linux-kernel - Re: [PATCH 2/2] mm: free memblock.memory in free_all

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Date:	Wed, 8 Jan 2014 12:08:04 +0800
From:	Jianguo Wu <wujianguo@...wei.com>
To:	Philipp Hachtmann <phacht@...ux.vnet.ibm.com>
CC:	<akpm@...ux-foundation.org>, <jiang.liu@...wei.com>,
	<linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>,
	<iamjoonsoo.kim@....com>, <hannes@...xchg.org>,
	<tangchen@...fujitsu.com>, <tj@...nel.org>, <toshi.kani@...com>
Subject: Re: [PATCH 2/2] mm: free memblock.memory in free_all_bootmem

On 2014/1/7 23:16, Philipp Hachtmann wrote:

> When calling free_all_bootmem() the free areas under memblock's
> control are released to the buddy allocator. Additionally the
> reserved list is freed if it was reallocated by memblock.
> The same should apply for the memory list.
> 
> Signed-off-by: Philipp Hachtmann <phacht@...ux.vnet.ibm.com>
> ---
>  include/linux/memblock.h |  1 +
>  mm/memblock.c            | 12 ++++++++++++
>  mm/nobootmem.c           |  7 ++++++-
>  3 files changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/include/linux/memblock.h b/include/linux/memblock.h
> index 77c60e5..d174922 100644
> --- a/include/linux/memblock.h
> +++ b/include/linux/memblock.h
> @@ -52,6 +52,7 @@ phys_addr_t memblock_find_in_range_node(phys_addr_t start, phys_addr_t end,
>  phys_addr_t memblock_find_in_range(phys_addr_t start, phys_addr_t end,
>  				   phys_addr_t size, phys_addr_t align);
>  phys_addr_t get_allocated_memblock_reserved_regions_info(phys_addr_t *addr);
> +phys_addr_t get_allocated_memblock_memory_regions_info(phys_addr_t *addr);
>  void memblock_allow_resize(void);
>  int memblock_add_node(phys_addr_t base, phys_addr_t size, int nid);
>  int memblock_add(phys_addr_t base, phys_addr_t size);
> diff --git a/mm/memblock.c b/mm/memblock.c
> index 53e477b..1a11d04 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -271,6 +271,18 @@ phys_addr_t __init_memblock get_allocated_memblock_reserved_regions_info(
>  			  memblock.reserved.max);
>  }
>  
> +phys_addr_t __init_memblock get_allocated_memblock_memory_regions_info(
> +					phys_addr_t *addr)
> +{
> +	if (memblock.memory.regions == memblock_memory_init_regions)
> +		return 0;
> +
> +	*addr = __pa(memblock.memory.regions);
> +
> +	return PAGE_ALIGN(sizeof(struct memblock_region) *
> +			  memblock.memory.max);
> +}
> +
>  /**
>   * memblock_double_array - double the size of the memblock regions array
>   * @type: memblock type of the regions array being doubled
> diff --git a/mm/nobootmem.c b/mm/nobootmem.c
> index 3a7e14d..83f36d3 100644
> --- a/mm/nobootmem.c
> +++ b/mm/nobootmem.c
> @@ -122,11 +122,16 @@ static unsigned long __init free_low_memory_core_early(void)
>  	for_each_free_mem_range(i, MAX_NUMNODES, &start, &end, NULL)
>  		count += __free_memory_core(start, end);
>  
> -	/* free range that is used for reserved array if we allocate it */
> +	/* Free memblock.reserved array if it was allocated */
>  	size = get_allocated_memblock_reserved_regions_info(&start);
>  	if (size)
>  		count += __free_memory_core(start, start + size);
>  
> +	/* Free memblock.memory array if it was allocated */
> +	size = get_allocated_memblock_memory_regions_info(&start);
> +	if (size)
> +		count += __free_memory_core(start, start + size);
> +

Hi Philipp,

For some archs, like arm64, would use memblock.memory after system booting,
so we can not simply released to the buddy allocator, maybe need !defined(CONFIG_ARCH_DISCARD_MEMBLOCK).

#ifdef CONFIG_HAVE_ARCH_PFN_VALID
int pfn_valid(unsigned long pfn)
{
	return memblock_is_memory(pfn << PAGE_SHIFT);
}
EXPORT_SYMBOL(pfn_valid);

Thanks,
Jianguo Wu

>  	return count;
>  }
>  



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