Re: [PATCH v2 05/20] mm, hugetlb: grab a page_table_lock after page_cache_release

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

Joonsoo Kim <iamjoonsoo.kim@lge.com> writes:

> We don't need to grab a page_table_lock when we try to release a page.
> So, defer to grab a page_table_lock.
>
> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>


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

>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index c017c52..6c8eec2 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -2627,10 +2627,11 @@ retry_avoidcopy:
>  	}
>  	spin_unlock(&mm->page_table_lock);
>  	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
> -	/* Caller expects lock to be held */
> -	spin_lock(&mm->page_table_lock);
>  	page_cache_release(new_page);
>  	page_cache_release(old_page);
> +
> +	/* Caller expects lock to be held */
> +	spin_lock(&mm->page_table_lock);
>  	return 0;
>  }
>
> -- 
> 1.7.9.5