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

[Wei Yang <richard.weiyang@gmail.com>]

On Tue, Jun 11, 2024 at 04:26:56PM +0200, David Hildenbrand wrote:
>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.
>

Sure.

>> 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?

Ok, if this is preferred.

>
>> +{
>> +	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

-- 
Wei Yang
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