diff options
Diffstat (limited to 'debian/patches-rt/0004-net-Rename-rps_lock-to-backlog_lock.patch')
| -rw-r--r-- | debian/patches-rt/0004-net-Rename-rps_lock-to-backlog_lock.patch | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/debian/patches-rt/0004-net-Rename-rps_lock-to-backlog_lock.patch b/debian/patches-rt/0004-net-Rename-rps_lock-to-backlog_lock.patch new file mode 100644 index 000000000..70de5b94e --- /dev/null +++ b/debian/patches-rt/0004-net-Rename-rps_lock-to-backlog_lock.patch @@ -0,0 +1,164 @@ +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Sat, 9 Mar 2024 10:05:12 +0100 +Subject: [PATCH 4/4] net: Rename rps_lock to backlog_lock. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.8/older/patches-6.8.2-rt11.tar.xz + +The rps_lock.*() functions use the inner lock of a sk_buff_head for +locking. This lock is used if RPS is enabled, otherwise the list is +accessed lockless and disabling interrupts is enough for the +synchronisation because it is only accessed CPU local. Not only the list +is protected but also the NAPI state protected. +With the addition of backlog threads, the lock is also needed because of +the cross CPU access even without RPS. The clean up of the defer_list +list is also done via backlog threads (if enabled). + +It has been suggested to rename the locking function since it is no +longer just RPS. + +Rename the rps_lock*() functions to backlog_lock*(). + +Suggested-by: Jakub Kicinski <kuba@kernel.org> +Acked-by: Jakub Kicinski <kuba@kernel.org> +Link: https://lore.kernel.org/r/20240309090824.2956805-5-bigeasy@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + net/core/dev.c | 34 +++++++++++++++++----------------- + 1 file changed, 17 insertions(+), 17 deletions(-) + +--- a/net/core/dev.c ++++ b/net/core/dev.c +@@ -242,8 +242,8 @@ static bool use_backlog_threads(void) + + #endif + +-static inline void rps_lock_irqsave(struct softnet_data *sd, +- unsigned long *flags) ++static inline void backlog_lock_irq_save(struct softnet_data *sd, ++ unsigned long *flags) + { + if (IS_ENABLED(CONFIG_RPS) || use_backlog_threads()) + spin_lock_irqsave(&sd->input_pkt_queue.lock, *flags); +@@ -251,7 +251,7 @@ static inline void rps_lock_irqsave(stru + local_irq_save(*flags); + } + +-static inline void rps_lock_irq_disable(struct softnet_data *sd) ++static inline void backlog_lock_irq_disable(struct softnet_data *sd) + { + if (IS_ENABLED(CONFIG_RPS) || use_backlog_threads()) + spin_lock_irq(&sd->input_pkt_queue.lock); +@@ -259,8 +259,8 @@ static inline void rps_lock_irq_disable( + local_irq_disable(); + } + +-static inline void rps_unlock_irq_restore(struct softnet_data *sd, +- unsigned long *flags) ++static inline void backlog_unlock_irq_restore(struct softnet_data *sd, ++ unsigned long *flags) + { + if (IS_ENABLED(CONFIG_RPS) || use_backlog_threads()) + spin_unlock_irqrestore(&sd->input_pkt_queue.lock, *flags); +@@ -268,7 +268,7 @@ static inline void rps_unlock_irq_restor + local_irq_restore(*flags); + } + +-static inline void rps_unlock_irq_enable(struct softnet_data *sd) ++static inline void backlog_unlock_irq_enable(struct softnet_data *sd) + { + if (IS_ENABLED(CONFIG_RPS) || use_backlog_threads()) + spin_unlock_irq(&sd->input_pkt_queue.lock); +@@ -4758,12 +4758,12 @@ void kick_defer_list_purge(struct softne + unsigned long flags; + + if (use_backlog_threads()) { +- rps_lock_irqsave(sd, &flags); ++ backlog_lock_irq_save(sd, &flags); + + if (!__test_and_set_bit(NAPI_STATE_SCHED, &sd->backlog.state)) + __napi_schedule_irqoff(&sd->backlog); + +- rps_unlock_irq_restore(sd, &flags); ++ backlog_unlock_irq_restore(sd, &flags); + + } else if (!cmpxchg(&sd->defer_ipi_scheduled, 0, 1)) { + smp_call_function_single_async(cpu, &sd->defer_csd); +@@ -4825,7 +4825,7 @@ static int enqueue_to_backlog(struct sk_ + reason = SKB_DROP_REASON_NOT_SPECIFIED; + sd = &per_cpu(softnet_data, cpu); + +- rps_lock_irqsave(sd, &flags); ++ backlog_lock_irq_save(sd, &flags); + if (!netif_running(skb->dev)) + goto drop; + qlen = skb_queue_len(&sd->input_pkt_queue); +@@ -4834,7 +4834,7 @@ static int enqueue_to_backlog(struct sk_ + enqueue: + __skb_queue_tail(&sd->input_pkt_queue, skb); + input_queue_tail_incr_save(sd, qtail); +- rps_unlock_irq_restore(sd, &flags); ++ backlog_unlock_irq_restore(sd, &flags); + return NET_RX_SUCCESS; + } + +@@ -4849,7 +4849,7 @@ static int enqueue_to_backlog(struct sk_ + + drop: + sd->dropped++; +- rps_unlock_irq_restore(sd, &flags); ++ backlog_unlock_irq_restore(sd, &flags); + + dev_core_stats_rx_dropped_inc(skb->dev); + kfree_skb_reason(skb, reason); +@@ -5880,7 +5880,7 @@ static void flush_backlog(struct work_st + local_bh_disable(); + sd = this_cpu_ptr(&softnet_data); + +- rps_lock_irq_disable(sd); ++ backlog_lock_irq_disable(sd); + skb_queue_walk_safe(&sd->input_pkt_queue, skb, tmp) { + if (skb->dev->reg_state == NETREG_UNREGISTERING) { + __skb_unlink(skb, &sd->input_pkt_queue); +@@ -5888,7 +5888,7 @@ static void flush_backlog(struct work_st + input_queue_head_incr(sd); + } + } +- rps_unlock_irq_enable(sd); ++ backlog_unlock_irq_enable(sd); + + skb_queue_walk_safe(&sd->process_queue, skb, tmp) { + if (skb->dev->reg_state == NETREG_UNREGISTERING) { +@@ -5906,14 +5906,14 @@ static bool flush_required(int cpu) + struct softnet_data *sd = &per_cpu(softnet_data, cpu); + bool do_flush; + +- rps_lock_irq_disable(sd); ++ backlog_lock_irq_disable(sd); + + /* as insertion into process_queue happens with the rps lock held, + * process_queue access may race only with dequeue + */ + do_flush = !skb_queue_empty(&sd->input_pkt_queue) || + !skb_queue_empty_lockless(&sd->process_queue); +- rps_unlock_irq_enable(sd); ++ backlog_unlock_irq_enable(sd); + + return do_flush; + #endif +@@ -6028,7 +6028,7 @@ static int process_backlog(struct napi_s + + } + +- rps_lock_irq_disable(sd); ++ backlog_lock_irq_disable(sd); + if (skb_queue_empty(&sd->input_pkt_queue)) { + /* + * Inline a custom version of __napi_complete(). +@@ -6044,7 +6044,7 @@ static int process_backlog(struct napi_s + skb_queue_splice_tail_init(&sd->input_pkt_queue, + &sd->process_queue); + } +- rps_unlock_irq_enable(sd); ++ backlog_unlock_irq_enable(sd); + } + + return work; |