dev.bce.3.mbuf_alloc_failed_count increases permanently

[David Christensen]

> > > dev.bce.3.l2fhdr_error_count: 0
> > > dev.bce.3.mbuf_alloc_failed_count: 2098856
> > > dev.bce.3.mbuf_frag_count: 2655288
> > > dev.bce.3.dma_map_addr_rx_failed_count: 0
> > > dev.bce.3.dma_map_addr_tx_failed_count: 57
> > > dev.bce.3.unexpected_attention_count: 0
> > > dev.bce.3.com_no_buffers: 0
> > >
> > >
> > > Any suggestions? What is the reason of this?
> >
> > It's normal in a system under load, the kernel can't always
> > allocate memory when requested by the driver.  The result
> > is that RX frames will be dropped as the driver reuses an
> > existing mbuf, a response taken by many other drivers.
> >
> > If you notice rapid increases during certain system operations
> > then you should consider increasing the amount of system
> > memory.
> >
> 
> Thanks for you answer, Dave.
> 
> What do you mean under "systems memory"? Is it the physical memory or the
> virtual one?

Virtual memory is likely sufficient in this case, though more frequent swapping
may cause an equivalent performance loss to the dropped network traffic (i.e.
you may be swapping one performance bottleneck for another).  The counter 
"dma_map_addr_*" is incremented when the OS cannot map an MBUF for DMA 
access.  If you see that incrementing as rapidly then you should definitely look
at adding physical memory.

Dave