76 lines
2.2 KiB
Diff
76 lines
2.2 KiB
Diff
Subject: softirq: Make serving softirqs a task flag
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Thu, 04 Oct 2012 14:30:25 +0100
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.0/patches-4.0.5-rt3.tar.xz
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Avoid the percpu softirq_runner pointer magic by using a task flag.
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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include/linux/sched.h | 1 +
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kernel/softirq.c | 20 +++-----------------
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2 files changed, 4 insertions(+), 17 deletions(-)
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--- a/include/linux/sched.h
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+++ b/include/linux/sched.h
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@@ -1999,6 +1999,7 @@ extern void thread_group_cputime_adjuste
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/*
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* Per process flags
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*/
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+#define PF_IN_SOFTIRQ 0x00000001 /* Task is serving softirq */
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#define PF_EXITING 0x00000004 /* getting shut down */
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#define PF_EXITPIDONE 0x00000008 /* pi exit done on shut down */
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#define PF_VCPU 0x00000010 /* I'm a virtual CPU */
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--- a/kernel/softirq.c
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+++ b/kernel/softirq.c
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@@ -403,7 +403,6 @@ static void ksoftirqd_clr_sched_params(u
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* On RT we serialize softirq execution with a cpu local lock
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*/
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static DEFINE_LOCAL_IRQ_LOCK(local_softirq_lock);
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-static DEFINE_PER_CPU(struct task_struct *, local_softirq_runner);
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static void __do_softirq_common(int need_rcu_bh_qs);
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@@ -482,22 +481,9 @@ void _local_bh_enable(void)
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}
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EXPORT_SYMBOL(_local_bh_enable);
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-/* For tracing */
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-int notrace __in_softirq(void)
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-{
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- if (__this_cpu_read(local_softirq_lock.owner) == current)
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- return __this_cpu_read(local_softirq_lock.nestcnt);
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- return 0;
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-}
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-
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int in_serving_softirq(void)
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{
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- int res;
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-
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- preempt_disable();
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- res = __this_cpu_read(local_softirq_runner) == current;
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- preempt_enable();
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- return res;
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+ return current->flags & PF_IN_SOFTIRQ;
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}
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EXPORT_SYMBOL(in_serving_softirq);
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@@ -515,7 +501,7 @@ asmlinkage void __do_softirq(void)
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/* Reset the pending bitmask before enabling irqs */
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set_softirq_pending(0);
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- __this_cpu_write(local_softirq_runner, current);
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+ current->flags |= PF_IN_SOFTIRQ;
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lockdep_softirq_enter();
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@@ -526,7 +512,7 @@ asmlinkage void __do_softirq(void)
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wakeup_softirqd();
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lockdep_softirq_exit();
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- __this_cpu_write(local_softirq_runner, NULL);
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+ current->flags &= ~PF_IN_SOFTIRQ;
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current->softirq_nestcnt--;
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}
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