List unnecessary mallocs

es-ude / elastic-ai.runtime.enV5

Elastic-ai.runtime implementation for the Elastic Node version 5.

https://www.uni-due.de/es/en/en_elastic_ai.php

MIT License

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List unnecessary mallocs #298

Open glencoe opened 1 month ago

glencoe commented 1 month ago

Throughout the runtime's code many unnecessary and sometimes dangerous calls to malloc are made. This leads to to four problems:

Hard to find memory leaks
Unclear and messy responsibilities (who owns memory?)
Fragmentation
Hard to reason about memory consumption during runtime

Walk through the source code and note these calls along with severeness and how easy a fix would be.

In a next step we should derive issues, an order and a priority for replacing these calls with other means of memory management, eg., ping pong buffers.

[x] check for malloc calls
[ ] check for calloc calls

glencoe commented 1 month ago

Building and running HardwareTestUsbProtocol prints

*** panic ***
OUT OF MEMORY

hence stopping work on #302 and continuing here.

glencoe commented 1 month ago

Mallocs

all the rest seems to be hardware test, will skip those for now

glencoe commented 1 month ago

Calloc

(3, 2): use ping pong buf here https://github.com/es-ude/elastic-ai.runtime.enV5/blob/63545ac48ba5098df1e02f46f0555a2afb85fb4a/src/network/http/HTTP.c#L57
(2, 3): might be one of the cases where we should keep the malloc https://github.com/es-ude/elastic-ai.runtime.enV5/blob/63545ac48ba5098df1e02f46f0555a2afb85fb4a/src/network/broker/MqttBroker.c#L280

The rest seems to live in hardware tests, will skip those for now. We can fix them as we go (boy scout rule)

glencoe commented 1 month ago

Summary

in the following order remove dynamic memory allocation in

[ ] Network.c
[ ] HTTP.c
[ ] MqqtBroker.c