Re: [PATCH v2] mm: increase totalram_pages on freeing to buddy system

[Mike Rapoport <rppt@kernel.org>]

On Fri, Jul 26, 2024 at 12:36:12AM +0000, Wei Yang wrote:
> Total memory represents pages managed by buddy system. After the
> introduction of DEFERRED_STRUCT_PAGE_INIT, it may count the pages before
> being managed.
> 
> 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.
> 
> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
> CC: David Hildenbrand <david@redhat.com>

Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
 
> ---
> v2:
>   * rebase on current master
>   * those places would be affected are merged
> ---
>  mm/memblock.c   | 22 ++++++----------------
>  mm/page_alloc.c |  4 +---
>  2 files changed, 7 insertions(+), 19 deletions(-)
> 
> diff --git a/mm/memblock.c b/mm/memblock.c
> index 213057603b65..592a22b64682 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -1711,10 +1711,8 @@ void __init memblock_free_late(phys_addr_t base, phys_addr_t size)
>  	cursor = PFN_UP(base);
>  	end = PFN_DOWN(base + size);
>  
> -	for (; cursor < end; cursor++) {
> +	for (; cursor < end; cursor++)
>  		memblock_free_pages(pfn_to_page(cursor), cursor, 0);
> -		totalram_pages_inc();
> -	}
>  }
>  
>  /*
> @@ -2140,7 +2138,7 @@ static void __init __free_pages_memory(unsigned long start, unsigned long end)
>  	}
>  }
>  
> -static unsigned long __init __free_memory_core(phys_addr_t start,
> +static void __init __free_memory_core(phys_addr_t start,
>  				 phys_addr_t end)
>  {
>  	unsigned long start_pfn = PFN_UP(start);
> @@ -2148,11 +2146,9 @@ static unsigned long __init __free_memory_core(phys_addr_t start,
>  				      PFN_DOWN(end), max_low_pfn);
>  
>  	if (start_pfn >= end_pfn)
> -		return 0;
> +		return;
>  
>  	__free_pages_memory(start_pfn, end_pfn);
> -
> -	return end_pfn - start_pfn;
>  }
>  
>  static void __init memmap_init_reserved_pages(void)
> @@ -2194,9 +2190,8 @@ static void __init memmap_init_reserved_pages(void)
>  	}
>  }
>  
> -static unsigned long __init free_low_memory_core_early(void)
> +static void __init free_low_memory_core_early(void)
>  {
> -	unsigned long count = 0;
>  	phys_addr_t start, end;
>  	u64 i;
>  
> @@ -2211,9 +2206,7 @@ static unsigned long __init free_low_memory_core_early(void)
>  	 */
>  	for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end,
>  				NULL)
> -		count += __free_memory_core(start, end);
> -
> -	return count;
> +		__free_memory_core(start, end);
>  }
>  
>  static int reset_managed_pages_done __initdata;
> @@ -2244,13 +2237,10 @@ void __init reset_all_zones_managed_pages(void)
>   */
>  void __init memblock_free_all(void)
>  {
> -	unsigned long pages;
> -
>  	free_unused_memmap();
>  	reset_all_zones_managed_pages();
>  
> -	pages = free_low_memory_core_early();
> -	totalram_pages_add(pages);
> +	free_low_memory_core_early();
>  }
>  
>  /* Keep a table to reserve named memory */
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 71d2716a554f..4701bc442df6 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -1248,16 +1248,14 @@ void __meminit __free_pages_core(struct page *page, unsigned int order,
>  		 * map it first.
>  		 */
>  		debug_pagealloc_map_pages(page, nr_pages);
> -		adjust_managed_page_count(page, nr_pages);
>  	} else {
>  		for (loop = 0; loop < nr_pages; loop++, p++) {
>  			__ClearPageReserved(p);
>  			set_page_count(p, 0);
>  		}
>  
> -		/* memblock adjusts totalram_pages() manually. */
> -		atomic_long_add(nr_pages, &page_zone(page)->managed_pages);
>  	}
> +	adjust_managed_page_count(page, nr_pages);
>  
>  	if (page_contains_unaccepted(page, order)) {
>  		if (order == MAX_PAGE_ORDER && __free_unaccepted(page))
> -- 
> 2.34.1
> 

-- 
Sincerely yours,
Mike.