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

From: Davidlohr Bueso
Date: Mon Aug 12 2013 - 09:35:32 EST


On Fri, 2013-08-09 at 18:26 +0900, Joonsoo Kim wrote:
> 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@xxxxxxxxxxxxx>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>

Reviewed-by: Davidlohr Bueso <davidlohr@xxxxxx>

>
> 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;
> }
>


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