linux-kernel - Re: [PATCH] ARM: mm: initialize pfn limits with find

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Date:   Thu, 10 Jan 2019 11:07:36 -0800
From:   Doug Berger <opendmb@...il.com>
To:     Russell King <linux@...linux.org.uk>
Cc:     Catalin Marinas <catalin.marinas@....com>,
        Michal Hocko <mhocko@...e.com>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Steven Rostedt (VMware)" <rostedt@...dmis.org>,
        Jinbum Park <jinb.park7@...il.com>,
        Nicolas Pitre <nicolas.pitre@...aro.org>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ARM: mm: initialize pfn limits with find_limits()

On 12/27/18 3:47 PM, Doug Berger wrote:
> The max_low_pfn value must be set before sparse_init() is called to
> keep the early memblock allocations and frees balanced for kmemleak
> initialization when sparsemem is enabled.
> 
> This commit accomplishes that by replacing the local variables min,
> max_low, and max_high with the global limit variables min_low_pfn,
> max_low_pfn, and max_pfn respectively in bootmem_init(). The global
> variables are initialized directly by find_limits() and used in the
> remainder of the function.
> 
> Fixes: 9099daed9c69 ("mm: kmemleak: avoid using __va() on addresses that don't have a lowmem mapping")
> Signed-off-by: Doug Berger <opendmb@...il.com>
> ---
>  arch/arm/mm/init.c | 20 ++++----------------
>  1 file changed, 4 insertions(+), 16 deletions(-)
> 
> diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
> index 32e4845af2b6..98a733f3a5b9 100644
> --- a/arch/arm/mm/init.c
> +++ b/arch/arm/mm/init.c
> @@ -302,15 +302,12 @@ void __init arm_memblock_init(const struct machine_desc *mdesc)
>  
>  void __init bootmem_init(void)
>  {
> -	unsigned long min, max_low, max_high;
> -
>  	memblock_allow_resize();
> -	max_low = max_high = 0;
>  
> -	find_limits(&min, &max_low, &max_high);
> +	find_limits(&min_low_pfn, &max_low_pfn, &max_pfn);
>  
> -	early_memtest((phys_addr_t)min << PAGE_SHIFT,
> -		      (phys_addr_t)max_low << PAGE_SHIFT);
> +	early_memtest((phys_addr_t)min_low_pfn << PAGE_SHIFT,
> +		      (phys_addr_t)max_low_pfn << PAGE_SHIFT);
>  
>  	/*
>  	 * Sparsemem tries to allocate bootmem in memory_present(),
> @@ -328,16 +325,7 @@ void __init bootmem_init(void)
>  	 * the sparse mem_map arrays initialized by sparse_init()
>  	 * for memmap_init_zone(), otherwise all PFNs are invalid.
>  	 */
> -	zone_sizes_init(min, max_low, max_high);
> -
> -	/*
> -	 * This doesn't seem to be used by the Linux memory manager any
> -	 * more, but is used by ll_rw_block.  If we can get rid of it, we
> -	 * also get rid of some of the stuff above as well.
> -	 */
> -	min_low_pfn = min;
> -	max_low_pfn = max_low;
> -	max_pfn = max_high;
> +	zone_sizes_init(min_low_pfn, max_low_pfn, max_pfn);
>  }
>  
>  /*
> 

Any feedback on this patch?

Thanks,
    Doug