From: Bob Liu <bob.liu@oracle.com>
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 <bob.liu@oracle.com>
Subject: [PATCH v3 9/9] xen/blkback: get number of hardware queues/rings from blkfront
Date: Sat, 5 Sep 2015 20:39:42 +0800 [thread overview]
Message-ID: <1441456782-31318-10-git-send-email-bob.liu@oracle.com> (raw)
In-Reply-To: <1441456782-31318-1-git-send-email-bob.liu@oracle.com>
Backend advertises "multi-queue-max-queues" to front, and then read back the
final negotiated queues/rings from "multi-queue-num-queues" which is wrote by
blkfront.
Signed-off-by: Bob Liu <bob.liu@oracle.com>
---
drivers/block/xen-blkback/blkback.c | 8 ++++++++
drivers/block/xen-blkback/xenbus.c | 36 ++++++++++++++++++++++++++++++-----
2 files changed, 39 insertions(+), 5 deletions(-)
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index fd02240..b904fe05f0 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -83,6 +83,11 @@ 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");
+
/*
* Maximum order of pages to be used for the shared ring between front and
* backend, 4KB page granularity is used.
@@ -1458,6 +1463,9 @@ static int __init xen_blkif_init(void)
xen_blkif_max_ring_order = XENBUS_MAX_RING_PAGE_ORDER;
}
+ /* 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 04b8d0d..aa97ea5 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -28,6 +28,8 @@
#define RINGREF_NAME_LEN (20)
#define RINGREF_NAME_LEN (20)
+extern unsigned int xenblk_max_queues;
+
struct backend_info {
struct xenbus_device *dev;
struct xen_blkif *blkif;
@@ -191,11 +193,6 @@ 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;
}
@@ -618,6 +615,14 @@ static int xen_blkbk_probe(struct xenbus_device *dev,
goto fail;
}
+ /* Multi-queue: wrte how many queues backend supported. */
+ 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;
@@ -1008,6 +1013,7 @@ 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;
pr_debug("%s %s\n", __func__, dev->otherend);
@@ -1035,6 +1041,26 @@ 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
+ || requested_num_queues == 0) {
+ /* 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;
+
pr_info("nr_rings:%d protocol %d (%s) %s\n", be->blkif->nr_rings,
be->blkif->blk_protocol, protocol,
pers_grants ? "persistent grants" : "");
--
1.7.10.4
next prev parent reply other threads:[~2015-09-05 12:42 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-05 12:39 [PATCH v3 0/9] xen-block: support multi hardware-queues/rings Bob Liu
2015-09-05 12:39 ` [PATCH v3 1/9] xen-blkfront: convert to blk-mq APIs Bob Liu
2015-09-23 20:31 ` Konrad Rzeszutek Wilk
2015-09-23 21:12 ` Konrad Rzeszutek Wilk
2015-09-05 12:39 ` [PATCH v3 2/9] xen-block: add document for mutli hardware queues/rings Bob Liu
2015-09-23 20:32 ` Konrad Rzeszutek Wilk
2015-10-02 16:04 ` Roger Pau Monné
2015-10-02 16:12 ` [Xen-devel] " Wei Liu
2015-10-02 16:22 ` Roger Pau Monné
2015-10-02 23:55 ` Bob Liu
2015-09-05 12:39 ` [PATCH v3 3/9] xen/blkfront: separate per ring information out of device info Bob Liu
2015-10-02 17:02 ` Roger Pau Monné
2015-10-03 0:34 ` Bob Liu
2015-10-05 15:17 ` Roger Pau Monné
2015-10-10 8:30 ` Bob Liu
2015-10-19 9:42 ` Roger Pau Monné
2015-09-05 12:39 ` [PATCH v3 4/9] xen/blkfront: pseudo support for multi hardware queues/rings Bob Liu
2015-10-05 10:52 ` Roger Pau Monné
2015-10-07 10:28 ` Bob Liu
2015-09-05 12:39 ` [PATCH v3 5/9] xen/blkfront: convert per device io_lock to per ring ring_lock Bob Liu
2015-10-05 14:13 ` Roger Pau Monné
2015-10-07 10:34 ` Bob Liu
2015-09-05 12:39 ` [PATCH v3 6/9] xen/blkfront: negotiate the number of hw queues/rings with backend Bob Liu
2015-10-05 14:40 ` Roger Pau Monné
2015-10-07 10:39 ` Bob Liu
2015-10-07 11:46 ` Roger Pau Monné
2015-10-07 12:19 ` Bob Liu
2015-09-05 12:39 ` [PATCH v3 7/9] xen/blkback: separate ring information out of struct xen_blkif Bob Liu
2015-10-05 14:55 ` Roger Pau Monné
2015-10-07 10:41 ` Bob Liu
2015-10-10 4:08 ` Bob Liu
2015-10-19 9:36 ` Roger Pau Monné
2015-10-19 10:03 ` Bob Liu
2015-10-05 14:55 ` Roger Pau Monné
2015-09-05 12:39 ` [PATCH v3 8/9] xen/blkback: pseudo support for multi hardware queues/rings Bob Liu
2015-10-05 15:08 ` Roger Pau Monné
2015-10-07 10:50 ` Bob Liu
2015-10-07 11:49 ` Roger Pau Monné
2015-09-05 12:39 ` Bob Liu [this message]
2015-10-05 15:15 ` [PATCH v3 9/9] xen/blkback: get number of hardware queues/rings from blkfront Roger Pau Monné
2015-10-07 10:54 ` Bob Liu
2015-10-02 9:57 ` [PATCH v3 0/9] xen-block: support multi hardware-queues/rings Rafal Mielniczuk
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