Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Tue, 26 Mar 2019 08:22:24 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Yafang Shao <laoar.shao@gmail.com>
Cc:     mingo@redhat.com, peterz@infradead.org, paulmck@linux.ibm.com,
        josh@joshtriplett.org, mathieu.desnoyers@efficios.com,
        jiangshanlai@gmail.com, joel@joelfernandes.org,
        linux-kernel@vger.kernel.org, shaoyafang@didiglobal.com
Subject: Re: [PATCH v2 3/3] rcu: validate arguments for rcu tracepoints
Message-ID: <20190326082224.1b7874c5@gandalf.local.home>
In-Reply-To: <1553602391-11926-4-git-send-email-laoar.shao@gmail.com>
References: <1553602391-11926-1-git-send-email-laoar.shao@gmail.com>
        <1553602391-11926-4-git-send-email-laoar.shao@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Paul,

Are you OK with this patch? If you ack it, I'll pull it in through my
tree.

-- Steve


On Tue, 26 Mar 2019 20:13:11 +0800
Yafang Shao <laoar.shao@gmail.com> wrote:

> When CONFIG_RCU_TRACE is not set, all these tracepoints are defined 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>
> ---
>  include/trace/events/rcu.h | 81 ++++++++++++++--------------------------------
>  kernel/rcu/rcu.h           |  9 ++----
>  kernel/rcu/tree.c          |  8 ++---
>  3 files changed, 31 insertions(+), 67 deletions(-)
> 
> diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
> index f0c4d10..e3f357b 100644
> --- a/include/trace/events/rcu.h
> +++ b/include/trace/events/rcu.h
> @@ -7,6 +7,12 @@
>  
>  #include <linux/tracepoint.h>
>  
> +#ifdef CONFIG_RCU_TRACE
> +#define TRACE_EVENT_RCU TRACE_EVENT
> +#else
> +#define TRACE_EVENT_RCU TRACE_EVENT_NOP
> +#endif
> +
>  /*
>   * Tracepoint for start/end markers used for utilization calculations.
>   * By convention, the string is of the following forms:
> @@ -35,8 +41,6 @@
>  	TP_printk("%s", __entry->s)
>  );
>  
> -#ifdef CONFIG_RCU_TRACE
> -
>  #if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU)
>  
>  /*
> @@ -62,7 +66,7 @@
>   *	"end": End a grace period.
>   *	"cpuend": CPU first notices a grace-period end.
>   */
> -TRACE_EVENT(rcu_grace_period,
> +TRACE_EVENT_RCU(rcu_grace_period,
>  
>  	TP_PROTO(const char *rcuname, unsigned long gp_seq, const char *gpevent),
>  
> @@ -101,7 +105,7 @@
>   * "Cleanup": Clean up rcu_node structure after previous GP.
>   * "CleanupMore": Clean up, and another GP is needed.
>   */
> -TRACE_EVENT(rcu_future_grace_period,
> +TRACE_EVENT_RCU(rcu_future_grace_period,
>  
>  	TP_PROTO(const char *rcuname, unsigned long gp_seq,
>  		 unsigned long gp_seq_req, u8 level, int grplo, int grphi,
> @@ -141,7 +145,7 @@
>   * rcu_node structure, and the mask of CPUs that will be waited for.
>   * All but the type of RCU are extracted from the rcu_node structure.
>   */
> -TRACE_EVENT(rcu_grace_period_init,
> +TRACE_EVENT_RCU(rcu_grace_period_init,
>  
>  	TP_PROTO(const char *rcuname, unsigned long gp_seq, u8 level,
>  		 int grplo, int grphi, unsigned long qsmask),
> @@ -186,7 +190,7 @@
>   *	"endwake": Woke piggybackers up.
>   *	"done": Someone else did the expedited grace period for us.
>   */
> -TRACE_EVENT(rcu_exp_grace_period,
> +TRACE_EVENT_RCU(rcu_exp_grace_period,
>  
>  	TP_PROTO(const char *rcuname, unsigned long gpseq, const char *gpevent),
>  
> @@ -218,7 +222,7 @@
>   *	"nxtlvl": Advance to next level of rcu_node funnel
>   *	"wait": Wait for someone else to do expedited GP
>   */
> -TRACE_EVENT(rcu_exp_funnel_lock,
> +TRACE_EVENT_RCU(rcu_exp_funnel_lock,
>  
>  	TP_PROTO(const char *rcuname, u8 level, int grplo, int grphi,
>  		 const char *gpevent),
> @@ -269,7 +273,7 @@
>   *	"WaitQueue": Enqueue partially done, timed wait for it to complete.
>   *	"WokeQueue": Partial enqueue now complete.
>   */
> -TRACE_EVENT(rcu_nocb_wake,
> +TRACE_EVENT_RCU(rcu_nocb_wake,
>  
>  	TP_PROTO(const char *rcuname, int cpu, const char *reason),
>  
> @@ -297,7 +301,7 @@
>   * include SRCU), the grace-period number that the task is blocking
>   * (the current or the next), and the task's PID.
>   */
> -TRACE_EVENT(rcu_preempt_task,
> +TRACE_EVENT_RCU(rcu_preempt_task,
>  
>  	TP_PROTO(const char *rcuname, int pid, unsigned long gp_seq),
>  
> @@ -324,7 +328,7 @@
>   * read-side critical section exiting that critical section.  Track the
>   * type of RCU (which one day might include SRCU) and the task's PID.
>   */
> -TRACE_EVENT(rcu_unlock_preempted_task,
> +TRACE_EVENT_RCU(rcu_unlock_preempted_task,
>  
>  	TP_PROTO(const char *rcuname, unsigned long gp_seq, int pid),
>  
> @@ -353,7 +357,7 @@
>   * whether there are any blocked tasks blocking the current grace period.
>   * All but the type of RCU are extracted from the rcu_node structure.
>   */
> -TRACE_EVENT(rcu_quiescent_state_report,
> +TRACE_EVENT_RCU(rcu_quiescent_state_report,
>  
>  	TP_PROTO(const char *rcuname, unsigned long gp_seq,
>  		 unsigned long mask, unsigned long qsmask,
> @@ -396,7 +400,7 @@
>   * state, which can be "dti" for dyntick-idle mode or "kick" when kicking
>   * a CPU that has been in dyntick-idle mode for too long.
>   */
> -TRACE_EVENT(rcu_fqs,
> +TRACE_EVENT_RCU(rcu_fqs,
>  
>  	TP_PROTO(const char *rcuname, unsigned long gp_seq, int cpu, const char *qsevent),
>  
> @@ -436,7 +440,7 @@
>   * events use two separate counters, and that the "++=" and "--=" events
>   * for irq/NMI will change the counter by two, otherwise by one.
>   */
> -TRACE_EVENT(rcu_dyntick,
> +TRACE_EVENT_RCU(rcu_dyntick,
>  
>  	TP_PROTO(const char *polarity, long oldnesting, long newnesting, atomic_t dynticks),
>  
> @@ -468,7 +472,7 @@
>   * number of lazy callbacks queued, and the fourth element is the
>   * total number of callbacks queued.
>   */
> -TRACE_EVENT(rcu_callback,
> +TRACE_EVENT_RCU(rcu_callback,
>  
>  	TP_PROTO(const char *rcuname, struct rcu_head *rhp, long qlen_lazy,
>  		 long qlen),
> @@ -504,7 +508,7 @@
>   * the fourth argument is the number of lazy callbacks queued, and the
>   * fifth argument is the total number of callbacks queued.
>   */
> -TRACE_EVENT(rcu_kfree_callback,
> +TRACE_EVENT_RCU(rcu_kfree_callback,
>  
>  	TP_PROTO(const char *rcuname, struct rcu_head *rhp, unsigned long offset,
>  		 long qlen_lazy, long qlen),
> @@ -539,7 +543,7 @@
>   * the total number of callbacks queued, and the fourth argument is
>   * the current RCU-callback batch limit.
>   */
> -TRACE_EVENT(rcu_batch_start,
> +TRACE_EVENT_RCU(rcu_batch_start,
>  
>  	TP_PROTO(const char *rcuname, long qlen_lazy, long qlen, long blimit),
>  
> @@ -569,7 +573,7 @@
>   * The first argument is the type of RCU, and the second argument is
>   * a pointer to the RCU callback itself.
>   */
> -TRACE_EVENT(rcu_invoke_callback,
> +TRACE_EVENT_RCU(rcu_invoke_callback,
>  
>  	TP_PROTO(const char *rcuname, struct rcu_head *rhp),
>  
> @@ -598,7 +602,7 @@
>   * is the offset of the callback within the enclosing RCU-protected
>   * data structure.
>   */
> -TRACE_EVENT(rcu_invoke_kfree_callback,
> +TRACE_EVENT_RCU(rcu_invoke_kfree_callback,
>  
>  	TP_PROTO(const char *rcuname, struct rcu_head *rhp, unsigned long offset),
>  
> @@ -631,7 +635,7 @@
>   * and the sixth argument (risk) is the return value from
>   * rcu_is_callbacks_kthread().
>   */
> -TRACE_EVENT(rcu_batch_end,
> +TRACE_EVENT_RCU(rcu_batch_end,
>  
>  	TP_PROTO(const char *rcuname, int callbacks_invoked,
>  		 char cb, char nr, char iit, char risk),
> @@ -673,7 +677,7 @@
>   * callback address can be NULL.
>   */
>  #define RCUTORTURENAME_LEN 8
> -TRACE_EVENT(rcu_torture_read,
> +TRACE_EVENT_RCU(rcu_torture_read,
>  
>  	TP_PROTO(const char *rcutorturename, struct rcu_head *rhp,
>  		 unsigned long secs, unsigned long c_old, unsigned long c),
> @@ -721,7 +725,7 @@
>   * The "cpu" argument is the CPU or -1 if meaningless, the "cnt" argument
>   * is the count of remaining callbacks, and "done" is the piggybacking count.
>   */
> -TRACE_EVENT(rcu_barrier,
> +TRACE_EVENT_RCU(rcu_barrier,
>  
>  	TP_PROTO(const char *rcuname, const char *s, int cpu, int cnt, unsigned long done),
>  
> @@ -748,41 +752,6 @@
>  		  __entry->done)
>  );
>  
> -#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)
> -
> -#endif /* #else #ifdef CONFIG_RCU_TRACE */
> -
>  #endif /* _TRACE_RCU_H */
>  
>  /* This part must be outside protection */
> 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;