72 lines
2.3 KiB
Diff
72 lines
2.3 KiB
Diff
From 49d2a425ffed7592c3ab05c01653311d6f2dc878 Mon Sep 17 00:00:00 2001
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From: Priyanka Jain <Priyanka.Jain@freescale.com>
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Date: Thu, 17 May 2012 09:35:11 +0530
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Subject: [PATCH 231/325] net: Remove preemption disabling in netif_rx()
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.115-rt48.tar.xz
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1)enqueue_to_backlog() (called from netif_rx) should be
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bind to a particluar CPU. This can be achieved by
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disabling migration. No need to disable preemption
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2)Fixes crash "BUG: scheduling while atomic: ksoftirqd"
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in case of RT.
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If preemption is disabled, enqueue_to_backog() is called
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in atomic context. And if backlog exceeds its count,
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kfree_skb() is called. But in RT, kfree_skb() might
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gets scheduled out, so it expects non atomic context.
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3)When CONFIG_PREEMPT_RT_FULL is not defined,
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migrate_enable(), migrate_disable() maps to
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preempt_enable() and preempt_disable(), so no
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change in functionality in case of non-RT.
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-Replace preempt_enable(), preempt_disable() with
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migrate_enable(), migrate_disable() respectively
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-Replace get_cpu(), put_cpu() with get_cpu_light(),
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put_cpu_light() respectively
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Signed-off-by: Priyanka Jain <Priyanka.Jain@freescale.com>
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Acked-by: Rajan Srivastava <Rajan.Srivastava@freescale.com>
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Cc: <rostedt@goodmis.orgn>
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Link: http://lkml.kernel.org/r/1337227511-2271-1-git-send-email-Priyanka.Jain@freescale.com
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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net/core/dev.c | 8 ++++----
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1 file changed, 4 insertions(+), 4 deletions(-)
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diff --git a/net/core/dev.c b/net/core/dev.c
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index efebf78b57b2..81174cf6bf9a 100644
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--- a/net/core/dev.c
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+++ b/net/core/dev.c
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@@ -4489,7 +4489,7 @@ static int netif_rx_internal(struct sk_buff *skb)
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struct rps_dev_flow voidflow, *rflow = &voidflow;
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int cpu;
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- preempt_disable();
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+ migrate_disable();
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rcu_read_lock();
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cpu = get_rps_cpu(skb->dev, skb, &rflow);
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@@ -4499,14 +4499,14 @@ static int netif_rx_internal(struct sk_buff *skb)
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ret = enqueue_to_backlog(skb, cpu, &rflow->last_qtail);
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rcu_read_unlock();
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- preempt_enable();
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+ migrate_enable();
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} else
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#endif
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{
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unsigned int qtail;
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- ret = enqueue_to_backlog(skb, get_cpu(), &qtail);
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- put_cpu();
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+ ret = enqueue_to_backlog(skb, get_cpu_light(), &qtail);
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+ put_cpu_light();
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}
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return ret;
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}
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--
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2.25.1
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