From mboxrd@z Thu Jan 1 00:00:00 1970 From: Baruch Siach Date: Mon, 27 Jun 2011 06:32:41 +0300 Subject: [Buildroot] device_table & /dev/shm In-Reply-To: References: <20110626032236.GA17733@tarshish> <87mxh47v71.fsf@macbook.be.48ers.dk> Message-ID: <20110627033240.GA3046@jasper.tkos.co.il> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Hi Charles, On Sun, Jun 26, 2011 at 10:51:19AM -0700, Charles Krinke wrote: > I would appreciate understanding more the two concepts of a) overriding > target/generic/device_table. txt so I can understand how the mounted jffs2 > became different then the contents of output/target/dev This is the general behaviour of mount on Unix like operating systems. Whenever you mount a filesystem on a directory, the previous content of this directory in no longer directly visible until umount. Instead, the content of the mounted filesystem takes over. > and the b) How we > get from what appears to be the default /etc/fstab mounting tmpfs to one > where we mount /dev/shm instead in our application space. > > Is there a busybox config setup for /dev/shm? I went through the busybox > menuconfig this morning and I don't see one. There is nothing related to Busybox here. All you need to do is to create the /dev/shm directory, and then mount tmpfs on it. baruch > Charles > On Jun 26, 2011 3:17 AM, "Peter Korsgaard" wrote: > >>>>>> "Baruch" == Baruch Siach writes: > > > > Hi, > > > > >> 1. I can see the generic device_table.txt and it includes a /dev/shm > > >> node. I can also see the /dev structure in output/target and it > > >> matches the generic device_table.txt. But, ... when I build the jffs2 > > >> and load it on my MPC8323 target, what I see in /dev does not include > > >> /dev/shm. In fact it is significantly different. So, my first question > > >> is: > > >> > > >> "What besides generic/device_table.txt can determine the contents of > > >> /dev on an MPC8323 target?" > > > > Baruch> Do you have devtmpfs mounted on /dev? If so, devtmpfs takes > > Baruch> over the content of /dev, and hides the device nodes and > > Baruch> directories from your device table. > > > > If so, it would be better to use the 'Dynamic using devmtpfs only' > > device table option to not waste jffs2 space on device nodes you are not > > going to use anyway. > > > > We might need to add a mkdir -p /dev/shm in inittab like we already do > > for /dev/pts, as those are not device nodes and hence do not get created > > by devtmpfs. -- ~. .~ Tk Open Systems =}------------------------------------------------ooO--U--Ooo------------{= - baruch at tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -