From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946026AbdEYWUA (ORCPT ); Thu, 25 May 2017 18:20:00 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:51362 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S942573AbdEYWAM (ORCPT ); Thu, 25 May 2017 18:00:12 -0400 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 33/88] rcu: Print out rcupdate.c non-default boot-time settings Date: Thu, 25 May 2017 14:59:06 -0700 X-Mailer: git-send-email 2.5.2 In-Reply-To: <20170525215934.GA11578@linux.vnet.ibm.com> References: <20170525215934.GA11578@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17052522-0040-0000-0000-0000034A3711 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007117; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000212; SDB=6.00865574; UDB=6.00429834; IPR=6.00645397; BA=6.00005375; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00015583; XFM=3.00000015; UTC=2017-05-25 22:00:09 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17052522-0041-0000-0000-0000073E6D4A Message-Id: <1495749601-21574-33-git-send-email-paulmck@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-05-25_17:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1705250401 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This commit adds a rcupdate_announce_bootup_oddness() function to print out non-default values of significant kernel boot parameter settings to aid in debugging. Signed-off-by: Paul E. McKenney --- include/linux/rcupdate.h | 1 + kernel/rcu/tree_plugin.h | 1 + kernel/rcu/update.c | 42 +++++++++++++++++++++++++++++++++++++++++- 3 files changed, 43 insertions(+), 1 deletion(-) diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index e1e5d002fdb9..393e461d3ea8 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -76,6 +76,7 @@ bool rcu_gp_is_normal(void); /* Internal RCU use. */ bool rcu_gp_is_expedited(void); /* Internal RCU use. */ void rcu_expedite_gp(void); void rcu_unexpedite_gp(void); +void rcupdate_announce_bootup_oddness(void); #endif /* #else #ifdef CONFIG_TINY_RCU */ enum rcutorture_type { diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 3b432fa4c45b..eb5ebdce25ff 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -92,6 +92,7 @@ static void __init rcu_bootup_announce_oddness(void) pr_info("\tRCU restricting CPUs from NR_CPUS=%d to nr_cpu_ids=%d.\n", NR_CPUS, nr_cpu_ids); if (IS_ENABLED(CONFIG_RCU_BOOST)) pr_info("\tRCU kthread priority: %d.\n", kthread_prio); + rcupdate_announce_bootup_oddness(); } #ifdef CONFIG_PREEMPT_RCU diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index 273e869ca21d..82a5aa10dbc5 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -560,7 +560,8 @@ static DEFINE_RAW_SPINLOCK(rcu_tasks_cbs_lock); DEFINE_SRCU(tasks_rcu_exit_srcu); /* Control stall timeouts. Disable with <= 0, otherwise jiffies till stall. */ -static int rcu_task_stall_timeout __read_mostly = HZ * 60 * 10; +#define RCU_TASK_STALL_TIMEOUT (HZ * 60 * 10) +static int rcu_task_stall_timeout __read_mostly = RCU_TASK_STALL_TIMEOUT; module_param(rcu_task_stall_timeout, int, 0644); static void rcu_spawn_tasks_kthread(void); @@ -851,6 +852,23 @@ static void rcu_spawn_tasks_kthread(void) #endif /* #ifdef CONFIG_TASKS_RCU */ +#ifndef CONFIG_TINY_RCU + +/* + * Print any non-default Tasks RCU settings. + */ +static void __init rcu_tasks_bootup_oddness(void) +{ +#ifdef CONFIG_TASKS_RCU + if (rcu_task_stall_timeout != RCU_TASK_STALL_TIMEOUT) + pr_info("\tTasks-RCU CPU stall warnings timeout set to %d (rcu_task_stall_timeout).\n", rcu_task_stall_timeout); + else + pr_info("\tTasks RCU enabled.\n"); +#endif /* #ifdef CONFIG_TASKS_RCU */ +} + +#endif /* #ifndef CONFIG_TINY_RCU */ + #ifdef CONFIG_PROVE_RCU /* @@ -935,3 +953,25 @@ late_initcall(rcu_verify_early_boot_tests); #else void rcu_early_boot_tests(void) {} #endif /* CONFIG_PROVE_RCU */ + +#ifndef CONFIG_TINY_RCU + +/* + * Print any significant non-default boot-time settings. + */ +void __init rcupdate_announce_bootup_oddness(void) +{ + if (rcu_normal) + pr_info("\tNo expedited grace period (rcu_normal).\n"); + else if (rcu_normal_after_boot) + pr_info("\tNo expedited grace period (rcu_normal_after_boot).\n"); + else if (rcu_expedited) + pr_info("\tAll grace periods are expedited (rcu_expedited).\n"); + if (rcu_cpu_stall_suppress) + pr_info("\tRCU CPU stall warnings suppressed (rcu_cpu_stall_suppress).\n"); + if (rcu_cpu_stall_timeout != CONFIG_RCU_CPU_STALL_TIMEOUT) + pr_info("\tRCU CPU stall warnings timeout set to %d (rcu_cpu_stall_timeout).\n", rcu_cpu_stall_timeout); + rcu_tasks_bootup_oddness(); +} + +#endif /* #ifndef CONFIG_TINY_RCU */ -- 2.5.2