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Date:   Thu, 17 Mar 2022 13:26:45 -0700
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Subject: Re: RCU: undefined reference to irq_work_queue
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To:     paulmck@kernel.org, Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc:     rcu@vger.kernel.org, Josh Triplett <josh@joshtriplett.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Joel Fernandes <joel@joelfernandes.org>,
        linux-kernel@vger.kernel.org
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From:   Randy Dunlap <rdunlap@infradead.org>
In-Reply-To: <20220317173621.GQ4285@paulmck-ThinkPad-P17-Gen-1>
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On 3/17/22 10:36, Paul E. McKenney wrote:
> On Thu, Mar 17, 2022 at 04:45:11PM +0000, Hyeonggon Yoo wrote:
>> On Thu, Mar 17, 2022 at 09:20:33AM -0700, Paul E. McKenney wrote:
>>> On Thu, Mar 17, 2022 at 03:24:42PM +0000, Hyeonggon Yoo wrote:
>>>> On Thu, Mar 17, 2022 at 07:00:00AM -0700, Paul E. McKenney wrote:
>>>>> On Thu, Mar 17, 2022 at 11:32:53AM +0000, Hyeonggon Yoo wrote:
>>>>>> Hello RCU folks,
>>>>>>

> ------------------------------------------------------------------------
> 
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 678a80713b21..66c5b5543511 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -38,6 +38,7 @@ config KPROBES
>  	depends on MODULES
>  	depends on HAVE_KPROBES
>  	select KALLSYMS
> +	select TASKS_RCU if PREEMPTION
>  	help
>  	  Kprobes allows you to trap at almost any kernel address and
>  	  execute a callback function.  register_kprobe() establishes
> diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
> index f559870fbf8b..4f665ae0cf55 100644
> --- a/kernel/rcu/Kconfig
> +++ b/kernel/rcu/Kconfig
> @@ -78,7 +78,8 @@ config TASKS_RCU_GENERIC
>  	  task-based RCU implementations.  Not for manual selection.
>  
>  config TASKS_RCU
> -	def_bool PREEMPTION
> +	def_bool 0

preferably
	def_bool n

but the 0 probably works...  :)

> +	select IRQ_WORK
>  	help
>  	  This option enables a task-based RCU implementation that uses
>  	  only voluntary context switch (not preemption!), idle, and
> diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
> index 752ed89a293b..a7aaf150b704 100644
> --- a/kernel/trace/Kconfig
> +++ b/kernel/trace/Kconfig
> @@ -127,6 +127,7 @@ config TRACING
>  	select BINARY_PRINTF
>  	select EVENT_TRACING
>  	select TRACE_CLOCK
> +	select TASKS_RCU if PREEMPTION
>  
>  config GENERIC_TRACER
>  	bool

-- 
~Randy