Re: [PATCH] mm/mm_init.c: don't initialize page->lru again

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

On Fri, Jun 07, 2024 at 10:33:41AM +0300, Mike Rapoport wrote:
>On Wed, Jun 05, 2024 at 10:14:36PM +0000, Wei Yang wrote:
>> After init_reserved_page(), we expect __init_single_page() has done its
>> work to the page, which already initialize page->lru properly.
>
>init_reserved_page only available with CONFIG_DEFERRED_STRUCT_PAGE_INIT

The common page initialize path is :

memmap_init
    memmap_init_zone_range
        memmap_init_range
	    defer_init
	    __init_single_page

If CONFIG_DEFERRED_STRUCT_PAGE_INIT set, we would skip initialization for pages
after first_init_pfn. So init_reserved_page would initialize page struct
before __SetPageReserved().

If CONFIG_DEFERRED_STRUCT_PAGE_INIT not set, page struct is already initialized.

Is my understanding correct?

> 
>> We don't need to do it again.
>> 
>> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
>> ---
>>  mm/mm_init.c | 3 ---
>>  1 file changed, 3 deletions(-)
>> 
>> diff --git a/mm/mm_init.c b/mm/mm_init.c
>> index 14133a1cfc7b..30379b0e7729 100644
>> --- a/mm/mm_init.c
>> +++ b/mm/mm_init.c
>> @@ -759,9 +759,6 @@ void __meminit reserve_bootmem_region(phys_addr_t start,
>>  
>>  			init_reserved_page(start_pfn, nid);
>>  
>> -			/* Avoid false-positive PageTail() */
>> -			INIT_LIST_HEAD(&page->lru);
>> -
>>  			/*
>>  			 * no need for atomic set_bit because the struct
>>  			 * page is not visible yet so nobody should
>> -- 
>> 2.34.1
>> 
>> 
>
>-- 
>Sincerely yours,
>Mike.

-- 
Wei Yang
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