linux-kernel - [PATCH tip/core/rcu 06/13] rcu: Add online/offline info to stall warning message

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Date:	Tue,  6 Oct 2015 09:13:41 -0700
From:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:	linux-kernel@...r.kernel.org
Cc:	mingo@...nel.org, jiangshanlai@...il.com, dipankar@...ibm.com,
	akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com,
	josh@...htriplett.org, tglx@...utronix.de, peterz@...radead.org,
	rostedt@...dmis.org, dhowells@...hat.com, edumazet@...gle.com,
	dvhart@...ux.intel.com, fweisbec@...il.com, oleg@...hat.com,
	bobby.prani@...il.com,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 06/13] rcu: Add online/offline info to stall warning message

This commit makes the RCU CPU stall warning message print online/offline
indications immediately after the CPU number.  A "?" indicates global
offline, a "," global online, and a "!" indicates RCU believes that the
CPU is offline and "." otherwise, both right after the CPU number.
So for CPU 10, you would normally see "10,.:" indicating that everything
believes that the CPU is online.

Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
---
 kernel/rcu/tree_plugin.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 06116ae6dfd7..57ed9c13ae5a 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1702,8 +1702,12 @@ static void print_cpu_stall_info(struct rcu_state *rsp, int cpu)
 		ticks_value = rsp->gpnum - rdp->gpnum;
 	}
 	print_cpu_stall_fast_no_hz(fast_no_hz, cpu);
-	pr_err("\t%d: (%lu %s) idle=%03x/%llx/%d softirq=%u/%u fqs=%ld %s\n",
-	       cpu, ticks_value, ticks_title,
+	pr_err("\t%d-%c%c%c: (%lu %s) idle=%03x/%llx/%d softirq=%u/%u fqs=%ld %s\n",
+	       cpu,
+	       "O."[!!cpu_online(cpu)],
+	       "o."[!!(rdp->grpmask & rdp->mynode->qsmaskinit)],
+	       "N."[!!(rdp->grpmask & rdp->mynode->qsmaskinitnext)],
+	       ticks_value, ticks_title,
 	       atomic_read(&rdtp->dynticks) & 0xfff,
 	       rdtp->dynticks_nesting, rdtp->dynticks_nmi_nesting,
 	       rdp->softirq_snap, kstat_softirqs_cpu(RCU_SOFTIRQ, cpu),
-- 
2.5.2

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