diff mbox series

[net] nfp: avoid soft lockups under control message storm

Message ID 20181002171014.19693-1-jakub.kicinski@netronome.com
State Accepted, archived
Delegated to: David Miller
Headers show
Series [net] nfp: avoid soft lockups under control message storm | expand

Commit Message

Jakub Kicinski Oct. 2, 2018, 5:10 p.m. UTC 
When FW floods the driver with control messages try to exit the cmsg
processing loop every now and then to avoid soft lockups.  Cmsg
processing is generally very lightweight so 512 seems like a reasonable
budget, which should not be exceeded under normal conditions.

Fixes: 77ece8d5f196 ("nfp: add control vNIC datapath")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Tested-by: Pieter Jansen van Vuuren <pieter.jansenvanvuuren@netronome.com>
---
 .../net/ethernet/netronome/nfp/nfp_net_common.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
index 8ed38fd5a852..c6d29fdbb880 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
@@ -2077,14 +2077,17 @@  nfp_ctrl_rx_one(struct nfp_net *nn, struct nfp_net_dp *dp,
 	return true;
 }
 
-static void nfp_ctrl_rx(struct nfp_net_r_vector *r_vec)
+static bool nfp_ctrl_rx(struct nfp_net_r_vector *r_vec)
 {
 	struct nfp_net_rx_ring *rx_ring = r_vec->rx_ring;
 	struct nfp_net *nn = r_vec->nfp_net;
 	struct nfp_net_dp *dp = &nn->dp;
+	unsigned int budget = 512;
 
-	while (nfp_ctrl_rx_one(nn, dp, r_vec, rx_ring))
+	while (nfp_ctrl_rx_one(nn, dp, r_vec, rx_ring) && budget--)
 		continue;
+
+	return budget;
 }
 
 static void nfp_ctrl_poll(unsigned long arg)
@@ -2096,9 +2099,13 @@  static void nfp_ctrl_poll(unsigned long arg)
 	__nfp_ctrl_tx_queued(r_vec);
 	spin_unlock_bh(&r_vec->lock);
 
-	nfp_ctrl_rx(r_vec);
-
-	nfp_net_irq_unmask(r_vec->nfp_net, r_vec->irq_entry);
+	if (nfp_ctrl_rx(r_vec)) {
+		nfp_net_irq_unmask(r_vec->nfp_net, r_vec->irq_entry);
+	} else {
+		tasklet_schedule(&r_vec->tasklet);
+		nn_dp_warn(&r_vec->nfp_net->dp,
+			   "control message budget exceeded!\n");
+	}
 }
 
 /* Setup and Configuration