Re: [PATCH] mm: increase totalram_pages on freeing to buddy system

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

On Sat, Jun 01, 2024 at 06:15:33PM +0200, David Hildenbrand wrote:
>On 01.06.24 17:32, David Hildenbrand wrote:
>> On 01.06.24 15:34, Wei Yang wrote:
>> > Total memory represents pages managed by buddy system.
>> 
>> No, that's managed pages.
>> 
>> > After the
>> > introduction of DEFERRED_STRUCT_PAGE_INIT, it may count the pages before
>> > being managed.
>> > 
>> 
>> I recall one reason that is done, so other subsystem know the total
>> memory size even before deferred init is done.
>> 
>> > free_low_memory_core_early() returns number of pages for all free pages,
>> > even at this moment only early initialized pages are freed to buddy
>> > system. This means the total memory at this moment is not correct.
>> > 
>> > Let's increase it when pages are freed to buddy system.
>> 
>> I'm missing the "why", and the very first sentence of this patch is wrong.
>
>Correction: your statement was correct :) That's why
>adjust_managed_page_count() adjusts that as well.
>
>__free_pages_core() only adjusts managed page count, because it assumes
>totalram has already been adjusted early during boot.
>
>The reason we have this split for now, I think, is because of subsystems that
>call totalram_pages() during init.
>
>So the "why" question remains, because this change has the potential to break
>other stuff.
>

Thanks, I didn't notice this.

>-- 
>Cheers,
>
>David / dhildenb

-- 
Wei Yang
Help you, Help me