From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753341Ab1AFSov (ORCPT ); Thu, 6 Jan 2011 13:44:51 -0500 Received: from mail-wy0-f174.google.com ([74.125.82.174]:61251 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751649Ab1AFSou (ORCPT ); Thu, 6 Jan 2011 13:44:50 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; b=eWofq67wcAvdNhaDfidAGfELBBEbiaWFf7qN+dENF9a3/FDCzb2jh+USC0H7en49Eq kfJ2wGYaV+/+ibuk8We5JFVZUFTabtlvl6LJneEsp6jIPnEbV4HaEU53mFN4XEPmS4On cHLqfw9K5Kcv04ZSFP83aymWG6vACHncpoiy0= Message-ID: <4D260A96.4020400@gmail.com> Date: Thu, 06 Jan 2011 19:31:50 +0100 From: Marco Stornelli User-Agent: Mozilla/5.0 (X11; U; Linux i686; it; rv:1.9.1.16) Gecko/20101125 SUSE/3.0.11 Thunderbird/3.0.11 MIME-Version: 1.0 To: "Luck, Tony" CC: Peter Zijlstra , Linux Kernel , Linux FS Devel , Linux Embedded , Tim Bird Subject: Re: [PATCH 00/17] pramfs: persistent and protected RAM filesystem References: <4D25AEEE.1050401@gmail.com> <1294322613.2016.333.camel@laptop> <4D25ED22.3070900@gmail.com> <4D25F4CF.1030009@gmail.com> <987664A83D2D224EAE907B061CE93D530193FC6AA2@orsmsx505.amr.corp.intel.com> In-Reply-To: <987664A83D2D224EAE907B061CE93D530193FC6AA2@orsmsx505.amr.corp.intel.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 06/01/2011 19:22, Luck, Tony ha scritto: >> Errata corrige: maybe I used the wrong term, I meant "volatile" instead >> of "temporary" information, i.e. I'd like to save this info to re-read >> it later but I don't want to store it in flash, a simple log, run-time >> information for debug like a flight-recorder or whatever you want. > > I'm puzzled by the use of "a generic piece of memory" to store "persistent" > things (Perhaps this is made clear in the 17 parts of the patch? I haven't > read them yet). On x86 f/w typically clears all of memory on reset ... so > you only get persistence if you use kexec to get from the old kernel to > the new one. > > -Tony > First of all, you can find a lot of information on the web site where there is an overview and a page with implementation details, benchmark and so on. With "a generic piece of memory" I mean a generic memory device directly addressable. Usually this generic device is an NVRAM, so we have a persistent store. If you haven't got this hw you can use other devices or the classic RAM, in this case you have a fs persistent only over reboot. The use of this fs is mainly for embedded systems, fw can be configured to not clear *all* the memory. Pramfs is indeed supported by U-Boot, you can see CONFIG_PRAM in the Das U-Boot manual. x86 in this case can be a "strange" world for this fs, but however if the user wants it can be used without problems because there aren't neither strict arch or hw dependency. Marco