Re: [Qemu-devel] [PATCH v2 6/8] qemu:virtio-net: Enable filtering based on MAC, promisc, broadcast and allmulti

[malc]

On Tue, 3 Feb 2009, Anthony Liguori wrote:

> Blue Swirl wrote:
> > On 2/3/09, Alex Williamson <address@hidden> wrote:
> >   
> > > Make use of the new RX_MODE control virtqueue class by dropping
> > >  packets the guest doesn't want to see.
> > > 
> > >  Signed-off-by: Alex Williamson <address@hidden>
> > >     
> > 
> >   
> > >  +    static uint8_t bcast[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
> > >     
> > 
> > 'const'?
> >   
> 
> It may be good practice but practically speaking, I don't think it will
> generate different code.  The only thing that uses bcast is memcmp() which
> should be a builtin.  Since bcast doesn't otherwise escape the function, it's
> an obvious candidate for optimization.  I think the compiler already has
> enough information that const doesn't tell it anything more.

It does generate different code, bcast is being put into rodata in case
of const and data otherwise, whether it makes practical difference for
QEMU is another matter.

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