Linux RCU subsystem development
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From: "Paul E. McKenney" <paulmck@kernel.org>
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com,
	rostedt@goodmis.org, "Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH v2 04/11] rcutorture: Suppress "Writer stall state" reports during boot
Date: Thu, 18 Sep 2025 03:29:45 -0700	[thread overview]
Message-ID: <20250918102952.2593045-4-paulmck@kernel.org> (raw)
In-Reply-To: <c0edd79a-f988-432c-b08a-18793b2e15d9@paulmck-laptop>

When rcutorture is running on only the one boot-time CPU while that CPU
is busy invoking initcall() functions, the added load is quite likely to
unduly delay the RCU grace-period kthread, rcutorture readers, and much
else besides.  This can result in rcu_torture_stats_print() reporting
rcutorture writer stalls, which are not really a bug in that environment.
After all, one CPU can only do so much.

This commit therefore suppresses rcutorture writer stalls while the
kernel is booting, that is, while rcu_inkernel_boot_has_ended() continues
returning false.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/rcu/rcutorture.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 7a893d51d02b6a..49e048da4f6810 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -2756,7 +2756,8 @@ rcu_torture_stats_print(void)
 		cur_ops->stats();
 	if (rtcv_snap == rcu_torture_current_version &&
 	    rcu_access_pointer(rcu_torture_current) &&
-	    !rcu_stall_is_suppressed()) {
+	    !rcu_stall_is_suppressed() &&
+	    rcu_inkernel_boot_has_ended()) {
 		int __maybe_unused flags = 0;
 		unsigned long __maybe_unused gp_seq = 0;
 
-- 
2.40.1


  parent reply	other threads:[~2025-09-18 10:29 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-09-18 10:29 [PATCH v2 0/11] RCU torture-test updates for v6.18 Paul E. McKenney
2025-09-18 10:29 ` [PATCH v2 01/11] rcutorture: Fix jitter.sh spin time Paul E. McKenney
2025-09-18 10:29 ` [PATCH v2 02/11] torture: Add --do-normal parameter to torture.sh help text Paul E. McKenney
2025-09-18 10:29 ` [PATCH v2 03/11] torture: Announce kernel boot status at torture-test startup Paul E. McKenney
2025-09-18 10:29 ` Paul E. McKenney [this message]
2025-09-18 10:29 ` [PATCH v2 05/11] rcutorture: Delay rcutorture readers and writers until boot completes Paul E. McKenney
2025-09-18 10:29 ` [PATCH v2 06/11] torture: Delay CPU-hotplug operations " Paul E. McKenney
2025-09-18 10:29 ` [PATCH v2 07/11] rcutorture: Delay forward-progress testing " Paul E. McKenney
2025-09-18 10:29 ` [PATCH v2 08/11] rcutorture: Use kcalloc() instead of kzalloc() Paul E. McKenney
2025-09-18 10:29 ` [PATCH v2 09/11] refscale: " Paul E. McKenney
2025-09-18 10:29 ` [PATCH v2 10/11] refperf: Remove redundant kfree() after torture_stop_kthread() Paul E. McKenney
2025-09-18 10:29 ` [PATCH v2 11/11] refperf: Set reader_tasks to NULL after kfree() Paul E. McKenney

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