From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754158AbeDWDE1 (ORCPT ); Sun, 22 Apr 2018 23:04:27 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:42524 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753986AbeDWDCk (ORCPT ); Sun, 22 Apr 2018 23:02:40 -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, joel.opensrc@gmail.com, torvalds@linux-foundation.org, npiggin@gmail.com, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 13/21] rcu: Clear request other than RCU_GP_FLAG_INIT at GP end Date: Sun, 22 Apr 2018 20:03:36 -0700 X-Mailer: git-send-email 2.5.2 In-Reply-To: <20180423030258.GA23370@linux.vnet.ibm.com> References: <20180423030258.GA23370@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18042303-0024-0000-0000-0000034CD031 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00008903; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000257; SDB=6.01021898; UDB=6.00521542; IPR=6.00801134; MB=3.00020719; MTD=3.00000008; XFM=3.00000015; UTC=2018-04-23 03:02:37 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18042303-0025-0000-0000-000047C2E84A Message-Id: <1524452624-27589-13-git-send-email-paulmck@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-04-23_01:,, 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 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1804230032 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Once the grace period has ended, any RCU_GP_FLAG_FQS requests are irrelevant: The grace period has ended, so there is no longer any point in forcing quiescent states in order to try to make it end sooner. This commit therefore causes rcu_gp_cleanup() to clear any bits other than RCU_GP_FLAG_INIT from ->gp_flags at the end of the grace period. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index c7b1e6b2a3da..25dbbc753fef 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2181,6 +2181,7 @@ static void rcu_gp_cleanup(struct rcu_state *rsp) READ_ONCE(rsp->gpnum), TPS("newreq")); } + WRITE_ONCE(rsp->gp_flags, rsp->gp_flags & RCU_GP_FLAG_INIT); raw_spin_unlock_irq_rcu_node(rnp); } -- 2.5.2