[ovs-dev] [PATCH v2 5/5] net: Add Open vSwitch kernel components.

Jesse Gross jesse at nicira.com
Mon Nov 21 23:18:43 UTC 2011


On Mon, Nov 21, 2011 at 1:59 PM, Stephen Hemminger
<shemminger at vyatta.com> wrote:
> On Mon, 21 Nov 2011 13:30:29 -0800
> Jesse Gross <jesse at nicira.com> wrote:
>
>> +/**
>> + *   vport_record_error - indicate device error to generic stats layer
>> + *
>> + * @vport: vport that encountered the error
>> + * @err_type: one of enum vport_err_type types to indicate the error type
>> + *
>> + * If using the vport generic stats layer indicate that an error of the given
>> + * type has occured.
>> + */
>> +void vport_record_error(struct vport *vport, enum vport_err_type err_type)
>> +{
>> +     spin_lock(&vport->stats_lock);
>
> Sorry for over analyzing this... but I don't think the stats_lock
> is necessary either. The only thing it is protecting is against 64 bit
> wrap. If you used another u64_stat_sync for that one, it could be eliminated.
>
> Maybe?

The reason for stats_lock is that the error stats are not expected to
be contended so in order to save some memory they're not per-cpu and
we just use a spin lock to protect them.



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