Re: [PATCH net-next 2/2] net/sched: act_police: don't use spinlock in the data path

[Davide Caratti <dcaratti@redhat.com>]

On Wed, 2018-11-14 at 22:46 -0800, Eric Dumazet wrote:
> 
> On 09/13/2018 10:29 AM, Davide Caratti wrote:
> > use RCU instead of spinlocks, to protect concurrent read/write on
> > act_police configuration. This reduces the effects of contention in the
> > data path, in case multiple readers are present.
> > 
> > Signed-off-by: Davide Caratti <dcaratti@redhat.com>
> > ---
> >  net/sched/act_police.c | 156 ++++++++++++++++++++++++-----------------
> >  1 file changed, 92 insertions(+), 64 deletions(-)
> > 
> 
> I must be missing something obvious with this patch.

hello Eric,

On the opposite, I missed something obvious when I wrote that patch: there
is a race condition on tcfp_toks, tcfp_ptoks and tcfp_t_c: thank you for
noticing it.

These variables still need to be protected with a spinlock. I will do a
patch and evaluate if 'act_police' is still faster than a version where   
2d550dbad83c ("net/sched: .... ") is reverted, and share results in the
next hours.

Ok?

-- 
davide