Subject: Re: [PATCH RFC] bonding: rate-limit bonding driver inspect messages

From: Jay Vosburgh <[email-masked]>
Date: Wed, 14 Feb 2024 10:34:35 -0800

Praveen Kumar Kannoju <[email-masked]> wrote:

>Rate limit bond driver log messages, to prevent a log flood in a run-away
>situation, e.g couldn't get rtnl lock. Message flood leads to instability
>of system and loss of other crucial messages.
>
>Signed-off-by: Praveen Kumar Kannoju <[email-masked]>
>---
> drivers/net/bonding/bond_main.c | 34 +++++++++++++++++++---------------
> include/net/bonding.h           | 11 +++++++++++
> 2 files changed, 30 insertions(+), 15 deletions(-)
>
>diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>index 4e0600c..32098dd 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) ?
>+				bond_info_rl(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);
>+					     bond->params.downdelay * bond->params.miimon);

	Why not use net_info_ratelimited() or net_ratelimit()?  The rest
of the bonding messages that are rate limited are almost all gated by
the net rate limiter.

	-J

> 			}
> 			fallthrough;
> 		case BOND_LINK_FAIL:
>@@ -2623,9 +2624,10 @@ static int bond_miimon_inspect(struct bonding *bond)
> 				/* recovered before downdelay expired */
> 				bond_propose_link_state(slave, BOND_LINK_UP);
> 				slave->last_link_up = jiffies;
>-				slave_info(bond->dev, slave->dev, "link status up again after %d ms\n",
>-					   (bond->params.downdelay - slave->delay) *
>-					   bond->params.miimon);
>+				bond_info_rl(bond->dev, slave->dev,
>+					     "link status up again after %d ms\n",
>+					     (bond->params.downdelay - slave->delay) *
>+					     bond->params.miimon);
> 				commit++;
> 				continue;
> 			}
>@@ -2648,18 +2650,20 @@ static int bond_miimon_inspect(struct bonding *bond)
> 			slave->delay = bond->params.updelay;
> 
> 			if (slave->delay) {
>-				slave_info(bond->dev, slave->dev, "link status up, enabling it in %d ms\n",
>-					   ignore_updelay ? 0 :
>-					   bond->params.updelay *
>-					   bond->params.miimon);
>+				bond_info_rl(bond->dev, slave->dev,
>+					     "link status up, enabling it in %d ms\n",
>+					     ignore_updelay ? 0 :
>+					     bond->params.updelay *
>+					     bond->params.miimon);
> 			}
> 			fallthrough;
> 		case BOND_LINK_BACK:
> 			if (!link_state) {
> 				bond_propose_link_state(slave, BOND_LINK_DOWN);
>-				slave_info(bond->dev, slave->dev, "link status down again after %d ms\n",
>-					   (bond->params.updelay - slave->delay) *
>-					   bond->params.miimon);
>+				bond_info_rl(bond->dev, slave->dev,
>+					     "link status down again after %d ms\n",
>+					     (bond->params.updelay - slave->delay) *
>+					     bond->params.miimon);
> 				commit++;
> 				continue;
> 			}
>diff --git a/include/net/bonding.h b/include/net/bonding.h
>index 5b8b1b6..ebdfaf0 100644
>--- a/include/net/bonding.h
>+++ b/include/net/bonding.h
>@@ -39,8 +39,19 @@
> #define __long_aligned __attribute__((aligned((sizeof(long)))))
> #endif
> 
>+DEFINE_RATELIMIT_STATE(bond_rs, DEFAULT_RATELIMIT_INTERVAL,
>+		       DEFAULT_RATELIMIT_BURST);
>+
>+#define bond_ratelimited_function(function, ...)	\
>+do {							\
>+	if (__ratelimit(&bond_rs))		\
>+		function(__VA_ARGS__);			\
>+} while (0)
>+
> #define slave_info(bond_dev, slave_dev, fmt, ...) \
> 	netdev_info(bond_dev, "(slave %s): " fmt, (slave_dev)->name, ##__VA_ARGS__)
>+#define bond_info_rl(bond_dev, slave_dev, fmt, ...) \
>+	bond_ratelimited_function(slave_info, fmt, ##__VA_ARGS__)
> #define slave_warn(bond_dev, slave_dev, fmt, ...) \
> 	netdev_warn(bond_dev, "(slave %s): " fmt, (slave_dev)->name, ##__VA_ARGS__)
> #define slave_dbg(bond_dev, slave_dev, fmt, ...) \
>-- 
>1.8.3.1
>
>

---
	-Jay Vosburgh, [email-masked]