linux-kernel - Re: [PATCH] memblock: update numa node of memblk reserved type

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Date:   Wed, 24 May 2023 14:47:26 +0800
From:   Kefeng Wang <wangkefeng.wang@...wei.com>
To:     Anshuman Khandual <anshuman.khandual@....com>,
        <20230519105321.333-1-ssawgyw@...il.com>,
        Mike Rapoport <rppt@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>, <linux-mm@...ck.org>
CC:     <linux-kernel@...r.kernel.org>, <tsahu@...ux.ibm.com>,
        <ssawgyw@...il.com>
Subject: Re: [PATCH] memblock: update numa node of memblk reserved type



On 2023/5/24 12:59, Anshuman Khandual wrote:
> 
> 
> On 5/23/23 17:27, Kefeng Wang wrote:
>> The numa node of memblk reserved type is wrong, it could update
>> according to the numa node information from memblk memory type,
>> let's fix it.
> 
> Indeed it's wrong at present and can be verified from sysfs file
> (/sys/kernel/debug/memblock/reserved) accessed in user space.

Yes, both memblock_dump() and sysfs show wrong value.
> 
>>
>> Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>
>> ---
>>   mm/memblock.c | 25 +++++++++++++++++++++++++
>>   1 file changed, 25 insertions(+)
>>
>> diff --git a/mm/memblock.c b/mm/memblock.c
>> index a50447d970ef..45a0781cda31 100644
>> --- a/mm/memblock.c
>> +++ b/mm/memblock.c
>> @@ -1922,6 +1922,28 @@ phys_addr_t __init_memblock memblock_get_current_limit(void)
>>   	return memblock.current_limit;
>>   }
>>   
>> +static void __init_memblock memblock_reserved_update_node(void)
>> +{
>> +	struct memblock_region *rgn;
>> +	phys_addr_t base, end, size;
>> +	int ret;
>> +
>> +	if (!IS_ENABLED(CONFIG_NUMA))
>> +		return;
>> +
>> +	for_each_mem_region(rgn) {
>> +		base = rgn->base;
>> +		size = rgn->size;
>> +		end = base + size - 1;
>> +
>> +		ret = memblock_set_node(base, size, &memblock.reserved,
>> +					memblock_get_region_node(rgn));
>> +		if (ret)
>> +			pr_err("memblock: Failed to update reserved [%pa-%pa] node",
>> +			       &base, &end);
>> +	}
>> +}
>> +
>>   static void __init_memblock memblock_dump(struct memblock_type *type)
>>   {
>>   	phys_addr_t base, end, size;
>> @@ -1955,6 +1977,7 @@ static void __init_memblock __memblock_dump_all(void)
>>   		&memblock.memory.total_size,
>>   		&memblock.reserved.total_size);
>>   
>> +	memblock_reserved_update_node();
> 
> __memblock_dump_all() gets called only when memblock_debug is enabled.
> This helper should be called directly inside memblock_dump_all() right
> at the beginning, regardless of memblock_debug.

This is my first though, but I found there are still many memblock_alloc 
and memblock_reserve after memblock_dump_all(), so I update it twice,

1) __memblock_dump_all()
2) memblock_debug_show()

and without the above two interface, no one care about the reserved node
info, so I put memblock_reserved_update_node into __memblock_dump_all().


>>   #ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
>> @@ -2196,6 +2219,8 @@ static int memblock_debug_show(struct seq_file *m, void *private)
>>   	unsigned int count = ARRAY_SIZE(flagname);
>>   	phys_addr_t end;
>>   
>> +	memblock_reserved_update_node();
>> +
> 

> This is redundant, should be dropped. Reserved memblock ranges need not
> be scanned, each time the sysfs file is accessed from user space.

Yes, it's better to move it into memblock_init_debugfs(),
which only called once.