Message-ID: <4A368BC8.3010006@am.sony.com>
Date: Mon, 15 Jun 2009 10:58:32 -0700
From: Tim Bird <tim.bird@am.sony.com>
User-Agent: Thunderbird 2.0.0.14 (X11/20080501)
MIME-Version: 1.0
To: Marco <marco.stornelli@gmail.com>
CC: Linux FS Devel <linux-fsdevel@vger.kernel.org>,
       Linux Embedded <linux-embedded@vger.kernel.org>,
       linux-kernel@vger.kernel.org, Daniel Walker <dwalker@soe.ucsc.edu>
Subject: Re: [PATCH 00/14] Pramfs: Persistent and protected ram filesystem
References: <4A33A7A2.1050608@gmail.com> <4A3681C2.5010508@am.sony.com> <4A36887C.1050906@gmail.com>
In-Reply-To: <4A36887C.1050906@gmail.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 2110
Lines: 50

Marco wrote:
> Tim Bird wrote:
>> Marco wrote:
>>> This is a second attempt at mainlining Pramfs. The first attempt was
>>> back in early 2004 by MontaVista. Since then the kernel code has almost
>>> been completely rewritten. So my first item on the list was porting the
>>> code on a recent kernel version. After that I added the XIP support.
>> It's very nice to see this technology revived.
>>
>> Is the information at:
>> http://pramfs.sourceforge.net/
>> and
>> http://pramfs.sourceforge.net/pramfs-spec.html
>> still valid - particularly the latter?
> 
> Yep. at 99%. I've done some modifications due to the porting and there
> will be some ones due to this review. I tried to talk with Steve
> Longerbeam to update the site but without success. I'd like to update it.
> 
>> It would be very nice to see this get mainlined.  I believe that
>> one of the main uses for this is to store crash information
>> over a reboot so the next kernel (not in crashing state) can have
>> a better chance of dealing with it.  As such, I think
>> it's important to keep the code paths for Pramfs short, synchronous,
>> and unentangled with other kernel systems (block IO, page cache, etc.).
>>
> 
> Yes, I quite agree. I think that this kind of feature would be very
> useful especially for the embedded world.

Just FYI - we have an "exception monitor" at Sony
which is used in several projects, that records application and
kernel crash information into the file system, for subsequent
(often in-field) analysis.  However, the data currently gets written
to a flash filesystem and the logs sometimes get truncated or otherwise
corrupted.  This seems like a perfect match for what we're trying
to do.
 -- Tim

=============================
Tim Bird
Architecture Group Chair, CE Linux Forum
Senior Staff Engineer, Sony Corporation of America
=============================

--
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/