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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 E93C8C48BD6 for ; Tue, 25 Jun 2019 18:53:47 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 43A852080C for ; Tue, 25 Jun 2019 18:53:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 43A852080C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 45YFgD2bVPzDqXY for ; Wed, 26 Jun 2019 04:53:44 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=linux.ibm.com (client-ip=148.163.158.5; helo=mx0a-001b2d01.pphosted.com; envelope-from=nathanl@linux.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 45YFd32lPczDqPR for ; Wed, 26 Jun 2019 04:51:50 +1000 (AEST) Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5PImHJW074333 for ; Tue, 25 Jun 2019 14:51:47 -0400 Received: from e32.co.us.ibm.com (e32.co.us.ibm.com [32.97.110.150]) by mx0b-001b2d01.pphosted.com with ESMTP id 2tbs0urm2j-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 25 Jun 2019 14:51:47 -0400 Received: from localhost by e32.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 25 Jun 2019 19:51:43 +0100 Received: from b03ledav002.gho.boulder.ibm.com (b03ledav002.gho.boulder.ibm.com [9.17.130.233]) by b03cxnp08025.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x5PIpfNL37224814 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 25 Jun 2019 18:51:41 GMT Received: from b03ledav002.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A2F0D136051; Tue, 25 Jun 2019 18:51:41 +0000 (GMT) Received: from b03ledav002.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 60A6013604F; Tue, 25 Jun 2019 18:51:41 +0000 (GMT) Received: from localhost (unknown [9.85.210.126]) by b03ledav002.gho.boulder.ibm.com (Postfix) with ESMTP; Tue, 25 Jun 2019 18:51:41 +0000 (GMT) From: Nathan Lynch To: Juliet Kim Subject: Re: [PATCH] powerpc/rtas: retry when cpu offline races with suspend/migration In-Reply-To: <5a825cec-234a-ee8a-a776-8ba305f9cb26@linux.vnet.ibm.com> References: <20190621060518.29616-1-nathanl@linux.ibm.com> <87h88eucbn.fsf@linux.ibm.com> <5a825cec-234a-ee8a-a776-8ba305f9cb26@linux.vnet.ibm.com> Date: Tue, 25 Jun 2019 13:51:40 -0500 MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 x-cbid: 19062518-0004-0000-0000-000015210BD9 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00011329; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000286; SDB=6.01223180; UDB=6.00643682; IPR=6.01004352; MB=3.00027465; MTD=3.00000008; XFM=3.00000015; UTC=2019-06-25 18:51:44 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19062518-0005-0000-0000-00008C38646F Message-Id: <877e99ts5f.fsf@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-06-25_12:, , 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=8.0.1-1810050000 definitions=main-1906250140 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: ego@linux.vnet.ibm.com, mmc , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Juliet Kim writes: > There's some concern this could retry forever, resulting in live lock. First of all the system will make progress in other areas even if there are repeated retries; we're not indefinitely holding locks or anything like that. Second, Linux checks the H_VASI_STATE result on every retry. If the platform wants to terminate the migration (say, if it imposes a timeout), Linux will abandon it when H_VASI_STATE fails to return H_VASI_SUSPENDING. And it seems incorrect to bail out before that happens, absent hard errors on the Linux side such as allocation failures.