From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0BF35C43334 for ; Wed, 29 Aug 2018 22:54:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B8EB420644 for ; Wed, 29 Aug 2018 22:54:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B8EB420644 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.vnet.ibm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728018AbeH3Cx1 (ORCPT ); Wed, 29 Aug 2018 22:53:27 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:52892 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727597AbeH3CxZ (ORCPT ); Wed, 29 Aug 2018 22:53:25 -0400 Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w7TMs0Ax122059 for ; Wed, 29 Aug 2018 18:54:16 -0400 Received: from e16.ny.us.ibm.com (e16.ny.us.ibm.com [129.33.205.206]) by mx0a-001b2d01.pphosted.com with ESMTP id 2m64a28kr9-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 29 Aug 2018 18:54:16 -0400 Received: from localhost by e16.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 29 Aug 2018 18:54:15 -0400 Received: from b01cxnp23033.gho.pok.ibm.com (9.57.198.28) by e16.ny.us.ibm.com (146.89.104.203) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 29 Aug 2018 18:54:09 -0400 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp23033.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w7TMs9oc18415710 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 29 Aug 2018 22:54:09 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D1445B2067; Wed, 29 Aug 2018 18:53:04 -0400 (EDT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AA5FDB206B; Wed, 29 Aug 2018 18:53:04 -0400 (EDT) Received: from paulmck-ThinkPad-W541 (unknown [9.70.82.159]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Wed, 29 Aug 2018 18:53:04 -0400 (EDT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id C80AF16C91DE; Wed, 29 Aug 2018 15:54:07 -0700 (PDT) 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, joel@joelfernandes.org, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 23/24] rcu: Define rcu_all_qs() only in !PREEMPT builds Date: Wed, 29 Aug 2018 15:54:04 -0700 X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180829225340.GA7019@linux.vnet.ibm.com> References: <20180829225340.GA7019@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18082922-0072-0000-0000-0000039969A9 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00009636; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000266; SDB=6.01080749; UDB=6.00557500; IPR=6.00860734; MB=3.00023002; MTD=3.00000008; XFM=3.00000015; UTC=2018-08-29 22:54:13 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18082922-0073-0000-0000-0000493EB981 Message-Id: <20180829225405.7275-23-paulmck@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-08-29_06:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1808290223 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Now that rcu_all_qs() is used only in !PREEMPT builds, move it to tree_plugin.h so that it is defined only in those builds. This in turn means that rcu_momentary_dyntick_idle() is only used in !PREEMPT builds, but it is simply marked __maybe_unused in order to keep it near the rest of the dyntick-idle code. Signed-off-by: Paul E. McKenney --- include/linux/rcutree.h | 2 ++ kernel/rcu/tree.c | 41 +--------------------------------------- kernel/rcu/tree_plugin.h | 39 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 42 insertions(+), 40 deletions(-) diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index d09a9abe9440..7f83179177d1 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -66,7 +66,9 @@ void rcu_scheduler_starting(void); extern int rcu_scheduler_active __read_mostly; void rcu_end_inkernel_boot(void); bool rcu_is_watching(void); +#ifndef CONFIG_PREEMPT void rcu_all_qs(void); +#endif /* RCUtree hotplug events */ int rcutree_prepare_cpu(unsigned int cpu); diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index e8fbb7ee76cc..5f2a12a65b42 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -356,7 +356,7 @@ bool rcu_eqs_special_set(int cpu) * * The caller must have disabled interrupts and must not be idle. */ -static void rcu_momentary_dyntick_idle(void) +static void __maybe_unused rcu_momentary_dyntick_idle(void) { struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks); int special; @@ -381,45 +381,6 @@ static int rcu_is_cpu_rrupt_from_idle(void) __this_cpu_read(rcu_dynticks.dynticks_nmi_nesting) <= 1; } -/* - * Register an urgently needed quiescent state. If there is an - * emergency, invoke rcu_momentary_dyntick_idle() to do a heavy-weight - * dyntick-idle quiescent state visible to other CPUs, which will in - * some cases serve for expedited as well as normal grace periods. - * Either way, register a lightweight quiescent state. - * - * The barrier() calls are redundant in the common case when this is - * called externally, but just in case this is called from within this - * file. - * - */ -void rcu_all_qs(void) -{ - unsigned long flags; - - if (!raw_cpu_read(rcu_dynticks.rcu_urgent_qs)) - return; - preempt_disable(); - /* Load rcu_urgent_qs before other flags. */ - if (!smp_load_acquire(this_cpu_ptr(&rcu_dynticks.rcu_urgent_qs))) { - preempt_enable(); - return; - } - this_cpu_write(rcu_dynticks.rcu_urgent_qs, false); - barrier(); /* Avoid RCU read-side critical sections leaking down. */ - if (unlikely(raw_cpu_read(rcu_dynticks.rcu_need_heavy_qs))) { - local_irq_save(flags); - rcu_momentary_dyntick_idle(); - local_irq_restore(flags); - } - if (unlikely(raw_cpu_read(rcu_data.cpu_no_qs.b.exp))) - rcu_qs(); - this_cpu_inc(rcu_dynticks.rcu_qs_ctr); - barrier(); /* Avoid RCU read-side critical sections leaking up. */ - preempt_enable(); -} -EXPORT_SYMBOL_GPL(rcu_all_qs); - #define DEFAULT_RCU_BLIMIT 10 /* Maximum callbacks per rcu_do_batch. */ static long blimit = DEFAULT_RCU_BLIMIT; #define DEFAULT_RCU_QHIMARK 10000 /* If this many pending, ignore blimit. */ diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index cd4c1b979446..7add1c297500 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -947,6 +947,45 @@ static void rcu_qs(void) rcu_report_exp_rdp(this_cpu_ptr(&rcu_data)); } +/* + * Register an urgently needed quiescent state. If there is an + * emergency, invoke rcu_momentary_dyntick_idle() to do a heavy-weight + * dyntick-idle quiescent state visible to other CPUs, which will in + * some cases serve for expedited as well as normal grace periods. + * Either way, register a lightweight quiescent state. + * + * The barrier() calls are redundant in the common case when this is + * called externally, but just in case this is called from within this + * file. + * + */ +void rcu_all_qs(void) +{ + unsigned long flags; + + if (!raw_cpu_read(rcu_dynticks.rcu_urgent_qs)) + return; + preempt_disable(); + /* Load rcu_urgent_qs before other flags. */ + if (!smp_load_acquire(this_cpu_ptr(&rcu_dynticks.rcu_urgent_qs))) { + preempt_enable(); + return; + } + this_cpu_write(rcu_dynticks.rcu_urgent_qs, false); + barrier(); /* Avoid RCU read-side critical sections leaking down. */ + if (unlikely(raw_cpu_read(rcu_dynticks.rcu_need_heavy_qs))) { + local_irq_save(flags); + rcu_momentary_dyntick_idle(); + local_irq_restore(flags); + } + if (unlikely(raw_cpu_read(rcu_data.cpu_no_qs.b.exp))) + rcu_qs(); + this_cpu_inc(rcu_dynticks.rcu_qs_ctr); + barrier(); /* Avoid RCU read-side critical sections leaking up. */ + preempt_enable(); +} +EXPORT_SYMBOL_GPL(rcu_all_qs); + /* * Note a PREEMPT=n context switch. The caller must have disabled interrupts. */ -- 2.17.1