Re: [PATCH tip/core/rcu 05/15] rcu: Add TPS() to event-traced strings
From: Steven Rostedt
Date: Thu Jul 27 2017 - 21:33:10 EST
On Mon, 24 Jul 2017 14:44:34 -0700
"Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> wrote:
> Strings used in event tracing need to be specially handled, for example,
> using the TPS() macro. Without the TPS() macro, although output looks
> fine from within a running kernel, extracting traces from a crash dump
> produces garbage instead of strings. This commit therefore adds the TPS()
> macro to some unadorned strings that were passed to event-tracing macros.
>
> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Acked-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
-- Steve
> ---
> kernel/rcu/tree_plugin.h | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
> index bb9e6e43130f..14ba496a13cd 100644
> --- a/kernel/rcu/tree_plugin.h
> +++ b/kernel/rcu/tree_plugin.h
> @@ -2073,7 +2073,7 @@ static void nocb_leader_wait(struct rcu_data *my_rdp)
>
> /* Wait for callbacks to appear. */
> if (!rcu_nocb_poll) {
> - trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu, "Sleep");
> + trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu, TPS("Sleep"));
> swait_event_interruptible(my_rdp->nocb_wq,
> !READ_ONCE(my_rdp->nocb_leader_sleep));
> raw_spin_lock_irqsave(&my_rdp->nocb_lock, flags);
> @@ -2083,7 +2083,7 @@ static void nocb_leader_wait(struct rcu_data *my_rdp)
> raw_spin_unlock_irqrestore(&my_rdp->nocb_lock, flags);
> } else if (firsttime) {
> firsttime = false; /* Don't drown trace log with "Poll"! */
> - trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu, "Poll");
> + trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu, TPS("Poll"));
> }
>
> /*
> @@ -2111,7 +2111,7 @@ static void nocb_leader_wait(struct rcu_data *my_rdp)
> schedule_timeout_interruptible(1);
> } else {
> trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu,
> - "WokeEmpty");
> + TPS("WokeEmpty"));
> }
> goto wait_again;
> }
> @@ -2155,7 +2155,7 @@ static void nocb_leader_wait(struct rcu_data *my_rdp)
> static void nocb_follower_wait(struct rcu_data *rdp)
> {
> for (;;) {
> - trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, "FollowerSleep");
> + trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("FollowerSleep"));
> swait_event_interruptible(rdp->nocb_wq,
> READ_ONCE(rdp->nocb_follower_head));
> if (smp_load_acquire(&rdp->nocb_follower_head)) {
> @@ -2163,7 +2163,7 @@ static void nocb_follower_wait(struct rcu_data *rdp)
> return;
> }
> WARN_ON(signal_pending(current));
> - trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, "WokeEmpty");
> + trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("WokeEmpty"));
> }
> }
>
> @@ -2198,7 +2198,7 @@ static int rcu_nocb_kthread(void *arg)
> rdp->nocb_follower_tail = &rdp->nocb_follower_head;
> raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags);
> BUG_ON(!list);
> - trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, "WokeNonEmpty");
> + trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("WokeNonEmpty"));
>
> /* Each pass through the following loop invokes a callback. */
> trace_rcu_batch_start(rdp->rsp->name,