>> >> /** >> + * System huge page sizes in bytes >> + * >> + * Returns the number of huge page sizes supported by the system. Outputs >> up to >> + * 'num' sizes when the 'size' array pointer is not NULL. If return value is >> + * larger than 'num', there are more supported sizes than the function was >> + * allowed to output. If return value (N) is less than 'num', only sizes >> + * [0 ... N-1] have been written. Returned values are ordered from smallest >> to >> + * largest. >> + * >> + * @param[out] size Points to an array of huge page sizes for output >> + * @param num Maximum number of huge page sizes to output >> + * >> + * @return Number of supported huge page sizes >> + * @retval 0 on no huge pages >> + */ >> +unsigned odp_sys_huge_page_size_all(uint64_t size[], unsigned num); >> + > > I think it has to be int. -1 on error, 0 - no hp, > 0 pages. > For linux it might be similar to getpagesizes() > https://linux.die.net/man/3/getpagesizes > """ > if pagesizes is NULL and n_elem is 0, then the number of pages the > system supports is returned. Otherwise, pagesizes is filled with at most > n_elem page sizes. > """ >
getpagesizes() returns -1 in a case of invalid function arguments. odp_sys_huge_page_size_all() is documented so that the application cannot pass invalid arguments. So an internal error would be the only possibility. I don't see this to be likely as the function is only reading system info. Adding -1 return value would also increase application complexity as the error return value would require special handling from application. > > But why do we need this inside ODP? It time be reasonable to say that > it's number of pages/sizes visible to current ODP instance (i.e. not the > system global.) > A system can simultaneously support multiple huge page sizes and an application may for example do some alignment decisions based on this information. I found this issues when implementing shm for odp-dpdk and trying to pass the validation tests. This API change enables adding a proper test for odp_shm_info_t.page_size. -Matias