Re: [PATCH] mm/show_mem: Optimize si_meminfo_node by reducing redundant code

[Ye Liu <ye.liu@linux.dev>]

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在 2025/3/27 03:29, Mike Rapoport 写道:
> On Tue, Mar 25, 2025 at 03:38:03PM +0800, Ye Liu wrote:
>> From: Ye Liu <liuye@kylinos.cn>
>>
>> Refactors the si_meminfo_node() function by reducing redundant code and
>> improving readability.
>>
>> Moved the calculation of managed_pages inside the existing loop that
>> processes pgdat->node_zones, eliminating the need for a separate loop.
>>
>> Simplified the logic by removing unnecessary preprocessor conditionals.
>>
>> Ensured that both totalram, totalhigh, and other memory statistics are
>> consistently set without duplication.
>>
>> This change results in cleaner and more efficient code without altering
>> functionality.
>>
>> Signed-off-by: Ye Liu <liuye@kylinos.cn>
>> ---
>>  mm/show_mem.c | 16 +++++-----------
>>  1 file changed, 5 insertions(+), 11 deletions(-)
>>
>> diff --git a/mm/show_mem.c b/mm/show_mem.c
>> index 6af13bcd2ab3..ad373b4b6e39 100644
>> --- a/mm/show_mem.c
>> +++ b/mm/show_mem.c
>> @@ -94,26 +94,20 @@ void si_meminfo_node(struct sysinfo *val, int nid)
>>  	unsigned long free_highpages = 0;
>>  	pg_data_t *pgdat = NODE_DATA(nid);
>>  
>> -	for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
>> -		managed_pages += zone_managed_pages(&pgdat->node_zones[zone_type]);
>> -	val->totalram = managed_pages;
>> -	val->sharedram = node_page_state(pgdat, NR_SHMEM);
>> -	val->freeram = sum_zone_node_page_state(nid, NR_FREE_PAGES);
>> -#ifdef CONFIG_HIGHMEM
>>  	for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
>>  		struct zone *zone = &pgdat->node_zones[zone_type];
>> -
>> +		managed_pages += zone_managed_pages(zone);
> nit: don't remove the empty line after the declaration
Agree.
>
>>  		if (is_highmem(zone)) {
>>  			managed_highpages += zone_managed_pages(zone);
> Looks like highmem pages get counted twice, no?


twice? The original logic has not been changed.

managed_highpages is just high memory, managed_pages is all.

I don't understand what you mean.


Thanks,

Ye Liu

>
>>  			free_highpages += zone_page_state(zone, NR_FREE_PAGES);
>>  		}
>>  	}
>> +
>> +	val->totalram = managed_pages;
>> +	val->sharedram = node_page_state(pgdat, NR_SHMEM);
>> +	val->freeram = sum_zone_node_page_state(nid, NR_FREE_PAGES);
>>  	val->totalhigh = managed_highpages;
>>  	val->freehigh = free_highpages;
>> -#else
>> -	val->totalhigh = managed_highpages;
>> -	val->freehigh = free_highpages;
>> -#endif
>>  	val->mem_unit = PAGE_SIZE;
>>  }
>>  #endif
>> -- 
>> 2.25.1
>>
>>

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