[riot-devel] .bss will not fit in region ram

Oleg Hahm oliver.hahm at inria.fr
Mon Feb 15 09:33:18 CET 2016


Hi Bernhard!

On Sat, Feb 13, 2016 at 10:56:19PM +0100, Bernhard Nägele wrote:
> today I got the linker message "...bss will not fit in region ram .....ram
> overlflowed by 912 bytes".
> I have used the examples/default Project with the STM32L053. This MCU has 8k
> RAM. On your
> web-site there is the information that the min. RAM footprint is about 1.5k.
> What could I do to
> make to make the program fit into this MCU?

Short answer:
Try compiling with
CFLAGS=-DGNRC_PKTBUF_SIZE=512

Long answer:
1.) The default example includes simple link-layer support using the lower
    layers of the GNRC network stack. This also includes the packet buffer
    which is per default configured to be 6kB. This size makes kind of sense
    for an IPv6 setting, where you may need to store several IP datagrams with
    a full MTU (1280 bytes for IPv6), but is most likely way too huge for
    simple link-layer usage. I will open an according PR.
2.) I agree that the statement about the min. RAM footprint as mentioned on the
    web page is a bit imprecise. The problem to make a sensible statement
    about the minimum memory requirements is manyfold: what do you consider as
    minimum? Only the kernel? Basic networking support? Simple IP support?
    Only peripheral drivers? And which platform and which toolchain do you
    consider?
    If I remember correctly the 1.5k of RAM represents the RAM usage on a
    MSP430 with hello-world.

Cheers,
Oleg
-- 
printk(KERN_CRIT "Whee.. Swapped out page in kernel page table\n");
        linux-2.6.6/mm/vmalloc.c
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