EVL Heap Clarification

EVL Heap Clarification

[Russell Johnson]

Am I correct in assuming that any dynamic allocation in an EVL thread needs
to use the EVL heap in order to avoid in-band context switching?

 

There are 4 calls in particular that I am using from the EVL heap API:
evl_init_heap (on startup), evl_alloc_block (may be called during realtime
processing to expand a data structure), evl_free_block (on shutdown),
evl_destroy_heap (on shutdown). The question is are all 4 of these calls
expected to only ever be called by an EVL thread? Looking at the source
code, I see that the alloc and free functions lock/unlock an EVL mutex so I
assume those can only be called from an EVL thread? Though the error codes
are not checked on those mutex calls, so if you call alloc or free from a
Linux thread, they do not fail. Can init and destroy be called from a Linux
thread? I was looking at the test code in libevl for heap-torture, and it
appeared that all 4 of these functions were being called from an EVL
attached thread.

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Re: EVL Heap Clarification

[Philippe Gerum]

Russell Johnson via Xenomai <xenomai@xenomai.org> writes:

> Am I correct in assuming that any dynamic allocation in an EVL thread needs
> to use the EVL heap in order to avoid in-band context switching?
>
>  
>
> There are 4 calls in particular that I am using from the EVL heap API:
> evl_init_heap (on startup), evl_alloc_block (may be called during realtime
> processing to expand a data structure), evl_free_block (on shutdown),
> evl_destroy_heap (on shutdown). The question is are all 4 of these calls
> expected to only ever be called by an EVL thread? Looking at the source
> code, I see that the alloc and free functions lock/unlock an EVL mutex so I
> assume those can only be called from an EVL thread? Though the error codes
> are not checked on those mutex calls, so if you call alloc or free from a
> Linux thread, they do not fail. Can init and destroy be called from a Linux
> thread? I was looking at the test code in libevl for heap-torture, and it
> appeared that all 4 of these functions were being called from an EVL
> attached thread.
>

Please check this documentation, the 3rd column gives the answer:
https://evlproject.org/core/user-api/function_index/#memory-heap-services

-- 
Philippe.