[All] (testing) Bumpe kernel to 6.6.14

buildroot-external/patches/linux/0015-net-Avoid-the-IPI-to-free-the.patch

@@ -0,0 +1,128 @@
+From 30de1da993f600f4771b3f3724ce0667f66ac69b Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Mon, 15 Aug 2022 17:29:50 +0200
+Subject: [PATCH 015/195] net: Avoid the IPI to free the
+
+skb_attempt_defer_free() collects a skbs, which was allocated on a
+remote CPU, on a per-CPU list. These skbs are either freed on that
+remote CPU once the CPU enters NET_RX or an remote IPI function is
+invoked in to raise the NET_RX softirq if a threshold of pending skb has
+been exceeded.
+This remote IPI can cause the wakeup of ksoftirqd on PREEMPT_RT if the
+remote CPU idle was idle. This is undesired because once the ksoftirqd
+is running it will acquire all pending softirqs and they will not be
+executed as part of the threaded interrupt until ksoftird goes idle
+again.
+
+To void all this, schedule the deferred clean up from a worker.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/netdevice.h |  4 ++++
+ net/core/dev.c            | 39 ++++++++++++++++++++++++++++++---------
+ net/core/skbuff.c         |  7 ++++++-
+ 3 files changed, 40 insertions(+), 10 deletions(-)
+
+diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
+index b8e60a20416b..ffa5248a90e2 100644
+--- a/include/linux/netdevice.h
++++ b/include/linux/netdevice.h
+@@ -3258,7 +3258,11 @@ struct softnet_data {
+ 	int			defer_count;
+ 	int			defer_ipi_scheduled;
+ 	struct sk_buff		*defer_list;
++#ifndef CONFIG_PREEMPT_RT
+ 	call_single_data_t	defer_csd;
++#else
++	struct work_struct	defer_work;
++#endif
+ };
+ 
+ static inline void input_queue_head_incr(struct softnet_data *sd)
+diff --git a/net/core/dev.c b/net/core/dev.c
+index e480afb50d4c..227338b8cda8 100644
+--- a/net/core/dev.c
++++ b/net/core/dev.c
+@@ -4705,15 +4705,6 @@ static void rps_trigger_softirq(void *data)
+ 
+ #endif /* CONFIG_RPS */
+ 
+-/* Called from hardirq (IPI) context */
+-static void trigger_rx_softirq(void *data)
+-{
+-	struct softnet_data *sd = data;
+-
+-	__raise_softirq_irqoff(NET_RX_SOFTIRQ);
+-	smp_store_release(&sd->defer_ipi_scheduled, 0);
+-}
+-
+ /*
+  * After we queued a packet into sd->input_pkt_queue,
+  * we need to make sure this queue is serviced soon.
+@@ -6682,6 +6673,32 @@ static void skb_defer_free_flush(struct softnet_data *sd)
+ 	}
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT
++
++/* Called from hardirq (IPI) context */
++static void trigger_rx_softirq(void *data)
++{
++	struct softnet_data *sd = data;
++
++	__raise_softirq_irqoff(NET_RX_SOFTIRQ);
++	smp_store_release(&sd->defer_ipi_scheduled, 0);
++}
++
++#else
++
++static void trigger_rx_softirq(struct work_struct *defer_work)
++{
++	struct softnet_data *sd;
++
++	sd = container_of(defer_work, struct softnet_data, defer_work);
++	smp_store_release(&sd->defer_ipi_scheduled, 0);
++	local_bh_disable();
++	skb_defer_free_flush(sd);
++	local_bh_enable();
++}
++
++#endif
++
+ static int napi_threaded_poll(void *data)
+ {
+ 	struct napi_struct *napi = data;
+@@ -11606,7 +11623,11 @@ static int __init net_dev_init(void)
+ 		INIT_CSD(&sd->csd, rps_trigger_softirq, sd);
+ 		sd->cpu = i;
+ #endif
++#ifndef CONFIG_PREEMPT_RT
+ 		INIT_CSD(&sd->defer_csd, trigger_rx_softirq, sd);
++#else
++		INIT_WORK(&sd->defer_work, trigger_rx_softirq);
++#endif
+ 		spin_lock_init(&sd->defer_lock);
+ 
+ 		init_gro_hash(&sd->backlog);
+diff --git a/net/core/skbuff.c b/net/core/skbuff.c
+index 011d69029112..9a9fbe18bf2f 100644
+--- a/net/core/skbuff.c
++++ b/net/core/skbuff.c
+@@ -6844,8 +6844,13 @@ nodefer:	__kfree_skb(skb);
+ 	/* Make sure to trigger NET_RX_SOFTIRQ on the remote CPU
+ 	 * if we are unlucky enough (this seems very unlikely).
+ 	 */
+-	if (unlikely(kick) && !cmpxchg(&sd->defer_ipi_scheduled, 0, 1))
++	if (unlikely(kick) && !cmpxchg(&sd->defer_ipi_scheduled, 0, 1)) {
++#ifndef CONFIG_PREEMPT_RT
+ 		smp_call_function_single_async(cpu, &sd->defer_csd);
++#else
++		schedule_work_on(cpu, &sd->defer_work);
++#endif
++	}
+ }
+ 
+ static void skb_splice_csum_page(struct sk_buff *skb, struct page *page,
+-- 
+2.43.0
+