Re: [PATCH 1/2] xen/netfront: set default upper limit of tx/rx queues to 8
From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Date: 2017-01-10 14:53:48
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On 01/10/2017 08:32 AM, Juergen Gross wrote:
quoted hunk ↗ jump to hunk
The default for the number of tx/rx queues of one interface is the number of vcpus 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-netfront.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index a479cd9..490c865 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c@@ -57,6 +57,7 @@ #include <xen/interface/grant_table.h> /* Module parameters */ +#define MAX_QUEUES_DEFAULT 8 static unsigned int xennet_max_queues; module_param_named(max_queues, xennet_max_queues, uint, 0644); MODULE_PARM_DESC(max_queues,@@ -2164,11 +2165,12 @@ static int __init netif_init(void) pr_info("Initialising Xen virtual ethernet driver\n"); - /* Allow as many queues as there are CPUs if user has not + /* Allow as many queues as there are CPUs inut max. 8 if user has not
Based on comment change in the second patch: s/inut/but/ ? Also, comment style in both patches. Other than that, for both: Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
* specified a value. */ if (xennet_max_queues == 0) - xennet_max_queues = num_online_cpus(); + xennet_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT, + num_online_cpus()); return xenbus_register_frontend(&netfront_driver); }