From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756544AbbIUJfb (ORCPT ); Mon, 21 Sep 2015 05:35:31 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:64628 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756526AbbIUJf1 (ORCPT ); Mon, 21 Sep 2015 05:35:27 -0400 Subject: Re: [PATCH] pramdisk: new block disk driver to perform persistent storage To: Ross Zwisler References: <1442562390-91051-1-git-send-email-linyongting@huawei.com> <20150918161813.GA4274@linux.intel.com> CC: "dan.j.williams@intel.com" , "axboe@fb.com" , "akpm@linux-foundation.org" , "richard@nod.at" , "willy@linux.intel.com" , Wangxiaozhe , "mingo@kernel.org" , "gregkh@linuxfoundation.org" , "linux-kernel@vger.kernel.org" From: Lin Yongting Message-ID: <55FFCE1F.4000605@huawei.com> Date: Mon, 21 Sep 2015 17:30:07 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <20150918161813.GA4274@linux.intel.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.66.68.239] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/9/19 0:18, Ross Zwisler wrote: > On Fri, Sep 18, 2015 at 03:46:30PM +0800, Lin Yongting wrote: >> In embed devices, user space applications will use reserved memory >> (i.e. persistent memory) to store business data, the data is kept >> in this memory region after system rebooting or panic. >> >> pramdisk is a block disk driver based on Persistent memory, it provide >> file system interface for application to read/write data in persistent >> memory. Application can use pramdisk to store log file or business data >> in persistent memory in the way of file system operation, avoid operating >> or managing memory directly. >> >> pramdisk support multiple Persistent menory regions and each one is a >> block device named as /dev/pram. >> >> Usage: >> modprobe pramdisk.ko pmem=@ [ pmem=@ ... ] >> >> For example: >> modprobe pramdisk.ko pmem=20M@2050M pmem=20M@2150M >> mkfs.ext3 /dev/pram1 >> mkdir /tmp/test1 >> mount -t ext3 /dev/pram1 /tmp/test1 >> >> Signed-off-by: Lin Yongting >> Signed-off-by: Wang xiaozhe > > I think you already have this functionality with the PMEM driver and the > memmap=nn[KMG]!ss[KMG] command line parameter? What are you trying to > accomplish with this driver that you can't do with PMEM? Hi Ross, thanks! I dig into nvdimm sub-system these two day and found that PMEM can make Reserved Memory as block disk to mount file system on it. But I am curious about two things: 1. seems memmap command line parameter is not available at ARM arch. Can we use module parameter rather than kernel command parameter? 2. If I specified two memmap regions(which they are Adjacent to each other), Can we get tow block device? Thanks Again. Best Regards! -- Lin Yongting