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

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Message-ID: <ab09bcea-a55d-e562-6637-0df909b03e22@gmail.com>
Date:   Mon, 21 Jan 2019 12:48:09 -0800
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Doug Berger <opendmb@...il.com>,
        Russell King <linux@...linux.org.uk>,
        Catalin Marinas <catalin.marinas@....com>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>
Cc:     Nicolas Pitre <nicolas.pitre@...aro.org>,
        Michal Hocko <mhocko@...e.com>, linux-kernel@...r.kernel.org,
        "Steven Rostedt (VMware)" <rostedt@...dmis.org>,
        Jinbum Park <jinb.park7@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] ARM: mm: initialize pfn limits with find_limits()

On 1/10/19 11:07 AM, Doug Berger wrote:
> 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?

Mike, Catalin, does this looks sensible to you? If so, should this be
thrown into Russell's patch tracking system?

Thanks
-- 
Florian