Re: [PATCH 3/8] mm: move free_reserved_area() to mm/memblock.c

[Vlastimil Babka <vbabka@kernel.org>]

On 3/18/26 11:58, Mike Rapoport wrote:
> From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
> 
> free_reserved_area() is related to memblock as it frees reserved memory
> back to the buddy allocator, similar to what memblock_free_late() does.
> 
> Move free_reserved_area() to mm/memblock.c to prepare for further
> consolidation of the functions that free reserved memory.
> 
> No functional changes.
> 
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>


> ---
>  mm/memblock.c   | 37 ++++++++++++++++++++++++++++++++++++-
>  mm/page_alloc.c | 36 ------------------------------------
>  2 files changed, 36 insertions(+), 37 deletions(-)
> 
> diff --git a/mm/memblock.c b/mm/memblock.c
> index b3ddfdec7a80..8f3010dddc58 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -893,6 +893,42 @@ int __init_memblock memblock_remove(phys_addr_t base, phys_addr_t size)
>  	return memblock_remove_range(&memblock.memory, base, size);
>  }
>  
> +unsigned long free_reserved_area(void *start, void *end, int poison, const char *s)
> +{
> +	void *pos;
> +	unsigned long pages = 0;
> +
> +	start = (void *)PAGE_ALIGN((unsigned long)start);
> +	end = (void *)((unsigned long)end & PAGE_MASK);
> +	for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
> +		struct page *page = virt_to_page(pos);
> +		void *direct_map_addr;
> +
> +		/*
> +		 * 'direct_map_addr' might be different from 'pos'
> +		 * because some architectures' virt_to_page()
> +		 * work with aliases.  Getting the direct map
> +		 * address ensures that we get a _writeable_
> +		 * alias for the memset().
> +		 */
> +		direct_map_addr = page_address(page);
> +		/*
> +		 * Perform a kasan-unchecked memset() since this memory
> +		 * has not been initialized.
> +		 */
> +		direct_map_addr = kasan_reset_tag(direct_map_addr);
> +		if ((unsigned int)poison <= 0xFF)
> +			memset(direct_map_addr, poison, PAGE_SIZE);
> +
> +		free_reserved_page(page);
> +	}
> +
> +	if (pages && s)
> +		pr_info("Freeing %s memory: %ldK\n", s, K(pages));
> +
> +	return pages;
> +}
> +
>  /**
>   * memblock_free - free boot memory allocation
>   * @ptr: starting address of the  boot memory allocation
> @@ -1776,7 +1812,6 @@ void __init memblock_free_late(phys_addr_t base, phys_addr_t size)
>  		totalram_pages_inc();
>  	}
>  }
> -
>  /*
>   * Remaining API functions
>   */
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 2d4b6f1a554e..df3d61253001 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -6234,42 +6234,6 @@ void adjust_managed_page_count(struct page *page, long count)
>  }
>  EXPORT_SYMBOL(adjust_managed_page_count);
>  
> -unsigned long free_reserved_area(void *start, void *end, int poison, const char *s)
> -{
> -	void *pos;
> -	unsigned long pages = 0;
> -
> -	start = (void *)PAGE_ALIGN((unsigned long)start);
> -	end = (void *)((unsigned long)end & PAGE_MASK);
> -	for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
> -		struct page *page = virt_to_page(pos);
> -		void *direct_map_addr;
> -
> -		/*
> -		 * 'direct_map_addr' might be different from 'pos'
> -		 * because some architectures' virt_to_page()
> -		 * work with aliases.  Getting the direct map
> -		 * address ensures that we get a _writeable_
> -		 * alias for the memset().
> -		 */
> -		direct_map_addr = page_address(page);
> -		/*
> -		 * Perform a kasan-unchecked memset() since this memory
> -		 * has not been initialized.
> -		 */
> -		direct_map_addr = kasan_reset_tag(direct_map_addr);
> -		if ((unsigned int)poison <= 0xFF)
> -			memset(direct_map_addr, poison, PAGE_SIZE);
> -
> -		free_reserved_page(page);
> -	}
> -
> -	if (pages && s)
> -		pr_info("Freeing %s memory: %ldK\n", s, K(pages));
> -
> -	return pages;
> -}
> -
>  void free_reserved_page(struct page *page)
>  {
>  	clear_page_tag_ref(page);