[PATCH 0/5] net: mvneta: some bug fix and trivial improvement

On Wed, 29 Aug 2018 16:51:31 +0800 Jisheng Zhang wrote:

On Wed, 29 Aug 2018 16:40:24 +0800 Jisheng Zhang wrote:

quoted

On Wed, 29 Aug 2018 16:25:57 +0800
Jisheng Zhang wrote:
  

quoted

patch1 fixes rx_offset_correction set and usage. Because the
rx_offset_correction is RX packet offset correction for platforms,
it's not related with SW BM, instead, it's only related with the
platform's NET_SKB_PAD.

patch2 fixes the wrong function to unmap rx buf    

I have question about the following two commits:

7e47fd84b56b ("net: mvneta: Allocate page for the descriptor"), it cause
a waste, for normal 1500 MTU, before this patch we allocate 1920Bytes for rx
after this patch, we always allocate PAGE_SIZE bytes, if PAGE_SIZE=4096, we
waste 53% memory for each rx buf. I'm not sure whether the performance
improvement deserve the pay.

562e2f467e71 ("net: mvneta: Improve the buffer allocation method for SWBM")
mentions that "With system having a small memory (around 256MB), the state
"cannot allocate memory to refill with new buffer" is reach pretty quickly"
is it due to the memory waste as said above? Anyway, by this commit, we
want to improve the situation on a small memory system, so should we firstly
revert commit 7e47fd84b56b ("net: mvneta: Allocate page for the descriptor")?

Any comments? 

Now I believe the situation is due to the memory waste introduced by 7e47fd84b56b
With linux 4.18, I tried to limit berlin platforms available memory to 256MB,
I didn't see "cannot allocate memory to refill with new buffer".

Thanks

quoted

If maintainers decide to revert the two commits: 7e47fd84b56b and 562e2f467e71
then, patch1,2,3 are useless, we can drop them. Only patch4 and patch5 are
still useful.

Thanks

quoted

Any comments are welcome!

Thanks

  

quoted

patch3 removes the NETIF_F_GRO check ourself, because the net subsystem
will handle it for us.

patch4 enables NETIF_F_RXCSUM by default, since the driver and HW
supports the feature.

patch5 is a trivial optimization, to reduce smp_processor_id() calling
in mvneta_tx_done_gbe.

Jisheng Zhang (5):
  net: mvneta: fix rx_offset_correction set and usage
  net: mvneta: fix the wrong function to unmap rx buf
  net: mvneta: Don't check NETIF_F_GRO ourself
  net: mvneta: enable NETIF_F_RXCSUM by default
  net: mvneta: reduce smp_processor_id() calling in mvneta_tx_done_gbe

 drivers/net/ethernet/marvell/mvneta.c | 49 ++++++++++++---------------
 1 file changed, 22 insertions(+), 27 deletions(-)