93 lines
3.2 KiB
Diff
93 lines
3.2 KiB
Diff
From 302b4d04008563db6601953efc2267fb2b5f2d63 Mon Sep 17 00:00:00 2001
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Message-Id: <302b4d04008563db6601953efc2267fb2b5f2d63.1596234183.git.zanussi@kernel.org>
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In-Reply-To: <378ee68279f6a7631221f2670a9298620148690d.1596234183.git.zanussi@kernel.org>
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References: <378ee68279f6a7631221f2670a9298620148690d.1596234183.git.zanussi@kernel.org>
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Wed, 20 Jan 2016 15:39:05 +0100
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Subject: [PATCH 199/329] net: provide a way to delegate processing a softirq
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to ksoftirqd
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.135-rt60.tar.xz
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If the NET_RX uses up all of his budget it moves the following NAPI
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invocations into the `ksoftirqd`. On -RT it does not do so. Instead it
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rises the NET_RX softirq in its current context again.
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In order to get closer to mainline's behaviour this patch provides
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__raise_softirq_irqoff_ksoft() which raises the softirq in the ksoftird.
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Cc: stable-rt@vger.kernel.org
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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include/linux/interrupt.h | 8 ++++++++
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kernel/softirq.c | 21 +++++++++++++++++++++
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net/core/dev.c | 2 +-
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3 files changed, 30 insertions(+), 1 deletion(-)
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diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
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index e1438fe66467..97d9ba26915e 100644
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--- a/include/linux/interrupt.h
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+++ b/include/linux/interrupt.h
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@@ -518,6 +518,14 @@ extern void thread_do_softirq(void);
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extern void open_softirq(int nr, void (*action)(struct softirq_action *));
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extern void softirq_init(void);
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extern void __raise_softirq_irqoff(unsigned int nr);
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+#ifdef CONFIG_PREEMPT_RT_FULL
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+extern void __raise_softirq_irqoff_ksoft(unsigned int nr);
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+#else
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+static inline void __raise_softirq_irqoff_ksoft(unsigned int nr)
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+{
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+ __raise_softirq_irqoff(nr);
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+}
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+#endif
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extern void raise_softirq_irqoff(unsigned int nr);
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extern void raise_softirq(unsigned int nr);
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diff --git a/kernel/softirq.c b/kernel/softirq.c
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index 27a4bb2303d0..25bcf2f2714b 100644
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--- a/kernel/softirq.c
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+++ b/kernel/softirq.c
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@@ -721,6 +721,27 @@ void __raise_softirq_irqoff(unsigned int nr)
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wakeup_proper_softirq(nr);
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}
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+/*
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+ * Same as __raise_softirq_irqoff() but will process them in ksoftirqd
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+ */
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+void __raise_softirq_irqoff_ksoft(unsigned int nr)
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+{
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+ unsigned int mask;
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+
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+ if (WARN_ON_ONCE(!__this_cpu_read(ksoftirqd) ||
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+ !__this_cpu_read(ktimer_softirqd)))
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+ return;
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+ mask = 1UL << nr;
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+
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+ trace_softirq_raise(nr);
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+ or_softirq_pending(mask);
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+ if (mask & TIMER_SOFTIRQS)
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+ __this_cpu_read(ktimer_softirqd)->softirqs_raised |= mask;
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+ else
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+ __this_cpu_read(ksoftirqd)->softirqs_raised |= mask;
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+ wakeup_proper_softirq(nr);
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+}
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+
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/*
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* This function must run with irqs disabled!
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*/
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diff --git a/net/core/dev.c b/net/core/dev.c
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index bb93ab3f0b1f..bd2d4195d238 100644
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--- a/net/core/dev.c
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+++ b/net/core/dev.c
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@@ -6374,7 +6374,7 @@ static __latent_entropy void net_rx_action(struct softirq_action *h)
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list_splice_tail(&repoll, &list);
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list_splice(&list, &sd->poll_list);
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if (!list_empty(&sd->poll_list))
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- __raise_softirq_irqoff(NET_RX_SOFTIRQ);
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+ __raise_softirq_irqoff_ksoft(NET_RX_SOFTIRQ);
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net_rps_action_and_irq_enable(sd);
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out:
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--
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2.17.1
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