Limit size of equeue for sigio netsocket test

[sarahmarshy]

Description

This fixes netsocket failure on arch pro target by limiting the size of EventQueue instance.

Status

READY

Related to #5335

@geky

[geky]

💯

[0xc0170]

For future, add a reason why we are setting this to 4 (previous number to current one). how was 4 selected? Any magic number has a reason, and could be stated in the code or rather in the commit message.

LGTM

[0xc0170]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 484
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/5474/

Triggering tests

/morph test
/morph uvisor-test
/morph export-build

[mbed-ci]

Test : SUCCESS

Build number : 304
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/5474/304

[mbed-ci]

Exporter Build : SUCCESS

Build number : 105
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/5474/

[kjbracey]

Stack overflow problem, was it?

This code looks a bit scary to me - you're declaring threads and event queues on the stack. I'm kind of surprised that it shuts down the thread cleanly on exit from the test function. Forcible thread termination is a bit scary.

Might I suggest having a static initialised-once event queue+thread? Which would be conveniently available thus:

EventQueue &queue = *mbed_event_queue();

That's an on-demand factory, so it would launch the thread and event queue on first call, and it would remain running between tests.

[sarahmarshy]

@kjbracey-arm, maybe that can come as a later PR. I'd like to get this merged ASAP, because #5335 needs to get through to allow network testing to resume.

[0xc0170]

@kjbracey-arm, maybe that can come as a later PR. I'd like to get this merged ASAP, because #5335 needs to get through to allow network testing to resume.

@kjbracey-arm Are you happy with this proposal? It will be reworked to as you suggested in the separate PR.

@kjbracey-arm, maybe that can come as a later PR. I'd like to get this merged ASAP, because #5335 needs to get through to allow network testing to resume.

@sarahmarshy Emphasize this type of requirement please, we should be aware of this dependency plus priority definition (the above comment only declares this as related to), will help to get priorities correctly.

[geky]

@sarahmarshy Emphasize this type of requirement please, we should be aware of this dependency plus priority definition (the above comment only declares this as related to), will help to get priorities correctly.

@0xc0170, what sort of emphasis are you looking for? We don't really have a system for naming priorities.

[pan-]

@kjbracey-arm Beside issues which may arise because there is no stack unwinding when a thread is abruptly terminated; the current code may operate on already released memory.

At the end of the scope, the event queue will be destroyed then the eventThread will be terminated; the kernel may schedule the eventThread between those two operations (this depends on the implementation details of the socket object).

[0xc0170]

@0xc0170, what sort of emphasis are you looking for? We don't really have a system for naming priorities.

@geky We shall clarify dependencies (this patch is required for another one to progress, not just related). I failed to see the connection for the other PR. It could be just me but after reading the requirement on another PR comment, this became a clear.