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pvPortMalloc() allocates extra bytes

Posted by chaabanemalki on August 25, 2014

Hello, I notice that if I allocate 6 bytes using pvPortMalloc(6), FreeRTOS+Trace shows me that the kernel allocated 16 bytes and not 6, I tried different values but FreeRTOS+Traces always shows me different values than the ones I put in my code and with no pattern between them.

I'm not sure if this is normal or it is freeRTOS+Trace who shows wronge values.

I checked the value passed to pvPortMalloc( size_t xWantedSize )

and the definition of sizet is : typedef __SIZETYPE__ size_t; /* type yielded by sizeof */

I'm using PIC32, and i'm not sure if size_t will be considered as int32 or int8.

Thank you.


pvPortMalloc() allocates extra bytes

Posted by bowerymarc on August 25, 2014

Take a look at the heap code and you’ll understand why there’s a difference.

On Aug 25, 2014, at 9:03 AMEDT, Hicham chaabanemalki@users.sf.net wrote:

Hello, I notice that if I allocate 6 bytes using pvPortMalloc(6), FreeRTOS+Trace shows me that the kernel allocated 16 bytes and not 6, I tried different values but FreeRTOS+Traces always shows me different values than the ones I put in my code and with no pattern between them.

I'm not sure if this is normal or it is freeRTOS+Trace who shows wronge values.

I checked the value passed to pvPortMalloc( size_t xWantedSize )

and the definition of sizet is : typedef SIZETYPE size_t; / type yielded by sizeof /

I'm using PIC32, and i'm not sure if size_t will be considered as int32 or int8.

Thank you.

pvPortMalloc() allocates extra bytes

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pvPortMalloc() allocates extra bytes

Posted by chaabanemalki on August 25, 2014
		/* The wanted size is increased so it can contain a BlockLink_t
		structure in addition to the requested amount of bytes. */

got it ;). I should take these 10 extra bytes in consideration when calculating the heap worst case scenario.


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