Re: [PATCH 1/2] xen/netfront: set default upper limit of tx/rx queues to 8

From: Juergen Gross
Date: Tue Jan 10 2017 - 10:02:53 EST


On 10/01/17 15:53, Boris Ostrovsky wrote:
> On 01/10/2017 08:32 AM, Juergen Gross wrote:
>> 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@xxxxxxxx>
>> ---
>> 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.

Typo: yes
Style: no. checkpatch tells me that the net directory doesn't follow
common kernel style.

>
> Other than that, for both:
>
> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>

Thanks,

Juergen