From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marco Stornelli Subject: Re: [PATCH 00/19] pramfs Date: Sun, 08 Sep 2013 11:34:14 +0200 Message-ID: <522C4496.2030009@gmail.com> References: <522AE04C.6000002@gmail.com> <522B52BA.6030202@gmail.com> <522C3DDC.4090209@parallels.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Vladimir Davydov , Linux FS Devel , Linux Kernel To: richard -rw- weinberger Return-path: Received: from mail-ea0-f169.google.com ([209.85.215.169]:51504 "EHLO mail-ea0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752159Ab3IHJlR (ORCPT ); Sun, 8 Sep 2013 05:41:17 -0400 In-Reply-To: <522C3DDC.4090209@parallels.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Il 08/09/2013 11:05, Vladimir Davydov ha scritto: > On 09/07/2013 08:22 PM, Marco Stornelli wrote: >> Il 07/09/2013 16:58, richard -rw- weinberger ha scritto: >>> On Sat, Sep 7, 2013 at 10:14 AM, Marco Stornelli >>> wrote: >>>> Hi all, >>>> >>>> this is an attempt to include pramfs in mainline. At the moment pramfs >>>> has been included in LTSI kernel. Since last review the code is more >>>> or less the same but, with a really big thanks to Vladimir Davydov and >>>> Parallels, the development of fsck has been started and we have now >>>> the possibility to correct fs errors due to corruption. It's a "young" >>>> tool but we are working on it. You can clone the code from our repos: >>>> >>>> git clone git://git.code.sf.net/p/pramfs/code pramfs-code >>>> git clone git://git.code.sf.net/p/pramfs/Tools pramfs-Tools >>> >>> I'm a bit confused, what kind of non-volatile RAM is your fs targeting? >>> Wouldn't it make sense to use pstore like >>> arch/powerpc/platforms/pseries/nvram.c does? >>> >> >> Usually battery-backed SRAM, but actually it can be used in any piece >> of ram directly accessible and it provides a normal and complete fs >> interface. Usually I do the fs test remapping my system ram. You can >> find documentation here: >> >> http://pramfs.sourceforge.net > > I'd like to add that in contrast to pstore, pramfs allows storing any > files in it, not only system logs. This can be of value even on machines > w/o special devices like sram/nvram: one can store data that should be > quickly restored after reboot in conventional ram and use kexec to boot > to a new kernel. One of the use cases of this could be checkpointing > time-critical services to ram (using criu.org) to be quickly restored > after a kernel update providing almost zero-downtime. > Yep. I add that if you use your system ram, your bootloader must be aware because it mustn't clear your memory after a reboot, indeed you can find reference of Pramfs in Uboot documentation: http://www.denx.de/wiki/view/DULG/PersistentRAMFileSystem Marco