@@ -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,
@@ -1622,11 +1623,12 @@ 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",
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> --- drivers/net/xen-netback/netback.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)