Increase L4linux ramdisk size ?

Adam Lackorzynski adam at os.inf.tu-dresden.de
Thu Apr 7 15:42:26 CEST 2011


Hi Julien,

On Wed Apr 06, 2011 at 16:42:07 +0200, Julien Heyman wrote:
> Here is what I notice now: it seems to be related to memory settings
> somehow. Even though my ramdisk is indeed smaller than half the ram size I
> assign to the linux instance loading it, the presence of other L4Re
> executables (that take their share of the global memory...) has an impact,
> as illustrated in the tests below:
> 
> Test 1:
> - I am running two instances of L4Linux simultaneously. The first instance
> gets 16Mb RAM and has a ramdisk of ~3Mb, while the second instance gets 40Mb
> RAM and has a ramdisk of 16Mb => in this case the boot fails in the second
> linux instance, with the symptoms I mentionned earlier, when loading the
> 16Mb ramdisk (full log attached)
> 
> Test 2:
> - same setup, but I comment out the creation of the first linux instance in
> the boot script => in this case the 16Mb ramdisk is properly loaded in the
> "second" linux and boot is OK (full log attached)
> 
> Test 3:
> - similar setup as test 1, running two linux instances, but this time
> reducing the ramdisk in the second instance to 8Mb instead of 16Mb: boot is
> OK in this case too (full log attached)

I'll try to reproduce this. It didn't work in the first try but I'll try
harder.

> Do the logs and/or my test descriptions above allow to understand the reason
> for the failed case ?
> As a side question, I see at boot time that Fiasco uses a total of only 128
> Mb of RAM, whereas the Beagleboard xM I am using has 512 Mb RAM. Is this
> amount predefined somewhere in Fiasco, or does it autodetect available RAM
> at boot time ? (and in this case why doesn't it see the full 512 Mb ?)

The reason is simple. The older Beagleboard (without 'xM') has 128MB, so
this is the default setting. When building the image, add
RAM_SIZE_MB=512 to the make command and it will use 512MB. Adding it to
conf/Makeconf.boot will make it the default.


Adam
-- 
Adam                 adam at os.inf.tu-dresden.de
  Lackorzynski         http://os.inf.tu-dresden.de/~adam/




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