From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755337AbcJUMAc (ORCPT ); Fri, 21 Oct 2016 08:00:32 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:44124 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752880AbcJUL7L (ORCPT ); Fri, 21 Oct 2016 07:59:11 -0400 From: Christian Borntraeger To: Peter Zijlstra Cc: Nicholas Piggin , linux-kernel@vger.kernel.org, linux-s390 , linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Heiko Carstens , Martin Schwidefsky , Noam Camus , Christian Borntraeger Subject: [PATCH 2/5] stop_machine: yield CPU during stop machine Date: Fri, 21 Oct 2016 13:58:55 +0200 X-Mailer: git-send-email 2.5.5 In-Reply-To: <1477051138-1610-1-git-send-email-borntraeger@de.ibm.com> References: <1477051138-1610-1-git-send-email-borntraeger@de.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16102111-0020-0000-0000-0000026606A7 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16102111-0021-0000-0000-00003EAEA652 Message-Id: <1477051138-1610-3-git-send-email-borntraeger@de.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-10-21_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1609300000 definitions=main-1610210220 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org stop_machine can take a very long time if the hypervisor does overcommitment for guest CPUs. When waiting for "the one", lets give up our CPU by using the new cpu_relax_yield. Signed-off-by: Christian Borntraeger --- kernel/stop_machine.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index ec9ab2f..1eb8266 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -194,7 +194,7 @@ static int multi_cpu_stop(void *data) /* Simple state machine */ do { /* Chill out and ensure we re-read multi_stop_state. */ - cpu_relax(); + cpu_relax_yield(); if (msdata->state != curstate) { curstate = msdata->state; switch (curstate) { -- 2.5.5