Re: [PATCH v3 1/7] hugetlb: code clean for hugetlb_hstate_alloc_pages

[Tim Chen]

On Tue, 2024-01-02 at 21:12 +0800, Gang Li wrote:
> The readability of `hugetlb_hstate_alloc_pages` is poor. By cleaning the
> code, its readability can be improved, facilitating future modifications.
> 
> This patch extracts two functions to reduce the complexity of
> `hugetlb_hstate_alloc_pages` and has no functional changes.
> 
> - hugetlb_hstate_alloc_pages_node_specific() to handle iterates through
>   each online node and performs allocation if necessary.
> - hugetlb_hstate_alloc_pages_report() report error during allocation.
>   And the value of h->max_huge_pages is updated accordingly.

Minor nit, I think hugetlb_hstate_alloc_pages_errcheck() is more
descriptive than hugetlb_hstate_alloc_pages_report().

Otherwise

Reviewed-by: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>

> 
> Signed-off-by: Gang Li <gang.li@xxxxxxxxx>
> ---
>  mm/hugetlb.c | 46 +++++++++++++++++++++++++++++-----------------
>  1 file changed, 29 insertions(+), 17 deletions(-)
> 
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index ed1581b670d42..2606135ec55e6 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -3482,6 +3482,33 @@ static void __init hugetlb_hstate_alloc_pages_onenode(struct hstate *h, int nid)
>  	h->max_huge_pages_node[nid] = i;
>  }
>  
> +static bool __init hugetlb_hstate_alloc_pages_node_specific(struct hstate *h)
> +{
> +	int i;
> +	bool node_specific_alloc = false;
> +
> +	for_each_online_node(i) {
> +		if (h->max_huge_pages_node[i] > 0) {
> +			hugetlb_hstate_alloc_pages_onenode(h, i);
> +			node_specific_alloc = true;
> +		}
> +	}
> +
> +	return node_specific_alloc;
> +}
> +
> +static void __init hugetlb_hstate_alloc_pages_report(unsigned long allocated, struct hstate *h)
> +{
> +	if (allocated < h->max_huge_pages) {
> +		char buf[32];
> +
> +		string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
> +		pr_warn("HugeTLB: allocating %lu of page size %s failed.  Only allocated %lu hugepages.\n",
> +			h->max_huge_pages, buf, allocated);
> +		h->max_huge_pages = allocated;
> +	}
> +}
> +
>  /*
>   * NOTE: this routine is called in different contexts for gigantic and
>   * non-gigantic pages.
> @@ -3499,7 +3526,6 @@ static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
>  	struct folio *folio;
>  	LIST_HEAD(folio_list);
>  	nodemask_t *node_alloc_noretry;
> -	bool node_specific_alloc = false;
>  
>  	/* skip gigantic hugepages allocation if hugetlb_cma enabled */
>  	if (hstate_is_gigantic(h) && hugetlb_cma_size) {
> @@ -3508,14 +3534,7 @@ static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
>  	}
>  
>  	/* do node specific alloc */
> -	for_each_online_node(i) {
> -		if (h->max_huge_pages_node[i] > 0) {
> -			hugetlb_hstate_alloc_pages_onenode(h, i);
> -			node_specific_alloc = true;
> -		}
> -	}
> -
> -	if (node_specific_alloc)
> +	if (hugetlb_hstate_alloc_pages_node_specific(h))
>  		return;
>  
>  	/* below will do all node balanced alloc */
> @@ -3558,14 +3577,7 @@ static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
>  	/* list will be empty if hstate_is_gigantic */
>  	prep_and_add_allocated_folios(h, &folio_list);
>  
> -	if (i < h->max_huge_pages) {
> -		char buf[32];
> -
> -		string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
> -		pr_warn("HugeTLB: allocating %lu of page size %s failed.  Only allocated %lu hugepages.\n",
> -			h->max_huge_pages, buf, i);
> -		h->max_huge_pages = i;
> -	}
> +	hugetlb_hstate_alloc_pages_report(i, h);
>  	kfree(node_alloc_noretry);
>  }
>