Re: [PATCH] mm/mm_init.c: print mem_init info after defer_init is done

[David Hildenbrand <david@redhat.com>]

On 11.06.24 05:08, Wei Yang wrote:
> Current call flow looks like this:
> 
> start_kernel
>    mm_core_init
>      mem_init
>      mem_init_print_info
>    rest_init
>      kernel_init
>        kernel_init_freeable
>          page_alloc_init_late
>            deferred_init_memmap
> 
> If CONFIG_DEFERRED_STRUCT_PAGE_INIT, the time mem_init_print_info()
> calls, pages are not totally initialized and freed to buddy.
> 
> This has one issue
> 
>    * nr_free_pages() just contains partial free pages in the system,
>      which is not we expect.
> 

Maybe mention that this will also help changing totalpage accounting.

> Let's print the mem info after defer_init is done.
> 
> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
> CC: David Hildenbrand <david@redhat.com>
> ---
>   mm/mm_init.c | 104 +++++++++++++++++++++++++--------------------------
>   1 file changed, 52 insertions(+), 52 deletions(-)
> 
> diff --git a/mm/mm_init.c b/mm/mm_init.c
> index f72b852bd5b8..34a6de20ef77 100644
> --- a/mm/mm_init.c
> +++ b/mm/mm_init.c
> @@ -2322,6 +2322,57 @@ void set_zone_contiguous(struct zone *zone)
>   	zone->contiguous = true;
>   }
>   
> +static void __init mem_init_print_info(void)

Can you avoid all that churn simply by doing a

static void __init mem_init_print_info(void);

somewhere at the beginning of this file?

> +{
> +	unsigned long physpages, codesize, datasize, rosize, bss_size;
> +	unsigned long init_code_size, init_data_size;
> +
> +	physpages = get_num_physpages();
> +	codesize = _etext - _stext;
> +	datasize = _edata - _sdata;
> +	rosize = __end_rodata - __start_rodata;
> +	bss_size = __bss_stop - __bss_start;
> +	init_data_size = __init_end - __init_begin;
> +	init_code_size = _einittext - _sinittext;
> +
> +	/*
> +	 * Detect special cases and adjust section sizes accordingly:
> +	 * 1) .init.* may be embedded into .data sections
> +	 * 2) .init.text.* may be out of [__init_begin, __init_end],
> +	 *    please refer to arch/tile/kernel/vmlinux.lds.S.
> +	 * 3) .rodata.* may be embedded into .text or .data sections.
> +	 */
> +#define adj_init_size(start, end, size, pos, adj) \
> +	do { \
> +		if (&start[0] <= &pos[0] && &pos[0] < &end[0] && size > adj) \
> +			size -= adj; \
> +	} while (0)
> +
> +	adj_init_size(__init_begin, __init_end, init_data_size,
> +		     _sinittext, init_code_size);
> +	adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
> +	adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
> +	adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
> +	adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);
> +
> +#undef	adj_init_size
> +
> +	pr_info("Memory: %luK/%luK available (%luK kernel code, %luK rwdata, %luK rodata, %luK init, %luK bss, %luK reserved, %luK cma-reserved"
> +#ifdef	CONFIG_HIGHMEM
> +		", %luK highmem"
> +#endif
> +		")\n",
> +		K(nr_free_pages()), K(physpages),
> +		codesize / SZ_1K, datasize / SZ_1K, rosize / SZ_1K,
> +		(init_data_size + init_code_size) / SZ_1K, bss_size / SZ_1K,
> +		K(physpages - totalram_pages() - totalcma_pages),
> +		K(totalcma_pages)
> +#ifdef	CONFIG_HIGHMEM
> +		, K(totalhigh_pages())
> +#endif
> +		);
> +}
> +
>   void __init page_alloc_init_late(void)
>   {
>   	struct zone *zone;
> @@ -2348,6 +2399,7 @@ void __init page_alloc_init_late(void)
>   	files_maxfiles_init();
>   #endif
>   

Maybe add a comment like

/* Accounting of total+free memory is stable at this point. */

> +	mem_init_print_info();


-- 
Cheers,

David / dhildenb