Re: [PATCH -V4 03/10] hugetlbfs: Add an inline helper for finding hstate index

[Michal Hocko <mhocko@suse.cz>]

On Fri 16-03-12 23:09:23, Aneesh Kumar K.V wrote:
> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
> 
> Add and inline helper and use it in the code.

OK, helper function looks much nicer.

> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Acked-by: Michal Hocko <mhocko@suse.cz>

> ---
>  include/linux/hugetlb.h |    6 ++++++
>  mm/hugetlb.c            |   18 ++++++++++--------
>  2 files changed, 16 insertions(+), 8 deletions(-)
> 
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index d9d6c86..a2675b0 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
> @@ -311,6 +311,11 @@ static inline unsigned hstate_index_to_shift(unsigned index)
>  	return hstates[index].order + PAGE_SHIFT;
>  }
>  
> +static inline int hstate_index(struct hstate *h)
> +{
> +	return h - hstates;
> +}
> +
>  #else
>  struct hstate {};
>  #define alloc_huge_page_node(h, nid) NULL
> @@ -329,6 +334,7 @@ static inline unsigned int pages_per_huge_page(struct hstate *h)
>  	return 1;
>  }
>  #define hstate_index_to_shift(index) 0
> +#define hstate_index(h) 0
>  #endif
>  
>  #endif /* _LINUX_HUGETLB_H */
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 3782da8..ebe245c 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -1557,7 +1557,7 @@ static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
>  				    struct attribute_group *hstate_attr_group)
>  {
>  	int retval;
> -	int hi = h - hstates;
> +	int hi = hstate_index(h);
>  
>  	hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
>  	if (!hstate_kobjs[hi])
> @@ -1652,11 +1652,13 @@ void hugetlb_unregister_node(struct node *node)
>  	if (!nhs->hugepages_kobj)
>  		return;		/* no hstate attributes */
>  
> -	for_each_hstate(h)
> -		if (nhs->hstate_kobjs[h - hstates]) {
> -			kobject_put(nhs->hstate_kobjs[h - hstates]);
> -			nhs->hstate_kobjs[h - hstates] = NULL;
> +	for_each_hstate(h) {
> +		int idx = hstate_index(h);
> +		if (nhs->hstate_kobjs[idx]) {
> +			kobject_put(nhs->hstate_kobjs[idx]);
> +			nhs->hstate_kobjs[idx] = NULL;
>  		}
> +	}
>  
>  	kobject_put(nhs->hugepages_kobj);
>  	nhs->hugepages_kobj = NULL;
> @@ -1759,7 +1761,7 @@ static void __exit hugetlb_exit(void)
>  	hugetlb_unregister_all_nodes();
>  
>  	for_each_hstate(h) {
> -		kobject_put(hstate_kobjs[h - hstates]);
> +		kobject_put(hstate_kobjs[hstate_index(h)]);
>  	}
>  
>  	kobject_put(hugepages_kobj);
> @@ -2587,7 +2589,7 @@ retry:
>  		 */
>  		if (unlikely(PageHWPoison(page))) {
>  			ret = VM_FAULT_HWPOISON |
> -			      VM_FAULT_SET_HINDEX(h - hstates);
> +				VM_FAULT_SET_HINDEX(hstate_index(h));
>  			goto backout_unlocked;
>  		}
>  	}
> @@ -2660,7 +2662,7 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
>  			return 0;
>  		} else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
>  			return VM_FAULT_HWPOISON_LARGE |
> -			       VM_FAULT_SET_HINDEX(h - hstates);
> +				VM_FAULT_SET_HINDEX(hstate_index(h));
>  	}
>  
>  	ptep = huge_pte_alloc(mm, address, huge_page_size(h));
> -- 
> 1.7.9
> 
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-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic