controlling ramdisk sizeForum: DSL Embedded Topic: controlling ramdisk size started by: colinbes Posted by colinbes on April 06 2007,14:08
I am busy refactoring DSL and am wanting to reduce the ramdisk size to make more memory available to application.Running "df" shows ramdisk size of 196000 (approx) bytes. (System memory is 256MB). I have experimented making changes in lilo conf and setting ramdisk_size to values other than 100000 but changes don't seem to take effect - running "df" always shows same size after booting (and running lilo command on modified config file). I have also tried modifying S00-autoconfig (in etc/rcS.d) where it sets ramsize using remount option by hardcoding ramsize.
Yet after refactoring and booting ramdisk size still remains at 196M. I can modify the ramsize in bootlocal.sh but I would prefer to do this as part of default setup. I have just started looking into minirt24 for idea but thought I would ask if anyone can explain where and how the ramdisk is sized. Should modifying ramdisk_size in lilo have worked? Thanks Colin Posted by ^thehatsrule^ on April 06 2007,15:50
ramdisk_size I think is used only for the minirt ramdisk, nothing more.Unless you plan on using a huge one (ie for pxe booting) that's over 100mb, it won't affect the DSL session. afaik it doesn't remount the ramsize by hardcoding - it does it by a factor of 3:1 It's calculated somewhere... maybe linuxrc ? I wouldn't suggest increasing it too much, unless you know you have a lot of ram, since the kernel and running things requires enough free space. However, since you posted this in dsl-embedded, are you saying you want to change the memory allocated to the qemu vm? Try the -m switch Posted by colinbes on April 06 2007,21:07
Actually I want to make the ramdisk smaller as it is allocating large percentage of free ram to ramdisk size which is why I thought I found the issue in S00-autoconfig.I also suspect ramdisk_size is only used at boot time for minirt. In minirt there is also tweaking of ramdisk size in linuxrc but I didn't feel like refactoring this as well if it was not the place to make the change. Posted by curaga on April 11 2007,14:55
Ramdisk space isn't actually used, until it is used ;)So if part of it shows up as free space, then that is not away from ram... Posted by colinbes on April 11 2007,18:16
"True" but that doesn't make for a 24/7 system. Also we have found that even thought ramdisk is not using physical ram (or so the documents state) available memory is affected. |