a26ac2455f
If RCU priority boosting is to be meaningful, callback invocation must be boosted in addition to preempted RCU readers. Otherwise, in presence of CPU real-time threads, the grace period ends, but the callbacks don't get invoked. If the callbacks don't get invoked, the associated memory doesn't get freed, so the system is still subject to OOM. But it is not reasonable to priority-boost RCU_SOFTIRQ, so this commit moves the callback invocations to a kthread, which can be boosted easily. Also add comments and properly synchronized all accesses to rcu_cpu_kthread_task, as suggested by Lai Jiangshan. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
149 lines
3.4 KiB
C
149 lines
3.4 KiB
C
#undef TRACE_SYSTEM
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#define TRACE_SYSTEM irq
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#if !defined(_TRACE_IRQ_H) || defined(TRACE_HEADER_MULTI_READ)
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#define _TRACE_IRQ_H
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#include <linux/tracepoint.h>
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struct irqaction;
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struct softirq_action;
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#define softirq_name(sirq) { sirq##_SOFTIRQ, #sirq }
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#define show_softirq_name(val) \
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__print_symbolic(val, \
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softirq_name(HI), \
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softirq_name(TIMER), \
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softirq_name(NET_TX), \
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softirq_name(NET_RX), \
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softirq_name(BLOCK), \
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softirq_name(BLOCK_IOPOLL), \
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softirq_name(TASKLET), \
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softirq_name(SCHED), \
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softirq_name(HRTIMER))
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/**
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* irq_handler_entry - called immediately before the irq action handler
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* @irq: irq number
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* @action: pointer to struct irqaction
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*
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* The struct irqaction pointed to by @action contains various
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* information about the handler, including the device name,
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* @action->name, and the device id, @action->dev_id. When used in
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* conjunction with the irq_handler_exit tracepoint, we can figure
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* out irq handler latencies.
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*/
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TRACE_EVENT(irq_handler_entry,
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TP_PROTO(int irq, struct irqaction *action),
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TP_ARGS(irq, action),
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TP_STRUCT__entry(
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__field( int, irq )
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__string( name, action->name )
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),
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TP_fast_assign(
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__entry->irq = irq;
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__assign_str(name, action->name);
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),
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TP_printk("irq=%d name=%s", __entry->irq, __get_str(name))
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);
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/**
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* irq_handler_exit - called immediately after the irq action handler returns
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* @irq: irq number
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* @action: pointer to struct irqaction
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* @ret: return value
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*
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* If the @ret value is set to IRQ_HANDLED, then we know that the corresponding
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* @action->handler scuccessully handled this irq. Otherwise, the irq might be
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* a shared irq line, or the irq was not handled successfully. Can be used in
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* conjunction with the irq_handler_entry to understand irq handler latencies.
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*/
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TRACE_EVENT(irq_handler_exit,
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TP_PROTO(int irq, struct irqaction *action, int ret),
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TP_ARGS(irq, action, ret),
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TP_STRUCT__entry(
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__field( int, irq )
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__field( int, ret )
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),
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TP_fast_assign(
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__entry->irq = irq;
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__entry->ret = ret;
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),
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TP_printk("irq=%d ret=%s",
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__entry->irq, __entry->ret ? "handled" : "unhandled")
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);
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DECLARE_EVENT_CLASS(softirq,
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TP_PROTO(unsigned int vec_nr),
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TP_ARGS(vec_nr),
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TP_STRUCT__entry(
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__field( unsigned int, vec )
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),
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TP_fast_assign(
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__entry->vec = vec_nr;
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),
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TP_printk("vec=%u [action=%s]", __entry->vec,
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show_softirq_name(__entry->vec))
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);
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/**
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* softirq_entry - called immediately before the softirq handler
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* @vec_nr: softirq vector number
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*
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* When used in combination with the softirq_exit tracepoint
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* we can determine the softirq handler runtine.
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*/
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DEFINE_EVENT(softirq, softirq_entry,
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TP_PROTO(unsigned int vec_nr),
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TP_ARGS(vec_nr)
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);
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/**
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* softirq_exit - called immediately after the softirq handler returns
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* @vec_nr: softirq vector number
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*
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* When used in combination with the softirq_entry tracepoint
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* we can determine the softirq handler runtine.
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*/
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DEFINE_EVENT(softirq, softirq_exit,
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TP_PROTO(unsigned int vec_nr),
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TP_ARGS(vec_nr)
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);
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/**
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* softirq_raise - called immediately when a softirq is raised
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* @vec_nr: softirq vector number
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*
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* When used in combination with the softirq_entry tracepoint
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* we can determine the softirq raise to run latency.
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*/
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DEFINE_EVENT(softirq, softirq_raise,
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TP_PROTO(unsigned int vec_nr),
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TP_ARGS(vec_nr)
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);
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#endif /* _TRACE_IRQ_H */
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/* This part must be outside protection */
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#include <trace/define_trace.h>
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