From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from top.free-electrons.com ([176.31.233.9] helo=mail.free-electrons.com) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Ve0qN-0003gy-0b for linux-mtd@lists.infradead.org; Wed, 06 Nov 2013 11:00:15 +0000 Date: Wed, 6 Nov 2013 07:59:52 -0300 From: Ezequiel Garcia To: Willy Tarreau Subject: Re: Ubiblock users call (Re: mvneta / openblocks switch) Message-ID: <20131106105951.GA2616@localhost> References: <20131031135322.GN26784@titan.lakedaemon.net> <52738D6A.1010900@hitachi.com> <20131101130528.716e53d9@skate> <20131105103555.GD16420@1wt.eu> <5278E824.8050405@hitachi.com> <20131105135323.GA17316@1wt.eu> <20131105144003.GB9632@localhost> <20131105145748.GE17316@1wt.eu> <20131106063007.GA17145@1wt.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20131106063007.GA17145@1wt.eu> Cc: piergiorgio.beruto@gmail.com, Mike Frysinger , linux-mtd@lists.infradead.org, Artem Bityutskiy List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, Nov 06, 2013 at 07:30:07AM +0100, Willy Tarreau wrote: > Hi Ezequiel, > > On Tue, Nov 05, 2013 at 03:57:48PM +0100, Willy Tarreau wrote: > > > Can you describe your usage? > > > > For example, one of my distro's boot scripts automatically detects > > the available partitions, checks for a mountable FS there, then > > locates the current config and loads it. With a block device, I have > > nothing to change at all. With other solutions, I have to reconsider > > the boot process. > > BTW, I forgot to describe the initial use case I had in mind which led to this: > many of my machines (including the test ones) boot from a rootfs which is a > squashfs stored as an initrd image. At the moment, the squashfs is read by > u-boot from the NAND into memory and the kernel boots from this. Loading a 10 > MB rootfs from NAND to RAM takes 1-2 seconds depending on the device, and > consumes 10 MB of RAM all the time. Also, you're always at risk that some bad > blocks appear in the middle of this image (I had one device where I had to > change the location of the initrd partition because of > this). > > With ubiblock, I can totally solve this issue : > - u-boot does not read anymore the initrd, thus saving time and RAM > - kernel simply mounts the squashfs at boot from ubiblock, resulting > in direct accesses > - ubi would take care of bad blocks itself > > Doing so prevents me from upgrading the image since it's always mounted, > which is why I wanted to try to write it from u-boot. It did not work so > I wanted to use 2 images and upgrade one while running on the other one. > But I did not make any progress on this yet. > > I'll definitely give your latest patches a try, I just don't know when :-) > Thanks for all these details! It'll be definitely interesting if you could jump in the discussion when the patch is finally submitted. -- Ezequiel García, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com