Commit be15a164 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu-tasks: Make RCU Tasks Trace stall warnings print full .b.need_qs field 



Currently, the RCU Tasks Trace CPU stall warning simply indicates
whether or not the .b.need_qs field is zero.  This commit shows the
three permitted values and flags other values with either "!" or "?".
This is a debugging aid.

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: KP Singh <kpsingh@kernel.org>
parent c8c03ad9

kernel/rcu/tasks.h

+3 −2
Original line number Diff line number Diff line
@@ -1502,13 +1502,14 @@ static void show_stalled_task_trace(struct task_struct *t, bool *firstreport) 
			 ".I"[t->trc_ipi_to_cpu >= 0],

			 ".i"[is_idle_tsk]);

	else

		pr_alert("P%d: %c%c%c nesting: %d%c cpu: %d%s\n",

		pr_alert("P%d: %c%c%c nesting: %d%c%c cpu: %d%s\n",

			 t->pid,

			 ".I"[trc_rdr.ipi_to_cpu >= 0],

			 ".i"[is_idle_tsk],

			 ".N"[cpu >= 0 && tick_nohz_full_cpu(cpu)],

			 trc_rdr.nesting,

			 " N"[!!trc_rdr.needqs],

			 " !CN"[trc_rdr.needqs & 0x3],

			 " ?"[trc_rdr.needqs > 0x3],

			 cpu, cpu_online(cpu) ? "" : "(offline)");

	sched_show_task(t);

}