[Bridge] Out of memory problem

Stephen Hemminger shemminger at vyatta.com
Mon Apr 13 23:04:31 PDT 2009


On Tue, 14 Apr 2009 13:21:13 +0800
"Tekale Sharad-FHJN78" <FHJN78 at motorola.com> wrote:

>  
> 
> Hi Stephen 
> > Most likely, you have created a loop and are not running spanning
> tree. When a loop happens, packets multiply until all > resources are
> exhausted.
> 
> > you have created a loop.
> Ya, I have bridge named br-lan created by($brctl), and I have attached
> two interfaces to it, and I'm sending traffic from PC1 to PC2. Some
> thing like this
> 
>  	    		 ----------------------- 
> 	   		|    ------------       |
> 	   		|   |   br-lan   |      |    <--- AP
> 	   		|    ------------       |      
> 	   		|  eth0.0       eth0.1  | 
> 	    		 ----|------------|-----
> 
> 	      	     |	      |
> 	      	     |	      |
>   	     		    PC1          PC2
> 
> Previously:
> root at none:/$ brctl show
> bridge name     bridge id               STP enabled     interfaces
> br-lan          8000.001570d8d8fd       no              eth0.0
>                                                         eth0.1
> 
> >are not running spanning tree.
> Is it always necessary to enable spanning tree when traffic is sent over
> loop?
> 
> I have enabled spanning tree using
> 
> root at none:/$ brctl stp br-lan on
> root at none:/$ brctl show
> bridge name     bridge id               STP enabled     interfaces
> br-lan          8000.001570d8d8fd       yes             eth0.0
>                                                         eth0.1
> 
> But again, when huge traffic is pumped from PC1 to PC2, The
> skbuff_head_cache value is increased rapidly and even after stop pumping
> the traffic, this value doesn't come down, and system goes for crash or
> reboot because of out of memory.
> 
> root at none:/$ cat /proc/slabinfo | grep skbuff_head
> skbuff_head_cache   4560   4560    192   20    1 : tunables  120   60
> 0 : slabdata    228    228      0
> 
> One more point, say I have each port attached to there own bridge, and
> when I route traffic from one host to other, I'll not face this
> behavior, This behavior is relevant only in above case.
> 
> Do I have to do any other setting to overcome out of memory problem? 
> Also, Please let me know if any other information is required to isolate
> this behavior.

What network device driver, that is probably the problem?


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