Re: [PATCH 1/4] mm/vmalloc: Remove unnecessary size ALIGN in __vmalloc_node_range_noprof

[liuye <liuye@kylinos.cn>]

在 2025/3/4 02:30, Uladzislau Rezki 写道:
> On Mon, Mar 03, 2025 at 05:44:07PM +0800, Liu Ye wrote:
>> The same operation already exists in the function __get_vm_area_node,
>> so delete the duplicate operation to simplify the code.
>>
>> Signed-off-by: Liu Ye <liuye@kylinos.cn>
>> ---
>>  mm/vmalloc.c | 1 -
>>  1 file changed, 1 deletion(-)
>>
>> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
>> index dc658d4af181..20d9b9de84b1 100644
>> --- a/mm/vmalloc.c
>> +++ b/mm/vmalloc.c
>> @@ -3798,7 +3798,6 @@ void *__vmalloc_node_range_noprof(unsigned long size, unsigned long align,
>>  			shift = arch_vmap_pte_supported_shift(size);
>>  
>>  		align = max(real_align, 1UL << shift);
>> -		size = ALIGN(real_size, 1UL << shift);
>>  	}
>>  
>>  again:
>> -- 
>> 2.25.1
>>
> There is a mess with:
>
>  unsigned long real_size = size;
>  unsigned long real_align = align;
>
> "real_size" and "real_align". Those are useless. What is about:

Sorry, the order of the patches may be misleading.

The correct order is as follows：

PATCH1.  mm/vmalloc: Size should be used instead of real_size "
PATCH2.  mm/vmalloc: Remove unnecessary size ALIGN in __vmalloc_node_range_noprof                 
PATCH3.  mm/vmalloc: Remove the real_size variable to simplify the code "
PATCH4.  mm/vmalloc: Rename the variable real_align to original_align to prevent misunderstanding

If PATCH1 is the correct fix, then consider PATCH2, PATCH3, and PATCH4.

> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 5c88d0e90c20..a381ffee1595 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -3771,8 +3771,6 @@ void *__vmalloc_node_range_noprof(unsigned long size, unsigned long align,
>  	struct vm_struct *area;
>  	void *ret;
>  	kasan_vmalloc_flags_t kasan_flags = KASAN_VMALLOC_NONE;
> -	unsigned long real_size = size;
> -	unsigned long real_align = align;
>  	unsigned int shift = PAGE_SHIFT;
>  
>  	if (WARN_ON_ONCE(!size))
> @@ -3781,7 +3779,7 @@ void *__vmalloc_node_range_noprof(unsigned long size, unsigned long align,
>  	if ((size >> PAGE_SHIFT) > totalram_pages()) {
>  		warn_alloc(gfp_mask, NULL,
>  			"vmalloc error: size %lu, exceeds total pages",
> -			real_size);
> +			size);
>  		return NULL;
>  	}
>  
> @@ -3798,19 +3796,18 @@ void *__vmalloc_node_range_noprof(unsigned long size, unsigned long align,
>  		else
>  			shift = arch_vmap_pte_supported_shift(size);
>  
> -		align = max(real_align, 1UL << shift);
> -		size = ALIGN(real_size, 1UL << shift);
> +		align = max(align, 1UL << shift);
>  	}
>  
>  again:
> -	area = __get_vm_area_node(real_size, align, shift, VM_ALLOC |
> +	area = __get_vm_area_node(size, align, shift, VM_ALLOC |
>  				  VM_UNINITIALIZED | vm_flags, start, end, node,
>  				  gfp_mask, caller);
>  	if (!area) {
>  		bool nofail = gfp_mask & __GFP_NOFAIL;
>  		warn_alloc(gfp_mask, NULL,
>  			"vmalloc error: size %lu, vm_struct allocation failed%s",
> -			real_size, (nofail) ? ". Retrying." : "");
> +			size, (nofail) ? ". Retrying." : "");
>  		if (nofail) {
>  			schedule_timeout_uninterruptible(1);
>  			goto again;
> @@ -3860,7 +3857,7 @@ void *__vmalloc_node_range_noprof(unsigned long size, unsigned long align,
>  	    (gfp_mask & __GFP_SKIP_ZERO))
>  		kasan_flags |= KASAN_VMALLOC_INIT;
>  	/* KASAN_VMALLOC_PROT_NORMAL already set if required. */
> -	area->addr = kasan_unpoison_vmalloc(area->addr, real_size, kasan_flags);
> +	area->addr = kasan_unpoison_vmalloc(area->addr, size, kasan_flags);
>  
>  	/*
>  	 * In this function, newly allocated vm_struct has VM_UNINITIALIZED
> @@ -3878,8 +3875,6 @@ void *__vmalloc_node_range_noprof(unsigned long size, unsigned long align,
>  fail:
>  	if (shift > PAGE_SHIFT) {
>  		shift = PAGE_SHIFT;
> -		align = real_align;
> -		size = real_size;
>  		goto again;
>  	}
>  
> ?
>
> --
> Uladzislau Rezki