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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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3f1756dc21
Joel Fernandes created a nice patch that cleaned up the duplicate hooks used by lockdep and irqsoff latency tracer. It made both use tracepoints. But the latency tracer is triggering warnings when using tracepoints to call into the latency tracer's routines. Mainly, they can be called from NMI context. If that happens, then the SRCU may not work properly because on some architectures, SRCU is not safe to be called in both NMI and non-NMI context. This is a partial revert of the clean up patchc3bc8fd637("tracing: Centralize preemptirq tracepoints and unify their usage") that adds back the direct calls into the latency tracer. It also only calls the trace events when not in NMI. Link: http://lkml.kernel.org/r/20180809210654.622445925@goodmis.org Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Fixes:c3bc8fd637("tracing: Centralize preemptirq tracepoints and unify their usage") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
90 lines
2.1 KiB
C
90 lines
2.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* preemptoff and irqoff tracepoints
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*
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* Copyright (C) Joel Fernandes (Google) <joel@joelfernandes.org>
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*/
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#include <linux/kallsyms.h>
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#include <linux/uaccess.h>
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#include <linux/module.h>
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#include <linux/ftrace.h>
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#include "trace.h"
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#define CREATE_TRACE_POINTS
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#include <trace/events/preemptirq.h>
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#ifdef CONFIG_TRACE_IRQFLAGS
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/* Per-cpu variable to prevent redundant calls when IRQs already off */
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static DEFINE_PER_CPU(int, tracing_irq_cpu);
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void trace_hardirqs_on(void)
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{
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if (this_cpu_read(tracing_irq_cpu)) {
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if (!in_nmi())
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trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
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tracer_hardirqs_on(CALLER_ADDR0, CALLER_ADDR1);
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this_cpu_write(tracing_irq_cpu, 0);
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}
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lockdep_hardirqs_on(CALLER_ADDR0);
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}
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EXPORT_SYMBOL(trace_hardirqs_on);
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void trace_hardirqs_off(void)
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{
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if (!this_cpu_read(tracing_irq_cpu)) {
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this_cpu_write(tracing_irq_cpu, 1);
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tracer_hardirqs_off(CALLER_ADDR0, CALLER_ADDR1);
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if (!in_nmi())
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trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
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}
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lockdep_hardirqs_off(CALLER_ADDR0);
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}
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EXPORT_SYMBOL(trace_hardirqs_off);
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__visible void trace_hardirqs_on_caller(unsigned long caller_addr)
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{
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if (this_cpu_read(tracing_irq_cpu)) {
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if (!in_nmi())
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trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);
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tracer_hardirqs_on(CALLER_ADDR0, caller_addr);
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this_cpu_write(tracing_irq_cpu, 0);
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}
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lockdep_hardirqs_on(CALLER_ADDR0);
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}
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EXPORT_SYMBOL(trace_hardirqs_on_caller);
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__visible void trace_hardirqs_off_caller(unsigned long caller_addr)
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{
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if (!this_cpu_read(tracing_irq_cpu)) {
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this_cpu_write(tracing_irq_cpu, 1);
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tracer_hardirqs_off(CALLER_ADDR0, caller_addr);
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if (!in_nmi())
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trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr);
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}
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lockdep_hardirqs_off(CALLER_ADDR0);
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}
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EXPORT_SYMBOL(trace_hardirqs_off_caller);
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#endif /* CONFIG_TRACE_IRQFLAGS */
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#ifdef CONFIG_TRACE_PREEMPT_TOGGLE
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void trace_preempt_on(unsigned long a0, unsigned long a1)
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{
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if (!in_nmi())
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trace_preempt_enable_rcuidle(a0, a1);
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tracer_preempt_on(a0, a1);
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}
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void trace_preempt_off(unsigned long a0, unsigned long a1)
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{
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if (!in_nmi())
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trace_preempt_disable_rcuidle(a0, a1);
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tracer_preempt_off(a0, a1);
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}
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#endif
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