[ovs-dev] [PATCH] mac-learning: Increase default mac table size to 8K from 2K

Eelco Chaudron echaudro at redhat.com
Wed Jun 27 15:02:31 UTC 2018

On 27 Jun 2018, at 16:09, Ben Pfaff wrote:

> On Wed, Jun 27, 2018 at 01:24:25PM +0200, Eelco Chaudron wrote:
>> In field deployments of OVS (mostly in combination with OpenStack) we
>> see that the 2K default MAC forwarding table is too small.
>> On average this tables is around 5k entries, hence this patch to
>> increase the default value to the next power of 2, i.e. 8K.
>> This increase in size does not automatically increase the memory
>> footprint, as the memory for the MAC entries, are allocated only when
>> needed.
>> Signed-off-by: Eelco Chaudron <echaudro at redhat.com>
> Applied, thanks!

Ben thanks for applying so quickly, however, I seem to have messed up 
the number :(

5K, was 50K (I counted zero’s wrong), which leads to 64K entries by 

This might make other people more opposed to the change, as it could 
result in a lot of memory being eaten when someone does a MAC sweep 
(attack), around 4Mbyte per bridge.

Any input here?



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