Re: [PATCH 3/3] rcu: validate arguments for rcu tracepoints

From: Paul E. McKenney
Date: Tue Mar 26 2019 - 10:33:05 EST


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@xxxxxxxxx>

With the naming changes suggested by Steven:

Acked-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>

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
>