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Wed, 15 Jul 2020 05:09:49 +0000 (GMT) Received: from oc0525413822.ibm.com (unknown [9.163.39.1]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTPS id 8BFC452051; Wed, 15 Jul 2020 05:09:46 +0000 (GMT) Date: Tue, 14 Jul 2020 22:09:43 -0700 From: Ram Pai To: Bharata B Rao Subject: Re: [v3 4/5] KVM: PPC: Book3S HV: retry page migration before erroring-out H_SVM_PAGE_IN Message-ID: <20200715050943.GD7339@oc0525413822.ibm.com> References: <1594458827-31866-1-git-send-email-linuxram@us.ibm.com> <1594458827-31866-5-git-send-email-linuxram@us.ibm.com> <20200713095043.GH7902@in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200713095043.GH7902@in.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235, 18.0.687 definitions=2020-07-15_02:2020-07-14, 2020-07-15 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 priorityscore=1501 suspectscore=0 spamscore=0 malwarescore=0 mlxlogscore=917 lowpriorityscore=0 phishscore=0 clxscore=1015 impostorscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007150042 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: , Reply-To: Ram Pai Cc: ldufour@linux.ibm.com, cclaudio@linux.ibm.com, kvm-ppc@vger.kernel.org, sathnaga@linux.vnet.ibm.com, aneesh.kumar@linux.ibm.com, sukadev@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org, bauerman@linux.ibm.com, david@gibson.dropbear.id.au Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Mon, Jul 13, 2020 at 03:20:43PM +0530, Bharata B Rao wrote: > On Sat, Jul 11, 2020 at 02:13:46AM -0700, Ram Pai wrote: > > The page requested for page-in; sometimes, can have transient > > references, and hence cannot migrate immediately. Retry a few times > > before returning error. > > As I noted in the previous patch, we need to understand what are these > transient errors and they occur on what type of pages? Its not clear when they occur. But they occur quite irregularly and they do occur on pages that were shared in the previous boot. > > The previous patch also introduced a bit of retry logic in the > page-in path. Can you consolidate the retry logic into a separate > patch? yes. having the retry logic in a seperate patch gives us the flexibility to drop it, if needed. The retry patch is not the core element of this patch series. RP