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 3FBAEC433F5 for ; Wed, 29 Aug 2018 22:22:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E7B7120661 for ; Wed, 29 Aug 2018 22:22:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E7B7120661 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 S1727708AbeH3CVS (ORCPT ); Wed, 29 Aug 2018 22:21:18 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:50884 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727294AbeH3CTy (ORCPT ); Wed, 29 Aug 2018 22:19:54 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w7TMIhtD094283 for ; Wed, 29 Aug 2018 18:20:55 -0400 Received: from e17.ny.us.ibm.com (e17.ny.us.ibm.com [129.33.205.207]) by mx0a-001b2d01.pphosted.com with ESMTP id 2m627rc13d-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 29 Aug 2018 18:20:55 -0400 Received: from localhost by e17.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 29 Aug 2018 18:20:55 -0400 Received: from b01cxnp23032.gho.pok.ibm.com (9.57.198.27) by e17.ny.us.ibm.com (146.89.104.204) 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 18:20:49 -0400 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp23032.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w7TMKmbb25821232 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 29 Aug 2018 22:20:48 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BAA96B2075; Wed, 29 Aug 2018 18:19:44 -0400 (EDT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A245EB2070; Wed, 29 Aug 2018 18:19:44 -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 18:19:44 -0400 (EDT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id 1D26016C91C9; Wed, 29 Aug 2018 15:20:49 -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 05/19] rcu: Remove now-unused ->b.exp_need_qs field from the rcu_special union Date: Wed, 29 Aug 2018 15:20:33 -0700 X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180829222021.GA29944@linux.vnet.ibm.com> References: <20180829222021.GA29944@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18082922-0040-0000-0000-0000046756CE X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00009636; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000266; SDB=6.01080738; UDB=6.00557494; IPR=6.00860724; MB=3.00023001; MTD=3.00000008; XFM=3.00000015; UTC=2018-08-29 22:20:53 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18082922-0041-0000-0000-0000086E70A1 Message-Id: <20180829222047.319-5-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-1808290217 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The ->b.exp_need_qs field is now set only to false, so this commit removes it. The job this field used to do is now done by the rcu_data structure's ->deferred_qs field, which is a consequence of a better split between task-based (the rcu_node structure's ->exp_tasks field) and CPU-based (the aforementioned rcu_data structure's ->deferred_qs field) tracking of quiescent states for RCU-preempt expedited grace periods. Signed-off-by: Paul E. McKenney --- include/linux/sched.h | 6 +----- kernel/rcu/tree_plugin.h | 13 ++++--------- 2 files changed, 5 insertions(+), 14 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 977cb57d7bc9..004ca21f7e80 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -571,12 +571,8 @@ union rcu_special { struct { u8 blocked; u8 need_qs; - u8 exp_need_qs; - - /* Otherwise the compiler can store garbage here: */ - u8 pad; } b; /* Bits. */ - u32 s; /* Set of bits. */ + u16 s; /* Set of bits. */ }; enum perf_event_task_context { diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 24c209676d20..527a52792dce 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -284,13 +284,10 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp) * no need to check for a subsequent expedited GP. (Though we are * still in a quiescent state in any case.) */ - if (blkd_state & RCU_EXP_BLKD && - t->rcu_read_unlock_special.b.exp_need_qs) { - t->rcu_read_unlock_special.b.exp_need_qs = false; + if (blkd_state & RCU_EXP_BLKD && rdp->deferred_qs) rcu_report_exp_rdp(rdp->rsp, rdp, true); - } else { - WARN_ON_ONCE(t->rcu_read_unlock_special.b.exp_need_qs); - } + else + WARN_ON_ONCE(rdp->deferred_qs); } /* @@ -509,9 +506,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags) * tasks are handled when removing the task from the * blocked-tasks list below. */ - if (special.b.exp_need_qs || rdp->deferred_qs) { - t->rcu_read_unlock_special.b.exp_need_qs = false; - rdp->deferred_qs = false; + if (rdp->deferred_qs) { rcu_report_exp_rdp(rcu_state_p, rdp, true); if (!t->rcu_read_unlock_special.s) { local_irq_restore(flags); -- 2.17.1