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Date:   Tue, 26 Mar 2019 07:32:00 -0700
From:   "Paul E. McKenney" <paulmck@linux.ibm.com>
To:     Yafang Shao <laoar.shao@gmail.com>
Cc:     rostedt@goodmis.org, mingo@redhat.com, peterz@infradead.org,
        josh@joshtriplett.org, mathieu.desnoyers@efficios.com,
        jiangshanlai@gmail.com, joel@joelfernandes.org,
        shaoyafang@didiglobal.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] rcu: validate arguments for rcu tracepoints
Reply-To: paulmck@linux.ibm.com
References: <1553564407-1162-1-git-send-email-laoar.shao@gmail.com>
 <1553564407-1162-4-git-send-email-laoar.shao@gmail.com>
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On Tue, Mar 26, 2019 at 09:40:07AM +0800, Yafang Shao wrote:
> When CONFIG_RCU_TRACE is not set, all these tracepoints are define as
> do-nothing macro.
> We'd better make those inline functions that take proper arguments.
> 
> As RCU_TRACE() is defined as do-nothing marco as well when
> CONFIG_RCU_TRACE is not set, so we can clean it up.
> 
> Signed-off-by: Yafang Shao <laoar.shao@gmail.com>

With the naming changes suggested by Steven:

Acked-by: Paul E. McKenney <paulmck@linux.ibm.com>

This area of the code should be relatively free from conflicts, so please
feel free to take it with the tracing updates.

> ---
>  include/trace/events/rcu.h | 84 +++++++++++++++++++++++++++++-----------------
>  kernel/rcu/rcu.h           |  9 ++---
>  kernel/rcu/tree.c          |  8 ++---
>  3 files changed, 60 insertions(+), 41 deletions(-)
> 
> diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
> index f0c4d10..357e1b6 100644
> --- a/include/trace/events/rcu.h
> +++ b/include/trace/events/rcu.h
> @@ -750,36 +750,60 @@
> 
>  #else /* #ifdef CONFIG_RCU_TRACE */
> 
> -#define trace_rcu_grace_period(rcuname, gp_seq, gpevent) do { } while (0)
> -#define trace_rcu_future_grace_period(rcuname, gp_seq, gp_seq_req, \
> -				      level, grplo, grphi, event) \
> -				      do { } while (0)
> -#define trace_rcu_grace_period_init(rcuname, gp_seq, level, grplo, grphi, \
> -				    qsmask) do { } while (0)
> -#define trace_rcu_exp_grace_period(rcuname, gqseq, gpevent) \
> -	do { } while (0)
> -#define trace_rcu_exp_funnel_lock(rcuname, level, grplo, grphi, gpevent) \
> -	do { } while (0)
> -#define trace_rcu_nocb_wake(rcuname, cpu, reason) do { } while (0)
> -#define trace_rcu_preempt_task(rcuname, pid, gp_seq) do { } while (0)
> -#define trace_rcu_unlock_preempted_task(rcuname, gp_seq, pid) do { } while (0)
> -#define trace_rcu_quiescent_state_report(rcuname, gp_seq, mask, qsmask, level, \
> -					 grplo, grphi, gp_tasks) do { } \
> -	while (0)
> -#define trace_rcu_fqs(rcuname, gp_seq, cpu, qsevent) do { } while (0)
> -#define trace_rcu_dyntick(polarity, oldnesting, newnesting, dyntick) do { } while (0)
> -#define trace_rcu_callback(rcuname, rhp, qlen_lazy, qlen) do { } while (0)
> -#define trace_rcu_kfree_callback(rcuname, rhp, offset, qlen_lazy, qlen) \
> -	do { } while (0)
> -#define trace_rcu_batch_start(rcuname, qlen_lazy, qlen, blimit) \
> -	do { } while (0)
> -#define trace_rcu_invoke_callback(rcuname, rhp) do { } while (0)
> -#define trace_rcu_invoke_kfree_callback(rcuname, rhp, offset) do { } while (0)
> -#define trace_rcu_batch_end(rcuname, callbacks_invoked, cb, nr, iit, risk) \
> -	do { } while (0)
> -#define trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c) \
> -	do { } while (0)
> -#define trace_rcu_barrier(name, s, cpu, cnt, done) do { } while (0)
> +TRACE_EVENT_NONE(rcu_grace_period,
> +	TP_PROTO(const char *rcuname, unsigned long gp_seq,
> +		 const char *gpevent));
> +TRACE_EVENT_NONE(rcu_future_grace_period,
> +	TP_PROTO(const char *rcuname, unsigned long gp_seq,
> +		 unsigned long gp_seq_req, u8 level, int grplo,
> +		 int grphi, const char *gpevent));
> +TRACE_EVENT_NONE(rcu_grace_period_init,
> +	TP_PROTO(const char *rcuname, unsigned long gp_seq, u8 level,
> +		 int grplo, int grphi, unsigned long qsmask));
> +TRACE_EVENT_NONE(rcu_exp_grace_period,
> +	TP_PROTO(const char *rcuname, unsigned long gpseq,
> +		 const char *gpevent));
> +TRACE_EVENT_NONE(rcu_exp_funnel_lock,
> +	TP_PROTO(const char *rcuname, u8 level, int grplo, int grphi,
> +		 const char *gpevent));
> +TRACE_EVENT_NONE(rcu_nocb_wake,
> +	TP_PROTO(const char *rcuname, int cpu, const char *reason));
> +TRACE_EVENT_NONE(rcu_preempt_task,
> +	TP_PROTO(const char *rcuname, int pid, unsigned long gp_seq));
> +TRACE_EVENT_NONE(rcu_unlock_preempted_task,
> +	TP_PROTO(const char *rcuname, unsigned long gp_seq, int pid));
> +TRACE_EVENT_NONE(rcu_quiescent_state_report,
> +	TP_PROTO(const char *rcuname, unsigned long gp_seq,
> +		 unsigned long mask, unsigned long qsmask,
> +		 u8 level, int grplo, int grphi, int gp_tasks));
> +TRACE_EVENT_NONE(rcu_fqs,
> +	TP_PROTO(const char *rcuname, unsigned long gp_seq, int cpu,
> +		 const char *qsevent));
> +TRACE_EVENT_NONE(rcu_dyntick,
> +	TP_PROTO(const char *polarity, long oldnesting, long newnesting,
> +		 atomic_t dynticks));
> +TRACE_EVENT_NONE(rcu_callback,
> +	TP_PROTO(const char *rcuname, struct rcu_head *rhp, long qlen_lazy,
> +		 long qlen));
> +TRACE_EVENT_NONE(rcu_kfree_callback,
> +	TP_PROTO(const char *rcuname, struct rcu_head *rhp,
> +		 unsigned long offset, long qlen_lazy, long qlen));
> +TRACE_EVENT_NONE(rcu_batch_start,
> +	TP_PROTO(const char *rcuname, long qlen_lazy, long qlen, long blimit));
> +TRACE_EVENT_NONE(rcu_invoke_callback,
> +	TP_PROTO(const char *rcuname, struct rcu_head *rhp));
> +TRACE_EVENT_NONE(rcu_invoke_kfree_callback,
> +	TP_PROTO(const char *rcuname, struct rcu_head *rhp,
> +		 unsigned long offset));
> +TRACE_EVENT_NONE(rcu_batch_end,
> +	TP_PROTO(const char *rcuname, int callbacks_invoked,
> +		 char cb, char nr, char iit, char risk));
> +TRACE_EVENT_NONE(rcu_torture_read,
> +	TP_PROTO(const char *rcutorturename, struct rcu_head *rhp,
> +		 unsigned long secs, unsigned long c_old, unsigned long c));
> +TRACE_EVENT_NONE(rcu_barrier,
> +	TP_PROTO(const char *rcuname, const char *s, int cpu, int cnt,
> +		 unsigned long done));
> 
>  #endif /* #else #ifdef CONFIG_RCU_TRACE */
> 
> diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
> index a393e24..2778e44 100644
> --- a/kernel/rcu/rcu.h
> +++ b/kernel/rcu/rcu.h
> @@ -24,11 +24,6 @@
>  #define __LINUX_RCU_H
> 
>  #include <trace/events/rcu.h>
> -#ifdef CONFIG_RCU_TRACE
> -#define RCU_TRACE(stmt) stmt
> -#else /* #ifdef CONFIG_RCU_TRACE */
> -#define RCU_TRACE(stmt)
> -#endif /* #else #ifdef CONFIG_RCU_TRACE */
> 
>  /* Offset to allow for unmatched rcu_irq_{enter,exit}(). */
>  #define DYNTICK_IRQ_NONIDLE	((LONG_MAX / 2) + 1)
> @@ -229,12 +224,12 @@ static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head)
> 
>  	rcu_lock_acquire(&rcu_callback_map);
>  	if (__is_kfree_rcu_offset(offset)) {
> -		RCU_TRACE(trace_rcu_invoke_kfree_callback(rn, head, offset);)
> +		trace_rcu_invoke_kfree_callback(rn, head, offset);
>  		kfree((void *)head - offset);
>  		rcu_lock_release(&rcu_callback_map);
>  		return true;
>  	} else {
> -		RCU_TRACE(trace_rcu_invoke_callback(rn, head);)
> +		trace_rcu_invoke_callback(rn, head);
>  		f = head->func;
>  		WRITE_ONCE(head->func, (rcu_callback_t)0L);
>  		f(head);
> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> index 9180158..d2ad39f 100644
> --- a/kernel/rcu/tree.c
> +++ b/kernel/rcu/tree.c
> @@ -2329,14 +2329,14 @@ static void rcu_report_qs_rnp(unsigned long mask, struct rcu_node *rnp,
>   */
>  int rcutree_dying_cpu(unsigned int cpu)
>  {
> -	RCU_TRACE(bool blkd;)
> -	RCU_TRACE(struct rcu_data *rdp = this_cpu_ptr(&rcu_data);)
> -	RCU_TRACE(struct rcu_node *rnp = rdp->mynode;)
> +	bool blkd;
> +	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
> +	struct rcu_node *rnp = rdp->mynode;
> 
>  	if (!IS_ENABLED(CONFIG_HOTPLUG_CPU))
>  		return 0;
> 
> -	RCU_TRACE(blkd = !!(rnp->qsmask & rdp->grpmask);)
> +	blkd = !!(rnp->qsmask & rdp->grpmask);
>  	trace_rcu_grace_period(rcu_state.name, rnp->gp_seq,
>  			       blkd ? TPS("cpuofl") : TPS("cpuofl-bgp"));
>  	return 0;
> -- 
> 1.8.3.1
>