NANO130: Change initial stack size to 1K

[ccli8]

Description

This PR tries to spare more memory for adding new feature by decreasing initial stack size, especially for IAR with which heap size is statically allocated.

Related PR

#6768

Pull request type

[X] Fix
[ ] Refactor
[ ] New target
[ ] Feature
[ ] Breaking change

@deepikabhavnani

[0xc0170]

This is decreasing stack size by half. This might break some apps, so we need to be careful about this change (definitely not patch release).

[ccli8]

@0xc0170 OK. Then just follow #6768. I would close this PR.

[0xc0170]

I was checking the target so its just for Mbed OS 5 - thus this stack is used as isr stack size.

Why it was closed? You preferred this solution to the one that decreased the heap?

[ccli8]

@0xc0170 Do you also approve this change? In fact, both #6768 and this one would break some apps. But we need to pick one.

[0xc0170]

@0xc0170 Do you also approve this change? In fact, both #6768 and this one would break some apps. But we need to pick one.

I would like to understand the drive for this change and the heap. What @deepikabhavnani proposed was just for the limitation of current IAR version we support (its change to one toolchain). This one is changing it to all thus the scope is much bigger.

will the heap IAR fix solve the issue you are having? was 0x1200 too big heap for that target? This is again application specific, would be nice to have this configured

[ccli8]

Per our experience, decreasing heap size (0x1200) would fail some Greentea/CI tests at run-time, so I send this PR to spare memory from other source - initial stack here. But as you point out, scope of this PR is much bigger. #6768 would be safer.

As far as I know, Mbed OS doesn't export interface to configure initial stack (ISR stack) and heap size by user application. The issue gets worse with IAR 7.8 because it doesn't allow using available SRAM for heap. Heap size in IAR 7.8 must be hard-coded. Larger heap size is well for run-time, but it also makes less static memory which would cause application failed to build. That's a dilemma.

[deepikabhavnani]

@ccli8 - We can change stack size to 0x400, instead of heap size but only for IAR and not other tool chains.

[ccli8]

@deepikabhavnani Continuing #6768, go with 0x1000 or 0x1200 heap size and 0x400 stack size only for IAR toolchain.