Deallocate

deallocate a block of memory

This function deallocates memory by returning it to the appropriate private free memory pool. This function can be used to free an entire block allocated with the above function, or it can be used to free a sub-block of a previously allocated block. Sub-blocks must be an even multiple of the memory chunk size (currently 8 bytes).

This function can even be used to add a new free region to an existing MemHeader, however the extent pointers in the MemHeader will no longer be valid.

If memoryBlock is not on a block boundary (MEM_BLOCKSIZE) then it will be rounded down in a manner compatible with Allocate(). Note that this will work correctly with all the memory allocation functions, but may cause surprises if one is freeing only part of a region. The size of the block will be rounded up, so the freed block will fill to an even memory block boundary.

memHeader

points to the memory header this block is part of.

memoryBlock

address of memory block to free.

byteSize

the size of the block in bytes. If NULL, nothing happens.

Memory allocation and deallocation as well as querying how much memory is available requires a Task or, by extension, a Process. None of the exec kernel memory management operations is safe to call from interrupt code!

Allocate, exec/memory.h