On 9/11/24 19:01, Kabuli Chana wrote:
Why is this kernel 5.15 based?
On 2024-09-11 06:18, webmas...@jbsky.fr wrote:
From: Julien Blais <webmas...@jbsky.fr>
This patch is submitted to the kernel.
For your information, this fixes the problem identified during a test
with
iperf, the packet sending stall and above all the use of a 100% CPU
because of the softIRQ.
Before:
root@wrt1900acv1:~# cat /proc/interrupts
CPU0 CPU1
24: 18652404 15171396 MPIC 5 Level
armada_370_xp_per_cpu_tick
26: 292136 78 MPIC 31 Level mv64xxx_i2c
27: 26 0 MPIC 41 Level ttyS0
33: 1024678 0 MPIC 45 Level ehci_hcd:usb1
34: 23007175 0 MPIC 8 Level eth0
After:
root@OpenWrt:/# cat /proc/interrupts
CPU0 CPU1
24: 194183 161947 MPIC 5 Level
armada_370_xp_per_cpu_tick
25: 0 0 MPIC 3 Level arm-pmu
26: 246 0 MPIC 31 Level mv64xxx_i2c
27: 5488 0 MPIC 41 Level ttyS0
33: 0 0 MPIC 45 Level ehci_hcd:usb1
34: 2015130 6330694 MPIC 8 Level eth0
.....
new file mode 100644
index 0000000000..0fa191ea14
--- /dev/null
+++ b/target/linux/mvebu/patches-5.15/701-mvneta-fix-napi-poll-
infinite-loop.patch
@@ -0,0 +1,38 @@
+From bbeea07de50e925df3877f63a24aee1d35828a02 Mon Sep 17 00:00:00 2001
+From: Julien Blais <webmas...@jbsky.fr>
+Date: Wed, 11 Sep 2024 13:27:09 +0200
+Subject: [PATCH v2] mvneta: fix "napi poll" infinite loop
+
+In percpu mode, when there's a network load, one of the cpus can be
+solicited without having anything to process.
+If 0 is returned to napi poll, napi will ignore the next requests,
+causing an infinite loop with ISR handling.
+
+Without this change, patches hang around fixing the queue at 0 and
+the interrupt remains stuck on the 1st CPU.
+The percpu conf is useless in this case, so we might as well remove it.
+
+Signed-off-by: Julien Blais <webmas...@jbsky.fr>
+---
+ drivers/net/ethernet/marvell/mvneta.c | 5 ++++-
+ 1 file changed, 4 insertions(+), 1 deletion(-)
+
+diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/
ethernet/marvell/mvneta.c
+index 3f124268b..b6e89b888 100644
+--- a/drivers/net/ethernet/marvell/mvneta.c
++++ b/drivers/net/ethernet/marvell/mvneta.c
+@@ -3186,7 +3186,10 @@ static int mvneta_poll(struct napi_struct
*napi, int budget)
+
+ if (rx_done < budget) {
+ cause_rx_tx = 0;
+- napi_complete_done(napi, rx_done);
++ if (rx_done)
++ napi_complete_done(napi, rx_done);
++ else
++ napi_complete(napi);
+
+ if (pp->neta_armada3700) {
+ unsigned long flags;
+--
+2.39.2
+
This patch is doing nothing and was rejected, see:
https://lore.kernel.org/netdev/20240911082035.403f4...@kernel.org/T/
Hauke
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