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[148.163.156.1]) by mx.google.com with ESMTPS id h144si4014596iof.146.2019.06.14.10.40.44 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 14 Jun 2019 10:40:45 -0700 (PDT) Received-SPF: pass (google.com: domain of aneesh.kumar@linux.ibm.com designates 148.163.156.1 as permitted sender) client-ip=148.163.156.1; Authentication-Results: mx.google.com; spf=pass (google.com: domain of aneesh.kumar@linux.ibm.com designates 148.163.156.1 as permitted sender) smtp.mailfrom=aneesh.kumar@linux.ibm.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5EHaflD045564; Fri, 14 Jun 2019 13:40:42 -0400 Received: from ppma01wdc.us.ibm.com (fd.55.37a9.ip4.static.sl-reverse.com [169.55.85.253]) by mx0a-001b2d01.pphosted.com with ESMTP id 2t4ehrmetu-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 14 Jun 2019 13:40:42 -0400 Received: from pps.filterd (ppma01wdc.us.ibm.com [127.0.0.1]) by ppma01wdc.us.ibm.com (8.16.0.27/8.16.0.27) with SMTP id x5EHdUO1029699; Fri, 14 Jun 2019 17:40:43 GMT Received: from b03cxnp07029.gho.boulder.ibm.com (b03cxnp07029.gho.boulder.ibm.com [9.17.130.16]) by ppma01wdc.us.ibm.com with ESMTP id 2t1qcty05s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 14 Jun 2019 17:40:43 +0000 Received: from b03ledav001.gho.boulder.ibm.com (b03ledav001.gho.boulder.ibm.com [9.17.130.232]) by b03cxnp07029.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x5EHeeTL17236386 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 14 Jun 2019 17:40:40 GMT Received: from b03ledav001.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7C4B16E04C; Fri, 14 Jun 2019 17:40:40 +0000 (GMT) Received: from b03ledav001.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D6FEA6E050; Fri, 14 Jun 2019 17:40:37 +0000 (GMT) Received: from [9.199.60.77] (unknown [9.199.60.77]) by b03ledav001.gho.boulder.ibm.com (Postfix) with ESMTP; Fri, 14 Jun 2019 17:40:37 +0000 (GMT) Subject: Re: [PATCH -next] mm/hotplug: skip bad PFNs from pfn_to_online_page() To: Jeff Moyer Cc: Dan Williams , Oscar Salvador , Qian Cai , Andrew Morton , Linux MM , Linux Kernel Mailing List , linux-nvdimm References: <1560366952-10660-1-git-send-email-cai@lca.pw> <1560376072.5154.6.camel@lca.pw> <87lfy4ilvj.fsf@linux.ibm.com> <20190614153535.GA9900@linux> <24fcb721-5d50-2c34-f44b-69281c8dd760@linux.ibm.com> <16108dac-a4ca-aa87-e3b0-a79aebdcfafd@linux.ibm.com> From: "Aneesh Kumar K.V" Message-ID: <4e912883-4a85-6579-0779-6c366ccee407@linux.ibm.com> Date: Fri, 14 Jun 2019 23:10:36 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-14_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=27 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-1906140142 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 6/14/19 10:38 PM, Jeff Moyer wrote: > "Aneesh Kumar K.V" writes: > >> On 6/14/19 10:06 PM, Dan Williams wrote: >>> On Fri, Jun 14, 2019 at 9:26 AM Aneesh Kumar K.V >>> wrote: >> >>>> Why not let the arch >>>> arch decide the SUBSECTION_SHIFT and default to one subsection per >>>> section if arch is not enabled to work with subsection. >>> >>> Because that keeps the implementation from ever reaching a point where >>> a namespace might be able to be moved from one arch to another. If we >>> can squash these arch differences then we can have a common tool to >>> initialize namespaces outside of the kernel. The one wrinkle is >>> device-dax that wants to enforce the mapping size, >> >> The fsdax have a much bigger issue right? The file system block size >> is the same as PAGE_SIZE and we can't make it portable across archs >> that support different PAGE_SIZE? > > File system blocks are not tied to page size. They can't be *bigger* > than the page size currently, but they can be smaller. > ppc64 page size is 64K. > Still, I don't see that as an arugment against trying to make the > namespaces work across architectures. Consider a user who only has > sector mode namespaces. We'd like that to work if at all possible. > agreed. I was trying to list out the challenges here. -aneesh