Re: commit 16ecba59 breaks 82574L under heavy load.

[Benjamin Poirier]

On 2017/07/20 10:00, Lennart Sorensen wrote:
> On Wed, Jul 19, 2017 at 05:07:47PM -0700, Benjamin Poirier wrote:
> > Are you sure about this? In my testing, while triggering the overrun
> > with the msleep, I read ICR when entering e1000_msix_other() and RXO is
> > consistently set.
> 
> I had thousands of calls to e1000_msix_other where the only bit set
> was OTHER.
> 
> I don't know if the cause is overruns, it just seems plausible.
> 
> > I'm working on a patch that uses that fact to handle the situation and
> > limit the interrupt.
> 
> Excellent.
> 

Could you please test the following patch and let me know if it:
1) reduces the interrupt rate of the Other msi-x vector
2) avoids the link flaps
or
3) logs some dmesg warnings of the form "Other interrupt with unhandled [...]"
In this case, please paste icr values printed.

Thanks

diff --git a/drivers/net/ethernet/intel/e1000e/defines.h b/drivers/net/ethernet/intel/e1000e/defines.h
index 0641c0098738..afb7ebe20b24 100644
--- a/drivers/net/ethernet/intel/e1000e/defines.h
+++ b/drivers/net/ethernet/intel/e1000e/defines.h
@@ -398,6 +398,7 @@
 #define E1000_ICR_LSC           0x00000004 /* Link Status Change */
 #define E1000_ICR_RXSEQ         0x00000008 /* Rx sequence error */
 #define E1000_ICR_RXDMT0        0x00000010 /* Rx desc min. threshold (0) */
+#define E1000_ICR_RXO           0x00000040 /* Receiver Overrun */
 #define E1000_ICR_RXT0          0x00000080 /* Rx timer intr (ring 0) */
 #define E1000_ICR_ECCER         0x00400000 /* Uncorrectable ECC Error */
 /* If this bit asserted, the driver should claim the interrupt */
diff --git a/drivers/net/ethernet/intel/e1000e/e1000.h b/drivers/net/ethernet/intel/e1000e/e1000.h
index c7c994eb410e..f7b46eba3efb 100644
--- a/drivers/net/ethernet/intel/e1000e/e1000.h
+++ b/drivers/net/ethernet/intel/e1000e/e1000.h
@@ -351,6 +351,10 @@ struct e1000_adapter {
 	s32 ptp_delta;
 
 	u16 eee_advert;
+
+	unsigned int uh_count;
+	u32 uh_values[16];
+	unsigned int uh_values_nb;
 };
 
 struct e1000_info {
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index b3679728caac..46697338c0e1 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -46,6 +46,8 @@
 
 #include "e1000.h"
 
+DEFINE_RATELIMIT_STATE(other_uh_ratelimit_state, HZ, 1);
+
 #define DRV_EXTRAVERSION "-k"
 
 #define DRV_VERSION "3.2.6" DRV_EXTRAVERSION
@@ -1904,12 +1906,60 @@ static irqreturn_t e1000_msix_other(int __always_unused irq, void *data)
 	struct net_device *netdev = data;
 	struct e1000_adapter *adapter = netdev_priv(netdev);
 	struct e1000_hw *hw = &adapter->hw;
+	u32 icr;
+	bool enable = true;
+	bool handled = false;
+	unsigned int i;
 
-	hw->mac.get_link_status = true;
+	icr = er32(ICR);
+	if (icr & E1000_ICR_RXO) {
+		ew32(ICR, E1000_ICR_RXO);
+		enable = false;
+		/* napi poll will re-enable Other, make sure it runs */
+		if (napi_schedule_prep(&adapter->napi)) {
+			adapter->total_rx_bytes = 0;
+			adapter->total_rx_packets = 0;
+			__napi_schedule(&adapter->napi);
+		}
+		handled = true;
+	}
+	if (icr & E1000_ICR_LSC) {
+		ew32(ICR, E1000_ICR_LSC);
+		hw->mac.get_link_status = true;
+		/* guard against interrupt when we're going down */
+		if (!test_bit(__E1000_DOWN, &adapter->state)) {
+			mod_timer(&adapter->watchdog_timer, jiffies + 1);
+		}
+		handled = true;
+	}
 
-	/* guard against interrupt when we're going down */
-	if (!test_bit(__E1000_DOWN, &adapter->state)) {
-		mod_timer(&adapter->watchdog_timer, jiffies + 1);
+	if (!handled) {
+		adapter->uh_count++;
+		/* only print unseen icr values */
+		if (adapter->uh_values_nb < ARRAY_SIZE(adapter->uh_values)) {
+			for (i = 0; i < ARRAY_SIZE(adapter->uh_values); i++) {
+				if (adapter->uh_values[i] == icr) {
+					break;
+				}
+			}
+			if (i == ARRAY_SIZE(adapter->uh_values)) {
+				adapter->uh_values[adapter->uh_values_nb] =
+					icr;
+				adapter->uh_values_nb++;
+				netdev_warn(netdev,
+					    "Other interrupt with unhandled icr 0x%08x\n",
+					    icr);
+			}
+		}
+	}
+	if (adapter->uh_count && __ratelimit(&other_uh_ratelimit_state)) {
+		netdev_warn(netdev,
+			    "Other interrupt with unhandled cause, count %u\n",
+			    adapter->uh_count);
+		adapter->uh_count = 0;
+	}
+
+	if (enable && !test_bit(__E1000_DOWN, &adapter->state)) {
 		ew32(IMS, E1000_IMS_OTHER);
 	}
 
@@ -2681,7 +2731,8 @@ static int e1000e_poll(struct napi_struct *napi, int weight)
 		napi_complete_done(napi, work_done);
 		if (!test_bit(__E1000_DOWN, &adapter->state)) {
 			if (adapter->msix_entries)
-				ew32(IMS, adapter->rx_ring->ims_val);
+				ew32(IMS, adapter->rx_ring->ims_val |
+				     E1000_IMS_OTHER);
 			else
 				e1000_irq_enable(adapter);
 		}
@@ -4197,7 +4248,7 @@ static void e1000e_trigger_lsc(struct e1000_adapter *adapter)
 	struct e1000_hw *hw = &adapter->hw;
 
 	if (adapter->msix_entries)
-		ew32(ICS, E1000_ICS_OTHER);
+		ew32(ICS, E1000_ICS_LSC | E1000_ICS_OTHER);
 	else
 		ew32(ICS, E1000_ICS_LSC);
 }
@@ -7572,6 +7623,8 @@ static int __init e1000_init_module(void)
 		e1000e_driver_version);
 	pr_info("Copyright(c) 1999 - 2015 Intel Corporation.\n");
 
+	ratelimit_set_flags(&other_uh_ratelimit_state, RATELIMIT_MSG_ON_RELEASE);
+
 	return pci_register_driver(&e1000_driver);
 }
 module_init(e1000_init_module);