mm/iob: add ostest test

[hujun260]

Summary

testing: add iob test

Impact

iob

Testing

ostest

[nuttxpr]

[Experimental Bot, please feedback here]

No, this PR description does not adequately meet the NuttX requirements. Here's why:

• Insufficient Summary: While it mentions adding configurations to ostest, it doesn't explain why these changes are necessary. Is it fixing a bug? Adding a new feature? Improving performance? What part of ostest is affected? How do these configuration options interact and change the behavior?
• Vague Impact: Simply stating "iob" isn't helpful. Be specific about how these IOB configurations impact the user, the build process, hardware, documentation, security, and compatibility. For example, do these changes increase memory usage? Do they change the behavior of any tests? Do they require any new dependencies?
• Missing Testing Details: "ostest" is not sufficient testing information. Specify the host operating system, compiler, and target architecture and board configuration. Provide actual testing logs (or links to them) demonstrating the behavior before and after the change. Just saying "ostest" doesn't prove anything.

Example of how to improve this PR description:

Summary

This change adds IOB configurations to the ostest example to demonstrate and test the IOB throttling mechanism. This is necessary to verify the correct behavior of IOB throttling under various buffer and chain configurations. Specifically, it enables CONFIG_IOB_THROTTLE and sets related parameters like CONFIG_IOB_NBUFFERS, CONFIG_IOB_NCHAINS, and enables the notifier. This allows testing of the IOB allocation behavior when the number of allocated buffers exceeds the throttle limit.

Impact

• Is new feature added? Is existing feature changed? No new feature is added, but existing ostest functionality is extended to demonstrate IOB throttling.
• Impact on user: NO. This change is specific to the ostest example and doesn't impact regular users of NuttX.
• Impact on build: NO. No changes to the build process are required.
• Impact on hardware: NO. No specific hardware dependencies are introduced.
• Impact on documentation: YES. The ostest documentation should be updated to explain the new configurations and their purpose. (A separate documentation PR will be created for this).
• Impact on security: NO.
• Impact on compatibility: NO.
• Anything else to consider? None.

Testing

I confirm that changes are verified on local setup and works as intended:

• Build Host(s): Linux (Ubuntu 20.04), x86_64, GCC 9.4.0
• Target(s): qemu-x86_64:nsh

Testing logs before change:

(Previous ostest output showing IOB allocation without throttling - include relevant snippets)

Testing logs after change:

(New ostest output showing IOB allocation with throttling engaged - demonstrating the intended throttling behavior)

[cederom]

Thank you @hujun260 :-)

Could you also please add Kconfig part so it stays in sync with CMake? :-)

[cederom]

Perfect! Thank you @hujun260 :-)