Alignment reuirement for memory pools
Posted: Fri Jul 06, 2018 11:52 pm
Hi All,
I have a memory pool object and associated object memory aligned to stkalign_t as well as another pool and associated object memory without any alignment.
On looking at the source code of ChibiOS, I see chPoolAdd() is called by chPoolLoadArray() on loading both above pools after their initialization. The function description for chPoolAdd() says:
Why is there a requirement that the alignment should be stkalign_t and not the PORT_NATURAL_ALIGN.
My code works with both the pools mentioned above, with and without the objects being aligne to stkalign_t.
My setup:
version: ChibiOS 18.2.0.
platform: simulator posix.
Regards,
Yusuf Husainy,
I have a memory pool object and associated object memory aligned to stkalign_t as well as another pool and associated object memory without any alignment.
On looking at the source code of ChibiOS, I see chPoolAdd() is called by chPoolLoadArray() on loading both above pools after their initialization. The function description for chPoolAdd() says:
Code: Select all
/**
* @brief Adds an object to a memory pool.
* @pre The memory pool must be already been initialized.
* @pre The added object must be of the right size for the specified
* memory pool.
[glow=red]* @pre The added object must be memory aligned to the size of
* @p stkalign_t type.
[/glow] * @note This function is just an alias for @p chPoolFree() and has been
* added for clarity.
*
* @param[in] mp pointer to a @p memory_pool_t structure
* @param[in] objp the pointer to the object to be added
*
* @api
*/
static inline void chPoolAdd(memory_pool_t *mp, void *objp) {
chPoolFree(mp, objp);
}
Why is there a requirement that the alignment should be stkalign_t and not the PORT_NATURAL_ALIGN.
My code works with both the pools mentioned above, with and without the objects being aligne to stkalign_t.
My setup:
version: ChibiOS 18.2.0.
platform: simulator posix.
Regards,
Yusuf Husainy,