Re: [RFC PATCH 5/8] hugetlb: change free_pool_huge_page to remove_pool_huge_page

[Michal Hocko <mhocko@suse.com>]

On Fri 19-03-21 15:42:06, Mike Kravetz wrote:
[...]
> @@ -2090,9 +2084,15 @@ static void return_unused_surplus_pages(struct hstate *h,
>  	while (nr_pages--) {
>  		h->resv_huge_pages--;
>  		unused_resv_pages--;
> -		if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
> +		page = remove_pool_huge_page(h, &node_states[N_MEMORY], 1);
> +		if (!page)
>  			goto out;
> -		cond_resched_lock(&hugetlb_lock);
> +
> +		/* Drop lock and free page to buddy as it could sleep */
> +		spin_unlock(&hugetlb_lock);
> +		update_and_free_page(h, page);
> +		cond_resched();
> +		spin_lock(&hugetlb_lock);
>  	}
>  
>  out:

This is likely a matter of taste but the repeated pattern of unlock,
update_and_free_page, cond_resched and lock seems rather clumsy.
Would it be slightly better/nicer to remove_pool_huge_page into a
list_head under a single lock invocation and then free up the whole lot
after the lock is dropped?

-- 
Michal Hocko
SUSE Labs