From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764734AbdAJDBF (ORCPT ); Mon, 9 Jan 2017 22:01:05 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:35236 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753102AbdAJDBC (ORCPT ); Mon, 9 Jan 2017 22:01:02 -0500 From: Pan Xinhui To: linux-kernel@vger.kernel.org Cc: mingo@redhat.com, peterz@infradead.org, longman@redhat.com, Pan Xinhui Subject: [PATCH v2] locking/pvqspinlock: Wait early if vCPU is preempted Date: Tue, 10 Jan 2017 02:56:46 -0500 X-Mailer: git-send-email 2.4.11 X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 17011003-0044-0000-0000-0000021ADA9E X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17011003-0045-0000-0000-000006534848 Message-Id: <1484035006-6787-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-01-10_02:,, 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=8.0.1-1612050000 definitions=main-1701100039 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If prev node is not in runnig state or its vCPU is preempted, we can give up our vCPU slices ASAP in pv_wait_node. After commit d9345c65eb79 ("sched/core: Introduce the vcpu_is_preempted(cpu) interface") kernel has knowledge of one vCPU is running or not. Signed-off-by: Pan Xinhui --- v2: rewrite the commit message as Ingo pointed out the mistake. --- kernel/locking/qspinlock_paravirt.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h index e3b5520..48648dc 100644 --- a/kernel/locking/qspinlock_paravirt.h +++ b/kernel/locking/qspinlock_paravirt.h @@ -263,7 +263,8 @@ pv_wait_early(struct pv_node *prev, int loop) if ((loop & PV_PREV_CHECK_MASK) != 0) return false; - return READ_ONCE(prev->state) != vcpu_running; + return READ_ONCE(prev->state) != vcpu_running || + vcpu_is_preempted(prev->cpu); } /* -- 2.4.11