On Wed, Jul 03, 2024 at 12:51:49AM +0000, Wei Yang wrote:
> Instead of using raw memblock api, we wrap a new helper for user.
The changelog should be more elaborate and explain why this function is
needed.
> Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
> ---
> include/linux/memblock.h | 1 +
> mm/memblock.c | 19 +++++++++++++++++++
> 2 files changed, 20 insertions(+)
>
> diff --git a/include/linux/memblock.h b/include/linux/memblock.h
> index 40c62aca36ec..7d1c32b3dc12 100644
> --- a/include/linux/memblock.h
> +++ b/include/linux/memblock.h
> @@ -486,6 +486,7 @@ static inline __init_memblock bool memblock_bottom_up(void)
>
> phys_addr_t memblock_phys_mem_size(void);
> phys_addr_t memblock_reserved_size(void);
> +unsigned long memblock_estimated_nr_pages(void);
> phys_addr_t memblock_start_of_DRAM(void);
> phys_addr_t memblock_end_of_DRAM(void);
> void memblock_enforce_memory_limit(phys_addr_t memory_limit);
> diff --git a/mm/memblock.c b/mm/memblock.c
> index e81fb68f7f88..c1f1aac0459f 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -1729,6 +1729,25 @@ phys_addr_t __init_memblock memblock_reserved_size(void)
> return memblock.reserved.total_size;
> }
>
> +/**
> + * memblock_estimated_nr_pages - return number of pages from memblock point of
> + * view
This function returns the estimate for free pages, not the number of pages
in RAM.
How about memblock_estimated_nr_free_pages()?
> + * some calculation before all pages are freed to buddy system, especially
> + * when CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled.
I'm failing to parse this sentence. The return value here won't depend on
CONFIG_DEFERRED_STRUCT_PAGE_INIT.
> + *
> + * At this point, we can get this information from memblock. Since the system
> + * state is not settle down and address alignment, the value is an estimation.
> + *
> + * Return:
> + * An estimated number of pages from memblock point of view.
^ free
> + */
> +unsigned long __init memblock_estimated_nr_pages(void)
> +{
> + return PHYS_PFN(memblock_phys_mem_size() - memblock_reserved_size());
> +}
> +
> /* lowest address */
> phys_addr_t __init_memblock memblock_start_of_DRAM(void)
> {
> --
> 2.34.1
>
--
Sincerely yours,
Mike.
