Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756672AbZFVX1E (ORCPT ); Mon, 22 Jun 2009 19:27:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751789AbZFVX0w (ORCPT ); Mon, 22 Jun 2009 19:26:52 -0400 Received: from zcars04e.nortel.com ([47.129.242.56]:61709 "EHLO zcars04e.nortel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751577AbZFVX0v (ORCPT ); Mon, 22 Jun 2009 19:26:51 -0400 Message-ID: <4A401335.1090307@nortel.com> Date: Mon, 22 Jun 2009 17:26:45 -0600 From: "Chris Friesen" User-Agent: Mozilla Thunderbird 1.0.2-6 (X11/20050513) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Pavel Machek CC: Tim Bird , Marco , Jamie Lokier , Linux Embedded , Linux Kernel , Linux FS Devel , Daniel Walker Subject: Re: [PATCH 00/14] Pramfs: Persistent and protected ram filesystem References: <4A3E6F28.4090404@gmail.com> <20090621205245.GC3254@elf.ucw.cz> <2ea1731b0906212333r20deb71q2f021fc79bcc8a8e@mail.gmail.com> <20090622172003.GB21149@elf.ucw.cz> <4A3FBFF0.40006@am.sony.com> <20090622173704.GC21299@elf.ucw.cz> <4A3FC84A.6060608@gmail.com> <20090622204031.GA24236@elf.ucw.cz> <4A3FFC89.4070006@am.sony.com> <20090622215753.GA25434@elf.ucw.cz> <20090622223855.GA25996@elf.ucw.cz> In-Reply-To: <20090622223855.GA25996@elf.ucw.cz> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 22 Jun 2009 23:26:50.0253 (UTC) FILETIME=[EB22B3D0:01C9F390] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1272 Lines: 28 Pavel Machek wrote: > More politely said: "I believe you would be better off modifying > ramdisk to include the functionality for persistence." New filesystem > should not really be neccessary. ext2 for performance, ext3 if you > need robustness from journalling, maybe something else makes sense, > too. I agree that a persistent block device makes more sense. However, as someone with some experience in using this type of mechanism, a special filesystem (separate from the special block device) could also be useful. We often use things like circular buffers, per-cpu areas, both log-structured and variable-length records, etc. A filesystem that would take care of this type of thing under the hood might simplify a few things. Also note that it's very useful for the kernel itself to be able to access the contents of this persistent area...we use it for parts of the log stream, various forms of "flight recorder" information, panic tracebacks, etc. as well as making it available to select userspace apps. Chris -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/