| From foo@baz Thu Nov 9 09:48:01 CET 2017 |
| From: Juergen Gross <jgross@suse.com> |
| Date: Tue, 10 Jan 2017 14:32:52 +0100 |
| Subject: xen/netback: set default upper limit of tx/rx queues to 8 |
| |
| From: Juergen Gross <jgross@suse.com> |
| |
| |
| [ 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> |
| --- |
| drivers/net/xen-netback/netback.c | 6 ++++-- |
| 1 file changed, 4 insertions(+), 2 deletions(-) |
| |
| --- a/drivers/net/xen-netback/netback.c |
| +++ b/drivers/net/xen-netback/netback.c |
| @@ -67,6 +67,7 @@ module_param(rx_drain_timeout_msecs, uin |
| 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, |
| @@ -1626,11 +1627,12 @@ 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", |
