netdev - [PATCH net-next v2 2/2] amd-xgbe: schedule NAPI on Rx Buffer Unavailable (RBU)

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Message-ID: <20251129175016.3034185-3-Raju.Rangoju@amd.com>
Date: Sat, 29 Nov 2025 23:20:16 +0530
From: Raju Rangoju <Raju.Rangoju@....com>
To: <netdev@...r.kernel.org>
CC: <pabeni@...hat.com>, <kuba@...nel.org>, <edumazet@...gle.com>,
	<davem@...emloft.net>, <andrew+netdev@...n.ch>, <Shyam-sundar.S-k@....com>,
	Raju Rangoju <Raju.Rangoju@....com>
Subject: [PATCH net-next v2 2/2] amd-xgbe: schedule NAPI on Rx Buffer Unavailable (RBU)

Under heavy load, Rx Buffer Unavailable (RBU) can occur if Rx processing
is slower than network. When an RBU is signaled, try to schedule NAPI to
help recover from such situation (including cases where an IRQ may be
missed or such)

Signed-off-by: Raju Rangoju <Raju.Rangoju@....com>
---
 drivers/net/ethernet/amd/xgbe/xgbe-drv.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
index aca1c57554d7..3ddd896d6987 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
@@ -410,15 +410,29 @@ static void xgbe_isr_bh_work(struct work_struct *work)
 		 * Decide which NAPI to use and whether to schedule:
 		 * - When not using per-channel IRQs: schedule on global NAPI
 		 *   if TI or RI are set.
+		 * - RBU should also trigger NAPI (either per-channel or global)
+		 *   to allow refill.
 		 */
 		if (!per_ch_irq && (ti || ri))
 			schedule_napi = true;
 
+		if (rbu) {
+			schedule_napi = true;
+			pdata->ext_stats.rx_buffer_unavailable++;
+		}
+
 		napi = per_ch_irq ? &channel->napi : &pdata->napi;
 
 		if (schedule_napi && napi_schedule_prep(napi)) {
 			/* Disable interrupts appropriately before polling */
-			xgbe_disable_rx_tx_ints(pdata);
+			if (per_ch_irq) {
+				if (pdata->channel_irq_mode)
+					xgbe_disable_rx_tx_int(pdata, channel);
+				else
+					disable_irq_nosync(channel->dma_irq);
+			} else {
+				xgbe_disable_rx_tx_ints(pdata);
+			}
 
 			/* Turn on polling */
 			__napi_schedule(napi);
@@ -436,9 +450,6 @@ static void xgbe_isr_bh_work(struct work_struct *work)
 			XGMAC_SET_BITS(dma_ch_isr, DMA_CH_SR, RI, 0);
 		}
 
-		if (rbu)
-			pdata->ext_stats.rx_buffer_unavailable++;
-
 		/* Restart the device on a Fatal Bus Error */
 		if (fbe)
 			schedule_work(&pdata->restart_work);
-- 
2.34.1