RE: [EXT] Re: [PATCH RFC net-next 06/19] net: mvpp2: increase BM pool size to 2048 buffers

[Stefan Chulski]

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> 
> ----------------------------------------------------------------------
> On Sun, Jan 10, 2021 at 05:30:10PM +0200, stefanc@xxxxxxxxxxx wrote:
> > From: Stefan Chulski <stefanc@xxxxxxxxxxx>
> >
> > BM pool size increased to support Firmware Flow Control.
> > Minimum depletion thresholds to support FC is 1024 buffers.
> > BM pool size increased to 2048 to have some 1024 buffers space between
> > depletion thresholds and BM pool size.
> >
> > Signed-off-by: Stefan Chulski <stefanc@xxxxxxxxxxx>
> > ---
> >  drivers/net/ethernet/marvell/mvpp2/mvpp2.h | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2.h
> > b/drivers/net/ethernet/marvell/mvpp2/mvpp2.h
> > index 89b3ede..8dc669d 100644
> > --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2.h
> > +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2.h
> > @@ -851,8 +851,8 @@ enum mvpp22_ptp_packet_format {
> >  #define MVPP22_PTP_TIMESTAMPQUEUESELECT	BIT(18)
> >
> >  /* BM constants */
> > -#define MVPP2_BM_JUMBO_BUF_NUM		512
> > -#define MVPP2_BM_LONG_BUF_NUM		1024
> > +#define MVPP2_BM_JUMBO_BUF_NUM		2048
> > +#define MVPP2_BM_LONG_BUF_NUM		2048
> 
> Hi Stefan
> 
> Jumbo used to be 1/2 of regular. Do you know why?
> 
> It would be nice to have a comment in the commit message about why it is
> O.K. to change the ratio of jumbo to regular frames, and what if anything this
> does for memory requirements.
> 
> 	 Andrew

I don't know why it is half(no hardware restrictions for this). I would add to commit message new memory requirements for buffer allocations.

Thanks.