Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755663AbdDLRp4 (ORCPT ); Wed, 12 Apr 2017 13:45:56 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:57798 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754808AbdDLRkg (ORCPT ); Wed, 12 Apr 2017 13:40:36 -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 17/40] srcu: Allow SRCU to access rcu_scheduler_active Date: Wed, 12 Apr 2017 10:40:02 -0700 X-Mailer: git-send-email 2.5.2 In-Reply-To: <20170412174003.GA23207@linux.vnet.ibm.com> References: <20170412174003.GA23207@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17041217-0040-0000-0000-0000031335AC X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00006924; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000208; SDB=6.00846603; UDB=6.00417608; IPR=6.00625041; BA=6.00005286; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00015023; XFM=3.00000013; UTC=2017-04-12 17:40:33 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17041217-0041-0000-0000-000007073F73 Message-Id: <1492018825-25634-17-git-send-email-paulmck@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-04-12_13:,, 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=8.0.1-1702020001 definitions=main-1704120145 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5859 Lines: 179 This is primarily a code-movement commit in preparation for allowing SRCU to handle early-boot SRCU grace periods. Signed-off-by: Paul E. McKenney --- include/linux/rcutiny.h | 6 +++--- kernel/rcu/tiny_plugin.h | 9 +++++---- kernel/rcu/tree.c | 2 +- kernel/rcu/tree_exp.h | 12 ----------- kernel/rcu/update.c | 52 +++++++++++++++++++++++++++++++----------------- 5 files changed, 43 insertions(+), 38 deletions(-) diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 6c9d941e3962..5219be250f00 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -217,14 +217,14 @@ static inline void exit_rcu(void) { } -#ifdef CONFIG_DEBUG_LOCK_ALLOC +#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SRCU) extern int rcu_scheduler_active __read_mostly; void rcu_scheduler_starting(void); -#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ +#else /* #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SRCU) */ static inline void rcu_scheduler_starting(void) { } -#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ +#endif /* #else #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SRCU) */ #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) diff --git a/kernel/rcu/tiny_plugin.h b/kernel/rcu/tiny_plugin.h index df3a60e19f07..371034e77f87 100644 --- a/kernel/rcu/tiny_plugin.h +++ b/kernel/rcu/tiny_plugin.h @@ -52,7 +52,7 @@ static struct rcu_ctrlblk rcu_bh_ctrlblk = { RCU_TRACE(.name = "rcu_bh") }; -#ifdef CONFIG_DEBUG_LOCK_ALLOC +#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SRCU) #include int rcu_scheduler_active __read_mostly; @@ -65,15 +65,16 @@ EXPORT_SYMBOL_GPL(rcu_scheduler_active); * to RCU_SCHEDULER_RUNNING, skipping the RCU_SCHEDULER_INIT stage. * The reason for this is that Tiny RCU does not need kthreads, so does * not have to care about the fact that the scheduler is half-initialized - * at a certain phase of the boot process. + * at a certain phase of the boot process. Unless SRCU is in the mix. */ void __init rcu_scheduler_starting(void) { WARN_ON(nr_context_switches() > 0); - rcu_scheduler_active = RCU_SCHEDULER_RUNNING; + rcu_scheduler_active = IS_ENABLED(CONFIG_SRCU) + ? RCU_SCHEDULER_INIT : RCU_SCHEDULER_RUNNING; } -#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ +#endif /* #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SRCU) */ #ifdef CONFIG_RCU_TRACE diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 00390965c843..5e827d636e0b 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3981,7 +3981,7 @@ early_initcall(rcu_spawn_gp_kthread); * task is booting the system, and such primitives are no-ops). After this * function is called, any synchronous grace-period primitives are run as * expedited, with the requesting task driving the grace period forward. - * A later core_initcall() rcu_exp_runtime_mode() will switch to full + * A later core_initcall() rcu_set_runtime_mode() will switch to full * runtime RCU functionality. */ void rcu_scheduler_starting(void) diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index a1f52bbe9db6..51ca287828a2 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -737,15 +737,3 @@ void synchronize_rcu_expedited(void) EXPORT_SYMBOL_GPL(synchronize_rcu_expedited); #endif /* #else #ifdef CONFIG_PREEMPT_RCU */ - -/* - * Switch to run-time mode once Tree RCU has fully initialized. - */ -static int __init rcu_exp_runtime_mode(void) -{ - rcu_test_sync_prims(); - rcu_scheduler_active = RCU_SCHEDULER_RUNNING; - rcu_test_sync_prims(); - return 0; -} -core_initcall(rcu_exp_runtime_mode); diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index 55c8530316c7..c5df0d756900 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -124,7 +124,7 @@ EXPORT_SYMBOL(rcu_read_lock_sched_held); * non-expedited counterparts? Intended for use within RCU. Note * that if the user specifies both rcu_expedited and rcu_normal, then * rcu_normal wins. (Except during the time period during boot from - * when the first task is spawned until the rcu_exp_runtime_mode() + * when the first task is spawned until the rcu_set_runtime_mode() * core_initcall() is invoked, at which point everything is expedited.) */ bool rcu_gp_is_normal(void) @@ -190,6 +190,39 @@ void rcu_end_inkernel_boot(void) #endif /* #ifndef CONFIG_TINY_RCU */ +/* + * Test each non-SRCU synchronous grace-period wait API. This is + * useful just after a change in mode for these primitives, and + * during early boot. + */ +void rcu_test_sync_prims(void) +{ + if (!IS_ENABLED(CONFIG_PROVE_RCU)) + return; + synchronize_rcu(); + synchronize_rcu_bh(); + synchronize_sched(); + synchronize_rcu_expedited(); + synchronize_rcu_bh_expedited(); + synchronize_sched_expedited(); +} + +#if !defined(CONFIG_TINY_RCU) || defined(CONFIG_SRCU) + +/* + * Switch to run-time mode once RCU has fully initialized. + */ +static int __init rcu_set_runtime_mode(void) +{ + rcu_test_sync_prims(); + rcu_scheduler_active = RCU_SCHEDULER_RUNNING; + rcu_test_sync_prims(); + return 0; +} +core_initcall(rcu_set_runtime_mode); + +#endif /* #if !defined(CONFIG_TINY_RCU) || defined(CONFIG_SRCU) */ + #ifdef CONFIG_PREEMPT_RCU /* @@ -817,23 +850,6 @@ static void rcu_spawn_tasks_kthread(void) #endif /* #ifdef CONFIG_TASKS_RCU */ -/* - * Test each non-SRCU synchronous grace-period wait API. This is - * useful just after a change in mode for these primitives, and - * during early boot. - */ -void rcu_test_sync_prims(void) -{ - if (!IS_ENABLED(CONFIG_PROVE_RCU)) - return; - synchronize_rcu(); - synchronize_rcu_bh(); - synchronize_sched(); - synchronize_rcu_expedited(); - synchronize_rcu_bh_expedited(); - synchronize_sched_expedited(); -} - #ifdef CONFIG_PROVE_RCU /* -- 2.5.2