Re: [PATCH 2/3] mm/vmalloc: extract vmap_insert_free_area helper

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

在 2026/9/15 01:02, Uladzislau Rezki 写道:
> On Mon, Sep 14, 2026 at 11:34:01AM +0800, Ye Liu wrote:
>> From: Ye Liu <liuye@kylinos.cn>
>>
>> The allocation and insertion of a free vmap_area is duplicated
>> between the loop body and the tail of vmap_init_free_space.  Factor
>> it into a small helper so the main function only deals with computing
>> the free gaps between busy regions.
>>
>> Signed-off-by: Ye Liu <liuye@kylinos.cn>
>> ---
>>  mm/vmalloc.c | 41 ++++++++++++++++++-----------------------
>>  1 file changed, 18 insertions(+), 23 deletions(-)
>>
>> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
>> index 117483dd048c..797933ba9451 100644
>> --- a/mm/vmalloc.c
>> +++ b/mm/vmalloc.c
>> @@ -5433,11 +5433,23 @@ module_init(proc_vmalloc_init);
>>  
>>  #endif
>>  
>> +static void __init vmap_insert_free_area(unsigned long start, unsigned long end)
>> +{
>> +	struct vmap_area *free = kmem_cache_zalloc(vmap_area_cachep, GFP_NOWAIT);
>> +
>> +	if (!WARN_ON_ONCE(!free)) {
>> +		free->va_start = start;
>> +		free->va_end = end;
>> +		insert_vmap_area_augment(free, NULL,
>> +					 &free_vmap_area_root,
>> +					 &free_vmap_area_list);
>> +	}
>> +}
>> +
>>  static void __init vmap_init_free_space(void)
>>  {
>>  	unsigned long vmap_start = 1;
>>  	const unsigned long vmap_end = ULONG_MAX;
>> -	struct vmap_area *free;
>>  	struct vm_struct *busy;
>>  
>>  	/*
>> @@ -5447,32 +5459,15 @@ static void __init vmap_init_free_space(void)
>>  	 *  |<--------------------------------->|
>>  	 */
>>  	for (busy = vmlist; busy; busy = busy->next) {
>> -		if ((unsigned long) busy->addr - vmap_start > 0) {
>>
> This line gets removed and then re-added below because of removing space
> after (unsigned long). Maybe it is better to keep that space.
However, the '{' is still there, but I'll add a space anyway.
> 
>> -			free = kmem_cache_zalloc(vmap_area_cachep, GFP_NOWAIT);
>> -			if (!WARN_ON_ONCE(!free)) {
>> -				free->va_start = vmap_start;
>> -				free->va_end = (unsigned long) busy->addr;
>> -
>> -				insert_vmap_area_augment(free, NULL,
>> -					&free_vmap_area_root,
>> -						&free_vmap_area_list);
>> -			}
>> -		}
>> +		if ((unsigned long)busy->addr - vmap_start > 0)
>> +			vmap_insert_free_area(vmap_start,
>> +					      (unsigned long)busy->addr);
>>  
>>  		vmap_start = (unsigned long) busy->addr + busy->size;
>>  	}
>>  
>> -	if (vmap_end - vmap_start > 0) {
>> -		free = kmem_cache_zalloc(vmap_area_cachep, GFP_NOWAIT);
>> -		if (!WARN_ON_ONCE(!free)) {
>> -			free->va_start = vmap_start;
>> -			free->va_end = vmap_end;
>> -
>> -			insert_vmap_area_augment(free, NULL,
>> -				&free_vmap_area_root,
>> -					&free_vmap_area_list);
>> -		}
>> -	}
>> +	if (vmap_end - vmap_start > 0)
>> +		vmap_insert_free_area(vmap_start, vmap_end);
>>  }
>>  
>>  static void vmap_init_nodes(void)
>>
>> -- 
>> 2.25.1
>>
> LGTM:
> 
> Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
> 
> --
> Uladzislau Rezki

-- 
Thanks,
Ye Liu