RAM usage not affected by heap/stack size

[silvio3105]

Hi,

working with nRF52840 with S140 v7.2.0, not sure about SDK version. VS Code + ARM GCC + LD Gold linker.

I changed stack and heap sizes via __HEAP_SIZE and __STACK_SIZE defines. Change is confirmed by .map file, but RAM usage(reported by linker flag --print-memory-usage) is not affected.

No matter what size I set to defines, RAM usage reported by linker stays the same.

How to fix this?

[Susheel Nuguru]

I think by default head and stack are defined as COPY sections and not the NOLOAD (modules/nrfx/mdk/nrf_common.ld: line 137) , COPY sections are not included in the print mem usage option.

if you want --print-memory-usage to include heap and stack aswell then you need to change the linker script to NOLOAD , prestine build and check if that works.

[silvio3105]

Does not help. Even if I remove (NOLOAD) / (COPY), RAM usage does not change. 

[Susheel Nuguru]

If you have changed from COPY->NOLOAD, that should have worked.

can you show me your arm-none-eabi-ld --version?

Are you using bfd or gold version of the linker. if you were using bfd, then my suggestion should have helped.

[silvio3105]

arm-none-eabi-gcc --version
arm-none-eabi-gcc (Arm GNU Toolchain 14.2.Rel1 (Build arm-14.52)) 14.2.1 20241119
Copyright (C) 2024 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

GNU ld (Arm GNU Toolchain 14.2.Rel1 (Build arm-14.52)) 2.43.1.20241119
Copyright (C) 2024 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License version 3 or (at your option) a later version.
This program has absolutely no warranty.

I'm using gold. Tried with BFD, same result. 
Linker command is

$(DIR_BUILD)/$(BUILD_NAME).elf: $(OBJECTS) $(MAKEFILE)

    $(TC_CC) $(OBJECTS) $(LINKER_FLAGS) -o $@

Linked with gcc, not ld.

[Susheel Nuguru]

hmm, then nrf_common.ld does not seem to be built to count the heap and stack usage using --print-memory-usage. 

Else change     .heap (COPY) : -> .heap (NOLOAD) :

and add       . = MAX(., __HeapBase + __HEAP_SIZE); in the heap definition for heap to actually take space somethign like below

.heap (NOLOAD):
{
    __HeapBase = .;
    __end__ = .;
    PROVIDE(end = .);
    KEEP(*(.heap*))
    . = MAX(., __HeapBase + __HEAP_SIZE);  ///// add this
    __HeapLimit = .;
} > RAM

[silvio3105]

Still nothing.