From 41ed0a00ffcd903ece4304a4a65d95706115ffcb Mon Sep 17 00:00:00 2001
From: "Dwip N. Banerjee" <dnbanerg@us.ibm.com>
Date: Wed, 18 Nov 2020 19:12:25 -0600
Subject: [PATCH] ibmvnic: Do not replenish RX buffers after every polling loop

References: bsc#1184114 ltc#192237 bsc#1179243 ltc#189290
Patch-mainline: v5.11-rc1
Git-commit: 41ed0a00ffcd903ece4304a4a65d95706115ffcb

Reduce the amount of time spent replenishing RX buffers by only doing
so once available buffers has fallen under a certain threshold, in this
case half of the total number of buffers, or if the polling loop exits
before the packets processed is less than its budget. Non-exhaustion of
NAPI budget implies lower incoming packet pressure, allowing the leeway
to refill the buffers in preparation for any impending burst.

Signed-off-by: Dwip N. Banerjee <dnbanerg@us.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 96df6d8fa277..9fe43ab0496d 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -2537,7 +2537,10 @@ static int ibmvnic_poll(struct napi_struct *napi, int budget)
 		frames_processed++;
 	}
 
-	if (adapter->state != VNIC_CLOSING)
+	if (adapter->state != VNIC_CLOSING &&
+	    ((atomic_read(&adapter->rx_pool[scrq_num].available) <
+	      adapter->req_rx_add_entries_per_subcrq / 2) ||
+	      frames_processed < budget))
 		replenish_rx_pool(adapter, &adapter->rx_pool[scrq_num]);
 	if (frames_processed < budget) {
 		if (napi_complete_done(napi, frames_processed)) {
-- 
2.26.2