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authorJuergen Gross <jgross@suse.com>2017-01-10 14:32:52 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-11-15 17:13:09 +0100
commit4e0d26b22e79219771e5ffe954986154d37b1439 (patch)
tree198ba2b00cdbf65cdeff65a69c1e8bea05adc414 /drivers
parentf3170e6607be5521f3964822d3eb4052c5517774 (diff)
xen/netback: set default upper limit of tx/rx queues to 8
[ Upstream commit 56dd5af9bc23d0d5d23bb207c477715b4c2216c5 ] The default for the maximum number of tx/rx queues of one interface is the number of cpus of the system today. As each queue pair reserves 512 grant pages this default consumes a ridiculous number of grants for large guests. Limit the queue number to 8 as default. This value can be modified via a module parameter if required. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/net/xen-netback/netback.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 72ee1c305cc4..02db20b26749 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -67,6 +67,7 @@ module_param(rx_drain_timeout_msecs, uint, 0444);
unsigned int rx_stall_timeout_msecs = 60000;
module_param(rx_stall_timeout_msecs, uint, 0444);
+#define MAX_QUEUES_DEFAULT 8
unsigned int xenvif_max_queues;
module_param_named(max_queues, xenvif_max_queues, uint, 0644);
MODULE_PARM_DESC(max_queues,
@@ -2157,11 +2158,12 @@ static int __init netback_init(void)
if (!xen_domain())
return -ENODEV;
- /* Allow as many queues as there are CPUs if user has not
+ /* Allow as many queues as there are CPUs but max. 8 if user has not
* specified a value.
*/
if (xenvif_max_queues == 0)
- xenvif_max_queues = num_online_cpus();
+ xenvif_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
+ num_online_cpus());
if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",