Re: [PART5 Patch 1/5] page_alloc: add kernelcore_max_addr

[Tang Chen <tangchen@cn.fujitsu.com>]

Hi Randy,

Thank you for your reviewing. :)

I think this boot option has been dropped. And we are implementing a new
boot option called "movablecore_map" to replace it.

Please refer to the following url if you like:
https://lkml.org/lkml/2012/12/19/51

Thanks. :)



On 12/20/2012 03:26 AM, Randy Dunlap wrote:
> On 10/31/12 02:21, Wen Congyang wrote:
>> From: Lai Jiangshan<laijs@cn.fujitsu.com>
>>
>> Current ZONE_MOVABLE (kernelcore=) setting policy with boot option doesn't meet
>> our requirement. We need something like kernelcore_max_addr=XX boot option
>> to limit the kernelcore upper address.
>>
>> The memory with higher address will be migratable(movable) and they
>> are easier to be offline(always ready to be offline when the system don't require
>> so much memory).
>>
>> It makes things easy when we dynamic hot-add/remove memory, make better
>> utilities of memories, and helps for THP.
>>
>> All kernelcore_max_addr=, kernelcore= and movablecore= can be safely specified
>> at the same time(or any 2 of them).
>>
>> Signed-off-by: Lai Jiangshan<laijs@cn.fujitsu.com>
>> ---
>>   Documentation/kernel-parameters.txt |  9 +++++++++
>>   mm/page_alloc.c                     | 29 ++++++++++++++++++++++++++++-
>>   2 files changed, 37 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
>> index 9776f06..2b72ffb 100644
>> --- a/Documentation/kernel-parameters.txt
>> +++ b/Documentation/kernel-parameters.txt
>> @@ -1223,6 +1223,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
>>   			use the HighMem zone if it exists, and the Normal
>>   			zone if it does not.
>>
>> +	kernelcore_max_addr=nn[KMG]	[KNL,X86,IA-64,PPC] This parameter
>> +			is the same effect as kernelcore parameter, except it
>> +			specifies the up physical address of memory range
>
> 			upper (or maximum)
>
>> +			usable by the kernel for non-movable allocations.
>> +			If both kernelcore and kernelcore_max_addr are
>> +			specified, this requested's priority is higher than
>
> 			specified, this parameter has a higher priority than
> 			the kernelcore parameter.
>
>> +			kernelcore's.
>> +			See the kernelcore parameter.
>> +
>>   	kgdbdbgp=	[KGDB,HW] kgdb over EHCI usb debug port.
>>   			Format:<Controller#>[,poll interval]
>>   			The controller # is the number of the ehci usb debug
>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>> index 5b74de6..9c35fe5 100644
>> --- a/mm/page_alloc.c
>> +++ b/mm/page_alloc.c
>> @@ -200,6 +200,7 @@ static unsigned long __meminitdata dma_reserve;
>>   #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
>>   static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
>>   static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
>> +static unsigned long __initdata required_kernelcore_max_pfn;
>>   static unsigned long __initdata required_kernelcore;
>>   static unsigned long __initdata required_movablecore;
>>   static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
>> @@ -4715,6 +4716,7 @@ static void __init find_zone_movable_pfns_for_nodes(void)
>>   {
>>   	int i, nid;
>>   	unsigned long usable_startpfn;
>> +	unsigned long kernelcore_max_pfn;
>>   	unsigned long kernelcore_node, kernelcore_remaining;
>>   	/* save the state before borrow the nodemask */
>>   	nodemask_t saved_node_state = node_states[N_HIGH_MEMORY];
>> @@ -4743,6 +4745,9 @@ static void __init find_zone_movable_pfns_for_nodes(void)
>>   		required_kernelcore = max(required_kernelcore, corepages);
>>   	}
>>
>> +	if (required_kernelcore_max_pfn&&  !required_kernelcore)
>> +		required_kernelcore = totalpages;
>> +
>>   	/* If kernelcore was not specified, there is no ZONE_MOVABLE */
>>   	if (!required_kernelcore)
>>   		goto out;
>> @@ -4751,6 +4756,12 @@ static void __init find_zone_movable_pfns_for_nodes(void)
>>   	find_usable_zone_for_movable();
>>   	usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
>>
>> +	if (required_kernelcore_max_pfn)
>> +		kernelcore_max_pfn = required_kernelcore_max_pfn;
>> +	else
>> +		kernelcore_max_pfn = ULONG_MAX>>  PAGE_SHIFT;
>> +	kernelcore_max_pfn = max(kernelcore_max_pfn, usable_startpfn);
>> +
>>   restart:
>>   	/* Spread kernelcore memory as evenly as possible throughout nodes */
>>   	kernelcore_node = required_kernelcore / usable_nodes;
>> @@ -4777,8 +4788,12 @@ restart:
>>   			unsigned long size_pages;
>>
>>   			start_pfn = max(start_pfn, zone_movable_pfn[nid]);
>> -			if (start_pfn>= end_pfn)
>> +			end_pfn = min(kernelcore_max_pfn, end_pfn);
>> +			if (start_pfn>= end_pfn) {
>> +				if (!zone_movable_pfn[nid])
>> +					zone_movable_pfn[nid] = start_pfn;
>>   				continue;
>> +			}
>>
>>   			/* Account for what is only usable for kernelcore */
>>   			if (start_pfn<  usable_startpfn) {
>> @@ -4965,6 +4980,18 @@ static int __init cmdline_parse_core(char *p, unsigned long *core)
>>   	return 0;
>>   }
>>
>> +#ifdef CONFIG_MOVABLE_NODE
>> +/*
>> + * kernelcore_max_addr=addr sets the up physical address of memory range
>
>                                          upper
>
>> + * for use for allocations that cannot be reclaimed or migrated.
>> + */
>> +static int __init cmdline_parse_kernelcore_max_addr(char *p)
>> +{
>> +	return cmdline_parse_core(p,&required_kernelcore_max_pfn);
>> +}
>> +early_param("kernelcore_max_addr", cmdline_parse_kernelcore_max_addr);
>> +#endif
>> +
>>   /*
>>    * kernelcore=size sets the amount of memory for use for allocations that
>>    * cannot be reclaimed or migrated.
>>
>
>

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