From: Imran Khan <imran.f.khan@oracle.com>
Date: Mon, 8 May 2023 22:31:23 +0000 (+1000)
Subject: smp: Reduce logging due to dump_stack of CSD waiters
X-Git-Tag: v6.6.17~4137^2~1
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=5bd00f6db012f75b42434d39b7fec98b95c1afcc;p=platform%2Fkernel%2Flinux-rpi.git

smp: Reduce logging due to dump_stack of CSD waiters

If a waiter is waiting for CSD lock, its call stack will not change
between first and subsequent hang detection for the same CSD lock.
Therefore, do dump_stack only for first-time detection for a given waiter.

This avoids excessive logging on systems with hundreds of CPUs where
repetitive dump_stack from hundreds of CPUs would otherwise flood the
console.

Signed-off-by: Imran Khan <imran.f.khan@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---

diff --git a/kernel/smp.c b/kernel/smp.c
index 385179d..1d41a0c 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -259,7 +259,8 @@ static bool csd_lock_wait_toolong(struct __call_single_data *csd, u64 ts0, u64 *
 			arch_send_call_function_single_ipi(cpu);
 		}
 	}
-	dump_stack();
+	if (firsttime)
+		dump_stack();
 	*ts1 = ts2;
 
 	return false;