RE: [PATCH net-next v4] bonding: rate-limit bonding driver inspect messages

[Praveen Kannoju <praveen.kannoju@oracle.com>]

> -----Original Message-----
> From: Simon Horman <horms@kernel.org>
> Sent: 20 February 2024 06:38 PM
> To: Praveen Kannoju <praveen.kannoju@oracle.com>
> Cc: j.vosburgh@gmail.com; andy@greyhouse.net; davem@davemloft.net; edumazet@google.com; kuba@kernel.org;
> pabeni@redhat.com; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Rajesh Sivaramasubramaniom
> <rajesh.sivaramasubramaniom@oracle.com>; Rama Nichanamatlu <rama.nichanamatlu@oracle.com>; Manjunath Patil
> <manjunath.b.patil@oracle.com>
> Subject: Re: [PATCH net-next v4] bonding: rate-limit bonding driver inspect messages
> 
> On Tue, Feb 20, 2024 at 10:34:37AM +0530, Praveen Kumar Kannoju wrote:
> > Through the routine bond_mii_monitor(), bonding driver inspects and
> > commits the slave state changes. During the times when slave state
> > change and failure in aqcuiring rtnl lock happen at the same time, the
> > routine
> > bond_mii_monitor() reschedules itself to come around after 1 msec to
> > commit the new state.
> >
> > During this, it executes the routine bond_miimon_inspect() to
> > re-inspect the state chane and prints the corresponding slave state on to the console.
> > Hence we do see a message at every 1 msec till the rtnl lock is
> > acquired and state chage is committed.
> >
> > This patch doesn't change how bond functions. It only simply limits
> > this kind of log flood.
> >
> > Signed-off-by: Praveen Kumar Kannoju <praveen.kannoju@oracle.com>
> > ---
> > v4:
> >   - Rectification in the patch subject and versioning details.
> > v3: https://lore.kernel.org/lkml/20240219133721.4567-1-praveen.kannoju@oracle.com/
> >   - Commit message is modified to provide summary of the issue, because of
> >     which rate-limiting the bonding driver messages is needed.
> > v2: https://lore.kernel.org/lkml/20240215172554.4211-1-praveen.kannoju@oracle.com/
> >   - Use exising net_ratelimit() instead of introducing new rate-limit
> >     parameter.
> > v1:
> > https://lore.kernel.org/lkml/20240214044245.33170-1-praveen.kannoju@or
> > acle.com/
> > ---
> >  drivers/net/bonding/bond_main.c | 36
> > ++++++++++++++++++++----------------
> >  1 file changed, 20 insertions(+), 16 deletions(-)
> >
> > diff --git a/drivers/net/bonding/bond_main.c
> > b/drivers/net/bonding/bond_main.c index 4e0600c..e92eba1 100644
> > --- a/drivers/net/bonding/bond_main.c
> > +++ b/drivers/net/bonding/bond_main.c
> > @@ -2610,12 +2610,13 @@ static int bond_miimon_inspect(struct bonding *bond)
> >  			commit++;
> >  			slave->delay = bond->params.downdelay;
> >  			if (slave->delay) {
> > -				slave_info(bond->dev, slave->dev, "link status down for %sinterface, disabling it in %d ms\n",
> > -					   (BOND_MODE(bond) ==
> > -					    BOND_MODE_ACTIVEBACKUP) ?
> > -					    (bond_is_active_slave(slave) ?
> > -					     "active " : "backup ") : "",
> > -					   bond->params.downdelay * bond->params.miimon);
> > +				if (net_ratelimit())
> > +					slave_info(bond->dev, slave->dev, "link status down for %sinterface, disabling it in %d ms\n",
> > +						   (BOND_MODE(bond) ==
> > +						   BOND_MODE_ACTIVEBACKUP) ?
> > +						   (bond_is_active_slave(slave) ?
> > +						   "active " : "backup ") : "",
> > +						   bond->params.downdelay * bond->params.miimon);
> >  			}
> 
> Hi Praveen,
> 
> As this is used several times I think that it would be worth introducing a slave_info_ratelimit() helper. That is  assuming slave_info() is
> still used without a rate limit. If not, you could just add net_ratelimit directly to slave_info().
> 
> If none of this is desirable for some reason, then could you consider reducing indentation somehow. f.e.:
> 
> 		if (slave->delayi && net_ratelimit())
> 			slave_info(...

Thank you, Simon. 
Jay insisted upon using the existing net_ratelimit() instead of introducing a new helper. I've modified the patch to reduce the indentation as suggested by you. Please review.

-
Praveen.