; module_param_named(max_ring_page_order, xen_blkif_max_ring_order, int, S_IRUGO); MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages to be used for the shared ring"); +static unsigned int xen_blkif_max_queues; +module_param_named(max_queues, xen_blkif_max_queues, uint, S_IRUGO); +MODULE_PARM_DESC(max_queues, "Maximum number of hardware queues/rings per virtual disk"); + #define BLK_RING_SIZE(dinfo) __CONST_RING_SIZE(blkif, PAGE_SIZE * (dinfo)->pages_per_ring) #define BLK_MAX_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE * XENBUS_MAX_RING_PAGES) /* @@ -114,6 +118,7 @@ MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages to be used for the * characters are enough. Define to 20 to keep consist with backend. */ #define RINGREF_NAME_LEN (20) +#define QUEUE_NAME_LEN (12) /* * Per-ring info. @@ -687,7 +692,7 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size, memset(&dinfo->tag_set, 0, sizeof(dinfo->tag_set)); dinfo->tag_set.ops = &blkfront_mq_ops; - dinfo->tag_set.nr_hw_queues = 1; + dinfo->tag_set.nr_hw_queues = dinfo->nr_rings; dinfo->tag_set.queue_depth = BLK_RING_SIZE(dinfo); dinfo->tag_set.numa_node = NUMA_NO_NODE; dinfo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE; @@ -1350,6 +1355,51 @@ fail: return err; } +static int write_per_ring_nodes(struct xenbus_transaction xbt, + struct blkfront_ring_info *rinfo, const char *dir) +{ + int err, i; + const char *message = NULL; + struct blkfront_dev_info *dinfo = rinfo->dinfo; + + if (dinfo->pages_per_ring == 1) { + err = xenbus_printf(xbt, dir, "ring-ref", "%u", rinfo->ring_ref[0]); + if (err) { + message = "writing ring-ref"; + goto abort_transaction; + } + pr_info("%s: write ring-ref:%d\n", dir, rinfo->ring_ref[0]); + } else { + for (i = 0; i < dinfo->pages_per_ring; i++) { + char ring_ref_name[RINGREF_NAME_LEN]; + + snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i); + err = xenbus_printf(xbt, dir, ring_ref_name, + "%u", rinfo->ring_ref[i]); + if (err) { + message = "writing ring-ref"; + goto abort_transaction; + } + pr_info("%s: write ring-ref:%d\n", dir, rinfo->ring_ref[i]); + } + } + + err = xenbus_printf(xbt, dir, "event-channel", "%u", rinfo->evtchn); + if (err) { + message = "writing event-channel"; + goto abort_transaction; + } + pr_info("%s: write event-channel:%d\n", dir, rinfo->evtchn); + + return 0; + +abort_transaction: + xenbus_transaction_end(xbt, 1); + if (message) + xenbus_dev_fatal(dinfo->xbdev, err, "%s", message); + + return err; +} /* Common code used when first setting up, and when resuming. */ static int talk_to_blkback(struct xenbus_device *dev, @@ -1386,45 +1436,51 @@ again: goto out; } + if (dinfo->pages_per_ring > 1) { + err = xenbus_printf(xbt, dev->nodename, "ring-page-order", "%u", + ring_page_order); + if (err) { + message = "writing ring-page-order"; + goto abort_transaction; + } + } + + /* We already got the number of queues in _probe */ if (dinfo->nr_rings == 1) { rinfo = &dinfo->rinfo[0]; - if (dinfo->pages_per_ring == 1) { - err = xenbus_printf(xbt, dev->nodename, - "ring-ref", "%u", rinfo->ring_ref[0]); - if (err) { - message = "writing ring-ref"; - goto abort_transaction; - } - } else { - err = xenbus_printf(xbt, dev->nodename, - "ring-page-order", "%u", ring_page_order); - if (err) { - message = "writing ring-page-order"; - goto abort_transaction; - } - - for (i = 0; i < dinfo->pages_per_ring; i++) { - char ring_ref_name[RINGREF_NAME_LEN]; + err = write_per_ring_nodes(xbt, &dinfo->rinfo[0], dev->nodename); + if (err) + goto out; + } else { + char *path; + size_t pathsize; - snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i); - err = xenbus_printf(xbt, dev->nodename, ring_ref_name, - "%u", rinfo->ring_ref[i]); - if (err) { - message = "writing ring-ref"; - goto abort_transaction; - } - } - } - err = xenbus_printf(xbt, dev->nodename, - "event-channel", "%u", rinfo->evtchn); + err = xenbus_printf(xbt, dev->nodename, "multi-queue-num-queues", "%u", + dinfo->nr_rings); if (err) { - message = "writing event-channel"; + message = "writing multi-queue-num-queues"; goto abort_transaction; } - } else { - /* Not supported at this stage */ - goto abort_transaction; + + pathsize = strlen(dev->nodename) + QUEUE_NAME_LEN; + path = kzalloc(pathsize, GFP_KERNEL); + if (!path) { + err = -ENOMEM; + message = "ENOMEM while writing ring references"; + goto abort_transaction; + } + + for (i = 0; i < dinfo->nr_rings; i++) { + memset(path, 0, pathsize); + snprintf(path, pathsize, "%s/queue-%u", dev->nodename, i); + err = write_per_ring_nodes(xbt, &dinfo->rinfo[i], path); + if (err) { + kfree(path); + goto out; + } + } + kfree(path); } err = xenbus_printf(xbt, dev->nodename, "protocol", "%s", @@ -1480,6 +1536,7 @@ static int blkfront_probe(struct xenbus_device *dev, int err, vdevice, r_index; struct blkfront_dev_info *dinfo; struct blkfront_ring_info *rinfo; + unsigned int back_max_queues = 0; /* FIXME: Use dynamic device id if this is not set. */ err = xenbus_scanf(XBT_NIL, dev->nodename, @@ -1534,7 +1591,17 @@ static int blkfront_probe(struct xenbus_device *dev, dinfo->vdevice = vdevice; dinfo->connected = BLKIF_STATE_DISCONNECTED; - dinfo->nr_rings = 1; + /* Check if backend supports multiple queues */ + err = xenbus_scanf(XBT_NIL, dinfo->xbdev->otherend, + "multi-queue-max-queues", "%u", &back_max_queues); + if (err < 0) + back_max_queues = 1; + + dinfo->nr_rings = min(back_max_queues, xen_blkif_max_queues); + if (dinfo->nr_rings <= 0) + dinfo->nr_rings = 1; + pr_info("dinfo->nr_rings:%u, backend support max-queues:%u\n", dinfo->nr_rings, back_max_queues); + dinfo->rinfo = kzalloc(sizeof(*rinfo) * dinfo->nr_rings, GFP_KERNEL); if (!dinfo->rinfo) { xenbus_dev_fatal(dev, -ENOMEM, "allocating ring_info structure"); @@ -2257,6 +2324,7 @@ static struct xenbus_driver blkfront_driver = { static int __init xlblk_init(void) { int ret; + int nr_cpus = num_online_cpus(); if (!xen_domain()) return -ENODEV; @@ -2267,6 +2335,12 @@ static int __init xlblk_init(void) xen_blkif_max_ring_order = 0; } + if (xen_blkif_max_queues > nr_cpus) { + pr_info("Invalid max_queues (%d), will use default max: %d.\n", + xen_blkif_max_queues, nr_cpus); + xen_blkif_max_queues = nr_cpus; + } + if (!xen_has_pv_disk_devices()) return -ENODEV; -- 1.7.10.4